Messages in this thread | | | Date | Mon, 8 Jan 2018 18:03:56 +0100 | From | Willy Tarreau <> | Subject | Re: [PATCH RFC 1/4] x86/thread_info: add TIF_NOPTI to disable PTI per task |
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On Mon, Jan 08, 2018 at 05:57:11PM +0100, Thomas Gleixner wrote: > On Mon, 8 Jan 2018, Willy Tarreau wrote: > > > This flag indicates that the task will not use isolated page tables. > > > > Signed-off-by: Willy Tarreau <w@1wt.eu> > > --- > > arch/x86/include/asm/thread_info.h | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h > > index 0022333..2f92cf1 100644 > > --- a/arch/x86/include/asm/thread_info.h > > +++ b/arch/x86/include/asm/thread_info.h > > @@ -126,6 +126,14 @@ struct thread_info { > > #define _TIF_X32 (1 << TIF_X32) > > #define _TIF_FSCHECK (1 << TIF_FSCHECK) > > > > +/* The following flags only exist on x86-64. We can't use the shift anymore > > Please do not use this horrible comment syle
You mean, the fact that there is no '/*' alone on the first line or anything else ?
> And what's wrong with (1UL << 32)?
It fails when inherited in assembly parts. Initially the test was based on "testq $(_TIF_NOPTI), reg" and 1UL doesn't parse there, which is why I had to abandon it. In the latest patch I dropped "testq" for "bt" so I didn't need the mask anymore and it wouldn't be a problem... until someone wants to use it again.
> > + * due to C using signed ints by default and asm using unsigned longs. > > + */ > > +#ifdef CONFIG_X86_64 > > +# define TIF_NOPTI 32 /* disable PTI for this task */ > > No tail comments please.
OK but I did exactly like is done for all other flags above :-/
Thanks, Willy
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