Messages in this thread Patch in this message |  | | Subject | [RFC][PATCH 1/7] x86, mpx: introduce per-mm MPX table size tracking | From | Dave Hansen <> | Date | Wed, 01 Feb 2017 15:24:09 -0800 |
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Larger address spaces mean larger MPX bounds table sizes. This tracks which size tables we are using.
"MAWA" is what the hardware documentation calls this feature: MPX Address-Width Adjust.
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b/arch/x86/include/asm/mmu.h | 1 + b/arch/x86/include/asm/mpx.h | 6 ++++++ 2 files changed, 7 insertions(+)
diff -puN arch/x86/include/asm/mmu.h~mawa-020-mmu_context-mawa arch/x86/include/asm/mmu.h --- a/arch/x86/include/asm/mmu.h~mawa-020-mmu_context-mawa 2017-02-01 15:12:15.699124140 -0800 +++ b/arch/x86/include/asm/mmu.h 2017-02-01 15:12:15.702124275 -0800 @@ -34,6 +34,7 @@ typedef struct { #ifdef CONFIG_X86_INTEL_MPX /* address of the bounds directory */ void __user *bd_addr; + int mpx_bd_shift; #endif } mm_context_t; diff -puN arch/x86/include/asm/mpx.h~mawa-020-mmu_context-mawa arch/x86/include/asm/mpx.h --- a/arch/x86/include/asm/mpx.h~mawa-020-mmu_context-mawa 2017-02-01 15:12:15.700124185 -0800 +++ b/arch/x86/include/asm/mpx.h 2017-02-01 15:12:15.702124275 -0800 @@ -68,6 +68,12 @@ static inline void mpx_mm_init(struct mm * directory, so point this at an invalid address. */ mm->context.bd_addr = MPX_INVALID_BOUNDS_DIR; + /* + * All processes start out in "legacy" MPX mode with + * the old bounds directory size. This corresponds to + * what the specs call MAWA=0. + */ + mm->context.mpx_bd_shift = 0; } void mpx_notify_unmap(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long start, unsigned long end); _
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