From: Mark Brown broonie@kernel.org
mainline inclusion from mainline-v5.16-rc1 commit 0423eedcf4e1ba49f262a9e925ad9ab8ad8eaa36 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8E73O CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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In a system with SME there are parallel vector length controls for SVE and SME vectors which function in much the same way so it is desirable to share the code for handling them as much as possible. In order to prepare for doing this add a layer of accessor functions for the various VL related operations on tasks.
Since almost all current interactions are actually via task->thread rather than directly with the thread_info the accessors use that. Accessors are provided for both generic and SVE specific usage, the generic accessors should be used for cases where register state is being manipulated since the registers are shared between streaming and regular SVE so we know that when SME support is implemented we will always have to be in the appropriate mode already and hence can generalise now.
Since we are using task_struct and we don't want to cause widespread inclusion of sched.h the acessors are all out of line, it is hoped that none of the uses are in a sufficiently critical path for this to be an issue. Those that are most likely to present an issue are in the same translation unit so hopefully the compiler may be able to inline anyway.
This is purely adding the layer of abstraction, additional work will be needed to support tasks using SME.
Signed-off-by: Mark Brown broonie@kernel.org Link: https://lore.kernel.org/r/20211019172247.3045838-7-broonie@kernel.org Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Wang ShaoBo bobo.shaobowang@huawei.com --- arch/arm64/include/asm/fpsimd.h | 2 +- arch/arm64/include/asm/processor.h | 10 ++++++ arch/arm64/kernel/fpsimd.c | 55 +++++++++++++++++++++--------- arch/arm64/kernel/ptrace.c | 4 +-- arch/arm64/kernel/signal.c | 6 ++-- 5 files changed, 54 insertions(+), 23 deletions(-)
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index ed2def998377f..6f858f7ecaee5 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -63,7 +63,7 @@ static inline size_t sve_ffr_offset(int vl)
static inline void *sve_pffr(struct thread_struct *thread) { - return (char *)thread->sve_state + sve_ffr_offset(thread->sve_vl); + return (char *)thread->sve_state + sve_ffr_offset(thread_get_sve_vl(thread)); }
extern void sve_save_state(void *state, u32 *pfpsr, int save_ffr); diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 99584ac844f97..10db9052e25e0 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -170,6 +170,16 @@ struct thread_struct { KABI_RESERVE(8) };
+static inline unsigned int thread_get_sve_vl(struct thread_struct *thread) +{ + return thread->sve_vl; +} + +unsigned int task_get_sve_vl(const struct task_struct *task); +void task_set_sve_vl(struct task_struct *task, unsigned long vl); +unsigned int task_get_sve_vl_onexec(const struct task_struct *task); +void task_set_sve_vl_onexec(struct task_struct *task, unsigned long vl); + static inline void arch_thread_struct_whitelist(unsigned long *offset, unsigned long *size) { diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index c356aaa28d70a..31f9652b3a945 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -226,6 +226,26 @@ static void sve_free(struct task_struct *task) __sve_free(task); }
+unsigned int task_get_sve_vl(const struct task_struct *task) +{ + return task->thread.sve_vl; +} + +void task_set_sve_vl(struct task_struct *task, unsigned long vl) +{ + task->thread.sve_vl = vl; +} + +unsigned int task_get_sve_vl_onexec(const struct task_struct *task) +{ + return task->thread.sve_vl_onexec; +} + +void task_set_sve_vl_onexec(struct task_struct *task, unsigned long vl) +{ + task->thread.sve_vl_onexec = vl; +} + /* * TIF_SVE controls whether a task can use SVE without trapping while * in userspace, and also the way a task's FPSIMD/SVE state is stored @@ -288,7 +308,7 @@ static void task_fpsimd_load(void) if (IS_ENABLED(CONFIG_ARM64_SVE) && test_thread_flag(TIF_SVE)) sve_load_state(sve_pffr(¤t->thread), ¤t->thread.uw.fpsimd_state.fpsr, true, - sve_vq_from_vl(current->thread.sve_vl) - 1); + sve_vq_from_vl(task_get_sve_vl(current)) - 1); else fpsimd_load_state(¤t->thread.uw.fpsimd_state); } @@ -456,7 +476,7 @@ static void fpsimd_to_sve(struct task_struct *task) if (!system_supports_sve()) return;
- vq = sve_vq_from_vl(task->thread.sve_vl); + vq = sve_vq_from_vl(task_get_sve_vl(task)); __fpsimd_to_sve(sst, fst, vq); }
@@ -482,7 +502,7 @@ static void sve_to_fpsimd(struct task_struct *task) if (!system_supports_sve()) return;
- vq = sve_vq_from_vl(task->thread.sve_vl); + vq = sve_vq_from_vl(task_get_sve_vl(task)); for (i = 0; i < SVE_NUM_ZREGS; ++i) { p = (__uint128_t const *)ZREG(sst, vq, i); fst->vregs[i] = arm64_le128_to_cpu(*p); @@ -497,7 +517,7 @@ static void sve_to_fpsimd(struct task_struct *task) */ size_t sve_state_size(struct task_struct const *task) { - return SVE_SIG_REGS_SIZE(sve_vq_from_vl(task->thread.sve_vl)); + return SVE_SIG_REGS_SIZE(sve_vq_from_vl(task_get_sve_vl(task))); }
/* @@ -572,7 +592,7 @@ void sve_sync_from_fpsimd_zeropad(struct task_struct *task) if (!test_tsk_thread_flag(task, TIF_SVE)) return;
- vq = sve_vq_from_vl(task->thread.sve_vl); + vq = sve_vq_from_vl(task_get_sve_vl(task));
memset(sst, 0, SVE_SIG_REGS_SIZE(vq)); __fpsimd_to_sve(sst, fst, vq); @@ -600,16 +620,16 @@ int sve_set_vector_length(struct task_struct *task,
if (flags & (PR_SVE_VL_INHERIT | PR_SVE_SET_VL_ONEXEC)) - task->thread.sve_vl_onexec = vl; + task_set_sve_vl_onexec(task, vl); else /* Reset VL to system default on next exec: */ - task->thread.sve_vl_onexec = 0; + task_set_sve_vl_onexec(task, 0);
/* Only actually set the VL if not deferred: */ if (flags & PR_SVE_SET_VL_ONEXEC) goto out;
- if (vl == task->thread.sve_vl) + if (vl == task_get_sve_vl(task)) goto out;
/* @@ -636,7 +656,7 @@ int sve_set_vector_length(struct task_struct *task, */ sve_free(task);
- task->thread.sve_vl = vl; + task_set_sve_vl(task, vl);
out: update_tsk_thread_flag(task, TIF_SVE_VL_INHERIT, @@ -656,9 +676,9 @@ static int sve_prctl_status(unsigned long flags) int ret;
if (flags & PR_SVE_SET_VL_ONEXEC) - ret = current->thread.sve_vl_onexec; + ret = task_get_sve_vl_onexec(current); else - ret = current->thread.sve_vl; + ret = task_get_sve_vl(current);
if (test_thread_flag(TIF_SVE_VL_INHERIT)) ret |= PR_SVE_VL_INHERIT; @@ -958,7 +978,7 @@ void do_sve_acc(unsigned int esr, struct pt_regs *regs) */ if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { unsigned long vq_minus_one = - sve_vq_from_vl(current->thread.sve_vl) - 1; + sve_vq_from_vl(task_get_sve_vl(current)) - 1; sve_set_vq(vq_minus_one); sve_flush_live(true, vq_minus_one); fpsimd_bind_task_to_cpu(); @@ -1058,8 +1078,9 @@ void fpsimd_flush_thread(void) * If a bug causes this to go wrong, we make some noise and * try to fudge thread.sve_vl to a safe value here. */ - vl = current->thread.sve_vl_onexec ? - current->thread.sve_vl_onexec : get_sve_default_vl(); + vl = task_get_sve_vl_onexec(current); + if (!vl) + vl = get_sve_default_vl();
if (WARN_ON(!sve_vl_valid(vl))) vl = SVE_VL_MIN; @@ -1068,14 +1089,14 @@ void fpsimd_flush_thread(void) if (WARN_ON(supported_vl != vl)) vl = supported_vl;
- current->thread.sve_vl = vl; + task_set_sve_vl(current, vl);
/* * If the task is not set to inherit, ensure that the vector * length will be reset by a subsequent exec: */ if (!test_thread_flag(TIF_SVE_VL_INHERIT)) - current->thread.sve_vl_onexec = 0; + task_set_sve_vl_onexec(current, 0); }
put_cpu_fpsimd_context(); @@ -1120,7 +1141,7 @@ void fpsimd_bind_task_to_cpu(void) WARN_ON(!system_supports_fpsimd()); last->st = ¤t->thread.uw.fpsimd_state; last->sve_state = current->thread.sve_state; - last->sve_vl = current->thread.sve_vl; + last->sve_vl = task_get_sve_vl(current); current->thread.fpsimd_cpu = smp_processor_id();
if (system_supports_sve()) { diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 03b84ab27519e..39dc37a6784af 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -726,7 +726,7 @@ static void sve_init_header_from_task(struct user_sve_header *header, if (test_tsk_thread_flag(target, TIF_SVE_VL_INHERIT)) header->flags |= SVE_PT_VL_INHERIT;
- header->vl = target->thread.sve_vl; + header->vl = task_get_sve_vl(target); vq = sve_vq_from_vl(header->vl);
header->max_vl = sve_max_vl; @@ -821,7 +821,7 @@ static int sve_set(struct task_struct *target, goto out;
/* Actual VL set may be less than the user asked for: */ - vq = sve_vq_from_vl(target->thread.sve_vl); + vq = sve_vq_from_vl(task_get_sve_vl(target));
/* Registers: FPSIMD-only case */
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index d45d94049e89c..5ddad9c2a134d 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -180,7 +180,7 @@ int preserve_sve_context(struct sve_context __user *ctx) { int err = 0; u16 reserved[ARRAY_SIZE(ctx->__reserved)]; - unsigned int vl = current->thread.sve_vl; + unsigned int vl = task_get_sve_vl(current); unsigned int vq = 0;
if (test_thread_flag(TIF_SVE)) @@ -219,7 +219,7 @@ int restore_sve_fpsimd_context(struct user_ctxs *user) if (__copy_from_user(&sve, user->sve, sizeof(sve))) return -EFAULT;
- if (sve.vl != current->thread.sve_vl) + if (sve.vl != task_get_sve_vl(current)) return -EINVAL;
if (sve.head.size <= sizeof(*user->sve)) { @@ -474,7 +474,7 @@ int setup_sigframe_layout(struct rt_sigframe_user_layout *user, bool add_all) int vl = sve_max_vl;
if (!add_all) - vl = current->thread.sve_vl; + vl = task_get_sve_vl(current);
vq = sve_vq_from_vl(vl); }