04235c00b6
This tests assumptions about how fast syscall works wrt pt_regs and, in particular, what happens if IP is decremented by 2 during a syscall. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1c44dbfe59000ba135bbf35ccc5d2433a0b31618.1444091584.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
47 lines
864 B
ArmAsm
47 lines
864 B
ArmAsm
.global sys32_helper
|
|
sys32_helper:
|
|
/* Args: syscall_args_32*, function pointer */
|
|
pushl %ebp
|
|
pushl %ebx
|
|
pushl %esi
|
|
pushl %edi
|
|
movl 5*4(%esp), %eax /* pointer to args struct */
|
|
|
|
movl 1*4(%eax), %ebx
|
|
movl 2*4(%eax), %ecx
|
|
movl 3*4(%eax), %edx
|
|
movl 4*4(%eax), %esi
|
|
movl 5*4(%eax), %edi
|
|
movl 6*4(%eax), %ebp
|
|
movl 0*4(%eax), %eax
|
|
|
|
call *(6*4)(%esp) /* Do the syscall */
|
|
|
|
/* Now we need to recover without losing any reg values */
|
|
pushl %eax
|
|
movl 6*4(%esp), %eax
|
|
popl 0*4(%eax)
|
|
movl %ebx, 1*4(%eax)
|
|
movl %ecx, 2*4(%eax)
|
|
movl %edx, 3*4(%eax)
|
|
movl %esi, 4*4(%eax)
|
|
movl %edi, 5*4(%eax)
|
|
movl %ebp, 6*4(%eax)
|
|
|
|
popl %edi
|
|
popl %esi
|
|
popl %ebx
|
|
popl %ebp
|
|
ret
|
|
|
|
.type sys32_helper, @function
|
|
.size sys32_helper, .-sys32_helper
|
|
|
|
.global int80_and_ret
|
|
int80_and_ret:
|
|
int $0x80
|
|
ret
|
|
|
|
.type int80_and_ret, @function
|
|
.size int80_and_ret, .-int80_and_ret
|