Messages in this thread | | | Date | Tue, 23 Dec 2014 10:19:44 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 1/2] x86, mpx: explicitly disable 32-bit MPX support on 64-bit kernels |
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* Andy Lutomirski <luto@amacapital.net> wrote:
> On Mon, Dec 22, 2014 at 12:21 PM, Dave Hansen <dave@sr71.net> wrote: > > On 12/22/2014 12:17 PM, Andy Lutomirski wrote: > >>> > /* > >>> > + * 32-bit binaries on 64-bit kernels are currently > >>> > + * unsupported. > >>> > + */ > >>> > + if (IS_ENABLED(CONFIG_X86_64) && test_thread_flag(TIF_IA32)) > >>> > + return MPX_INVALID_BOUNDS_DIR; > >> Should this check mm->ia32_compat instead? > > > > set_personality_64bit/ia32() seem to make that and TIF_IA32 awfully > > equivalent. Is there a specific reason for wanting it done this way? > > My general desire to remove various bogus TIF_IA32 references. > [...]
So we generally want to use mm->context.ia32_compat instead of TIF_IA32, because in the end TIF_IA32 will go away altogether?
Or do you just want to audit all TIF_IA32 places (because most of them are wrong), and using mm->context.ia32_compat where it's justified and eliminating TIF_IA32 use is a nice way to document that ongoing audit without breaking stuff and such?
> [...] But this is only temporary, so I don't really care.
New code that touches this area should better use new principles, so I have no problem with requiring this, as long as it's well explained and logical and desirable to everyone.
Thanks,
Ingo
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