[PATCH v5 0/2] PTRACE_SET_SYSCALL_INFO: add support for seccomp syscall skipping

Renzo Davoli renzo at cs.unibo.it
Fri Jul 10 16:49:11 UTC 2026


Hi Michal,
	 I am not an expert of the powerpc architecture.

On Fri, Jul 10, 2026 at 05:38:32PM +0200, Michal Suchánek wrote:
> On these architectures the syscall number and the syscall return value
> share the same register.

Reading the file arch/powerpc/include/asm/syscall.h
the functions
 	syscall_get_nr()
	syscall_set_nr()
read and write regs->gpr[0]

while
	syscall_get_return_value()
	syscall_set_return_value()
read and write regs->gpr[3] (and one bit in regs->ccr as an error flag).

Am I missing another part of the entry/exit path where the two overlap?

Thank you.

	renzo



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