From 366d4a43b1a7a861c356a0e407c4f03f454d42ea Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 4 Oct 2010 09:31:27 +0200 Subject: [PATCH] x86, cpu: Fix X86_FEATURE_NOPL ba0593bf553c450a03dbc5f8c1f0ff58b778a0c8 cleared the aforementioned cpuid bit only on 32-bit due to various problems with Virtual PC. This somehow got lost during the 32- + 64-bit merge so restore the feature bit on 64-bit. For that, set it explicitly for non-constant arguments of cpu_has(). Update comment for future reference. Signed-off-by: Borislav Petkov LKML-Reference: <20101004073127.GA20305@liondog.tnic> Cc: Ryan O'Neill Cc: Linus Torvalds Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/common.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index f2f9ac7da25c..927e630aeaf3 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -704,16 +704,21 @@ void __init early_cpu_init(void) } /* - * The NOPL instruction is supposed to exist on all CPUs with - * 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. In the latter case it doesn't even *fail* - * reliably, so probing for it doesn't even work. Disable it completely + * The NOPL instruction is supposed to exist on all CPUs of 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. In the latter case it doesn't even *fail* reliably, so + * probing for it doesn't even work. Disable it completely on 32-bit * unless we can find a reliable way to detect all the broken cases. + * Enable it explicitly on 64-bit for non-constant inputs of cpu_has(). */ static void __cpuinit detect_nopl(struct cpuinfo_x86 *c) { +#ifdef CONFIG_X86_32 clear_cpu_cap(c, X86_FEATURE_NOPL); +#else + set_cpu_cap(c, X86_FEATURE_NOPL); +#endif } static void __cpuinit generic_identify(struct cpuinfo_x86 *c) -- 2.30.2