Commit-ID: 67d7a982bab6702d84415ea889996fae72a7d3b2
Gitweb: http://git.kernel.org/tip/67d7a982bab6702d84415ea889996fae72a7d3b2
Author: Mathias Krause <[email protected]>
AuthorDate: Tue, 10 May 2016 23:07:02 +0200
Committer: Ingo Molnar <[email protected]>
CommitDate: Wed, 11 May 2016 11:14:06 +0200
x86/extable: Ensure entries are swapped completely when sorting
The x86 exception table sorting was changed in this recent 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:
https://lkml.org/lkml/2016/1/27/232
The committed version kind of attempted to incorporate the changes of
contemporary commit done in the x86 tree:
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 be partly 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.
Fix this by providing a swap_ex_entry_fixup() macro that takes care of
the 'handler' member.
Signed-off-by: Mathias Krause <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tony Luck <[email protected]>
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/include/asm/uaccess.h | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 8b3fb76..86c48f3 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);
