From: Alex Sverdlin alexander.sverdlin@nokia.com

stable inclusion from stable-5.10.69 commit f91d25a7c89e2f246a541603430ce2420bab58c5 bugzilla: 182675 https://gitee.com/openeuler/kernel/issues/I4I3ED

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

-------------------------------------------------

commit 79f32b221b18c15a98507b101ef4beb52444cc6f upstream

Teach ftrace_make_call() and ftrace_make_nop() about PLTs. Teach PLT code about FTRACE and all its callbacks. Otherwise the following might happen:

------------[ cut here ]------------ WARNING: CPU: 14 PID: 2265 at .../arch/arm/kernel/insn.c:14 __arm_gen_branch+0x83/0x8c() ... Hardware name: LSI Axxia AXM55XX [<c0314a49>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14) [<c03115e9>] (show_stack) from [<c0519f51>] (dump_stack+0x81/0xa8) [<c0519f51>] (dump_stack) from [<c032185d>] (warn_slowpath_common+0x69/0x90) [<c032185d>] (warn_slowpath_common) from [<c03218f3>] (warn_slowpath_null+0x17/0x1c) [<c03218f3>] (warn_slowpath_null) from [<c03143cf>] (__arm_gen_branch+0x83/0x8c) [<c03143cf>] (__arm_gen_branch) from [<c0314337>] (ftrace_make_nop+0xf/0x24) [<c0314337>] (ftrace_make_nop) from [<c038ebcb>] (ftrace_process_locs+0x27b/0x3e8) [<c038ebcb>] (ftrace_process_locs) from [<c0378d79>] (load_module+0x11e9/0x1a44) [<c0378d79>] (load_module) from [<c037974d>] (SyS_finit_module+0x59/0x84) [<c037974d>] (SyS_finit_module) from [<c030e981>] (ret_fast_syscall+0x1/0x18) ---[ end trace e1b64ced7a89adcc ]--- ------------[ cut here ]------------ WARNING: CPU: 14 PID: 2265 at .../kernel/trace/ftrace.c:1979 ftrace_bug+0x1b1/0x234() ... Hardware name: LSI Axxia AXM55XX [<c0314a49>] (unwind_backtrace) from [<c03115e9>] (show_stack+0x11/0x14) [<c03115e9>] (show_stack) from [<c0519f51>] (dump_stack+0x81/0xa8) [<c0519f51>] (dump_stack) from [<c032185d>] (warn_slowpath_common+0x69/0x90) [<c032185d>] (warn_slowpath_common) from [<c03218f3>] (warn_slowpath_null+0x17/0x1c) [<c03218f3>] (warn_slowpath_null) from [<c038e87d>] (ftrace_bug+0x1b1/0x234) [<c038e87d>] (ftrace_bug) from [<c038ebd5>] (ftrace_process_locs+0x285/0x3e8) [<c038ebd5>] (ftrace_process_locs) from [<c0378d79>] (load_module+0x11e9/0x1a44) [<c0378d79>] (load_module) from [<c037974d>] (SyS_finit_module+0x59/0x84) [<c037974d>] (SyS_finit_module) from [<c030e981>] (ret_fast_syscall+0x1/0x18) ---[ end trace e1b64ced7a89adcd ]--- ftrace failed to modify [<e9ef7006>] 0xe9ef7006 actual: 02:f0:3b:fa ftrace record flags: 0 (0) expected tramp: c0314265

Signed-off-by: Alexander Sverdlin alexander.sverdlin@nokia.com Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Florian Fainelli f.fainelli@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

Conflicts: arch/arm/include/asm/module.h arch/arm/kernel/module-plts.c arch/arm/kernel/ftrace.c

[ hf: To support both the ftrace and livepatch scenarios, roll back some modifications of the commit ee3cc1bededf ("arm/module: Use plt section indices for relocations"). ]

Signed-off-by: Li Huafei lihuafei1@huawei.com Reviewed-by: Yang Jihong yangjihong1@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- arch/arm/include/asm/ftrace.h | 3 ++ arch/arm/include/asm/module.h | 2 + arch/arm/kernel/ftrace.c | 46 ++++++++++++++++---- arch/arm/kernel/module-plts.c | 80 +++++++++++++++++++++++++---------- 4 files changed, 101 insertions(+), 30 deletions(-)

diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h index 48ec1d0337da..a4dbac07e4ef 100644 --- a/arch/arm/include/asm/ftrace.h +++ b/arch/arm/include/asm/ftrace.h @@ -15,6 +15,9 @@ extern void __gnu_mcount_nc(void);

#ifdef CONFIG_DYNAMIC_FTRACE struct dyn_arch_ftrace { +#ifdef CONFIG_ARM_MODULE_PLTS + struct module *mod; +#endif };

static inline unsigned long ftrace_call_adjust(unsigned long addr) diff --git a/arch/arm/include/asm/module.h b/arch/arm/include/asm/module.h index 9b17d2f5ab53..734b8fe36896 100644 --- a/arch/arm/include/asm/module.h +++ b/arch/arm/include/asm/module.h @@ -29,6 +29,8 @@ struct plt_entries { };

struct mod_plt_sec { + struct elf32_shdr *plt; + struct plt_entries *plt_ent; int plt_shndx; int plt_count; }; diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index 61de8172a044..3a0d5890d68d 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -68,9 +68,10 @@ int ftrace_arch_code_modify_post_process(void) return 0; }

-static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) +static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr, + bool warn) { - return arm_gen_branch_link(pc, addr, true); + return arm_gen_branch_link(pc, addr, warn); }

static int ftrace_modify_code(unsigned long pc, unsigned long old, @@ -104,14 +105,14 @@ int ftrace_update_ftrace_func(ftrace_func_t func) int ret;

pc = (unsigned long)&ftrace_call; - new = ftrace_call_replace(pc, (unsigned long)func); + new = ftrace_call_replace(pc, (unsigned long)func, true);

ret = ftrace_modify_code(pc, 0, new, false);

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS if (!ret) { pc = (unsigned long)&ftrace_regs_call; - new = ftrace_call_replace(pc, (unsigned long)func); + new = ftrace_call_replace(pc, (unsigned long)func, true);

ret = ftrace_modify_code(pc, 0, new, false); } @@ -124,10 +125,22 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) { unsigned long new, old; unsigned long ip = rec->ip; + unsigned long aaddr = adjust_address(rec, addr); + struct module *mod = NULL; + +#ifdef CONFIG_ARM_MODULE_PLTS + mod = rec->arch.mod; +#endif

old = ftrace_nop_replace(rec);

- new = ftrace_call_replace(ip, adjust_address(rec, addr)); + new = ftrace_call_replace(ip, aaddr, !mod); +#ifdef CONFIG_ARM_MODULE_PLTS + if (!new && mod) { + aaddr = get_module_plt(mod, NULL, ip, aaddr); + new = ftrace_call_replace(ip, aaddr, true); + } +#endif

return ftrace_modify_code(rec->ip, old, new, true); } @@ -140,9 +153,9 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long new, old; unsigned long ip = rec->ip;

- old = ftrace_call_replace(ip, adjust_address(rec, old_addr)); + old = ftrace_call_replace(ip, adjust_address(rec, old_addr), true);

- new = ftrace_call_replace(ip, adjust_address(rec, addr)); + new = ftrace_call_replace(ip, adjust_address(rec, addr), true);

return ftrace_modify_code(rec->ip, old, new, true); } @@ -152,12 +165,29 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { + unsigned long aaddr = adjust_address(rec, addr); unsigned long ip = rec->ip; unsigned long old; unsigned long new; int ret;

- old = ftrace_call_replace(ip, adjust_address(rec, addr)); +#ifdef CONFIG_ARM_MODULE_PLTS + /* mod is only supplied during module loading */ + if (!mod) + mod = rec->arch.mod; + else + rec->arch.mod = mod; +#endif + + old = ftrace_call_replace(ip, aaddr, + !IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || !mod); +#ifdef CONFIG_ARM_MODULE_PLTS + if (!old && mod) { + aaddr = get_module_plt(mod, NULL, ip, aaddr); + old = ftrace_call_replace(ip, aaddr, true); + } +#endif + new = ftrace_nop_replace(rec); ret = ftrace_modify_code(ip, old, new, true);

diff --git a/arch/arm/kernel/module-plts.c b/arch/arm/kernel/module-plts.c index f019f389337b..dcd00665911d 100644 --- a/arch/arm/kernel/module-plts.c +++ b/arch/arm/kernel/module-plts.c @@ -4,6 +4,7 @@ */

#include <linux/elf.h> +#include <linux/ftrace.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/sort.h> @@ -20,21 +21,55 @@ (PLT_ENT_STRIDE - 8)) #endif

+static const u32 fixed_plts[] = { +#ifdef CONFIG_FUNCTION_TRACER + FTRACE_ADDR, + MCOUNT_ADDR, +#endif +}; + static bool in_init(const struct module *mod, unsigned long loc) { return loc - (u32)mod->init_layout.base < mod->init_layout.size; }

+static void prealloc_fixed(struct mod_plt_sec *pltsec, struct plt_entries *plt) +{ + int i; + + if (!ARRAY_SIZE(fixed_plts) || pltsec->plt_count) + return; + pltsec->plt_count = ARRAY_SIZE(fixed_plts); + + for (i = 0; i < ARRAY_SIZE(plt->ldr); ++i) + plt->ldr[i] = PLT_ENT_LDR; + + BUILD_BUG_ON(sizeof(fixed_plts) > sizeof(plt->lit)); + memcpy(plt->lit, fixed_plts, sizeof(fixed_plts)); +} + u32 get_module_plt(struct module *mod, Elf32_Shdr *sechdrs, unsigned long loc, Elf32_Addr val) { struct mod_plt_sec *pltsec = !in_init(mod, loc) ? &mod->arch.core : &mod->arch.init; + Elf32_Shdr *plt_shdr = sechdrs ? &sechdrs[pltsec->plt_shndx] : + pltsec->plt; + struct plt_entries *plt; + int idx; + + /* cache the address, ELF header is available only during module load */ + if (!pltsec->plt_ent) + pltsec->plt_ent = (struct plt_entries *)plt_shdr->sh_addr; + plt = pltsec->plt_ent;

- struct plt_entries *plt = - (struct plt_entries *)sechdrs[pltsec->plt_shndx].sh_addr; - int idx = 0; + prealloc_fixed(pltsec, plt); + + for (idx = 0; idx < ARRAY_SIZE(fixed_plts); ++idx) + if (plt->lit[idx] == val) + return (u32)&plt->ldr[idx];

+ idx = 0; /* * Look for an existing entry pointing to 'val'. Given that the * relocations are sorted, this will be the last entry we allocated. @@ -183,11 +218,10 @@ static unsigned int count_plts(const Elf32_Sym *syms, Elf32_Addr base, int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings, struct module *mod) { - unsigned long core_plts = 0; - unsigned long init_plts = 0; + unsigned long core_plts = ARRAY_SIZE(fixed_plts); + unsigned long init_plts = ARRAY_SIZE(fixed_plts); Elf32_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum; Elf32_Sym *syms = NULL; - Elf32_Shdr *core_pltsec, *init_pltsec; int i = 0;

/* @@ -195,11 +229,13 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, * and for initialization code. */ for (s = sechdrs; s < sechdrs_end; ++s, ++i) { - if (strcmp(".plt", secstrings + s->sh_name) == 0) + if (strcmp(".plt", secstrings + s->sh_name) == 0) { + mod->arch.core.plt = s; mod->arch.core.plt_shndx = i; - else if (strcmp(".init.plt", secstrings + s->sh_name) == 0) + } else if (strcmp(".init.plt", secstrings + s->sh_name) == 0) { + mod->arch.init.plt = s; mod->arch.init.plt_shndx = i; - else if (s->sh_type == SHT_SYMTAB) + } else if (s->sh_type == SHT_SYMTAB) syms = (Elf32_Sym *)s->sh_addr; }

@@ -235,23 +271,23 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, numrels, s->sh_info); }

- core_pltsec = sechdrs + mod->arch.core.plt_shndx; - core_pltsec->sh_type = SHT_NOBITS; - core_pltsec->sh_flags = SHF_EXECINSTR | SHF_ALLOC; - core_pltsec->sh_addralign = L1_CACHE_BYTES; - core_pltsec->sh_size = round_up(core_plts * PLT_ENT_SIZE, - sizeof(struct plt_entries)); + mod->arch.core.plt->sh_type = SHT_NOBITS; + mod->arch.core.plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC; + mod->arch.core.plt->sh_addralign = L1_CACHE_BYTES; + mod->arch.core.plt->sh_size = round_up(core_plts * PLT_ENT_SIZE, + sizeof(struct plt_entries)); mod->arch.core.plt_count = 0; + mod->arch.core.plt_ent = NULL;

- init_pltsec = sechdrs + mod->arch.init.plt_shndx; - init_pltsec->sh_type = SHT_NOBITS; - init_pltsec->sh_flags = SHF_EXECINSTR | SHF_ALLOC; - init_pltsec->sh_addralign = L1_CACHE_BYTES; - init_pltsec->sh_size = round_up(init_plts * PLT_ENT_SIZE, - sizeof(struct plt_entries)); + mod->arch.init.plt->sh_type = SHT_NOBITS; + mod->arch.init.plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC; + mod->arch.init.plt->sh_addralign = L1_CACHE_BYTES; + mod->arch.init.plt->sh_size = round_up(init_plts * PLT_ENT_SIZE, + sizeof(struct plt_entries)); mod->arch.init.plt_count = 0; + mod->arch.init.plt_ent = NULL;

pr_debug("%s: plt=%x, init.plt=%x\n", __func__, - core_pltsec->sh_size, init_pltsec->sh_size); + mod->arch.core.plt->sh_size, mod->arch.init.plt->sh_size); return 0; }