diff options
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 25 | ||||
| -rw-r--r-- | arch/arm64/kernel/signal.c | 5 |
2 files changed, 19 insertions, 11 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 5ebe73b69961..62c37f0ac946 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -550,7 +550,6 @@ int sve_set_vector_length(struct task_struct *task, local_bh_disable(); fpsimd_save(); - set_thread_flag(TIF_FOREIGN_FPSTATE); } fpsimd_flush_task_state(task); @@ -816,12 +815,11 @@ asmlinkage void do_sve_acc(unsigned int esr, struct pt_regs *regs) local_bh_disable(); fpsimd_save(); - fpsimd_to_sve(current); /* Force ret_to_user to reload the registers: */ fpsimd_flush_task_state(current); - set_thread_flag(TIF_FOREIGN_FPSTATE); + fpsimd_to_sve(current); if (test_and_set_thread_flag(TIF_SVE)) WARN_ON(1); /* SVE access shouldn't have trapped */ @@ -894,9 +892,9 @@ void fpsimd_flush_thread(void) local_bh_disable(); + fpsimd_flush_task_state(current); memset(¤t->thread.uw.fpsimd_state, 0, sizeof(current->thread.uw.fpsimd_state)); - fpsimd_flush_task_state(current); if (system_supports_sve()) { clear_thread_flag(TIF_SVE); @@ -933,8 +931,6 @@ void fpsimd_flush_thread(void) current->thread.sve_vl_onexec = 0; } - set_thread_flag(TIF_FOREIGN_FPSTATE); - local_bh_enable(); } @@ -1043,12 +1039,29 @@ void fpsimd_update_current_state(struct user_fpsimd_state const *state) /* * Invalidate live CPU copies of task t's FPSIMD state + * + * This function may be called with preemption enabled. The barrier() + * ensures that the assignment to fpsimd_cpu is visible to any + * preemption/softirq that could race with set_tsk_thread_flag(), so + * that TIF_FOREIGN_FPSTATE cannot be spuriously re-cleared. + * + * The final barrier ensures that TIF_FOREIGN_FPSTATE is seen set by any + * subsequent code. */ void fpsimd_flush_task_state(struct task_struct *t) { t->thread.fpsimd_cpu = NR_CPUS; + + barrier(); + set_tsk_thread_flag(t, TIF_FOREIGN_FPSTATE); + + barrier(); } +/* + * Invalidate any task's FPSIMD state that is present on this cpu. + * This function must be called with softirqs disabled. + */ void fpsimd_flush_cpu_state(void) { __this_cpu_write(fpsimd_last_state.st, NULL); diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 867a7cea70e5..a9b0485df074 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -296,11 +296,6 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user) */ fpsimd_flush_task_state(current); - barrier(); - /* From now, fpsimd_thread_switch() won't clear TIF_FOREIGN_FPSTATE */ - - set_thread_flag(TIF_FOREIGN_FPSTATE); - barrier(); /* From now, fpsimd_thread_switch() won't touch thread.sve_state */ sve_alloc(current); |