Messages in this thread Patch in this message | | | Date | Sun, 31 Mar 2019 23:40:29 +0200 | From | Thomas Gleixner <> | Subject | [patch 09/14] x86/traps: Use cpu_entry_area instead of orig_ist |
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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 <tglx@linutronix.de> --- arch/x86/mm/fault.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -28,6 +28,7 @@ #include <asm/mmu_context.h> /* vma_pkey() */ #include <asm/efi.h> /* efi_recover_from_page_fault()*/ #include <asm/desc.h> /* store_idt(), ... */ +#include <asm/cpu_entry_area.h> /* exception stack */ #define CREATE_TRACE_POINTS #include <asm/trace/exceptions.h> @@ -793,7 +794,7 @@ no_context(struct pt_regs *regs, unsigne 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[DOUBLEFAULT_STACK]) - 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
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