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-rw-r--r--arch/arm64/include/asm/simd.h2
-rw-r--r--arch/arm64/kernel/fpsimd.c25
2 files changed, 20 insertions, 7 deletions
diff --git a/arch/arm64/include/asm/simd.h b/arch/arm64/include/asm/simd.h
index 8e86c9e70e48..abd642c92f86 100644
--- a/arch/arm64/include/asm/simd.h
+++ b/arch/arm64/include/asm/simd.h
@@ -29,7 +29,7 @@ static __must_check inline bool may_use_simd(void)
*/
return !WARN_ON(!system_capabilities_finalized()) &&
system_supports_fpsimd() &&
- !in_hardirq() && !irqs_disabled() && !in_nmi();
+ !in_hardirq() && !in_nmi();
}
#else /* ! CONFIG_KERNEL_MODE_NEON */
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 3d848c89604e..6d956ed23bd2 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -225,10 +225,21 @@ static void fpsimd_bind_task_to_cpu(void);
*/
static void get_cpu_fpsimd_context(void)
{
- if (!IS_ENABLED(CONFIG_PREEMPT_RT))
- local_bh_disable();
- else
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
+ /*
+ * The softirq subsystem lacks a true unmask/mask API, and
+ * re-enabling softirq processing using local_bh_enable() will
+ * not only unmask softirqs, it will also result in immediate
+ * delivery of any pending softirqs.
+ * This is undesirable when running with IRQs disabled, but in
+ * that case, there is no need to mask softirqs in the first
+ * place, so only bother doing so when IRQs are enabled.
+ */
+ if (!irqs_disabled())
+ local_bh_disable();
+ } else {
preempt_disable();
+ }
}
/*
@@ -240,10 +251,12 @@ static void get_cpu_fpsimd_context(void)
*/
static void put_cpu_fpsimd_context(void)
{
- if (!IS_ENABLED(CONFIG_PREEMPT_RT))
- local_bh_enable();
- else
+ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
+ if (!irqs_disabled())
+ local_bh_enable();
+ } else {
preempt_enable();
+ }
}
unsigned int task_get_vl(const struct task_struct *task, enum vec_type type)