diff options
| 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/include/asm | |
| parent | 01acc269083015e2f78407f59dc8d6378fce22ee (diff) | |
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/include/asm')
| -rw-r--r-- | arch/x86/include/asm/thread_info.h | 3 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 2 |
2 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index a1fe5c127b52..25ebd792725b 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -40,7 +40,8 @@ struct thread_info { */ __u8 supervisor_stack[0]; #endif - int uaccess_err; + int sig_on_uaccess_error:1; + int uaccess_err:1; /* uaccess failed */ }; #define INIT_THREAD_INFO(tsk) \ diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 36361bf6fdd1..8be5f54d9360 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -462,7 +462,7 @@ struct __large_struct { unsigned long buf[100]; }; barrier(); #define uaccess_catch(err) \ - (err) |= current_thread_info()->uaccess_err; \ + (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0); \ current_thread_info()->uaccess_err = prev_err; \ } while (0) |