From d876b67343a648f3613506c7dbfed088fa0c875b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 14 Apr 2019 17:59:50 +0200 Subject: [PATCH] x86/traps: 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. Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Cc: "H. Peter Anvin" Cc: Andy Lutomirski Cc: Dave Hansen Cc: Ingo Molnar Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Sean Christopherson Cc: x86-ml Link: https://lkml.kernel.org/r/20190414160144.784487230@linutronix.de --- arch/x86/mm/fault.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 0524e1d74f24..06c089513d39 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -28,6 +28,7 @@ #include /* vma_pkey() */ #include /* efi_recover_from_page_fault()*/ #include /* store_idt(), ... */ +#include /* exception stack */ #define CREATE_TRACE_POINTS #include @@ -793,7 +794,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, if (is_vmalloc_addr((void *)address) && (((unsigned long)tsk->stack - 1 - address < PAGE_SIZE) || address - ((unsigned long)tsk->stack + THREAD_SIZE) < PAGE_SIZE)) { - unsigned long stack = this_cpu_read(orig_ist.ist[ESTACK_DF]) - sizeof(void *); + unsigned long stack = __this_cpu_ist_top_va(DF) - sizeof(void *); /* * We're likely to be running with very little stack space * left. It's plausible that we'd hit this condition but