diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 22 | ||||
| -rw-r--r-- | arch/x86/kernel/irq_64.c | 6 |
3 files changed, 21 insertions, 9 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 845c8a46cf7b..c5e23f351f67 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1739,7 +1739,7 @@ DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned = &init_task; EXPORT_PER_CPU_SYMBOL(current_task); -DEFINE_PER_CPU(struct irq_stack *, hardirq_stack_ptr); +DEFINE_PER_CPU(void *, hardirq_stack_ptr); DEFINE_PER_CPU(bool, hardirq_stack_inuse); DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT; diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 1dd851397bd9..5601b95944fa 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -128,12 +128,21 @@ static __always_inline bool in_exception_stack(unsigned long *stack, struct stac static __always_inline bool in_irq_stack(unsigned long *stack, struct stack_info *info) { - unsigned long *end = (unsigned long *)this_cpu_read(hardirq_stack_ptr); - unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long)); + unsigned long *end = (unsigned long *)this_cpu_read(hardirq_stack_ptr); + unsigned long *begin; /* - * This is a software stack, so 'end' can be a valid stack pointer. - * It just means the stack is empty. + * @end points directly to the top most stack entry to avoid a -8 + * adjustment in the stack switch hotpath. Adjust it back before + * calculating @begin. + */ + end++; + begin = end - (IRQ_STACK_SIZE / sizeof(long)); + + /* + * Due to the switching logic RSP can never be == @end because the + * final operation is 'popq %rsp' which means after that RSP points + * to the original stack and not to @end. */ if (stack < begin || stack >= end) return false; @@ -143,8 +152,9 @@ static __always_inline bool in_irq_stack(unsigned long *stack, struct stack_info info->end = end; /* - * The next stack pointer is the first thing pushed by the entry code - * after switching to the irq stack. + * The next stack pointer is stored at the top of the irq stack + * before switching to the irq stack. Actual stack entries are all + * below that. */ info->next_sp = (unsigned long *)*(end - 1); diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c index 440eed558558..7103f9889930 100644 --- a/arch/x86/kernel/irq_64.c +++ b/arch/x86/kernel/irq_64.c @@ -48,7 +48,8 @@ static int map_irq_stack(unsigned int cpu) if (!va) return -ENOMEM; - per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE; + /* Store actual TOS to avoid adjustment in the hotpath */ + per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8; return 0; } #else @@ -60,7 +61,8 @@ static int map_irq_stack(unsigned int cpu) { void *va = per_cpu_ptr(&irq_stack_backing_store, cpu); - per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE; + /* Store actual TOS to avoid adjustment in the hotpath */ + per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8; return 0; } #endif |