Re: [PATCH v2 3/7] Introduce a new clone4 syscall with more flag bits and extensible arguments

[josh]

On Mon, Mar 23, 2015 at 02:11:45PM +0000, David Drysdale wrote:
> On Sun, Mar 15, 2015 at 7:59 AM, Josh Triplett <josh@xxxxxxxxxxxxxxxx> wrote:
> > diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
> > index 0286735..ba28306 100644
> > --- a/arch/x86/ia32/ia32entry.S
> > +++ b/arch/x86/ia32/ia32entry.S
> > @@ -483,6 +483,7 @@ GLOBAL(\label)
> >         PTREGSCALL stub32_execveat, compat_sys_execveat
> >         PTREGSCALL stub32_fork, sys_fork
> >         PTREGSCALL stub32_vfork, sys_vfork
> > +       PTREGSCALL stub32_clone4, compat_sys_clone4
> >
> >         ALIGN
> >  GLOBAL(stub32_clone)
> > diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> > index 1d74d16..ead143f 100644
> > --- a/arch/x86/kernel/entry_64.S
> > +++ b/arch/x86/kernel/entry_64.S
> > @@ -520,6 +520,7 @@ END(\label)
> >         FORK_LIKE  clone
> >         FORK_LIKE  fork
> >         FORK_LIKE  vfork
> > +       FORK_LIKE  clone4
> >         FIXED_FRAME stub_iopl, sys_iopl
> >
> >  ENTRY(stub_execve)
> > diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl
> > index b3560ec..56fcc90 100644
> > --- a/arch/x86/syscalls/syscall_32.tbl
> > +++ b/arch/x86/syscalls/syscall_32.tbl
> > @@ -365,3 +365,4 @@
> >  356    i386    memfd_create            sys_memfd_create
> >  357    i386    bpf                     sys_bpf
> >  358    i386    execveat                sys_execveat                    stub32_execveat
> > +359    i386    clone4                  sys_clone4                      stub32_clone4
> > diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
> > index 8d656fb..af15b0f 100644
> > --- a/arch/x86/syscalls/syscall_64.tbl
> > +++ b/arch/x86/syscalls/syscall_64.tbl
> > @@ -329,6 +329,7 @@
> >  320    common  kexec_file_load         sys_kexec_file_load
> >  321    common  bpf                     sys_bpf
> >  322    64      execveat                stub_execveat
> > +323    64      clone4                  stub_clone4
> >
> >  #
> >  # x32-specific system call numbers start at 512 to avoid cache impact
> > @@ -368,3 +369,4 @@
> >  543    x32     io_setup                compat_sys_io_setup
> >  544    x32     io_submit               compat_sys_io_submit
> >  545    x32     execveat                stub_x32_execveat
> > +546    x32     clone4                  stub32_clone4
> 
> Doesn't this need an x32 specific wrapper (to ensure the full
> set of registers are saved)?

I'm not an x32 expert; I don't know how x32 interacts with pt_regs and
compat syscalls.  Could an x32 expert weigh in, please?

- Josh Triplett
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