diff options
| -rw-r--r-- | arch/arm64/kernel/entry.S | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/process.c | 18 | ||||
| -rw-r--r-- | include/linux/sched.h | 1 |
3 files changed, 20 insertions, 1 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index e304fe04b098..e1859e010c5f 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -680,7 +680,7 @@ alternative_if ARM64_HAS_IRQ_PRIO_MASKING orr x24, x24, x0 alternative_else_nop_endif cbnz x24, 1f // preempt count != 0 || NMI return path - bl preempt_schedule_irq // irq en/disable is done inside + bl arm64_preempt_schedule_irq // irq en/disable is done inside 1: #endif diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 1fb2819fc048..71f788cd2b18 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -17,6 +17,7 @@ #include <linux/sched/task.h> #include <linux/sched/task_stack.h> #include <linux/kernel.h> +#include <linux/lockdep.h> #include <linux/mm.h> #include <linux/stddef.h> #include <linux/sysctl.h> @@ -44,6 +45,7 @@ #include <asm/alternative.h> #include <asm/arch_gicv3.h> #include <asm/compat.h> +#include <asm/cpufeature.h> #include <asm/cacheflush.h> #include <asm/exec.h> #include <asm/fpsimd.h> @@ -631,3 +633,19 @@ static int __init tagged_addr_init(void) core_initcall(tagged_addr_init); #endif /* CONFIG_ARM64_TAGGED_ADDR_ABI */ + +asmlinkage void __sched arm64_preempt_schedule_irq(void) +{ + lockdep_assert_irqs_disabled(); + + /* + * Preempting a task from an IRQ means we leave copies of PSTATE + * on the stack. cpufeature's enable calls may modify PSTATE, but + * resuming one of these preempted tasks would undo those changes. + * + * Only allow a task to be preempted once cpufeatures have been + * enabled. + */ + if (static_branch_likely(&arm64_const_caps_ready)) + preempt_schedule_irq(); +} diff --git a/include/linux/sched.h b/include/linux/sched.h index 2c2e56bd8913..67a1d86981a9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -223,6 +223,7 @@ extern long schedule_timeout_uninterruptible(long timeout); extern long schedule_timeout_idle(long timeout); asmlinkage void schedule(void); extern void schedule_preempt_disabled(void); +asmlinkage void preempt_schedule_irq(void); extern int __must_check io_schedule_prepare(void); extern void io_schedule_finish(int token); |