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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2017-07-17 00:59:51 +0200
committerIngo Molnar <mingo@kernel.org>2017-07-21 10:05:18 +0200
commit44b04912fa72489d403738f39e1c782614b7ae7c (patch)
tree460fe18da21058de8080c90500fdc688d59902d8 /arch/x86/mm/hugetlbpage.c
parentx86/mm: Rename tasksize_32bit/64bit to task_size_32bit/64bit() (diff)
downloadlinux-44b04912fa72489d403738f39e1c782614b7ae7c.tar.xz
linux-44b04912fa72489d403738f39e1c782614b7ae7c.zip
x86/mpx: Do not allow MPX if we have mappings above 47-bit
MPX (without MAWA extension) cannot handle addresses above 47 bits, so we need to make sure that MPX cannot be enabled if we already have a VMA above the boundary and forbid creating such VMAs once MPX is enabled. The patch implements mpx_unmapped_area_check() which is called from all variants of get_unmapped_area() to check if the requested address fits mpx. On enabling MPX, we check if we already have any vma above 47-bit boundary and forbit the enabling if we do. As long as DEFAULT_MAP_WINDOW is equal to TASK_SIZE_MAX, the change is nop. It will change when we allow userspace to have mappings above 47-bits. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170716225954.74185-6-kirill.shutemov@linux.intel.com [ Readability edits. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/hugetlbpage.c')
-rw-r--r--arch/x86/mm/hugetlbpage.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index 868f02cf58ce..3cf89ad00f87 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -18,6 +18,7 @@
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#include <asm/elf.h>
+#include <asm/mpx.h>
#if 0 /* This is just for testing */
struct page *
@@ -135,6 +136,11 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
if (len & ~huge_page_mask(h))
return -EINVAL;
+
+ addr = mpx_unmapped_area_check(addr, len, flags);
+ if (IS_ERR_VALUE(addr))
+ return addr;
+
if (len > TASK_SIZE)
return -ENOMEM;