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| author | Andy Lutomirski <luto@amacapital.net> | 2011-11-07 16:33:40 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-12-05 12:17:27 +0100 |
| commit | 4fc3490114bb159bd4fff1b3c96f4320fe6fb08f (patch) | |
| tree | 71941c92c7352b1b78c169020946fecf1eae8f4a /arch/x86/mm/extable.c | |
| parent | 01acc269083015e2f78407f59dc8d6378fce22ee (diff) | |
| download | lwn-4fc3490114bb159bd4fff1b3c96f4320fe6fb08f.tar.gz lwn-4fc3490114bb159bd4fff1b3c96f4320fe6fb08f.zip | |
x86-64: Set siginfo and context on vsyscall emulation faults
To make this work, we teach the page fault handler how to send
signals on failed uaccess. This only works for user addresses
(kernel addresses will never hit the page fault handler in the
first place), so we need to generate signals for those
separately.
This gets the tricky case right: if the user buffer spans
multiple pages and only the second page is invalid, we set
cr2 and si_addr correctly. UML relies on this behavior to
"fault in" pages as needed.
We steal a bit from thread_info.uaccess_err to enable this.
Before this change, uaccess_err was a 32-bit boolean value.
This fixes issues with UML when vsyscall=emulate.
Reported-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/4c8f91de7ec5cd2ef0f59521a04e1015f11e42b4.1320712291.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/mm/extable.c')
| -rw-r--r-- | arch/x86/mm/extable.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index d0474ad2a6e5..1fb85dbe390a 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -25,7 +25,7 @@ int fixup_exception(struct pt_regs *regs) if (fixup) { /* If fixup is less than 16, it means uaccess error */ if (fixup->fixup < 16) { - current_thread_info()->uaccess_err = -EFAULT; + current_thread_info()->uaccess_err = 1; regs->ip += fixup->fixup; return 1; } |