![Andy Lutomirski](/assets/img/avatar_default.png)
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
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sys32_helper:
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/* Args: syscall_args_32*, function pointer */
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pushl %ebp
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pushl %ebx
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pushl %esi
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pushl %edi
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movl 5*4(%esp), %eax /* pointer to args struct */
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movl 1*4(%eax), %ebx
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movl 2*4(%eax), %ecx
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movl 3*4(%eax), %edx
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movl 4*4(%eax), %esi
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movl 5*4(%eax), %edi
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movl 6*4(%eax), %ebp
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movl 0*4(%eax), %eax
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call *(6*4)(%esp) /* Do the syscall */
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/* Now we need to recover without losing any reg values */
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pushl %eax
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movl 6*4(%esp), %eax
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popl 0*4(%eax)
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movl %ebx, 1*4(%eax)
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movl %ecx, 2*4(%eax)
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movl %edx, 3*4(%eax)
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movl %esi, 4*4(%eax)
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movl %edi, 5*4(%eax)
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movl %ebp, 6*4(%eax)
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popl %edi
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popl %esi
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popl %ebx
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popl %ebp
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ret
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.type sys32_helper, @function
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.size sys32_helper, .-sys32_helper
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.global int80_and_ret
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int80_and_ret:
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int $0x80
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ret
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.type int80_and_ret, @function
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.size int80_and_ret, .-int80_and_ret
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