Re: [PATCH v3 2/6] syscall.h: add syscall_set_arguments() and syscall_set_return_value()

Sven Schnelle
2025-01-30T09:27:07Z

"Dmitry V. Levin" <ldv@strace.io> writes:

> These functions are going to be needed on all HAVE_ARCH_TRACEHOOK
> architectures to implement PTRACE_SET_SYSCALL_INFO API.
>
> This partially reverts commit 7962c2eddbfe ("arch: remove unused
> function syscall_set_arguments()") by reusing some of old
> syscall_set_arguments() implementations.
>
> Signed-off-by: Dmitry V. Levin <ldv@strace.io>
> Tested-by: Charlie Jenkins <charlie@rivosinc.com>
> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
> ---
> arch/arc/include/asm/syscall.h | 14 +++++++++++
> arch/arm/include/asm/syscall.h | 13 ++++++++++
> arch/arm64/include/asm/syscall.h | 13 ++++++++++
> arch/csky/include/asm/syscall.h | 13 ++++++++++
> arch/hexagon/include/asm/syscall.h | 14 +++++++++++
> arch/loongarch/include/asm/syscall.h | 8 ++++++
> arch/mips/include/asm/syscall.h | 32 ++++++++++++++++++++++++
> arch/nios2/include/asm/syscall.h | 11 ++++++++
> arch/openrisc/include/asm/syscall.h | 7 ++++++
> arch/parisc/include/asm/syscall.h | 12 +++++++++
> arch/powerpc/include/asm/syscall.h | 10 ++++++++
> arch/riscv/include/asm/syscall.h | 9 +++++++
> arch/s390/include/asm/syscall.h | 12 +++++++++
> arch/sh/include/asm/syscall_32.h | 12 +++++++++
> arch/sparc/include/asm/syscall.h | 10 ++++++++
> arch/um/include/asm/syscall-generic.h | 14 +++++++++++
> arch/x86/include/asm/syscall.h | 36 +++++++++++++++++++++++++++
> arch/xtensa/include/asm/syscall.h | 11 ++++++++
> include/asm-generic/syscall.h | 16 ++++++++++++
> 19 files changed, 267 insertions(+)
>
> diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h
> index 27e3d804b311..b3dd883699e7 100644
> --- a/arch/s390/include/asm/syscall.h
> +++ b/arch/s390/include/asm/syscall.h
> @@ -78,6 +78,18 @@ static inline void syscall_get_arguments(struct task_struct *task,
> args[0] = regs->orig_gpr2 & mask;
> }
>
> +static inline void syscall_set_arguments(struct task_struct *task,
> + struct pt_regs *regs,
> + const unsigned long *args)
> +{
> + unsigned int n = 6;
> +
> + while (n-- > 0)
> + if (n > 0)
> + regs->gprs[2 + n] = args[n];
> + regs->orig_gpr2 = args[0];
> +}

Could that be changed to something like:

for (int n = 1; n < 6; n++)
regs->gprs[2 + n] = args[n];
regs->orig_gpr2 = args[0];

I think this is way easier to parse.