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author | Mathias Krause <minipli@googlemail.com> | 2016-05-11 00:07:02 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-11 21:17:47 +0300 |
commit | 50c73890d314921e2097d47e98c2ca59b3876ec7 (patch) | |
tree | a6cc6fca6df55ef8396d22b218020af849600df0 /arch | |
parent | e0d09e32c9d34edafd790020222050d7701f986f (diff) | |
download | linux-50c73890d314921e2097d47e98c2ca59b3876ec7.tar.xz |
x86/extable: ensure entries are swapped completely when sorting
The x86 exception table sorting was changed in commit 29934b0fb8ff
("x86/extable: use generic search and sort routines") to use the arch
independent code in lib/extable.c. However, the patch was mangled
somehow on its way into the kernel from the last version posted at [1].
The committed version kind of attempted to incorporate the changes of
commit 548acf19234d ("x86/mm: Expand the exception table logic to allow
new handling options") as in _completely_ _ignoring_ the x86 specific
'handler' member of struct exception_table_entry. This effectively
broke the sorting as entries will only partly be swapped now.
Fortunately, the x86 Kconfig selects BUILDTIME_EXTABLE_SORT, so the
exception table doesn't need to be sorted at runtime. However, in case
that ever changes, we better not break the exception table sorting just
because of that.
[ Ard Biesheuvel points out that BUILDTIME_EXTABLE_SORT applies to the
core image only, but we still rely on the sorting routines for modules
in that case - Linus ]
Fix this by providing a swap_ex_entry_fixup() macro that takes care of
the 'handler' member.
[1] https://lkml.org/lkml/2016/1/27/232
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Fixes: 29934b0fb8f ("x86/extable: use generic search and sort routines")
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/include/asm/uaccess.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index a969ae607be8..2e7513d1f1f4 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -108,6 +108,14 @@ struct exception_table_entry { #define ARCH_HAS_RELATIVE_EXTABLE +#define swap_ex_entry_fixup(a, b, tmp, delta) \ + do { \ + (a)->fixup = (b)->fixup + (delta); \ + (b)->fixup = (tmp).fixup - (delta); \ + (a)->handler = (b)->handler + (delta); \ + (b)->handler = (tmp).handler - (delta); \ + } while (0) + extern int fixup_exception(struct pt_regs *regs, int trapnr); extern bool ex_has_fault_handler(unsigned long ip); extern int early_fixup_exception(unsigned long *ip); |