Re: [PATCH v2 2/2] syscall.2: add x32 ABI

["Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>]

Hi Jann,

On 24 March 2015 at 19:40, Jann Horn <jann@thejh.net> wrote:
> [added H. Peter Anvin to CC for this patch because he
> seems to have contributed large parts of the X32 code]

It looks like I did not reply to this mail. But as you'll probably have seen
from the man-pages-3.83 release announcement, I did apply this patch.
Thanks!

Cheers,

Michael


>
> ---
>  man2/syscall.2 | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/man2/syscall.2 b/man2/syscall.2
> index ef8f3cf..1f25255 100644
> --- a/man2/syscall.2
> +++ b/man2/syscall.2
> @@ -170,12 +170,18 @@ s390      svc 0   r1      r2      See below
>  s390x  svc 0   r1      r2      See below
>  sparc/32       t 0x10  g1      o0
>  sparc/64       t 0x6d  g1      o0
> -x86_64 syscall rax     rax
> +x86_64 syscall rax     rax     See below
> +x32    syscall rax     rax     See below
>  .TE
>  .PP
>  For s390 and s390x, NR (the system call number)
>  may be passed directly with "svc NR" if it is less than 256.
>
> +The x32 ABI uses the same instruction as the x86_64 ABI and is used on
> +the same processors. To differentiate between them, the bitmask
> +.I __X32_SYSCALL_BIT
> +is bitwise-ORed into the syscall number for syscalls under the x32 ABI.
> +
>  On a few architectures,
>  a register is used to indicate simple boolean failure of the system call:
>  ia64 uses
> @@ -210,6 +216,7 @@ s390x       r2    r3    r4    r5    r6    r7    -
>  sparc/32    o0    o1    o2    o3    o4    o5    -
>  sparc/64    o0    o1    o2    o3    o4    o5    -
>  x86_64      rdi   rsi   rdx   r10   r8    r9    -
> +x32         rdi   rsi   rdx   r10   r8    r9    -
>  .TE
>  .PP
>  The mips/o32 system call convention passes
> --
> 2.1.4



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/