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

[Rohan McLure <rmclure@linux.ibm.com>]

> On 12 Sep 2022, at 8:33 pm, Nicholas Piggin <npiggin@gmail.com> wrote:
> 
> 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?

Good spot. I’ll introduce that with syscall wrappers.

>> +
>> +/*
>> + * 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.

Cool. I’ll neaten this up and change that comment.

> 
> Thanks,
> Nick