https://github.com/torvalds/linux
Revision 84c6f6046c5a2189160a8f0dca8b90427bf690ea authored by Roland McGrath on 07 March 2008, 22:56:02 UTC, committed by Linus Torvalds on 08 March 2008, 03:05:58 UTC
This makes 64-bit ptrace calls setting the 64-bit orig_ax field for a 32-bit task sign-extend the low 32 bits up to 64. This matches what a 64-bit debugger expects when tracing a 32-bit task. This follows on my "x86_64 ia32 syscall restart fix". This didn't matter until that was fixed. The debugger ignores or zeros the high half of every register slot it sets (including the orig_rax pseudo-register) uniformly. It expects that the setting of the low 32 bits always has the same meaning as a 32-bit debugger setting those same 32 bits with native 32-bit facilities. This never arose before because the syscall restart check never matched any -ERESTART* values due to lack of sign extension. Before that fix, even 32-bit ptrace setting orig_eax to -1 failed to trigger the restart check anyway. So this was never noticed as a regression of 64-bit debuggers vs 32-bit debuggers on the same 64-bit kernel. Signed-off-by: Roland McGrath <roland@redhat.com> [ Changed to just do the sign-extension unconditionally on x86-64, since orig_ax is always just a small integer and doesn't need the full 64-bit range ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 60d5bce
Tip revision: 84c6f6046c5a2189160a8f0dca8b90427bf690ea authored by Roland McGrath on 07 March 2008, 22:56:02 UTC
x86_64: make ptrace always sign-extend orig_ax to 64 bits
x86_64: make ptrace always sign-extend orig_ax to 64 bits
Tip revision: 84c6f60
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Kconfig | -rw-r--r-- | 1.6 KB |
Makefile | -rw-r--r-- | 2.7 KB |
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