From 5f2fb7abc9b122929f614cb394f08a923f059051 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Tue, 16 Sep 2008 09:29:40 -0700 Subject: [PATCH] --- yaml --- r: 109881 b: refs/heads/master c: ba0593bf553c450a03dbc5f8c1f0ff58b778a0c8 h: refs/heads/master i: 109879: 5c3fea04cccac9960f05153ef6de5564191f6c8d v: v3 --- [refs] | 2 +- trunk/arch/x86/kernel/cpu/common.c | 24 ++++-------------------- 2 files changed, 5 insertions(+), 21 deletions(-) diff --git a/[refs] b/[refs] index 92f3caf48eea..580ab5840949 100644 --- a/[refs] +++ b/[refs] @@ -1,2 +1,2 @@ --- -refs/heads/master: 5132895f14a57607152f7865dc862fb076ce2585 +refs/heads/master: ba0593bf553c450a03dbc5f8c1f0ff58b778a0c8 diff --git a/trunk/arch/x86/kernel/cpu/common.c b/trunk/arch/x86/kernel/cpu/common.c index 8aab8517642e..4e456bd955bb 100644 --- a/trunk/arch/x86/kernel/cpu/common.c +++ b/trunk/arch/x86/kernel/cpu/common.c @@ -344,31 +344,15 @@ static void __init early_cpu_detect(void) /* * The NOPL instruction is supposed to exist on all CPUs with - * family >= 6, unfortunately, that's not true in practice because + * family >= 6; unfortunately, that's not true in practice because * of early VIA chips and (more importantly) broken virtualizers that - * are not easy to detect. Hence, probe for it based on first - * principles. + * are not easy to detect. In the latter case it doesn't even *fail* + * reliably, so probing for it doesn't even work. Disable it completely + * unless we can find a reliable way to detect all the broken cases. */ static void __cpuinit detect_nopl(struct cpuinfo_x86 *c) { - const u32 nopl_signature = 0x888c53b1; /* Random number */ - u32 has_nopl = nopl_signature; - clear_cpu_cap(c, X86_FEATURE_NOPL); - if (c->x86 >= 6) { - asm volatile("\n" - "1: .byte 0x0f,0x1f,0xc0\n" /* nopl %eax */ - "2:\n" - " .section .fixup,\"ax\"\n" - "3: xor %0,%0\n" - " jmp 2b\n" - " .previous\n" - _ASM_EXTABLE(1b,3b) - : "+a" (has_nopl)); - - if (has_nopl == nopl_signature) - set_cpu_cap(c, X86_FEATURE_NOPL); - } } static void __cpuinit generic_identify(struct cpuinfo_x86 *c)