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. We will carry that nomenclature throughout
this series.
The new field will be optimized and get packed into 'bd_addr' in a later
patch. But, leave it separate for now to make the series simpler.
---
b/arch/x86/include/asm/mmu.h | 1 +
b/arch/x86/include/asm/mpx.h | 9 +++++++++
2 files changed, 10 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 2017-01-26
14:31:32.643673297 -0800
+++ b/arch/x86/include/asm/mmu.h 2017-01-26 14:31:32.647673476 -0800
@@ -34,6 +34,7 @@ typedef struct {
#ifdef CONFIG_X86_INTEL_MPX
/* address of the bounds directory */
void __user *bd_addr;
+ int mpx_mawa;
#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 2017-01-26
14:31:32.644673342 -0800
+++ b/arch/x86/include/asm/mpx.h 2017-01-26 14:31:32.648673521 -0800
@@ -68,6 +68,15 @@ 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
+ * MAWA=0.
+ */
+ mm->context.mpx_mawa = 0;
+}
+static inline int mpx_mawa_shift(struct mm_struct *mm)
+{
+ return mm->context.mpx_mawa;
}
void mpx_notify_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long start, unsigned long end);
_
