Re: Linux powerpc new system call instruction and ABI

On Thu, May 20, 2021 at 12:45:57PM +1000, Nicholas Piggin wrote:

Excerpts from Dmitry V. Levin's message of May 20, 2021 11:06 am:

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On Wed, May 19, 2021 at 07:48:47PM -0400, Rich Felker wrote:

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On Wed, May 19, 2021 at 06:09:25PM +0000, Joakim Tjernlund wrote:

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W.r.t breaking ABI, isn't that what PowerPC is trying to do with the new syscall I/F? 

No, it's a new independent interface.

Unfortunately, being a new independent interface doesn't mean it isn't
an ABI break.  In fact, it was a severe ABI break, and this thread is
an attempt to find a hotfix.

It is an ABI break, that was known. The ptrace info stuff I fixed with 
the patch earlier was obviously a bug in my initial implementation and 
not intended (sorry my ptrace testing was not sufficient, and thanks for
reporting it, by the way).

Could you check whether tools/testing/selftests/ptrace/get_syscall_info.c
passes again with your fix, please?
If yes, then PTRACE_GET_SYSCALL_INFO is fixed.

By the way, kernel tracing and audit subsystems also use those functions
from asm/syscall.h and asm/ptrace.h, so your ptrace fix is likely to fix
these subsystems as well.


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