Messages in this thread | | | Date | Thu, 6 Nov 2014 09:02:59 +0100 | Subject | Re: [RFC][PATCH] x86: Make x32 syscall support conditional on a kernel parameter | From | Geert Uytterhoeven <> |
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On Thu, Nov 6, 2014 at 4:53 AM, Ben Hutchings <ben@decadent.org.uk> wrote:
> --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -2455,6 +2455,14 @@ config X86_X32 > elf32_x86_64 support enabled to compile a kernel with this > option set. > > +config X86_X32_DISABLED > + bool "x32 ABI disabled by default" > + depends on X86_X32 > + default n > + help > + Disable the x32 ABI unless explicitly enabled using the > + kernel paramter "syscall.x32=y".
parameter
> diff --git a/arch/x86/kernel/syscall_64.c b/arch/x86/kernel/syscall_64.c > index 4ac730b..7a6e66f 100644 > --- a/arch/x86/kernel/syscall_64.c > +++ b/arch/x86/kernel/syscall_64.c
> +static int __init x32_enable(void) > +{ > + BUG_ON(system_call_fast_compare_end - system_call_fast_compare != 10); > + BUG_ON(system_call_trace_compare_end - system_call_trace_compare != 10); > + BUG_ON(system_call_mask_compare_end - system_call_mask_compare != 10);
BUILD_BUG_ON
> + > + if (x32_enabled) { > + text_poke_early(system_call_fast_compare, > + system_call_mask_compare, 10); > + text_poke_early(system_call_trace_compare, > + system_call_mask_compare, 10); > +#ifdef CONFIG_X86_X32_DISABLED > + pr_info("Enabled x32 syscalls\n"); > +#endif
I don't think it hurts to print this unconditionally.
> + } > +#ifndef CONFIG_X86_X32_DISABLED > + else > + pr_info("Disabled x32 syscalls\n"); > +#endif > + > + return 0; > +} > +late_initcall(x32_enable); > + > +#endif
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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