diff options
Diffstat (limited to 'arch/arm64/kernel/fpsimd.c')
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 3599b9a2f1df..f1665b1b2d38 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -177,10 +177,19 @@ static void __get_cpu_fpsimd_context(void) * * The double-underscore version must only be called if you know the task * can't be preempted. + * + * On RT kernels local_bh_disable() is not sufficient because it only + * serializes soft interrupt related sections via a local lock, but stays + * preemptible. Disabling preemption is the right choice here as bottom + * half processing is always in thread context on RT kernels so it + * implicitly prevents bottom half processing as well. */ static void get_cpu_fpsimd_context(void) { - local_bh_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_disable(); + else + preempt_disable(); __get_cpu_fpsimd_context(); } @@ -201,7 +210,10 @@ static void __put_cpu_fpsimd_context(void) static void put_cpu_fpsimd_context(void) { __put_cpu_fpsimd_context(); - local_bh_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_enable(); + else + preempt_enable(); } static bool have_cpu_fpsimd_context(void) @@ -1033,6 +1045,7 @@ void fpsimd_thread_switch(struct task_struct *next) void fpsimd_flush_thread(void) { int vl, supported_vl; + void *sve_state = NULL; if (!system_supports_fpsimd()) return; @@ -1045,7 +1058,10 @@ void fpsimd_flush_thread(void) if (system_supports_sve()) { clear_thread_flag(TIF_SVE); - sve_free(current); + + /* Defer kfree() while in atomic context */ + sve_state = current->thread.sve_state; + current->thread.sve_state = NULL; /* * Reset the task vector length as required. @@ -1079,6 +1095,7 @@ void fpsimd_flush_thread(void) } put_cpu_fpsimd_context(); + kfree(sve_state); } /* |