From afcd21dad88b68d646e91ed36948117d58b4c197 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 14 Apr 2019 17:59:52 +0200 Subject: [PATCH] x86/dumpstack/64: Use cpu_entry_area instead of orig_ist The orig_ist[] array is a shadow copy of the IST array in the TSS. The reason why it exists is that older kernels used two TSS variants with different pointers into the debug stack. orig_ist[] contains the real starting points. There is no point anymore to do so because the same information can be retrieved using the base address of the cpu entry area mapping and the offsets of the various exception stacks. No functional change. Preparation for removing orig_ist. Cc: Josh Poimboeuf Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Cc: "H. Peter Anvin" Cc: Andy Lutomirski Cc: Ingo Molnar Cc: Josh Poimboeuf Cc: Sean Christopherson Cc: x86-ml Link: https://lkml.kernel.org/r/20190414160144.974900463@linutronix.de --- arch/x86/kernel/dumpstack_64.c | 39 +++++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 455b47e..f6fbd04 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -16,6 +16,7 @@ #include #include +#include #include static const char *exception_stack_names[N_EXCEPTION_STACKS] = { @@ -25,11 +26,6 @@ static const char *exception_stack_names[N_EXCEPTION_STACKS] = { [ ESTACK_MCE ] = "#MC", }; -static const unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = { - [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ, - [ESTACK_DB] = DEBUG_STKSZ -}; - const char *stack_type_name(enum stack_type type) { BUILD_BUG_ON(N_EXCEPTION_STACKS != 4); @@ -52,25 +48,44 @@ const char *stack_type_name(enum stack_type type) return NULL; } +struct estack_layout { + unsigned int begin; + unsigned int end; +}; + +#define ESTACK_ENTRY(x) { \ + .begin = offsetof(struct cea_exception_stacks, x## _stack), \ + .end = offsetof(struct cea_exception_stacks, x## _stack_guard) \ + } + +static const struct estack_layout layout[N_EXCEPTION_STACKS] = { + [ ESTACK_DF ] = ESTACK_ENTRY(DF), + [ ESTACK_NMI ] = ESTACK_ENTRY(NMI), + [ ESTACK_DB ] = ESTACK_ENTRY(DB), + [ ESTACK_MCE ] = ESTACK_ENTRY(MCE), +}; + static bool in_exception_stack(unsigned long *stack, struct stack_info *info) { - unsigned long *begin, *end; + unsigned long estacks, begin, end, stk = (unsigned long)stack; struct pt_regs *regs; - unsigned k; + unsigned int k; BUILD_BUG_ON(N_EXCEPTION_STACKS != 4); + estacks = (unsigned long)__this_cpu_read(cea_exception_stacks); + for (k = 0; k < N_EXCEPTION_STACKS; k++) { - end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k]; - begin = end - (exception_stack_sizes[k] / sizeof(long)); + begin = estacks + layout[k].begin; + end = estacks + layout[k].end; regs = (struct pt_regs *)end - 1; - if (stack < begin || stack >= end) + if (stk < begin || stk >= end) continue; info->type = STACK_TYPE_EXCEPTION + k; - info->begin = begin; - info->end = end; + info->begin = (unsigned long *)begin; + info->end = (unsigned long *)end; info->next_sp = (unsigned long *)regs->sp; return true; -- 2.7.4