Commit-ID: be739f4b5ddece74ef25e2304b17a7fd24575e9b
Gitweb: https://git.kernel.org/tip/be739f4b5ddece74ef25e2304b17a7fd24575e9b
Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
AuthorDate: Tue, 7 Nov 2017 13:38:04 +0300
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 9 Nov 2017 18:20:20 +0100
x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging
On machines with 5-level paging we don't want to allocate mapping above
47-bit unless user explicitly asked for it. See b569bab78d8d ("x86/mm:
Prepare to expose larger address space to userspace") for details.
c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base
changes") broke the behaviour. After the commit elf binary and heap got
mapped above 47-bits.
Use DEFAULT_MAP_WINDOW instead of TASK_SIZE to determine ELF_ET_DYN_BASE so
it's forced to be below 47-bits unconditionally.
Fixes: c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base changes")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20171107103804.47341-1-kirill.shutemov@xxxxxxxxxxxxxxx
---
arch/x86/include/asm/elf.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index c1a125e4..3a091ce 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -253,7 +253,7 @@ extern int force_personality32;
* space open for things that want to use the area for 32-bit pointers.
*/
#define ELF_ET_DYN_BASE (mmap_is_ia32() ? 0x000400000UL : \
- (TASK_SIZE / 3 * 2))
+ (DEFAULT_MAP_WINDOW / 3 * 2))
/* This yields a mask that user programs can use to figure out what
instruction set this CPU supports. This could be done in user space,
--
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