From: "H. Peter Anvin" <hpa@zytor.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86, cpu: X86_FEATURE_NOPL should be disabled on 32-bit only
Date: Sun, 03 Oct 2010 15:22:13 -0700 [thread overview]
Message-ID: <dc1a5ce2-0414-4f15-9e7b-fcfa4435adb5@email.android.com> (raw)
In-Reply-To: <20101003201139.GA16532@liondog.tnic>
Sort of... only if the input is a constant.
"Borislav Petkov" <bp@alien8.de> wrote:
>From: "H. Peter Anvin" <hpa@zytor.com>
>Date: Sun, Oct 03, 2010 at 11:19:18AM -0700
>
>> I think we actually need to set it on 64 bits.
>
>Ok, correct me if I'm wrong but I think it is already "indirectly" set
>on 64-bits through REQUIRED_MASK3:
>
>#define REQUIRED_MASK3 (NEED_NOPL)
>
>which is defined as
>
>#define NEED_NOPL (1<<(X86_FEATURE_NOPL & 31))
>
>when either CONFIG_X86_P6_NOP or CONFIG_X86_64 are selected.
>
>and cpu_has() does
>
>#define cpu_has(c, bit) \
> (__builtin_constant_p(bit) && \
> ...
> (((bit)>>5)==3 && (1UL<<((bit)&31) & REQUIRED_MASK3)) || \
> ...
> ? 1 : test_cpu_cap(c, bit))
>
>which returns 1 when testing for X86_FEATURE_NOPL, no?
>
>--
>Regards/Gruss,
> Boris.
--
Sent from my mobile phone. Please pardon any lack of formatting.
next prev parent reply other threads:[~2010-10-03 22:23 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-03 9:37 NOPL on 32-bit Borislav Petkov
2010-10-03 14:43 ` H. Peter Anvin
2010-10-03 15:22 ` [PATCH] x86, cpu: X86_FEATURE_NOPL should be disabled on 32-bit only Borislav Petkov
2010-10-03 18:19 ` H. Peter Anvin
2010-10-03 20:11 ` Borislav Petkov
2010-10-03 22:22 ` H. Peter Anvin [this message]
2010-10-04 7:31 ` [PATCH] x86, cpu: Fix X86_FEATURE_NOPL Borislav Petkov
2010-10-04 20:36 ` [tip:x86/cpu] " tip-bot for Borislav Petkov
2010-10-05 9:47 ` Borislav Petkov
2010-10-05 16:30 ` H. Peter Anvin
2010-10-05 16:53 ` Borislav Petkov
2010-10-04 20:47 ` [PATCH] " Linus Torvalds
2010-10-04 21:02 ` H. Peter Anvin
2010-10-04 21:12 ` Linus Torvalds
2010-10-04 21:21 ` H. Peter Anvin
2010-10-04 21:48 ` Borislav Petkov
2010-10-04 21:50 ` H. Peter Anvin
2010-10-04 21:53 ` H. Peter Anvin
2010-10-05 6:19 ` Borislav Petkov
2010-10-04 22:17 ` Hugh Dickins
2010-10-04 22:19 ` H. Peter Anvin
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