Re: [PATCH v2] signal: add procfd_signal() syscall

[Christian Brauner]

On November 30, 2018 5:54:18 AM GMT+13:00, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>
>
>> On Nov 29, 2018, at 4:28 AM, Florian Weimer <fweimer@xxxxxxxxxx>
>wrote:
>> 
>> Disclaimer: I'm looking at this patch because Christian requested it.
>> I'm not a kernel developer.
>> 
>> * Christian Brauner:
>> 
>>> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl
>b/arch/x86/entry/syscalls/syscall_32.tbl
>>> index 3cf7b533b3d1..3f27ffd8ae87 100644
>>> --- a/arch/x86/entry/syscalls/syscall_32.tbl
>>> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
>>> @@ -398,3 +398,4 @@
>>> 384    i386    arch_prctl        sys_arch_prctl           
>__ia32_compat_sys_arch_prctl
>>> 385    i386    io_pgetevents        sys_io_pgetevents       
>__ia32_compat_sys_io_pgetevents
>>> 386    i386    rseq            sys_rseq            __ia32_sys_rseq
>>> +387    i386    procfd_signal        sys_procfd_signal       
>__ia32_compat_sys_procfd_signal
>>> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl
>b/arch/x86/entry/syscalls/syscall_64.tbl
>>> index f0b1709a5ffb..8a30cde82450 100644
>>> --- a/arch/x86/entry/syscalls/syscall_64.tbl
>>> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
>>> @@ -343,6 +343,7 @@
>>> 332    common    statx            __x64_sys_statx
>>> 333    common    io_pgetevents        __x64_sys_io_pgetevents
>>> 334    common    rseq            __x64_sys_rseq
>>> +335    64    procfd_signal        __x64_sys_procfd_signal
>>> 
>>> #
>>> # x32-specific system call numbers start at 512 to avoid cache
>impact
>>> @@ -386,3 +387,4 @@
>>> 545    x32    execveat        __x32_compat_sys_execveat/ptregs
>>> 546    x32    preadv2            __x32_compat_sys_preadv64v2
>>> 547    x32    pwritev2        __x32_compat_sys_pwritev64v2
>>> +548    x32    procfd_signal        __x32_compat_sys_procfd_signal
>> 
>> Is there a reason why these numbers have to be different?
>> 
>> (See the recent discussion with Andy Lutomirski.)
>
>Hah, I missed this part of the patch.  Letâs not add new x32 syscall
>numbers.
>
>Also, can we perhaps rework this a bit to get rid of the compat entry
>point?  The easier way would be to check in_compat_syscall(). The nicer
>way IMO would be to use the 64-bit structure for 32-bit as well.

Do you have a syscall which set precedence/did this before I could look at?
Just if you happen to remember one.
Fwiw, I followed the other signal syscalls.
They all introduce compat syscalls.