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| author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2008-10-09 21:31:58 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2008-10-09 21:31:58 +0100 |
| commit | 9e165acf1b9e37af7c0fa39399b43d0bd8600039 (patch) | |
| tree | 7ffdb0ad4c35ac9c19c4096b4f22ccc9b1eeefad /arch/x86/kernel/cpu/common.c | |
| parent | 6a4690c22f5da1eb1c898b61b6a80da52fbd976f (diff) | |
| parent | 791ccf2e4deeea8426b389fd0f5bb0e9167bb75d (diff) | |
| download | linux-9e165acf1b9e37af7c0fa39399b43d0bd8600039.tar.gz linux-9e165acf1b9e37af7c0fa39399b43d0bd8600039.tar.bz2 linux-9e165acf1b9e37af7c0fa39399b43d0bd8600039.zip | |
Merge branch 'at91' into devel
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 34 |
1 files changed, 32 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 80ab20d4fa39..8aab8517642e 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -13,6 +13,7 @@ #include <asm/mtrr.h> #include <asm/mce.h> #include <asm/pat.h> +#include <asm/asm.h> #ifdef CONFIG_X86_LOCAL_APIC #include <asm/mpspec.h> #include <asm/apic.h> @@ -334,11 +335,40 @@ static void __init early_cpu_detect(void) get_cpu_vendor(c, 1); + early_get_cap(c); + if (c->x86_vendor != X86_VENDOR_UNKNOWN && cpu_devs[c->x86_vendor]->c_early_init) cpu_devs[c->x86_vendor]->c_early_init(c); +} - early_get_cap(c); +/* + * 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. Hence, probe for it based on first + * principles. + */ +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) @@ -395,8 +425,8 @@ static void __cpuinit generic_identify(struct cpuinfo_x86 *c) } init_scattered_cpuid_features(c); + detect_nopl(c); } - } static void __cpuinit squash_the_stupid_serial_number(struct cpuinfo_x86 *c) |