On Mon, Apr 09, 2018 at 08:49:45AM +0200, Ingo Molnar wrote:
>
> * Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> > +emit_stub() {
> > + entry="$1"
> > + if [ "${entry}" != "${entry#__ia32_sys_}" ]; then
> > + # We need a stub named __ia32_sys which is common to 64-bit
> > + # except for a different pt_regs layout.
> > + stubname=${entry#__ia32_sys_}
> > + echo "#define __IA32_SYS_STUBx_${stubname} __IA32_SYS_STUBx"
> > + echo "#define ASM_X86_HAS__ia32_sys_${stubname} 1"
> > + elif [ "$entry" != "${entry#__x32_compat_sys}" ]; then
> > + # We need a stub named __x32_compat_sys_ which decodes a
> > + # 64-bit pt_regs and then calls the real syscall function
> > + stubname="${entry%%/*}" # handle qualifier
> > + stubname=${stubname#__x32_compat_sys_} # handle prefix
> > + echo "#define __X32_COMPAT_SYS_STUBx_${stubname} __X32_COMPAT_SYS_STUBx"
> > + echo "#define ASM_X86_HAS__x32_compat_sys_${stubname} 1"
> > + elif [ "$entry" != "${entry#__ia32_compat_sys_x86}" ]; then
> > + # The compat entry starts with __ia32_compat_sys_x86, so it
> > + # is a specific x86 compat syscall; no need for __ia32_sys_*()
> > + stubname=${entry#__ia32_compat_sys_x86_}
> > + echo "#define __IA32_SYS_STUBx_${stubname} __SYSCALL_STUBx_UNUSED"
> > + echo "#define ASM_X86_HAS__ia32_sys_${stubname} 1"
> > + elif [ "$entry" != "${entry#__ia32_compat_sys_}" ]; then
> > + # The compat entry starts with __ia32_compat_sys, so it is
> > + # is a generic x86 compat syscall; no need for __ia32_sys_*()
> > + stubname=${entry#__ia32_compat_sys_}
> > + echo "#define __IA32_SYS_STUBx_${stubname} __SYSCALL_STUBx_UNUSED"
> > + echo "#define ASM_X86_HAS__ia32_sys_${stubname} 1"
> > + fi;
> > +}
>
> I only have a bikeshed painting comment, even in shell scripts please try to
> follow the kernel comment style visually, i.e. something like:
>
> > + if [ "${entry}" != "${entry#__ia32_sys_}" ]; then
> > +
> > + #
> > + # We need a stub named __ia32_sys which is common to 64-bit
> > + # except for a different pt_regs layout.
> > + #
> > + stubname=${entry#__ia32_sys_}
> > + echo "#define __IA32_SYS_STUBx_${stubname} __IA32_SYS_STUBx"
> > + echo "#define ASM_X86_HAS__ia32_sys_${stubname} 1"
> > +
> > + elif [ "$entry" != "${entry#__x32_compat_sys}" ]; then
> > +
> > + #
> > + # We need a stub named __x32_compat_sys_ which decodes a
> > + # 64-bit pt_regs and then calls the real syscall function
> > + #
> > + stubname="${entry%%/*}" # handle qualifier
> > + stubname=${stubname#__x32_compat_sys_} # handle prefix
> > + echo "#define __X32_COMPAT_SYS_STUBx_${stubname} __X32_COMPAT_SYS_STUBx"
> > + echo "#define ASM_X86_HAS__x32_compat_sys_${stubname} 1"
> > +
> > + elif [ "$entry" != "${entry#__ia32_compat_sys_x86}" ]; then
> > +
> > + #
> > + # The compat entry starts with __ia32_compat_sys_x86, so it
> > + # is a specific x86 compat syscall; no need for __ia32_sys_*()
> > + #
> > + stubname=${entry#__ia32_compat_sys_x86_}
> > + echo "#define __IA32_SYS_STUBx_${stubname} __SYSCALL_STUBx_UNUSED"
> > + echo "#define ASM_X86_HAS__ia32_sys_${stubname} 1"
> > +
> > + elif [ "$entry" != "${entry#__ia32_compat_sys_}" ]; then
> > +
> > + #
> > + # The compat entry starts with __ia32_compat_sys, so it is
> > + # is a generic x86 compat syscall; no need for __ia32_sys_*()
> > + #
> > + stubname=${entry#__ia32_compat_sys_}
> > + echo "#define __IA32_SYS_STUBx_${stubname} __SYSCALL_STUBx_UNUSED"
> > + echo "#define ASM_X86_HAS__ia32_sys_${stubname} 1"
> > +
> > + fi;
>
> ( Also note the vertical separation that helps see the overall structure a bit
> better. )
>
> But more fundamentally, that's an awful lot of complex scripting to save 4K
> (unused) kernel text, not sure it's worth it.
Yes. I just wanted to see myself whether it's worthwile, and it indeed
doesn't seem so. That's exactly why I didn't sign off on it so far...
Thanks,
Dominik
