Re: [PATCH v4 08/20] powerpc: Include all arch-specific syscall prototypes

["Nicholas Piggin" <npiggin@gmail.com>]

On Wed Aug 24, 2022 at 12:05 PM AEST, Rohan McLure wrote:
> Forward declare all syscall handler prototypes where a generic prototype
> is not provided in either linux/syscalls.h or linux/compat.h in
> asm/syscalls.h. This is required for compile-time type-checking for
> syscall handlers, which is implemented later in this series.
>
> 32-bit compatibility syscall handlers are expressed in terms of types in
> ppc32.h. Expose this header globally.
>
> Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
> ---
> V1 -> V2: Explicitly include prototypes.
> V2 -> V3: Remove extraneous #include <asm/compat.h> and ppc_fallocate
> prototype. Rename header.
> ---
>  arch/powerpc/include/asm/syscalls.h          | 90 +++++++++++++-----
>  .../ppc32.h => include/asm/syscalls_32.h}    |  0
>  arch/powerpc/kernel/signal_32.c              |  2 +-
>  arch/powerpc/perf/callchain_32.c             |  2 +-
>  4 files changed, 70 insertions(+), 24 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/syscalls.h b/arch/powerpc/include/asm/syscalls.h
> index 3e3aff0835a6..91417dee534e 100644
> --- a/arch/powerpc/include/asm/syscalls.h
> +++ b/arch/powerpc/include/asm/syscalls.h
> @@ -8,45 +8,91 @@
>  #include <linux/types.h>
>  #include <linux/compat.h>
>  
> +#ifdef CONFIG_PPC64
> +#include <asm/syscalls_32.h>
> +#endif
> +#include <asm/unistd.h>
> +#include <asm/ucontext.h>
> +
>  struct rtas_args;
>  
> +#ifndef CONFIG_ARCH_HAS_SYSCALL_WRAPPER

Do you need this ifdef?

> +
> +/*
> + * PowerPC architecture-specific syscalls
> + */
> +
> +long sys_rtas(struct rtas_args __user *uargs);
> +long sys_ni_syscall(void);
> +
> +#ifdef CONFIG_PPC64
> +long sys_ppc64_personality(unsigned long personality);
> +#ifdef CONFIG_COMPAT
> +long compat_sys_ppc64_personality(unsigned long personality);
> +#endif /* CONFIG_COMPAT */
> +#endif /* CONFIG_PPC64 */
> +
> +/* Parameters are reordered for powerpc to avoid padding */
> +long sys_ppc_fadvise64_64(int fd, int advice,
> +			  u32 offset_high, u32 offset_low,
> +			  u32 len_high, u32 len_low);

Should this be under PPC32 since you're adding the ifdefs?

Because you added a new comment here... This is register padding
to do with something, even/odd pair calling convention? I can't
remember the details would you be able to expand the comment a bit
because I'm sure I'll forget it again too.

Thanks,
Nick