[PATCH openEuler-22.03-LTS v2 00/16] arm64: fix a concurrency issue in emulation_proc_handler()
In linux-6.1, the related code is refactored in commit 124c49b1b5d9 ("arm64: armv8_deprecated: rework deprected instruction handling") and this issue was incidentally fixed. This patch set try to adapt the refactoring stable 5.10 patches to solve the problem of repeated addition of linked lists described below. How to reproduce: CONFIG_ARMV8_DEPRECATED=y, CONFIG_SWP_EMULATION=y, and CONFIG_DEBUG_LIST=y, then launch two shell executions: #!/bin/bash while [ 1 ]; do echo 1 > /proc/sys/abi/swp done or "echo 1 > /proc/sys/abi/swp" and then launch two shell executions: #!/bin/bash while [ 1 ]; do echo 0 > /proc/sys/abi/swp done In emulation_proc_handler(), read and write operations are performed on insn->current_mode. In the concurrency scenario, mutex only protects writing insn->current_mode, and not protects the read. Suppose there are two concurrent tasks, task1 updates insn->current_mode to INSN_EMULATE in the critical section, the prev_mode of task2 is still the old data INSN_UNDEF of insn->current_mode. As a result, two tasks call update_insn_emulation_mode twice with prev_mode = INSN_UNDEF and current_mode = INSN_EMULATE, then call register_emulation_hooks twice, resulting in a list_add double problem. commit 124c49b1b5d9 ("arm64: armv8_deprecated: rework deprected instruction handling") remove the dynamic registration and unregistration so remove the register_undef_hook() function, so the below problem was incidentally fixed. Call trace: __list_add_valid+0xd8/0xe4 register_undef_hook+0x94/0x13c update_insn_emulation_mode+0xd0/0x12c emulation_proc_handler+0xd8/0xf4 proc_sys_call_handler+0x140/0x250 proc_sys_write+0x1c/0x2c new_sync_write+0xec/0x18c vfs_write+0x214/0x2ac ksys_write+0x70/0xfc __arm64_sys_write+0x24/0x30 el0_svc_common.constprop.0+0x7c/0x1bc do_el0_svc+0x2c/0x94 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb4 el0_sync+0x160/0x180 Call trace: __list_del_entry_valid+0xac/0x110 unregister_undef_hook+0x34/0x80 update_insn_emulation_mode+0xf0/0x180 emulation_proc_handler+0x8c/0xd8 proc_sys_call_handler+0x1d8/0x208 proc_sys_write+0x14/0x20 new_sync_write+0xf0/0x190 vfs_write+0x304/0x388 ksys_write+0x6c/0x100 __arm64_sys_write+0x1c/0x28 el0_svc_common.constprop.4+0x68/0x188 do_el0_svc+0x24/0xa0 el0_svc+0x14/0x20 el0_sync_handler+0x90/0xb8 el0_sync+0x160/0x180 The first patch is the self-developed patch, so revert it. The next 5 patches is a patch set which provides context for subsequent refactoring 9 patches, especially commit 0f2cb928a154 ("arm64: consistently pass ESR_ELx to die()") which modify do_undefinstr() to add a ESR_ELx value arg, and then commit 61d64a376ea8 ("arm64: split EL0/EL1 UNDEF handlers") splits do_undefinstr() handler into separate do_el0_undef() and do_el1_undef() handlers. The 9 patches after that is another refactoring patch set, which is in preparation for the main rework commit 124c49b1b5d9 ("arm64: armv8_deprecated: rework deprected instruction handling"). To remove struct undef_hook, commit bff8f413c71f ("arm64: factor out EL1 SSBS emulation hook") factor out EL1 SSBS emulation hook, which also avoid call call_undef_hook() in do_el1_undef(), commit f5962add74b6 ("arm64: rework EL0 MRS emulation") factor out EL0 MRS emulation hook, which also prepare for replacing call_undef_hook() in do_el0_undef(). To replace call_undef_hook() function, commit 61d64a376ea8 ("arm64: split EL0/EL1 UNDEF handlers") split the do_undefinstr() into do_el0_undef() and do_el1_undef() functions, and commit dbfbd87efa79 ("arm64: factor insn read out of call_undef_hook()") factor user_insn_read() from call_undef_hook() so the main rework patch can replace the call_undef_hook() in do_el0_undef(). The last patch is a bugfix for the main rework patch. Fixes: af483947d472 ("arm64: fix oops in concurrently setting insn_emulation sysctls") Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Jinjie Ruan (1): Revert "arm64: fix a concurrency issue in emulation_proc_handler()" Mark Rutland (14): arm64: report EL1 UNDEFs better arm64: die(): pass 'err' as long arm64: consistently pass ESR_ELx to die() arm64: rework FPAC exception handling arm64: rework BTI exception handling arm64: allow kprobes on EL0 handlers arm64: split EL0/EL1 UNDEF handlers arm64: factor out EL1 SSBS emulation hook arm64: factor insn read out of call_undef_hook() arm64: rework EL0 MRS emulation arm64: armv8_deprecated: fold ops into insn_emulation arm64: armv8_deprecated move emulation functions arm64: armv8_deprecated: move aarch32 helper earlier arm64: armv8_deprecated: rework deprected instruction handling Ren Zhijie (1): arm64: armv8_deprecated: fix unused-function error arch/arm64/include/asm/cpufeature.h | 3 +- arch/arm64/include/asm/exception.h | 13 +- arch/arm64/include/asm/spectre.h | 2 + arch/arm64/include/asm/system_misc.h | 2 +- arch/arm64/include/asm/traps.h | 19 +- arch/arm64/kernel/armv8_deprecated.c | 574 +++++++++++++-------------- arch/arm64/kernel/cpufeature.c | 23 +- arch/arm64/kernel/entry-common.c | 36 +- arch/arm64/kernel/proton-pack.c | 26 +- arch/arm64/kernel/traps.c | 125 +++--- 10 files changed, 396 insertions(+), 427 deletions(-) -- 2.34.1
hulk inclusion category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA -------------------------------- This reverts commit a569e359009d31a736879ba182f7b8a2e42e4436. Because the list_add double bug has been fixed in linux stable 5.10 and the related patches will be merged in this patch set. Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/kernel/armv8_deprecated.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index ab955c249f37..4a0ba2800e45 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -208,12 +208,10 @@ static int emulation_proc_handler(struct ctl_table *table, int write, loff_t *ppos) { int ret = 0; - struct insn_emulation *insn; - enum insn_emulation_mode prev_mode; + struct insn_emulation *insn = container_of(table->data, struct insn_emulation, current_mode); + enum insn_emulation_mode prev_mode = insn->current_mode; mutex_lock(&insn_emulation_mutex); - insn = container_of(table->data, struct insn_emulation, current_mode); - prev_mode = insn->current_mode; ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (ret || !write || prev_mode == insn->current_mode) -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 835cb1f78d746dc668997f723c804441c36e8540 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit b502c87d2a26c349acbc231ff2acd6f17147926b upstream. If an UNDEFINED exception is taken from EL1, and do_undefinstr() doesn't find any suitable undef_hook, it will call: BUG_ON(!user_mode(regs)) ... and the kernel will report a failure witin do_undefinstr() rather than reporting the original context that the UNDEFINED exception was taken from. The pt_regs and ESR value reported within the BUG() handler will be from within do_undefinstr() and the code dump will be for the BRK in BUG_ON(), which isn't sufficient to debug the cause of the original exception. This patch makes the reporting better by having do_undefinstr() call die() directly in this case to report the original context from which the UNDEFINED exception was taken. Prior to this patch, an undefined instruction is reported as: | kernel BUG at arch/arm64/kernel/traps.c:497! | Internal error: Oops - BUG: 0 [#1] PREEMPT SMP | Modules linked in: | CPU: 0 PID: 0 Comm: swapper Not tainted 5.19.0-rc3-00127-geff044f1b04e-dirty #3 | Hardware name: linux,dummy-virt (DT) | pstate: 000000c5 (nzcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : do_undefinstr+0x28c/0x2ac | lr : do_undefinstr+0x298/0x2ac | sp : ffff800009f63bc0 | x29: ffff800009f63bc0 x28: ffff800009f73c00 x27: ffff800009644a70 | x26: ffff8000096778a8 x25: 0000000000000040 x24: 0000000000000000 | x23: 00000000800000c5 x22: ffff800009894060 x21: ffff800009f63d90 | x20: 0000000000000000 x19: ffff800009f63c40 x18: 0000000000000006 | x17: 0000000000403000 x16: 00000000bfbfd000 x15: ffff800009f63830 | x14: ffffffffffffffff x13: 0000000000000000 x12: 0000000000000019 | x11: 0101010101010101 x10: 0000000000161b98 x9 : 0000000000000000 | x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 | x5 : ffff800009f761d0 x4 : 0000000000000000 x3 : ffff80000a2b80f8 | x2 : 0000000000000000 x1 : ffff800009f73c00 x0 : 00000000800000c5 | Call trace: | do_undefinstr+0x28c/0x2ac | el1_undef+0x2c/0x4c | el1h_64_sync_handler+0x84/0xd0 | el1h_64_sync+0x64/0x68 | setup_arch+0x550/0x598 | start_kernel+0x88/0x6ac | __primary_switched+0xb8/0xc0 | Code: 17ffff95 a9425bf5 17ffffb8 a9025bf5 (d4210000) With this patch applied, an undefined instruction is reported as: | Internal error: Oops - Undefined instruction: 0 [#1] PREEMPT SMP | Modules linked in: | CPU: 0 PID: 0 Comm: swapper Not tainted 5.19.0-rc3-00128-gf27cfcc80e52-dirty #5 | Hardware name: linux,dummy-virt (DT) | pstate: 800000c5 (Nzcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : setup_arch+0x550/0x598 | lr : setup_arch+0x50c/0x598 | sp : ffff800009f63d90 | x29: ffff800009f63d90 x28: 0000000081000200 x27: ffff800009644a70 | x26: ffff8000096778c8 x25: 0000000000000040 x24: 0000000000000000 | x23: 0000000000000100 x22: ffff800009f69a58 x21: ffff80000a2b80b8 | x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000000006 | x17: 0000000000403000 x16: 00000000bfbfd000 x15: ffff800009f63830 | x14: ffffffffffffffff x13: 0000000000000000 x12: 0000000000000019 | x11: 0101010101010101 x10: 0000000000161b98 x9 : 0000000000000000 | x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 | x5 : 0000000000000008 x4 : 0000000000000010 x3 : 0000000000000000 | x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 | Call trace: | setup_arch+0x550/0x598 | start_kernel+0x88/0x6ac | __primary_switched+0xb8/0xc0 | Code: b4000080 90ffed80 912ac000 97db745f (00000000) Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lore.kernel.org/r/20220913101732.3925290-2-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/kernel/traps.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 7c05bcf29013..7ba0660cc69d 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -405,7 +405,9 @@ void do_undefinstr(struct pt_regs *regs) if (call_undef_hook(regs) == 0) return; - BUG_ON(!user_mode(regs)); + if (!user_mode(regs)) + die("Oops - Undefined instruction", regs, 0); + force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } NOKPROBE_SYMBOL(do_undefinstr); -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 004bdab6edc70aa5bd0e61573bacaee7857c5790 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit 18906ff9af6517c20763ed63dab602a4150794f7 upstream. Recently, we reworked a lot of code to consistentlt pass ESR_ELx as a 64-bit quantity. However, we missed that this can be passed into die() and __die() as the 'err' parameter where it is truncated to a 32-bit int. As notify_die() already takes 'err' as a long, this patch changes die() and __die() to also take 'err' as a long, ensuring that the full value of ESR_ELx is retained. At the same time, die() is updated to consistently log 'err' as a zero-padded 64-bit quantity. Subsequent patches will pass the ESR_ELx value to die() for a number of exceptions. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20220913101732.3925290-3-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/system_misc.h | 2 +- arch/arm64/kernel/traps.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/system_misc.h b/arch/arm64/include/asm/system_misc.h index 1ab63cfbbaf1..624a608933f1 100644 --- a/arch/arm64/include/asm/system_misc.h +++ b/arch/arm64/include/asm/system_misc.h @@ -18,7 +18,7 @@ struct pt_regs; -void die(const char *msg, struct pt_regs *regs, int err); +void die(const char *msg, struct pt_regs *regs, long err); struct siginfo; void arm64_notify_die(const char *str, struct pt_regs *regs, diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 7ba0660cc69d..910472362c0f 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -91,12 +91,12 @@ static void dump_kernel_instr(const char *lvl, struct pt_regs *regs) #define S_SMP " SMP" -static int __die(const char *str, int err, struct pt_regs *regs) +static int __die(const char *str, long err, struct pt_regs *regs) { static int die_counter; int ret; - pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n", + pr_emerg("Internal error: %s: %016lx [#%d]" S_PREEMPT S_SMP "\n", str, err, ++die_counter); /* trap and error numbers are mostly meaningless on ARM */ @@ -117,7 +117,7 @@ static DEFINE_RAW_SPINLOCK(die_lock); /* * This function is protected against re-entrancy. */ -void die(const char *str, struct pt_regs *regs, int err) +void die(const char *str, struct pt_regs *regs, long err) { int ret; unsigned long flags; -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit a8d7c8484ff762bbdfde26e838d3bc451817454d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit 0f2cb928a1547ae8f89e80a4b8df2c6c02ae5f96 upstream. Currently, bug_handler() and kasan_handler() call die() with '0' as the 'err' value, whereas die_kernel_fault() passes the ESR_ELx value. For consistency, this patch ensures we always pass the ESR_ELx value to die(). As this is only called for exceptions taken from kernel mode, there should be no user-visible change as a result of this patch. For UNDEFINED exceptions, I've had to modify do_undefinstr() and its callers to pass the ESR_ELx value. In all cases the ESR_ELx value had already been read and was available. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Mark Brown <broonie@kernel.org> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20220913101732.3925290-4-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: arch/arm64/kernel/traps.c Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/exception.h | 2 +- arch/arm64/kernel/entry-common.c | 14 +++++++------- arch/arm64/kernel/traps.c | 14 +++++++------- 3 files changed, 15 insertions(+), 15 deletions(-) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 731cf01d9296..0519067ba2e1 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -51,7 +51,7 @@ asmlinkage void exit_to_user_mode(void); void arm64_enter_nmi(struct pt_regs *regs); void arm64_exit_nmi(struct pt_regs *regs); void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); -void do_undefinstr(struct pt_regs *regs); +void do_undefinstr(struct pt_regs *regs, unsigned long esr); void do_bti(struct pt_regs *regs); asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr); void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index 387c755b79f6..e77f5573e1d9 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -132,11 +132,11 @@ static void noinstr el1_pc(struct pt_regs *regs, unsigned long esr) exit_to_kernel_mode(regs); } -static void noinstr el1_undef(struct pt_regs *regs) +static void noinstr el1_undef(struct pt_regs *regs, unsigned long esr) { enter_from_kernel_mode(regs); local_daif_inherit(regs); - do_undefinstr(regs); + do_undefinstr(regs, esr); local_daif_mask(); exit_to_kernel_mode(regs); } @@ -210,7 +210,7 @@ asmlinkage void noinstr el1_sync_handler(struct pt_regs *regs) break; case ESR_ELx_EC_SYS64: case ESR_ELx_EC_UNKNOWN: - el1_undef(regs); + el1_undef(regs, esr); break; case ESR_ELx_EC_BREAKPT_CUR: case ESR_ELx_EC_SOFTSTP_CUR: @@ -316,11 +316,11 @@ static void noinstr el0_sp(struct pt_regs *regs, unsigned long esr) do_sp_pc_abort(regs->sp, esr, regs); } -static void noinstr el0_undef(struct pt_regs *regs) +static void noinstr el0_undef(struct pt_regs *regs, unsigned long esr) { enter_from_user_mode(); local_daif_restore(DAIF_PROCCTX); - do_undefinstr(regs); + do_undefinstr(regs, esr); } static void noinstr el0_bti(struct pt_regs *regs) @@ -394,7 +394,7 @@ asmlinkage void noinstr el0_sync_handler(struct pt_regs *regs) el0_pc(regs, esr); break; case ESR_ELx_EC_UNKNOWN: - el0_undef(regs); + el0_undef(regs, esr); break; case ESR_ELx_EC_BTI: el0_bti(regs); @@ -454,7 +454,7 @@ asmlinkage void noinstr el0_sync_compat_handler(struct pt_regs *regs) case ESR_ELx_EC_CP14_MR: case ESR_ELx_EC_CP14_LS: case ESR_ELx_EC_CP14_64: - el0_undef(regs); + el0_undef(regs, esr); break; case ESR_ELx_EC_CP15_32: case ESR_ELx_EC_CP15_64: diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 910472362c0f..872d86106582 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -396,7 +396,7 @@ void arm64_notify_segfault(unsigned long addr) force_signal_inject(SIGSEGV, code, addr, 0); } -void do_undefinstr(struct pt_regs *regs) +void do_undefinstr(struct pt_regs *regs, unsigned long esr) { /* check for AArch32 breakpoint instructions */ if (!aarch32_break_handler(regs)) @@ -406,7 +406,7 @@ void do_undefinstr(struct pt_regs *regs) return; if (!user_mode(regs)) - die("Oops - Undefined instruction", regs, 0); + die("Oops - Undefined instruction", regs, esr); force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } @@ -675,7 +675,7 @@ void do_cp15instr(unsigned int esr, struct pt_regs *regs) hook_base = cp15_64_hooks; break; default: - do_undefinstr(regs); + do_undefinstr(regs, esr); return; } @@ -690,7 +690,7 @@ void do_cp15instr(unsigned int esr, struct pt_regs *regs) * EL0. Fall back to our usual undefined instruction handler * so that we handle these consistently. */ - do_undefinstr(regs); + do_undefinstr(regs, esr); } NOKPROBE_SYMBOL(do_cp15instr); #endif @@ -710,7 +710,7 @@ void do_sysinstr(unsigned int esr, struct pt_regs *regs) * back to our usual undefined instruction handler so that we handle * these consistently. */ - do_undefinstr(regs); + do_undefinstr(regs, esr); } NOKPROBE_SYMBOL(do_sysinstr); @@ -913,7 +913,7 @@ static int bug_handler(struct pt_regs *regs, unsigned int esr) { switch (report_bug(regs->pc, regs)) { case BUG_TRAP_TYPE_BUG: - die("Oops - BUG", regs, 0); + die("Oops - BUG", regs, esr); break; case BUG_TRAP_TYPE_WARN: @@ -981,7 +981,7 @@ static int kasan_handler(struct pt_regs *regs, unsigned int esr) * This is something that might be fixed at some point in the future. */ if (!recover) - die("Oops - KASAN", regs, 0); + die("Oops - KASAN", regs, esr); /* If thread survives, skip over the brk instruction and continue: */ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE); -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 9113333d7c7cf87219c9b919ed2bc10f7042c5be category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit a1fafa3b24a70461bbf3e5c0770893feb0a49292 upstream. If an FPAC exception is taken from EL1, the entry code will call do_ptrauth_fault(), where due to: BUG_ON(!user_mode(regs)) ... the kernel will report a problem within do_ptrauth_fault() rather than reporting the original context the FPAC exception was taken from. The pt_regs and ESR value reported will be from within do_ptrauth_fault() and the code dump will be for the BRK in BUG_ON(), which isn't sufficient to debug the cause of the original exception. This patch makes the reporting better by having separate EL0 and EL1 FPAC exception handlers, with the latter calling die() directly to report the original context the FPAC exception was taken from. Note that we only need to prevent kprobes of the EL1 FPAC handler, since the EL0 FPAC handler cannot be called recursively. For consistency with do_el0_svc*(), I've named the split functions do_el{0,1}_fpac() rather than do_el{0,1}_ptrauth_fault(). I've also clarified the comment to not imply there are casues other than FPAC exceptions. Prior to this patch FPAC exceptions are reported as: | kernel BUG at arch/arm64/kernel/traps.c:517! | Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP | Modules linked in: | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-00130-g9c8a180a1cdf-dirty #12 | Hardware name: FVP Base RevC (DT) | pstate: 00400009 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : do_ptrauth_fault+0x3c/0x40 | lr : el1_fpac+0x34/0x54 | sp : ffff80000a3bbc80 | x29: ffff80000a3bbc80 x28: ffff0008001d8000 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: 0000000020400009 x22: ffff800008f70fa4 x21: ffff80000a3bbe00 | x20: 0000000072000000 x19: ffff80000a3bbcb0 x18: fffffbfffda37000 | x17: 3120676e696d7573 x16: 7361202c6e6f6974 x15: 0000000081a90000 | x14: 0040000000000041 x13: 0040000000000001 x12: ffff000001a90000 | x11: fffffbfffda37480 x10: 0068000000000703 x9 : 0001000080000000 | x8 : 0000000000090000 x7 : 0068000000000f03 x6 : 0060000000000783 | x5 : ffff80000a3bbcb0 x4 : ffff0008001d8000 x3 : 0000000072000000 | x2 : 0000000000000000 x1 : 0000000020400009 x0 : ffff80000a3bbcb0 | Call trace: | do_ptrauth_fault+0x3c/0x40 | el1h_64_sync_handler+0xc4/0xd0 | el1h_64_sync+0x64/0x68 | test_pac+0x8/0x10 | smp_init+0x7c/0x8c | kernel_init_freeable+0x128/0x28c | kernel_init+0x28/0x13c | ret_from_fork+0x10/0x20 | Code: 97fffe5e a8c17bfd d50323bf d65f03c0 (d4210000) With this patch applied FPAC exceptions are reported as: | Internal error: Oops - FPAC: 0000000072000000 [#1] PREEMPT SMP | Modules linked in: | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-00132-g78846e1c4757-dirty #11 | Hardware name: FVP Base RevC (DT) | pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : test_pac+0x8/0x10 | lr : 0x0 | sp : ffff80000a3bbe00 | x29: ffff80000a3bbe00 x28: 0000000000000000 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: ffff80000a2c8000 x22: 0000000000000000 x21: 0000000000000000 | x20: ffff8000099fa5b0 x19: ffff80000a007000 x18: fffffbfffda37000 | x17: 3120676e696d7573 x16: 7361202c6e6f6974 x15: 0000000081a90000 | x14: 0040000000000041 x13: 0040000000000001 x12: ffff000001a90000 | x11: fffffbfffda37480 x10: 0068000000000703 x9 : 0001000080000000 | x8 : 0000000000090000 x7 : 0068000000000f03 x6 : 0060000000000783 | x5 : ffff80000a2c6000 x4 : ffff0008001d8000 x3 : ffff800009f88378 | x2 : 0000000000000000 x1 : 0000000080210000 x0 : ffff000001a90000 | Call trace: | test_pac+0x8/0x10 | smp_init+0x7c/0x8c | kernel_init_freeable+0x128/0x28c | kernel_init+0x28/0x13c | ret_from_fork+0x10/0x20 | Code: d50323bf d65f03c0 d503233f aa1f03fe (d50323bf) Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20220913101732.3925290-5-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/exception.h | 3 ++- arch/arm64/kernel/entry-common.c | 4 ++-- arch/arm64/kernel/traps.c | 16 ++++++++++------ 3 files changed, 14 insertions(+), 9 deletions(-) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 0519067ba2e1..2af476d399d2 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -65,5 +65,6 @@ void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr); void do_cp15instr(unsigned int esr, struct pt_regs *regs); void do_el0_svc(struct pt_regs *regs); void do_el0_svc_compat(struct pt_regs *regs); -void do_ptrauth_fault(struct pt_regs *regs, unsigned int esr); +void do_el0_fpac(struct pt_regs *regs, unsigned long esr); +void do_el1_fpac(struct pt_regs *regs, unsigned long esr); #endif /* __ASM_EXCEPTION_H */ diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index e77f5573e1d9..f307968f87c3 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -187,7 +187,7 @@ static void noinstr el1_fpac(struct pt_regs *regs, unsigned long esr) { enter_from_kernel_mode(regs); local_daif_inherit(regs); - do_ptrauth_fault(regs, esr); + do_el1_fpac(regs, esr); local_daif_mask(); exit_to_kernel_mode(regs); } @@ -357,7 +357,7 @@ static void noinstr el0_fpac(struct pt_regs *regs, unsigned long esr) { enter_from_user_mode(); local_daif_restore(DAIF_PROCCTX); - do_ptrauth_fault(regs, esr); + do_el0_fpac(regs, esr); } asmlinkage void noinstr el0_sync_handler(struct pt_regs *regs) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 872d86106582..3bc81bbaeda7 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -419,16 +419,20 @@ void do_bti(struct pt_regs *regs) } NOKPROBE_SYMBOL(do_bti); -void do_ptrauth_fault(struct pt_regs *regs, unsigned int esr) +void do_el0_fpac(struct pt_regs *regs, unsigned long esr) +{ + force_signal_inject(SIGILL, ILL_ILLOPN, regs->pc, esr); +} + +void do_el1_fpac(struct pt_regs *regs, unsigned long esr) { /* - * Unexpected FPAC exception or pointer authentication failure in - * the kernel: kill the task before it does any more harm. + * Unexpected FPAC exception in the kernel: kill the task before it + * does any more harm. */ - BUG_ON(!user_mode(regs)); - force_signal_inject(SIGILL, ILL_ILLOPN, regs->pc, esr); + die("Oops - FPAC", regs, esr); } -NOKPROBE_SYMBOL(do_ptrauth_fault); +NOKPROBE_SYMBOL(do_el1_fpac); #define __user_cache_maint(insn, address, res) \ if (address >= user_addr_max()) { \ -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 793ed958b62ad4831e03de51b3d23ad6eb23eea7 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit 830a2a4d853f2c4a1e4606aa03341b7f273b0e9b upstream. If a BTI exception is taken from EL1, the entry code will treat this as an unhandled exception and will panic() the kernel. This is inconsistent with the way we handle FPAC exceptions, which have a dedicated handler and only necessarily kill the thread from which the exception was taken from, and we don't log all the information that could be relevant to debug the issue. The code in do_bti() has: BUG_ON(!user_mode(regs)); ... and it seems like the intent was to call this for EL1 BTI exceptions, as with FPAC, but this was omitted due to an oversight. This patch adds separate EL0 and EL1 BTI exception handlers, with the latter calling die() directly to report the original context the BTI exception was taken from. This matches our handling of FPAC exceptions. Prior to this patch, a BTI failure is reported as: | Unhandled 64-bit el1h sync exception on CPU0, ESR 0x0000000034000002 -- BTI | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-00131-g7d937ff0221d-dirty #9 | Hardware name: linux,dummy-virt (DT) | pstate: 20400809 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=-c) | pc : test_bti_callee+0x4/0x10 | lr : test_bti_caller+0x1c/0x28 | sp : ffff80000800bdf0 | x29: ffff80000800bdf0 x28: 0000000000000000 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: ffff80000a2b8000 x22: 0000000000000000 x21: 0000000000000000 | x20: ffff8000099fa5b0 x19: ffff800009ff7000 x18: fffffbfffda37000 | x17: 3120676e696d7573 x16: 7361202c6e6f6974 x15: 0000000041a90000 | x14: 0040000000000041 x13: 0040000000000001 x12: ffff000001a90000 | x11: fffffbfffda37480 x10: 0068000000000703 x9 : 0001000040000000 | x8 : 0000000000090000 x7 : 0068000000000f03 x6 : 0060000000000f83 | x5 : ffff80000a2b6000 x4 : ffff0000028d0000 x3 : ffff800009f78378 | x2 : 0000000000000000 x1 : 0000000040210000 x0 : ffff8000080257e4 | Kernel panic - not syncing: Unhandled exception | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-00131-g7d937ff0221d-dirty #9 | Hardware name: linux,dummy-virt (DT) | Call trace: | dump_backtrace.part.0+0xcc/0xe0 | show_stack+0x18/0x5c | dump_stack_lvl+0x64/0x80 | dump_stack+0x18/0x34 | panic+0x170/0x360 | arm64_exit_nmi.isra.0+0x0/0x80 | el1h_64_sync_handler+0x64/0xd0 | el1h_64_sync+0x64/0x68 | test_bti_callee+0x4/0x10 | smp_cpus_done+0xb0/0xbc | smp_init+0x7c/0x8c | kernel_init_freeable+0x128/0x28c | kernel_init+0x28/0x13c | ret_from_fork+0x10/0x20 With this patch applied, a BTI failure is reported as: | Internal error: Oops - BTI: 0000000034000002 [#1] PREEMPT SMP | Modules linked in: | CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc3-00132-g0ad98265d582-dirty #8 | Hardware name: linux,dummy-virt (DT) | pstate: 20400809 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=-c) | pc : test_bti_callee+0x4/0x10 | lr : test_bti_caller+0x1c/0x28 | sp : ffff80000800bdf0 | x29: ffff80000800bdf0 x28: 0000000000000000 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: ffff80000a2b8000 x22: 0000000000000000 x21: 0000000000000000 | x20: ffff8000099fa5b0 x19: ffff800009ff7000 x18: fffffbfffda37000 | x17: 3120676e696d7573 x16: 7361202c6e6f6974 x15: 0000000041a90000 | x14: 0040000000000041 x13: 0040000000000001 x12: ffff000001a90000 | x11: fffffbfffda37480 x10: 0068000000000703 x9 : 0001000040000000 | x8 : 0000000000090000 x7 : 0068000000000f03 x6 : 0060000000000f83 | x5 : ffff80000a2b6000 x4 : ffff0000028d0000 x3 : ffff800009f78378 | x2 : 0000000000000000 x1 : 0000000040210000 x0 : ffff800008025804 | Call trace: | test_bti_callee+0x4/0x10 | smp_cpus_done+0xb0/0xbc | smp_init+0x7c/0x8c | kernel_init_freeable+0x128/0x28c | kernel_init+0x28/0x13c | ret_from_fork+0x10/0x20 | Code: d50323bf d53cd040 d65f03c0 d503233f (d50323bf) Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20220913101732.3925290-6-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/exception.h | 3 ++- arch/arm64/kernel/entry-common.c | 14 +++++++++++++- arch/arm64/kernel/traps.c | 10 +++++++--- 3 files changed, 22 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 2af476d399d2..44b9d6701d84 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -52,7 +52,8 @@ void arm64_enter_nmi(struct pt_regs *regs); void arm64_exit_nmi(struct pt_regs *regs); void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); void do_undefinstr(struct pt_regs *regs, unsigned long esr); -void do_bti(struct pt_regs *regs); +void do_el0_bti(struct pt_regs *regs); +void do_el1_bti(struct pt_regs *regs, unsigned long esr); asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr); void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, struct pt_regs *regs); diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index f307968f87c3..be9184cd9297 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -141,6 +141,15 @@ static void noinstr el1_undef(struct pt_regs *regs, unsigned long esr) exit_to_kernel_mode(regs); } +static void noinstr el1_bti(struct pt_regs *regs, unsigned long esr) +{ + enter_from_kernel_mode(regs); + local_daif_inherit(regs); + do_el1_bti(regs, esr); + local_daif_mask(); + exit_to_kernel_mode(regs); +} + static void noinstr el1_inv(struct pt_regs *regs, unsigned long esr) { enter_from_kernel_mode(regs); @@ -212,6 +221,9 @@ asmlinkage void noinstr el1_sync_handler(struct pt_regs *regs) case ESR_ELx_EC_UNKNOWN: el1_undef(regs, esr); break; + case ESR_ELx_EC_BTI: + el1_bti(regs, esr); + break; case ESR_ELx_EC_BREAKPT_CUR: case ESR_ELx_EC_SOFTSTP_CUR: case ESR_ELx_EC_WATCHPT_CUR: @@ -327,7 +339,7 @@ static void noinstr el0_bti(struct pt_regs *regs) { enter_from_user_mode(); local_daif_restore(DAIF_PROCCTX); - do_bti(regs); + do_el0_bti(regs); } static void noinstr el0_inv(struct pt_regs *regs, unsigned long esr) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 3bc81bbaeda7..7b10333b6165 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -412,12 +412,16 @@ void do_undefinstr(struct pt_regs *regs, unsigned long esr) } NOKPROBE_SYMBOL(do_undefinstr); -void do_bti(struct pt_regs *regs) +void do_el0_bti(struct pt_regs *regs) { - BUG_ON(!user_mode(regs)); force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } -NOKPROBE_SYMBOL(do_bti); + +void do_el1_bti(struct pt_regs *regs, unsigned long esr) +{ + die("Oops - BTI", regs, esr); +} +NOKPROBE_SYMBOL(do_el1_bti); void do_el0_fpac(struct pt_regs *regs, unsigned long esr) { -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 8a8d4cc303ef53b456af2660e0f5753cb3622d31 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit b3a0c010e900a9f89dcd99f10bd8f7538d21b0a9 upstream. Currently do_sysinstr() and do_cp15instr() are marked with NOKPROBE_SYMBOL(). However, these are only called for exceptions taken from EL0, and there is no risk of recursion in kprobes, so this is not necessary. Remove the NOKPROBE_SYMBOL() annotation, and rename the two functions to more clearly indicate that these are solely for exceptions taken from EL0, better matching the names used by the lower level entry points in entry-common.c. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-2-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/exception.h | 4 ++-- arch/arm64/kernel/entry-common.c | 4 ++-- arch/arm64/kernel/traps.c | 6 ++---- 3 files changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 44b9d6701d84..08b5eb7e4a7c 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -60,10 +60,10 @@ void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr, void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs); void do_sve_acc(unsigned int esr, struct pt_regs *regs); void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs); -void do_sysinstr(unsigned int esr, struct pt_regs *regs); +void do_el0_sys(unsigned long esr, struct pt_regs *regs); void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr); -void do_cp15instr(unsigned int esr, struct pt_regs *regs); +void do_el0_cp15(unsigned long esr, struct pt_regs *regs); void do_el0_svc(struct pt_regs *regs); void do_el0_svc_compat(struct pt_regs *regs); void do_el0_fpac(struct pt_regs *regs, unsigned long esr); diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index be9184cd9297..f29cc9f2f5e8 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -306,7 +306,7 @@ static void noinstr el0_sys(struct pt_regs *regs, unsigned long esr) { enter_from_user_mode(); local_daif_restore(DAIF_PROCCTX); - do_sysinstr(esr, regs); + do_el0_sys(esr, regs); } static void noinstr el0_pc(struct pt_regs *regs, unsigned long esr) @@ -430,7 +430,7 @@ static void noinstr el0_cp15(struct pt_regs *regs, unsigned long esr) { enter_from_user_mode(); local_daif_restore(DAIF_PROCCTX); - do_cp15instr(esr, regs); + do_el0_cp15(esr, regs); } static void noinstr el0_svc_compat(struct pt_regs *regs) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 7b10333b6165..aebf9c54a53c 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -662,7 +662,7 @@ static const struct sys64_hook cp15_64_hooks[] = { {}, }; -void do_cp15instr(unsigned int esr, struct pt_regs *regs) +void do_el0_cp15(unsigned long esr, struct pt_regs *regs) { const struct sys64_hook *hook, *hook_base; @@ -700,10 +700,9 @@ void do_cp15instr(unsigned int esr, struct pt_regs *regs) */ do_undefinstr(regs, esr); } -NOKPROBE_SYMBOL(do_cp15instr); #endif -void do_sysinstr(unsigned int esr, struct pt_regs *regs) +void do_el0_sys(unsigned long esr, struct pt_regs *regs) { const struct sys64_hook *hook; @@ -720,7 +719,6 @@ void do_sysinstr(unsigned int esr, struct pt_regs *regs) */ do_undefinstr(regs, esr); } -NOKPROBE_SYMBOL(do_sysinstr); static const char *esr_class_str[] = { [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC", -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 7a76df1ae1b3a6d1cc806066d48c6b95dc4335fa category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit 61d64a376ea80f9097e7ea599bcd68671b836dc6 upstream. In general, exceptions taken from EL1 need to be handled separately from exceptions taken from EL0, as the logic to handle the two cases can be significantly divergent, and exceptions taken from EL1 typically have more stringent requirements on locking and instrumentation. Subsequent patches will rework the way EL1 UNDEFs are handled in order to address longstanding soundness issues with instrumentation and RCU. In preparation for that rework, this patch splits the existing do_undefinstr() handler into separate do_el0_undef() and do_el1_undef() handlers. Prior to this patch, do_undefinstr() was marked with NOKPROBE_SYMBOL(), preventing instrumentation via kprobes. However, do_undefinstr() invokes other code which can be instrumented, and: * For UNDEFINED exceptions taken from EL0, there is no risk of recursion within kprobes. Therefore it is safe for do_el0_undef to be instrumented with kprobes, and it does not need to be marked with NOKPROBE_SYMBOL(). * For UNDEFINED exceptions taken from EL1, either: (a) The exception is has been taken when manipulating SSBS; these cases are limited and do not occur within code that can be invoked recursively via kprobes. Hence, in these cases instrumentation with kprobes is benign. (b) The exception has been taken for an unknown reason, as other than manipulating SSBS we do not expect to take UNDEFINED exceptions from EL1. Any handling of these exception is best-effort. ... and in either case, marking do_el1_undef() with NOKPROBE_SYMBOL() isn't sufficient to prevent recursion via kprobes as functions it calls (including die()) are instrumentable via kprobes. Hence, it's not worthwhile to mark do_el1_undef() with NOKPROBE_SYMBOL(). The same applies to do_el1_bti() and do_el1_fpac(), so their NOKPROBE_SYMBOL() annotations are also removed. Aside from the new instrumentability, there should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-3-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: arch/arm64/kernel/traps.c Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/exception.h | 3 ++- arch/arm64/kernel/entry-common.c | 4 ++-- arch/arm64/kernel/traps.c | 22 ++++++++++++---------- 3 files changed, 16 insertions(+), 13 deletions(-) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 08b5eb7e4a7c..6fedf883e72d 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -51,7 +51,8 @@ asmlinkage void exit_to_user_mode(void); void arm64_enter_nmi(struct pt_regs *regs); void arm64_exit_nmi(struct pt_regs *regs); void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); -void do_undefinstr(struct pt_regs *regs, unsigned long esr); +void do_el0_undef(struct pt_regs *regs, unsigned long esr); +void do_el1_undef(struct pt_regs *regs, unsigned long esr); void do_el0_bti(struct pt_regs *regs); void do_el1_bti(struct pt_regs *regs, unsigned long esr); asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr); diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index f29cc9f2f5e8..258af7191782 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -136,7 +136,7 @@ static void noinstr el1_undef(struct pt_regs *regs, unsigned long esr) { enter_from_kernel_mode(regs); local_daif_inherit(regs); - do_undefinstr(regs, esr); + do_el1_undef(regs, esr); local_daif_mask(); exit_to_kernel_mode(regs); } @@ -332,7 +332,7 @@ static void noinstr el0_undef(struct pt_regs *regs, unsigned long esr) { enter_from_user_mode(); local_daif_restore(DAIF_PROCCTX); - do_undefinstr(regs, esr); + do_el0_undef(regs, esr); } static void noinstr el0_bti(struct pt_regs *regs) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index aebf9c54a53c..cf59951f3e3b 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -396,7 +396,7 @@ void arm64_notify_segfault(unsigned long addr) force_signal_inject(SIGSEGV, code, addr, 0); } -void do_undefinstr(struct pt_regs *regs, unsigned long esr) +void do_el0_undef(struct pt_regs *regs, unsigned long esr) { /* check for AArch32 breakpoint instructions */ if (!aarch32_break_handler(regs)) @@ -405,12 +405,16 @@ void do_undefinstr(struct pt_regs *regs, unsigned long esr) if (call_undef_hook(regs) == 0) return; - if (!user_mode(regs)) - die("Oops - Undefined instruction", regs, esr); - force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } -NOKPROBE_SYMBOL(do_undefinstr); + +void do_el1_undef(struct pt_regs *regs, unsigned long esr) +{ + if (call_undef_hook(regs) == 0) + return; + + die("Oops - Undefined instruction", regs, esr); +} void do_el0_bti(struct pt_regs *regs) { @@ -421,7 +425,6 @@ void do_el1_bti(struct pt_regs *regs, unsigned long esr) { die("Oops - BTI", regs, esr); } -NOKPROBE_SYMBOL(do_el1_bti); void do_el0_fpac(struct pt_regs *regs, unsigned long esr) { @@ -436,7 +439,6 @@ void do_el1_fpac(struct pt_regs *regs, unsigned long esr) */ die("Oops - FPAC", regs, esr); } -NOKPROBE_SYMBOL(do_el1_fpac); #define __user_cache_maint(insn, address, res) \ if (address >= user_addr_max()) { \ @@ -683,7 +685,7 @@ void do_el0_cp15(unsigned long esr, struct pt_regs *regs) hook_base = cp15_64_hooks; break; default: - do_undefinstr(regs, esr); + do_el0_undef(regs, esr); return; } @@ -698,7 +700,7 @@ void do_el0_cp15(unsigned long esr, struct pt_regs *regs) * EL0. Fall back to our usual undefined instruction handler * so that we handle these consistently. */ - do_undefinstr(regs, esr); + do_el0_undef(regs, esr); } #endif @@ -717,7 +719,7 @@ void do_el0_sys(unsigned long esr, struct pt_regs *regs) * back to our usual undefined instruction handler so that we handle * these consistently. */ - do_undefinstr(regs, esr); + do_el0_undef(regs, esr); } static const char *esr_class_str[] = { -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 0edde7fd1c3b5d0f52eb024ea8ef92e191d3dbe9 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit bff8f413c71ffc3cb679dbd9a5632b33af563f9f upstream. Currently call_undef_hook() is used to handle UNDEFINED exceptions from EL0 and EL1. As support for deprecated instructions may be enabled independently, the handlers for individual instructions are organised as a linked list of struct undef_hook which can be manipulated dynamically. As this can be manipulated dynamically, the list is protected with a raw_spinlock which must be acquired when handling UNDEFINED exceptions or when manipulating the list of handlers. This locking is unfortunate as it serialises handling of UNDEFINED exceptions, and requires RCU to be enabled for lockdep, requiring the use of RCU_NONIDLE() in resume path of cpu_suspend() since commit: a2c42bbabbe260b7 ("arm64: spectre: Prevent lockdep splat on v4 mitigation enable path") The list of UNDEFINED handlers largely consist of handlers for exceptions taken from EL0, and the only handler for exceptions taken from EL1 handles `MSR SSBS, #imm` on CPUs which feature PSTATE.SSBS but lack the corresponding MSR (Immediate) instruction. Other than this we never expect to take an UNDEFINED exception from EL1 in normal operation. This patch reworks do_el0_undef() to invoke the EL1 SSBS handler directly, relegating call_undef_hook() to only handle EL0 UNDEFs. This removes redundant work to iterate the list for EL1 UNDEFs, and removes the need for locking, permitting EL1 UNDEFs to be handled in parallel without contention. The RCU_NONIDLE() call in cpu_suspend() will be removed in a subsequent patch, as there are other potential issues with the use of instrumentable code and RCU in the CPU suspend code. I've tested this by forcing the detection of SSBS on a CPU that doesn't have it, and verifying that the try_emulate_el1_ssbs() callback is invoked. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-4-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: arch/arm64/kernel/proton-pack.c arch/arm64/kernel/traps.c Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/spectre.h | 2 ++ arch/arm64/kernel/proton-pack.c | 26 +++++++------------------- arch/arm64/kernel/traps.c | 15 ++++++++------- 3 files changed, 17 insertions(+), 26 deletions(-) diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h index 4b3a5f050f71..e48afcb69392 100644 --- a/arch/arm64/include/asm/spectre.h +++ b/arch/arm64/include/asm/spectre.h @@ -18,6 +18,7 @@ enum mitigation_state { SPECTRE_VULNERABLE, }; +struct pt_regs; struct task_struct; enum mitigation_state arm64_get_spectre_v2_state(void); @@ -33,4 +34,5 @@ enum mitigation_state arm64_get_spectre_bhb_state(void); bool is_spectre_bhb_affected(const struct arm64_cpu_capabilities *entry, int scope); u8 spectre_bhb_loop_affected(int scope); void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *__unused); +bool try_emulate_el1_ssbs(struct pt_regs *regs, u32 instr); #endif /* __ASM_SPECTRE_H */ diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c index 9c95d4955b6e..66aedd0a7ca2 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -537,10 +537,13 @@ bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope) return state != SPECTRE_UNAFFECTED; } -static int ssbs_emulation_handler(struct pt_regs *regs, u32 instr) +bool try_emulate_el1_ssbs(struct pt_regs *regs, u32 instr) { - if (user_mode(regs)) - return 1; + const u32 instr_mask = ~(1U << PSTATE_Imm_shift); + const u32 instr_val = 0xd500401f | PSTATE_SSBS; + + if ((instr & instr_mask) != instr_val) + return false; if (instr & BIT(PSTATE_Imm_shift)) regs->pstate |= PSR_SSBS_BIT; @@ -548,19 +551,11 @@ static int ssbs_emulation_handler(struct pt_regs *regs, u32 instr) regs->pstate &= ~PSR_SSBS_BIT; arm64_skip_faulting_instruction(regs, 4); - return 0; + return true; } -static struct undef_hook ssbs_emulation_hook = { - .instr_mask = ~(1U << PSTATE_Imm_shift), - .instr_val = 0xd500401f | PSTATE_SSBS, - .fn = ssbs_emulation_handler, -}; - static enum mitigation_state spectre_v4_enable_hw_mitigation(void) { - static bool undef_hook_registered = false; - static DEFINE_RAW_SPINLOCK(hook_lock); enum mitigation_state state; /* @@ -571,13 +566,6 @@ static enum mitigation_state spectre_v4_enable_hw_mitigation(void) if (state != SPECTRE_MITIGATED || !this_cpu_has_cap(ARM64_SSBS)) return state; - raw_spin_lock(&hook_lock); - if (!undef_hook_registered) { - register_undef_hook(&ssbs_emulation_hook); - undef_hook_registered = true; - } - raw_spin_unlock(&hook_lock); - if (spectre_v4_mitigations_off()) { sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_DSSBS); set_pstate_ssbs(1); diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index cf59951f3e3b..e18a8f03928a 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -312,12 +312,7 @@ static int call_undef_hook(struct pt_regs *regs) int (*fn)(struct pt_regs *regs, u32 instr) = NULL; void __user *pc = (void __user *)instruction_pointer(regs); - if (!user_mode(regs)) { - __le32 instr_le; - if (get_kernel_nofault(instr_le, (__force __le32 *)pc)) - goto exit; - instr = le32_to_cpu(instr_le); - } else if (a32_thumb_mode(regs)) { + if (a32_thumb_mode(regs)) { /* 16-bit Thumb instruction */ __le16 instr_le; if (get_user(instr_le, (__le16 __user *)pc)) @@ -410,9 +405,15 @@ void do_el0_undef(struct pt_regs *regs, unsigned long esr) void do_el1_undef(struct pt_regs *regs, unsigned long esr) { - if (call_undef_hook(regs) == 0) + u32 insn; + + if (aarch64_insn_read((void *)regs->pc, &insn)) + goto out_err; + + if (try_emulate_el1_ssbs(regs, insn)) return; +out_err: die("Oops - Undefined instruction", regs, esr); } -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 15e964971ff701c661936aa6103d51a895f32e24 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit dbfbd87efa79575491af0ba1a87bf567eaea6cae upstream. Subsequent patches will rework EL0 UNDEF handling, removing the need for struct undef_hook and call_undef_hook. In preparation for those changes, this patch factors the logic for reading user instructions out of call_undef_hook() and into a new user_insn_read() helper, matching the style of the existing aarch64_insn_read() helper used for reading kernel instructions. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-5-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: arch/arm64/kernel/traps.c Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/kernel/traps.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index e18a8f03928a..2ee92345a703 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -304,25 +304,22 @@ void unregister_undef_hook(struct undef_hook *hook) raw_spin_unlock_irqrestore(&undef_lock, flags); } -static int call_undef_hook(struct pt_regs *regs) +static int user_insn_read(struct pt_regs *regs, u32 *insnp) { - struct undef_hook *hook; - unsigned long flags; u32 instr; - int (*fn)(struct pt_regs *regs, u32 instr) = NULL; void __user *pc = (void __user *)instruction_pointer(regs); if (a32_thumb_mode(regs)) { /* 16-bit Thumb instruction */ __le16 instr_le; if (get_user(instr_le, (__le16 __user *)pc)) - goto exit; + return -EFAULT; instr = le16_to_cpu(instr_le); if (aarch32_insn_is_wide(instr)) { u32 instr2; if (get_user(instr_le, (__le16 __user *)(pc + 2))) - goto exit; + return -EFAULT; instr2 = le16_to_cpu(instr_le); instr = (instr << 16) | instr2; } @@ -330,10 +327,20 @@ static int call_undef_hook(struct pt_regs *regs) /* 32-bit ARM instruction */ __le32 instr_le; if (get_user(instr_le, (__le32 __user *)pc)) - goto exit; + return -EFAULT; instr = le32_to_cpu(instr_le); } + *insnp = instr; + return 0; +} + +static int call_undef_hook(struct pt_regs *regs, u32 instr) +{ + struct undef_hook *hook; + unsigned long flags; + int (*fn)(struct pt_regs *regs, u32 instr) = NULL; + raw_spin_lock_irqsave(&undef_lock, flags); list_for_each_entry(hook, &undef_hook, node) if ((instr & hook->instr_mask) == hook->instr_val && @@ -341,7 +348,7 @@ static int call_undef_hook(struct pt_regs *regs) fn = hook->fn; raw_spin_unlock_irqrestore(&undef_lock, flags); -exit: + return fn ? fn(regs, instr) : 1; } @@ -393,13 +400,19 @@ void arm64_notify_segfault(unsigned long addr) void do_el0_undef(struct pt_regs *regs, unsigned long esr) { + u32 insn; + /* check for AArch32 breakpoint instructions */ if (!aarch32_break_handler(regs)) return; - if (call_undef_hook(regs) == 0) + if (user_insn_read(regs, &insn)) + goto out_err; + + if (call_undef_hook(regs, insn) == 0) return; +out_err: force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0); } -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 5aa232345e4d18a40b3e0590c04e2f931903d46a category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit f5962add74b61f8ae31c6311f75ca35d7e1d2d8f upstream. On CPUs without FEAT_IDST, ID register emulation is slower than it needs to be, as all threads contend for the same lock to perform the emulation. This patch reworks the emulation to avoid this unnecessary contention. On CPUs with FEAT_IDST (which is mandatory from ARMv8.4 onwards), EL0 accesses to ID registers result in a SYS trap, and emulation of these is handled with a sys64_hook. These hooks are statically allocated, and no locking is required to iterate through the hooks and perform the emulation, allowing emulation to occur in parallel with no contention. On CPUs without FEAT_IDST, EL0 accesses to ID registers result in an UNDEFINED exception, and emulation of these accesses is handled with an undef_hook. When an EL0 MRS instruction is trapped to EL1, the kernel finds the relevant handler by iterating through all of the undef_hooks, requiring undef_lock to be held during this lookup. This locking is only required to safely traverse the list of undef_hooks (as it can be concurrently modified), and the actual emulation of the MRS does not require any mutual exclusion. This locking is an unfortunate bottleneck, especially given that MRS emulation is enabled unconditionally and is never disabled. This patch reworks the non-FEAT_IDST MRS emulation logic so that it can be invoked directly from do_el0_undef(). This removes the bottleneck, allowing MRS traps to be handled entirely in parallel, and is a stepping stone to making all of the undef_hooks lock-free. I've tested this in a 64-vCPU VM on a 64-CPU ThunderX2 host, with a benchmark which spawns a number of threads which each try to read ID_AA64ISAR0_EL1 1000000 times. This is vastly more contention than will ever be seen in realistic usage, but clearly demonstrates the removal of the bottleneck: | Threads || Time (seconds) | | || Before || After | | || Real | System || Real | System | |---------++--------+---------++--------+---------| | 1 || 0.29 | 0.20 || 0.24 | 0.12 | | 2 || 0.35 | 0.51 || 0.23 | 0.27 | | 4 || 1.08 | 3.87 || 0.24 | 0.56 | | 8 || 4.31 | 33.60 || 0.24 | 1.11 | | 16 || 9.47 | 149.39 || 0.23 | 2.15 | | 32 || 19.07 | 605.27 || 0.24 | 4.38 | | 64 || 65.40 | 3609.09 || 0.33 | 11.27 | Aside from the speedup, there should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-6-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: arch/arm64/include/asm/cpufeature.h Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/cpufeature.h | 3 ++- arch/arm64/kernel/cpufeature.c | 23 +++++------------------ arch/arm64/kernel/traps.c | 3 +++ 3 files changed, 10 insertions(+), 19 deletions(-) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 44c856df8848..c06cb3d211f6 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -764,7 +764,8 @@ static inline bool system_supports_tlb_range(void) cpus_have_const_cap(ARM64_HAS_TLB_RANGE); } -extern int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); +int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); +bool try_emulate_mrs(struct pt_regs *regs, u32 isn); static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange) { diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index d096942b57d6..28e7271c26a3 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -2948,35 +2948,22 @@ int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt) return rc; } -static int emulate_mrs(struct pt_regs *regs, u32 insn) +bool try_emulate_mrs(struct pt_regs *regs, u32 insn) { u32 sys_reg, rt; + if (compat_user_mode(regs) || !aarch64_insn_is_mrs(insn)) + return false; + /* * sys_reg values are defined as used in mrs/msr instruction. * shift the imm value to get the encoding. */ sys_reg = (u32)aarch64_insn_decode_immediate(AARCH64_INSN_IMM_16, insn) << 5; rt = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RT, insn); - return do_emulate_mrs(regs, sys_reg, rt); + return do_emulate_mrs(regs, sys_reg, rt) == 0; } -static struct undef_hook mrs_hook = { - .instr_mask = 0xfff00000, - .instr_val = 0xd5300000, - .pstate_mask = PSR_AA32_MODE_MASK, - .pstate_val = PSR_MODE_EL0t, - .fn = emulate_mrs, -}; - -static int __init enable_mrs_emulation(void) -{ - register_undef_hook(&mrs_hook); - return 0; -} - -core_initcall(enable_mrs_emulation); - ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) { diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 2ee92345a703..ba00c87840e2 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -409,6 +409,9 @@ void do_el0_undef(struct pt_regs *regs, unsigned long esr) if (user_insn_read(regs, &insn)) goto out_err; + if (try_emulate_mrs(regs, insn)) + return; + if (call_undef_hook(regs, insn) == 0) return; -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 2202536144bc37b6db8c6ebad09079108441e0c7 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit b4453cc8a7ebbd45436a8cd3ffeaa069ceac146f upstream. The code for emulating deprecated instructions has two related structures: struct insn_emulation_ops and struct insn_emulation, where each struct insn_emulation_ops is associated 1-1 with a struct insn_emulation. It would be simpler to combine the two into a single structure, removing the need for (unconditional) dynamic allocation at boot time, and simplifying some runtime pointer chasing. This patch merges the two structures together. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-7-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/kernel/armv8_deprecated.c | 76 ++++++++++++---------------- 1 file changed, 33 insertions(+), 43 deletions(-) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 4a0ba2800e45..36cc6cf3e2d2 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -41,16 +41,12 @@ enum legacy_insn_status { INSN_OBSOLETE, }; -struct insn_emulation_ops { - const char *name; - enum legacy_insn_status status; - struct undef_hook *hooks; - int (*set_hw_mode)(bool enable); -}; - struct insn_emulation { - struct list_head node; - struct insn_emulation_ops *ops; + const char *name; + struct list_head node; + enum legacy_insn_status status; + struct undef_hook *hooks; + int (*set_hw_mode)(bool enable); int current_mode; int min; int max; @@ -61,48 +57,48 @@ static int nr_insn_emulated __initdata; static DEFINE_RAW_SPINLOCK(insn_emulation_lock); static DEFINE_MUTEX(insn_emulation_mutex); -static void register_emulation_hooks(struct insn_emulation_ops *ops) +static void register_emulation_hooks(struct insn_emulation *insn) { struct undef_hook *hook; - BUG_ON(!ops->hooks); + BUG_ON(!insn->hooks); - for (hook = ops->hooks; hook->instr_mask; hook++) + for (hook = insn->hooks; hook->instr_mask; hook++) register_undef_hook(hook); - pr_notice("Registered %s emulation handler\n", ops->name); + pr_notice("Registered %s emulation handler\n", insn->name); } -static void remove_emulation_hooks(struct insn_emulation_ops *ops) +static void remove_emulation_hooks(struct insn_emulation *insn) { struct undef_hook *hook; - BUG_ON(!ops->hooks); + BUG_ON(!insn->hooks); - for (hook = ops->hooks; hook->instr_mask; hook++) + for (hook = insn->hooks; hook->instr_mask; hook++) unregister_undef_hook(hook); - pr_notice("Removed %s emulation handler\n", ops->name); + pr_notice("Removed %s emulation handler\n", insn->name); } static void enable_insn_hw_mode(void *data) { struct insn_emulation *insn = (struct insn_emulation *)data; - if (insn->ops->set_hw_mode) - insn->ops->set_hw_mode(true); + if (insn->set_hw_mode) + insn->set_hw_mode(true); } static void disable_insn_hw_mode(void *data) { struct insn_emulation *insn = (struct insn_emulation *)data; - if (insn->ops->set_hw_mode) - insn->ops->set_hw_mode(false); + if (insn->set_hw_mode) + insn->set_hw_mode(false); } /* Run set_hw_mode(mode) on all active CPUs */ static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable) { - if (!insn->ops->set_hw_mode) + if (!insn->set_hw_mode) return -EINVAL; if (enable) on_each_cpu(enable_insn_hw_mode, (void *)insn, true); @@ -126,9 +122,9 @@ static int run_all_insn_set_hw_mode(unsigned int cpu) raw_spin_lock_irqsave(&insn_emulation_lock, flags); list_for_each_entry(insn, &insn_emulation, node) { bool enable = (insn->current_mode == INSN_HW); - if (insn->ops->set_hw_mode && insn->ops->set_hw_mode(enable)) { + if (insn->set_hw_mode && insn->set_hw_mode(enable)) { pr_warn("CPU[%u] cannot support the emulation of %s", - cpu, insn->ops->name); + cpu, insn->name); rc = -EINVAL; } } @@ -145,11 +141,11 @@ static int update_insn_emulation_mode(struct insn_emulation *insn, case INSN_UNDEF: /* Nothing to be done */ break; case INSN_EMULATE: - remove_emulation_hooks(insn->ops); + remove_emulation_hooks(insn); break; case INSN_HW: if (!run_all_cpu_set_hw_mode(insn, false)) - pr_notice("Disabled %s support\n", insn->ops->name); + pr_notice("Disabled %s support\n", insn->name); break; } @@ -157,31 +153,25 @@ static int update_insn_emulation_mode(struct insn_emulation *insn, case INSN_UNDEF: break; case INSN_EMULATE: - register_emulation_hooks(insn->ops); + register_emulation_hooks(insn); break; case INSN_HW: ret = run_all_cpu_set_hw_mode(insn, true); if (!ret) - pr_notice("Enabled %s support\n", insn->ops->name); + pr_notice("Enabled %s support\n", insn->name); break; } return ret; } -static void __init register_insn_emulation(struct insn_emulation_ops *ops) +static void __init register_insn_emulation(struct insn_emulation *insn) { unsigned long flags; - struct insn_emulation *insn; - - insn = kzalloc(sizeof(*insn), GFP_KERNEL); - if (!insn) - return; - insn->ops = ops; insn->min = INSN_UNDEF; - switch (ops->status) { + switch (insn->status) { case INSN_DEPRECATED: insn->current_mode = INSN_EMULATE; /* Disable the HW mode if it was turned on at early boot time */ @@ -247,7 +237,7 @@ static void __init register_insn_emulation_sysctl(void) sysctl->mode = 0644; sysctl->maxlen = sizeof(int); - sysctl->procname = insn->ops->name; + sysctl->procname = insn->name; sysctl->data = &insn->current_mode; sysctl->extra1 = &insn->min; sysctl->extra2 = &insn->max; @@ -451,7 +441,7 @@ static struct undef_hook swp_hooks[] = { { } }; -static struct insn_emulation_ops swp_ops = { +static struct insn_emulation insn_swp = { .name = "swp", .status = INSN_OBSOLETE, .hooks = swp_hooks, @@ -538,7 +528,7 @@ static struct undef_hook cp15_barrier_hooks[] = { { } }; -static struct insn_emulation_ops cp15_barrier_ops = { +static struct insn_emulation insn_cp15_barrier = { .name = "cp15_barrier", .status = INSN_DEPRECATED, .hooks = cp15_barrier_hooks, @@ -611,7 +601,7 @@ static struct undef_hook setend_hooks[] = { {} }; -static struct insn_emulation_ops setend_ops = { +static struct insn_emulation insn_setend = { .name = "setend", .status = INSN_DEPRECATED, .hooks = setend_hooks, @@ -625,14 +615,14 @@ static struct insn_emulation_ops setend_ops = { static int __init armv8_deprecated_init(void) { if (IS_ENABLED(CONFIG_SWP_EMULATION)) - register_insn_emulation(&swp_ops); + register_insn_emulation(&insn_swp); if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION)) - register_insn_emulation(&cp15_barrier_ops); + register_insn_emulation(&insn_cp15_barrier); if (IS_ENABLED(CONFIG_SETEND_EMULATION)) { if (system_supports_mixed_endian_el0()) - register_insn_emulation(&setend_ops); + register_insn_emulation(&insn_setend); else pr_info("setend instruction emulation is not supported on this system\n"); } -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 0b6a7a9f6d944682237bd61bce7f590ebda6e716 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit 25eeac0cfe7c97ade1be07340e11e7143aab57a6 upstream. Subsequent patches will rework the logic in armv8_deprecated.c. In preparation for subsequent changes, this patch moves the emulation logic earlier in the file, and moves the infrastructure later in the file. This will make subsequent diffs simpler and easier to read. This is purely a move. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-8-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/kernel/armv8_deprecated.c | 394 +++++++++++++-------------- 1 file changed, 197 insertions(+), 197 deletions(-) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 36cc6cf3e2d2..5efc14807fb5 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -52,203 +52,6 @@ struct insn_emulation { int max; }; -static LIST_HEAD(insn_emulation); -static int nr_insn_emulated __initdata; -static DEFINE_RAW_SPINLOCK(insn_emulation_lock); -static DEFINE_MUTEX(insn_emulation_mutex); - -static void register_emulation_hooks(struct insn_emulation *insn) -{ - struct undef_hook *hook; - - BUG_ON(!insn->hooks); - - for (hook = insn->hooks; hook->instr_mask; hook++) - register_undef_hook(hook); - - pr_notice("Registered %s emulation handler\n", insn->name); -} - -static void remove_emulation_hooks(struct insn_emulation *insn) -{ - struct undef_hook *hook; - - BUG_ON(!insn->hooks); - - for (hook = insn->hooks; hook->instr_mask; hook++) - unregister_undef_hook(hook); - - pr_notice("Removed %s emulation handler\n", insn->name); -} - -static void enable_insn_hw_mode(void *data) -{ - struct insn_emulation *insn = (struct insn_emulation *)data; - if (insn->set_hw_mode) - insn->set_hw_mode(true); -} - -static void disable_insn_hw_mode(void *data) -{ - struct insn_emulation *insn = (struct insn_emulation *)data; - if (insn->set_hw_mode) - insn->set_hw_mode(false); -} - -/* Run set_hw_mode(mode) on all active CPUs */ -static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable) -{ - if (!insn->set_hw_mode) - return -EINVAL; - if (enable) - on_each_cpu(enable_insn_hw_mode, (void *)insn, true); - else - on_each_cpu(disable_insn_hw_mode, (void *)insn, true); - return 0; -} - -/* - * Run set_hw_mode for all insns on a starting CPU. - * Returns: - * 0 - If all the hooks ran successfully. - * -EINVAL - At least one hook is not supported by the CPU. - */ -static int run_all_insn_set_hw_mode(unsigned int cpu) -{ - int rc = 0; - unsigned long flags; - struct insn_emulation *insn; - - raw_spin_lock_irqsave(&insn_emulation_lock, flags); - list_for_each_entry(insn, &insn_emulation, node) { - bool enable = (insn->current_mode == INSN_HW); - if (insn->set_hw_mode && insn->set_hw_mode(enable)) { - pr_warn("CPU[%u] cannot support the emulation of %s", - cpu, insn->name); - rc = -EINVAL; - } - } - raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); - return rc; -} - -static int update_insn_emulation_mode(struct insn_emulation *insn, - enum insn_emulation_mode prev) -{ - int ret = 0; - - switch (prev) { - case INSN_UNDEF: /* Nothing to be done */ - break; - case INSN_EMULATE: - remove_emulation_hooks(insn); - break; - case INSN_HW: - if (!run_all_cpu_set_hw_mode(insn, false)) - pr_notice("Disabled %s support\n", insn->name); - break; - } - - switch (insn->current_mode) { - case INSN_UNDEF: - break; - case INSN_EMULATE: - register_emulation_hooks(insn); - break; - case INSN_HW: - ret = run_all_cpu_set_hw_mode(insn, true); - if (!ret) - pr_notice("Enabled %s support\n", insn->name); - break; - } - - return ret; -} - -static void __init register_insn_emulation(struct insn_emulation *insn) -{ - unsigned long flags; - - insn->min = INSN_UNDEF; - - switch (insn->status) { - case INSN_DEPRECATED: - insn->current_mode = INSN_EMULATE; - /* Disable the HW mode if it was turned on at early boot time */ - run_all_cpu_set_hw_mode(insn, false); - insn->max = INSN_HW; - break; - case INSN_OBSOLETE: - insn->current_mode = INSN_UNDEF; - insn->max = INSN_EMULATE; - break; - } - - raw_spin_lock_irqsave(&insn_emulation_lock, flags); - list_add(&insn->node, &insn_emulation); - nr_insn_emulated++; - raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); - - /* Register any handlers if required */ - update_insn_emulation_mode(insn, INSN_UNDEF); -} - -static int emulation_proc_handler(struct ctl_table *table, int write, - void *buffer, size_t *lenp, - loff_t *ppos) -{ - int ret = 0; - struct insn_emulation *insn = container_of(table->data, struct insn_emulation, current_mode); - enum insn_emulation_mode prev_mode = insn->current_mode; - - mutex_lock(&insn_emulation_mutex); - ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); - - if (ret || !write || prev_mode == insn->current_mode) - goto ret; - - ret = update_insn_emulation_mode(insn, prev_mode); - if (ret) { - /* Mode change failed, revert to previous mode. */ - insn->current_mode = prev_mode; - update_insn_emulation_mode(insn, INSN_UNDEF); - } -ret: - mutex_unlock(&insn_emulation_mutex); - return ret; -} - -static void __init register_insn_emulation_sysctl(void) -{ - unsigned long flags; - int i = 0; - struct insn_emulation *insn; - struct ctl_table *insns_sysctl, *sysctl; - - insns_sysctl = kcalloc(nr_insn_emulated + 1, sizeof(*sysctl), - GFP_KERNEL); - if (!insns_sysctl) - return; - - raw_spin_lock_irqsave(&insn_emulation_lock, flags); - list_for_each_entry(insn, &insn_emulation, node) { - sysctl = &insns_sysctl[i]; - - sysctl->mode = 0644; - sysctl->maxlen = sizeof(int); - - sysctl->procname = insn->name; - sysctl->data = &insn->current_mode; - sysctl->extra1 = &insn->min; - sysctl->extra2 = &insn->max; - sysctl->proc_handler = emulation_proc_handler; - i++; - } - raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); - - register_sysctl("abi", insns_sysctl); -} - /* * Implement emulation of the SWP/SWPB instructions using load-exclusive and * store-exclusive. @@ -608,6 +411,203 @@ static struct insn_emulation insn_setend = { .set_hw_mode = setend_set_hw_mode, }; +static LIST_HEAD(insn_emulation); +static int nr_insn_emulated __initdata; +static DEFINE_RAW_SPINLOCK(insn_emulation_lock); +static DEFINE_MUTEX(insn_emulation_mutex); + +static void register_emulation_hooks(struct insn_emulation *insn) +{ + struct undef_hook *hook; + + BUG_ON(!insn->hooks); + + for (hook = insn->hooks; hook->instr_mask; hook++) + register_undef_hook(hook); + + pr_notice("Registered %s emulation handler\n", insn->name); +} + +static void remove_emulation_hooks(struct insn_emulation *insn) +{ + struct undef_hook *hook; + + BUG_ON(!insn->hooks); + + for (hook = insn->hooks; hook->instr_mask; hook++) + unregister_undef_hook(hook); + + pr_notice("Removed %s emulation handler\n", insn->name); +} + +static void enable_insn_hw_mode(void *data) +{ + struct insn_emulation *insn = (struct insn_emulation *)data; + if (insn->set_hw_mode) + insn->set_hw_mode(true); +} + +static void disable_insn_hw_mode(void *data) +{ + struct insn_emulation *insn = (struct insn_emulation *)data; + if (insn->set_hw_mode) + insn->set_hw_mode(false); +} + +/* Run set_hw_mode(mode) on all active CPUs */ +static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable) +{ + if (!insn->set_hw_mode) + return -EINVAL; + if (enable) + on_each_cpu(enable_insn_hw_mode, (void *)insn, true); + else + on_each_cpu(disable_insn_hw_mode, (void *)insn, true); + return 0; +} + +/* + * Run set_hw_mode for all insns on a starting CPU. + * Returns: + * 0 - If all the hooks ran successfully. + * -EINVAL - At least one hook is not supported by the CPU. + */ +static int run_all_insn_set_hw_mode(unsigned int cpu) +{ + int rc = 0; + unsigned long flags; + struct insn_emulation *insn; + + raw_spin_lock_irqsave(&insn_emulation_lock, flags); + list_for_each_entry(insn, &insn_emulation, node) { + bool enable = (insn->current_mode == INSN_HW); + if (insn->set_hw_mode && insn->set_hw_mode(enable)) { + pr_warn("CPU[%u] cannot support the emulation of %s", + cpu, insn->name); + rc = -EINVAL; + } + } + raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); + return rc; +} + +static int update_insn_emulation_mode(struct insn_emulation *insn, + enum insn_emulation_mode prev) +{ + int ret = 0; + + switch (prev) { + case INSN_UNDEF: /* Nothing to be done */ + break; + case INSN_EMULATE: + remove_emulation_hooks(insn); + break; + case INSN_HW: + if (!run_all_cpu_set_hw_mode(insn, false)) + pr_notice("Disabled %s support\n", insn->name); + break; + } + + switch (insn->current_mode) { + case INSN_UNDEF: + break; + case INSN_EMULATE: + register_emulation_hooks(insn); + break; + case INSN_HW: + ret = run_all_cpu_set_hw_mode(insn, true); + if (!ret) + pr_notice("Enabled %s support\n", insn->name); + break; + } + + return ret; +} + +static void __init register_insn_emulation(struct insn_emulation *insn) +{ + unsigned long flags; + + insn->min = INSN_UNDEF; + + switch (insn->status) { + case INSN_DEPRECATED: + insn->current_mode = INSN_EMULATE; + /* Disable the HW mode if it was turned on at early boot time */ + run_all_cpu_set_hw_mode(insn, false); + insn->max = INSN_HW; + break; + case INSN_OBSOLETE: + insn->current_mode = INSN_UNDEF; + insn->max = INSN_EMULATE; + break; + } + + raw_spin_lock_irqsave(&insn_emulation_lock, flags); + list_add(&insn->node, &insn_emulation); + nr_insn_emulated++; + raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); + + /* Register any handlers if required */ + update_insn_emulation_mode(insn, INSN_UNDEF); +} + +static int emulation_proc_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret = 0; + struct insn_emulation *insn = container_of(table->data, struct insn_emulation, current_mode); + enum insn_emulation_mode prev_mode = insn->current_mode; + + mutex_lock(&insn_emulation_mutex); + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + + if (ret || !write || prev_mode == insn->current_mode) + goto ret; + + ret = update_insn_emulation_mode(insn, prev_mode); + if (ret) { + /* Mode change failed, revert to previous mode. */ + insn->current_mode = prev_mode; + update_insn_emulation_mode(insn, INSN_UNDEF); + } +ret: + mutex_unlock(&insn_emulation_mutex); + return ret; +} + +static void __init register_insn_emulation_sysctl(void) +{ + unsigned long flags; + int i = 0; + struct insn_emulation *insn; + struct ctl_table *insns_sysctl, *sysctl; + + insns_sysctl = kcalloc(nr_insn_emulated + 1, sizeof(*sysctl), + GFP_KERNEL); + if (!insns_sysctl) + return; + + raw_spin_lock_irqsave(&insn_emulation_lock, flags); + list_for_each_entry(insn, &insn_emulation, node) { + sysctl = &insns_sysctl[i]; + + sysctl->mode = 0644; + sysctl->maxlen = sizeof(int); + + sysctl->procname = insn->name; + sysctl->data = &insn->current_mode; + sysctl->extra1 = &insn->min; + sysctl->extra2 = &insn->max; + sysctl->proc_handler = emulation_proc_handler; + i++; + } + raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); + + register_sysctl("abi", insns_sysctl); +} + /* * Invoked as core_initcall, which guarantees that the instruction * emulation is ready for userspace. -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit 45a26d2a5394a29844ad530ef7a4ff3a81de88a3 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit 0c5f416219da3795dc8b33e5bb7865a6b3c4e55c upstream. Subsequent patches will rework the logic in armv8_deprecated.c. In preparation for subsequent changes, this patch moves some shared logic earlier in the file. This will make subsequent diffs simpler and easier to read. At the same time, drop the `__kprobes` annotation from aarch32_check_condition(), as this is only used for traps from compat userspace, and has no risk of recursion within kprobes. As this is the last kprobes annotation in armve8_deprecated.c, we no longer need to include <asm/kprobes.h>. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-9-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/kernel/armv8_deprecated.c | 39 ++++++++++++++-------------- 1 file changed, 19 insertions(+), 20 deletions(-) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 5efc14807fb5..13d5ad2aa821 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -17,7 +17,6 @@ #include <asm/sysreg.h> #include <asm/system_misc.h> #include <asm/traps.h> -#include <asm/kprobes.h> #define CREATE_TRACE_POINTS #include "trace-events-emulation.h" @@ -52,6 +51,25 @@ struct insn_emulation { int max; }; +#define ARM_OPCODE_CONDTEST_FAIL 0 +#define ARM_OPCODE_CONDTEST_PASS 1 +#define ARM_OPCODE_CONDTEST_UNCOND 2 + +#define ARM_OPCODE_CONDITION_UNCOND 0xf + +static unsigned int aarch32_check_condition(u32 opcode, u32 psr) +{ + u32 cc_bits = opcode >> 28; + + if (cc_bits != ARM_OPCODE_CONDITION_UNCOND) { + if ((*aarch32_opcode_cond_checks[cc_bits])(psr)) + return ARM_OPCODE_CONDTEST_PASS; + else + return ARM_OPCODE_CONDTEST_FAIL; + } + return ARM_OPCODE_CONDTEST_UNCOND; +} + /* * Implement emulation of the SWP/SWPB instructions using load-exclusive and * store-exclusive. @@ -138,25 +156,6 @@ static int emulate_swpX(unsigned int address, unsigned int *data, return res; } -#define ARM_OPCODE_CONDTEST_FAIL 0 -#define ARM_OPCODE_CONDTEST_PASS 1 -#define ARM_OPCODE_CONDTEST_UNCOND 2 - -#define ARM_OPCODE_CONDITION_UNCOND 0xf - -static unsigned int __kprobes aarch32_check_condition(u32 opcode, u32 psr) -{ - u32 cc_bits = opcode >> 28; - - if (cc_bits != ARM_OPCODE_CONDITION_UNCOND) { - if ((*aarch32_opcode_cond_checks[cc_bits])(psr)) - return ARM_OPCODE_CONDTEST_PASS; - else - return ARM_OPCODE_CONDTEST_FAIL; - } - return ARM_OPCODE_CONDTEST_UNCOND; -} - /* * swp_handler logs the id of calling process, dissects the instruction, sanity * checks the memory location, calls emulate_swpX for the actual operation and -- 2.34.1
From: Mark Rutland <mark.rutland@arm.com> stable inclusion from stable-v5.10.199 commit da7603cedb7da6e2e7150054e838079e3fbf65a9 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit 124c49b1b5d947b7180c5d6cbb09ddf76ea45ea2 upstream. Support for deprecated instructions can be enabled or disabled at runtime. To handle this, the code in armv8_deprecated.c registers and unregisters undef_hooks, and makes cross CPU calls to configure HW support. This is rather complicated, and the synchronization required to make this safe ends up serializing the handling of instructions which have been trapped. This patch simplifies the deprecated instruction handling by removing the dynamic registration and unregistration, and changing the trap handling code to determine whether a handler should be invoked. This removes the need for dynamic list management, and simplifies the locking requirements, making it possible to handle trapped instructions entirely in parallel. Where changing the emulation state requires a cross-call, this is serialized by locally disabling interrupts, ensuring that the CPU is not left in an inconsistent state. To simplify sysctl management, each insn_emulation is given a separate sysctl table, permitting these to be registered separately. The core sysctl code will iterate over all of these when walking sysfs. I've tested this with userspace programs which use each of the deprecated instructions, and I've concurrently modified the support level for each of the features back-and-forth between HW and emulated to check that there are no spurious SIGILLs sent to userspace when the support level is changed. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20221019144123.612388-10-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: arch/arm64/kernel/armv8_deprecated.c Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/include/asm/traps.h | 19 +- arch/arm64/kernel/armv8_deprecated.c | 287 ++++++++++++++------------- arch/arm64/kernel/traps.c | 40 +--- 3 files changed, 154 insertions(+), 192 deletions(-) diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h index d96dc2c7c09d..ca8f19956b92 100644 --- a/arch/arm64/include/asm/traps.h +++ b/arch/arm64/include/asm/traps.h @@ -13,17 +13,16 @@ struct pt_regs; -struct undef_hook { - struct list_head node; - u32 instr_mask; - u32 instr_val; - u64 pstate_mask; - u64 pstate_val; - int (*fn)(struct pt_regs *regs, u32 instr); -}; +#ifdef CONFIG_ARMV8_DEPRECATED +bool try_emulate_armv8_deprecated(struct pt_regs *regs, u32 insn); +#else +static inline bool +try_emulate_armv8_deprecated(struct pt_regs *regs, u32 insn) +{ + return false; +} +#endif /* CONFIG_ARMV8_DEPRECATED */ -void register_undef_hook(struct undef_hook *hook); -void unregister_undef_hook(struct undef_hook *hook); void force_signal_inject(int signal, int code, unsigned long address, unsigned int err); void arm64_notify_segfault(unsigned long addr); void arm64_force_sig_fault(int signo, int code, void __user *addr, const char *str); diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 13d5ad2aa821..acd72a3c4c8c 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -38,17 +38,24 @@ enum insn_emulation_mode { enum legacy_insn_status { INSN_DEPRECATED, INSN_OBSOLETE, + INSN_UNAVAILABLE, }; struct insn_emulation { const char *name; - struct list_head node; enum legacy_insn_status status; - struct undef_hook *hooks; + bool (*try_emulate)(struct pt_regs *regs, + u32 insn); int (*set_hw_mode)(bool enable); + int current_mode; int min; int max; + + /* + * sysctl for this emulation + a sentinal entry. + */ + struct ctl_table sysctl[2]; }; #define ARM_OPCODE_CONDTEST_FAIL 0 @@ -70,6 +77,7 @@ static unsigned int aarch32_check_condition(u32 opcode, u32 psr) return ARM_OPCODE_CONDTEST_UNCOND; } +#ifdef CONFIG_SWP_EMULATION /* * Implement emulation of the SWP/SWPB instructions using load-exclusive and * store-exclusive. @@ -228,28 +236,27 @@ static int swp_handler(struct pt_regs *regs, u32 instr) return 0; } -/* - * Only emulate SWP/SWPB executed in ARM state/User mode. - * The kernel must be SWP free and SWP{B} does not exist in Thumb. - */ -static struct undef_hook swp_hooks[] = { - { - .instr_mask = 0x0fb00ff0, - .instr_val = 0x01000090, - .pstate_mask = PSR_AA32_MODE_MASK, - .pstate_val = PSR_AA32_MODE_USR, - .fn = swp_handler - }, - { } -}; +static bool try_emulate_swp(struct pt_regs *regs, u32 insn) +{ + /* SWP{B} only exists in ARM state and does not exist in Thumb */ + if (!a32_user_mode(regs) || a32_thumb_mode(regs)) + return false; + + if ((insn & 0x0fb00ff0) != 0x01000090) + return false; + + return swp_handler(regs, insn) == 0; +} static struct insn_emulation insn_swp = { .name = "swp", .status = INSN_OBSOLETE, - .hooks = swp_hooks, + .try_emulate = try_emulate_swp, .set_hw_mode = NULL, }; +#endif /* CONFIG_SWP_EMULATION */ +#ifdef CONFIG_CP15_BARRIER_EMULATION static int cp15barrier_handler(struct pt_regs *regs, u32 instr) { perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc); @@ -312,31 +319,29 @@ static int cp15_barrier_set_hw_mode(bool enable) return 0; } -static struct undef_hook cp15_barrier_hooks[] = { - { - .instr_mask = 0x0fff0fdf, - .instr_val = 0x0e070f9a, - .pstate_mask = PSR_AA32_MODE_MASK, - .pstate_val = PSR_AA32_MODE_USR, - .fn = cp15barrier_handler, - }, - { - .instr_mask = 0x0fff0fff, - .instr_val = 0x0e070f95, - .pstate_mask = PSR_AA32_MODE_MASK, - .pstate_val = PSR_AA32_MODE_USR, - .fn = cp15barrier_handler, - }, - { } -}; +static bool try_emulate_cp15_barrier(struct pt_regs *regs, u32 insn) +{ + if (!a32_user_mode(regs) || a32_thumb_mode(regs)) + return false; + + if ((insn & 0x0fff0fdf) == 0x0e070f9a) + return cp15barrier_handler(regs, insn) == 0; + + if ((insn & 0x0fff0fff) == 0x0e070f95) + return cp15barrier_handler(regs, insn) == 0; + + return false; +} static struct insn_emulation insn_cp15_barrier = { .name = "cp15_barrier", .status = INSN_DEPRECATED, - .hooks = cp15_barrier_hooks, + .try_emulate = try_emulate_cp15_barrier, .set_hw_mode = cp15_barrier_set_hw_mode, }; +#endif /* CONFIG_CP15_BARRIER_EMULATION */ +#ifdef CONFIG_SETEND_EMULATION static int setend_set_hw_mode(bool enable) { if (!cpu_supports_mixed_endian_el0()) @@ -384,61 +389,41 @@ static int t16_setend_handler(struct pt_regs *regs, u32 instr) return rc; } -static struct undef_hook setend_hooks[] = { - { - .instr_mask = 0xfffffdff, - .instr_val = 0xf1010000, - .pstate_mask = PSR_AA32_MODE_MASK, - .pstate_val = PSR_AA32_MODE_USR, - .fn = a32_setend_handler, - }, - { - /* Thumb mode */ - .instr_mask = 0xfffffff7, - .instr_val = 0x0000b650, - .pstate_mask = (PSR_AA32_T_BIT | PSR_AA32_MODE_MASK), - .pstate_val = (PSR_AA32_T_BIT | PSR_AA32_MODE_USR), - .fn = t16_setend_handler, - }, - {} -}; +static bool try_emulate_setend(struct pt_regs *regs, u32 insn) +{ + if (a32_thumb_mode(regs) && + (insn & 0xfffffff7) == 0x0000b650) + return t16_setend_handler(regs, insn) == 0; + + if (a32_user_mode(regs) && + (insn & 0xfffffdff) == 0xf1010000) + return a32_setend_handler(regs, insn) == 0; + + return false; +} static struct insn_emulation insn_setend = { .name = "setend", .status = INSN_DEPRECATED, - .hooks = setend_hooks, + .try_emulate = try_emulate_setend, .set_hw_mode = setend_set_hw_mode, }; +#endif /* CONFIG_SETEND_EMULATION */ + +static struct insn_emulation *insn_emulations[] = { +#ifdef CONFIG_SWP_EMULATION + &insn_swp, +#endif +#ifdef CONFIG_CP15_BARRIER_EMULATION + &insn_cp15_barrier, +#endif +#ifdef CONFIG_SETEND_EMULATION + &insn_setend, +#endif +}; -static LIST_HEAD(insn_emulation); -static int nr_insn_emulated __initdata; -static DEFINE_RAW_SPINLOCK(insn_emulation_lock); static DEFINE_MUTEX(insn_emulation_mutex); -static void register_emulation_hooks(struct insn_emulation *insn) -{ - struct undef_hook *hook; - - BUG_ON(!insn->hooks); - - for (hook = insn->hooks; hook->instr_mask; hook++) - register_undef_hook(hook); - - pr_notice("Registered %s emulation handler\n", insn->name); -} - -static void remove_emulation_hooks(struct insn_emulation *insn) -{ - struct undef_hook *hook; - - BUG_ON(!insn->hooks); - - for (hook = insn->hooks; hook->instr_mask; hook++) - unregister_undef_hook(hook); - - pr_notice("Removed %s emulation handler\n", insn->name); -} - static void enable_insn_hw_mode(void *data) { struct insn_emulation *insn = (struct insn_emulation *)data; @@ -473,20 +458,27 @@ static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable) */ static int run_all_insn_set_hw_mode(unsigned int cpu) { + int i; int rc = 0; unsigned long flags; - struct insn_emulation *insn; - raw_spin_lock_irqsave(&insn_emulation_lock, flags); - list_for_each_entry(insn, &insn_emulation, node) { - bool enable = (insn->current_mode == INSN_HW); + /* + * Disable IRQs to serialize against an IPI from + * run_all_cpu_set_hw_mode(), ensuring the HW is programmed to the most + * recent enablement state if the two race with one another. + */ + local_irq_save(flags); + for (i = 0; i < ARRAY_SIZE(insn_emulations); i++) { + struct insn_emulation *insn = insn_emulations[i]; + bool enable = READ_ONCE(insn->current_mode) == INSN_HW; if (insn->set_hw_mode && insn->set_hw_mode(enable)) { pr_warn("CPU[%u] cannot support the emulation of %s", cpu, insn->name); rc = -EINVAL; } } - raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); + local_irq_restore(flags); + return rc; } @@ -499,7 +491,6 @@ static int update_insn_emulation_mode(struct insn_emulation *insn, case INSN_UNDEF: /* Nothing to be done */ break; case INSN_EMULATE: - remove_emulation_hooks(insn); break; case INSN_HW: if (!run_all_cpu_set_hw_mode(insn, false)) @@ -511,7 +502,6 @@ static int update_insn_emulation_mode(struct insn_emulation *insn, case INSN_UNDEF: break; case INSN_EMULATE: - register_emulation_hooks(insn); break; case INSN_HW: ret = run_all_cpu_set_hw_mode(insn, true); @@ -523,34 +513,6 @@ static int update_insn_emulation_mode(struct insn_emulation *insn, return ret; } -static void __init register_insn_emulation(struct insn_emulation *insn) -{ - unsigned long flags; - - insn->min = INSN_UNDEF; - - switch (insn->status) { - case INSN_DEPRECATED: - insn->current_mode = INSN_EMULATE; - /* Disable the HW mode if it was turned on at early boot time */ - run_all_cpu_set_hw_mode(insn, false); - insn->max = INSN_HW; - break; - case INSN_OBSOLETE: - insn->current_mode = INSN_UNDEF; - insn->max = INSN_EMULATE; - break; - } - - raw_spin_lock_irqsave(&insn_emulation_lock, flags); - list_add(&insn->node, &insn_emulation); - nr_insn_emulated++; - raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); - - /* Register any handlers if required */ - update_insn_emulation_mode(insn, INSN_UNDEF); -} - static int emulation_proc_handler(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) @@ -568,7 +530,7 @@ static int emulation_proc_handler(struct ctl_table *table, int write, ret = update_insn_emulation_mode(insn, prev_mode); if (ret) { /* Mode change failed, revert to previous mode. */ - insn->current_mode = prev_mode; + WRITE_ONCE(insn->current_mode, prev_mode); update_insn_emulation_mode(insn, INSN_UNDEF); } ret: @@ -576,21 +538,34 @@ static int emulation_proc_handler(struct ctl_table *table, int write, return ret; } -static void __init register_insn_emulation_sysctl(void) +static void __init register_insn_emulation(struct insn_emulation *insn) { - unsigned long flags; - int i = 0; - struct insn_emulation *insn; - struct ctl_table *insns_sysctl, *sysctl; + struct ctl_table *sysctl; + + insn->min = INSN_UNDEF; + + switch (insn->status) { + case INSN_DEPRECATED: + insn->current_mode = INSN_EMULATE; + /* Disable the HW mode if it was turned on at early boot time */ + run_all_cpu_set_hw_mode(insn, false); + insn->max = INSN_HW; + break; + case INSN_OBSOLETE: + insn->current_mode = INSN_UNDEF; + insn->max = INSN_EMULATE; + break; + case INSN_UNAVAILABLE: + insn->current_mode = INSN_UNDEF; + insn->max = INSN_UNDEF; + break; + } - insns_sysctl = kcalloc(nr_insn_emulated + 1, sizeof(*sysctl), - GFP_KERNEL); - if (!insns_sysctl) - return; + /* Program the HW if required */ + update_insn_emulation_mode(insn, INSN_UNDEF); - raw_spin_lock_irqsave(&insn_emulation_lock, flags); - list_for_each_entry(insn, &insn_emulation, node) { - sysctl = &insns_sysctl[i]; + if (insn->status != INSN_UNAVAILABLE) { + sysctl = &insn->sysctl[0]; sysctl->mode = 0644; sysctl->maxlen = sizeof(int); @@ -600,11 +575,34 @@ static void __init register_insn_emulation_sysctl(void) sysctl->extra1 = &insn->min; sysctl->extra2 = &insn->max; sysctl->proc_handler = emulation_proc_handler; - i++; + + register_sysctl("abi", sysctl); } - raw_spin_unlock_irqrestore(&insn_emulation_lock, flags); +} + +bool try_emulate_armv8_deprecated(struct pt_regs *regs, u32 insn) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(insn_emulations); i++) { + struct insn_emulation *ie = insn_emulations[i]; - register_sysctl("abi", insns_sysctl); + if (ie->status == INSN_UNAVAILABLE) + continue; + + /* + * A trap may race with the mode being changed + * INSN_EMULATE<->INSN_HW. Try to emulate the instruction to + * avoid a spurious UNDEF. + */ + if (READ_ONCE(ie->current_mode) == INSN_UNDEF) + continue; + + if (ie->try_emulate(regs, insn)) + return true; + } + + return false; } /* @@ -613,24 +611,27 @@ static void __init register_insn_emulation_sysctl(void) */ static int __init armv8_deprecated_init(void) { - if (IS_ENABLED(CONFIG_SWP_EMULATION)) - register_insn_emulation(&insn_swp); + int i; - if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION)) - register_insn_emulation(&insn_cp15_barrier); +#ifdef CONFIG_SETEND_EMULATION + if (!system_supports_mixed_endian_el0()) { + insn_setend.status = INSN_UNAVAILABLE; + pr_info("setend instruction emulation is not supported on this system\n"); + } - if (IS_ENABLED(CONFIG_SETEND_EMULATION)) { - if (system_supports_mixed_endian_el0()) - register_insn_emulation(&insn_setend); - else - pr_info("setend instruction emulation is not supported on this system\n"); +#endif + for (i = 0; i < ARRAY_SIZE(insn_emulations); i++) { + struct insn_emulation *ie = insn_emulations[i]; + + if (ie->status == INSN_UNAVAILABLE) + continue; + + register_insn_emulation(ie); } cpuhp_setup_state_nocalls(CPUHP_AP_ARM64_ISNDEP_STARTING, "arm64/isndep:starting", run_all_insn_set_hw_mode, NULL); - register_insn_emulation_sysctl(); - return 0; } diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index ba00c87840e2..cec7064afb01 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -283,27 +283,6 @@ void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size) regs->pstate &= ~PSR_BTYPE_MASK; } -static LIST_HEAD(undef_hook); -static DEFINE_RAW_SPINLOCK(undef_lock); - -void register_undef_hook(struct undef_hook *hook) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&undef_lock, flags); - list_add(&hook->node, &undef_hook); - raw_spin_unlock_irqrestore(&undef_lock, flags); -} - -void unregister_undef_hook(struct undef_hook *hook) -{ - unsigned long flags; - - raw_spin_lock_irqsave(&undef_lock, flags); - list_del(&hook->node); - raw_spin_unlock_irqrestore(&undef_lock, flags); -} - static int user_insn_read(struct pt_regs *regs, u32 *insnp) { u32 instr; @@ -335,23 +314,6 @@ static int user_insn_read(struct pt_regs *regs, u32 *insnp) return 0; } -static int call_undef_hook(struct pt_regs *regs, u32 instr) -{ - struct undef_hook *hook; - unsigned long flags; - int (*fn)(struct pt_regs *regs, u32 instr) = NULL; - - raw_spin_lock_irqsave(&undef_lock, flags); - list_for_each_entry(hook, &undef_hook, node) - if ((instr & hook->instr_mask) == hook->instr_val && - (regs->pstate & hook->pstate_mask) == hook->pstate_val) - fn = hook->fn; - - raw_spin_unlock_irqrestore(&undef_lock, flags); - - return fn ? fn(regs, instr) : 1; -} - void force_signal_inject(int signal, int code, unsigned long address, unsigned int err) { const char *desc; @@ -412,7 +374,7 @@ void do_el0_undef(struct pt_regs *regs, unsigned long esr) if (try_emulate_mrs(regs, insn)) return; - if (call_undef_hook(regs, insn) == 0) + if (try_emulate_armv8_deprecated(regs, insn)) return; out_err: -- 2.34.1
From: Ren Zhijie <renzhijie2@huawei.com> stable inclusion from stable-v5.10.199 commit 489818719a88e129f00719ca301379f7b720788a category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I65RG3?from=project-issue CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------------------------- commit 223d3a0d30b6e9f979f5642e430e1753d3e29f89 upstream. If CONFIG_SWP_EMULATION is not set and CONFIG_CP15_BARRIER_EMULATION is not set, aarch64-linux-gnu complained about unused-function : arch/arm64/kernel/armv8_deprecated.c:67:21: error: ‘aarch32_check_condition’ defined but not used [-Werror=unused-function] static unsigned int aarch32_check_condition(u32 opcode, u32 psr) ^~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors To fix this warning, modify aarch32_check_condition() with __maybe_unused. Fixes: 0c5f416219da ("arm64: armv8_deprecated: move aarch32 helper earlier") Signed-off-by: Ren Zhijie <renzhijie2@huawei.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20221124022429.19024-1-renzhijie2@huawei.com Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/kernel/armv8_deprecated.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index acd72a3c4c8c..637e57a4868e 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -64,7 +64,7 @@ struct insn_emulation { #define ARM_OPCODE_CONDITION_UNCOND 0xf -static unsigned int aarch32_check_condition(u32 opcode, u32 psr) +static unsigned int __maybe_unused aarch32_check_condition(u32 opcode, u32 psr) { u32 cc_bits = opcode >> 28; -- 2.34.1
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