From 57319d80e1d328e34cb24868a4f4405661485e30 Mon Sep 17 00:00:00 2001 From: Qiaowei Ren Date: Fri, 14 Nov 2014 07:18:27 -0800 Subject: x86, mpx: Add MPX-specific mmap interface We have chosen to perform the allocation of bounds tables in kernel (See the patch "on-demand kernel allocation of bounds tables") and to mark these VMAs with VM_MPX. However, there is currently no suitable interface to actually do this. Existing interfaces, like do_mmap_pgoff(), have no way to set a modified ->vm_ops or ->vm_flags and don't hold mmap_sem long enough to let a caller do it. This patch wraps mmap_region() and hold mmap_sem long enough to make the modifications to the VMA which we need. Also note the 32/64-bit #ifdef in the header. We actually need to do this at runtime eventually. But, for now, we don't support running 32-bit binaries on 64-bit kernels. Support for this will come in later patches. Signed-off-by: Qiaowei Ren Signed-off-by: Dave Hansen Cc: linux-mm@kvack.org Cc: linux-mips@linux-mips.org Cc: Dave Hansen Link: http://lkml.kernel.org/r/20141114151827.CE440F67@viggo.jf.intel.com Signed-off-by: Thomas Gleixner --- arch/x86/include/asm/mpx.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 arch/x86/include/asm/mpx.h (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/mpx.h b/arch/x86/include/asm/mpx.h new file mode 100644 index 000000000000..7d7c5f54cc5f --- /dev/null +++ b/arch/x86/include/asm/mpx.h @@ -0,0 +1,36 @@ +#ifndef _ASM_X86_MPX_H +#define _ASM_X86_MPX_H + +#include +#include + +#ifdef CONFIG_X86_64 + +/* upper 28 bits [47:20] of the virtual address in 64-bit used to + * index into bounds directory (BD). + */ +#define MPX_BD_ENTRY_OFFSET 28 +#define MPX_BD_ENTRY_SHIFT 3 +/* bits [19:3] of the virtual address in 64-bit used to index into + * bounds table (BT). + */ +#define MPX_BT_ENTRY_OFFSET 17 +#define MPX_BT_ENTRY_SHIFT 5 +#define MPX_IGN_BITS 3 + +#else + +#define MPX_BD_ENTRY_OFFSET 20 +#define MPX_BD_ENTRY_SHIFT 2 +#define MPX_BT_ENTRY_OFFSET 10 +#define MPX_BT_ENTRY_SHIFT 4 +#define MPX_IGN_BITS 2 + +#endif + +#define MPX_BD_SIZE_BYTES (1UL<<(MPX_BD_ENTRY_OFFSET+MPX_BD_ENTRY_SHIFT)) +#define MPX_BT_SIZE_BYTES (1UL<<(MPX_BT_ENTRY_OFFSET+MPX_BT_ENTRY_SHIFT)) + +#define MPX_BNDSTA_ERROR_CODE 0x3 + +#endif /* _ASM_X86_MPX_H */ -- cgit v1.2.3