diff options
Diffstat (limited to 'arch/x86/kernel/dumpstack_64.c')
| -rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 22 |
1 files changed, 16 insertions, 6 deletions
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); |