diff options
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 5d0f0cc7ea26..76348334b934 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1130,8 +1130,8 @@ DEFINE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __aligned(PAGE_SIZE) __visible; /* - * The following four percpu variables are hot. Align current_task to - * cacheline size such that all four fall in the same cacheline. + * The following percpu variables are hot. Align current_task to + * cacheline size such that they fall in the same cacheline. */ DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned = &init_task; @@ -1226,6 +1226,15 @@ DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT; EXPORT_PER_CPU_SYMBOL(__preempt_count); DEFINE_PER_CPU(struct task_struct *, fpu_owner_task); +/* + * On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find + * the top of the kernel stack. Use an extra percpu variable to track the + * top of the kernel stack directly. + */ +DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) = + (unsigned long)&init_thread_union + THREAD_SIZE; +EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack); + #ifdef CONFIG_CC_STACKPROTECTOR DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary); #endif |