From aef93c8bd506a78983d91cd576a97fee6e934ac1 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Sun, 14 Sep 2008 02:33:15 -0700 Subject: [PATCH] x86: identify_cpu_without_cpuid v2 Krzysztof found some old cyrix cpu where an mtrr-alike cpu feature was not detected properly. this one is based on Krzysztof' patch, and we call ->c_identify() in early_identify_cpu. need to call c_identify() for cpus without cpuid even earlier ... v2: Krzysztof point out need to give cyrix another chance about cpuid checking again, after ->c_identify() enables cpuid for it Signed-off-by: Yinghai Lu Cc: Krzysztof Helt Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 57 +++++++++++++++++++++++++----------- 1 file changed, 40 insertions(+), 17 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 9a57106c199..f5f25b85be9 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -485,6 +485,33 @@ static void __cpuinit get_cpu_cap(struct cpuinfo_x86 *c) c->x86_power = cpuid_edx(0x80000007); } + +static void __cpuinit identify_cpu_without_cpuid(struct cpuinfo_x86 *c) +{ +#ifdef CONFIG_X86_32 + int i; + + /* + * First of all, decide if this is a 486 or higher + * It's a 486 if we can modify the AC flag + */ + if (flag_is_changeable_p(X86_EFLAGS_AC)) + c->x86 = 4; + else + c->x86 = 3; + + for (i = 0; i < X86_VENDOR_NUM; i++) + if (cpu_devs[i] && cpu_devs[i]->c_identify) { + c->x86_vendor_id[0] = 0; + cpu_devs[i]->c_identify(c); + if (c->x86_vendor_id[0]) { + get_cpu_vendor(c); + break; + } + } +#endif +} + /* * Do minimum CPU detection early. * Fields really needed: vendor, cpuid_level, family, model, mask, @@ -503,13 +530,16 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) #endif c->x86_cache_alignment = c->x86_clflush_size; - if (!have_cpuid_p()) - return; - memset(&c->x86_capability, 0, sizeof c->x86_capability); - c->extended_cpuid_level = 0; + if (!have_cpuid_p()) + identify_cpu_without_cpuid(c); + + /* cyrix could have cpuid enabled via c_identify()*/ + if (!have_cpuid()) + return; + cpu_detect(c); get_cpu_vendor(c); @@ -583,10 +613,14 @@ static void __cpuinit detect_nopl(struct cpuinfo_x86 *c) static void __cpuinit generic_identify(struct cpuinfo_x86 *c) { + c->extended_cpuid_level = 0; + if (!have_cpuid_p()) - return; + identify_cpu_without_cpuid(c); - c->extended_cpuid_level = 0; + /* cyrix could have cpuid enabled via c_identify()*/ + if (!have_cpuid()) + return; cpu_detect(c); @@ -639,17 +673,6 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c) c->x86_cache_alignment = c->x86_clflush_size; memset(&c->x86_capability, 0, sizeof c->x86_capability); - if (!have_cpuid_p()) { - /* - * First of all, decide if this is a 486 or higher - * It's a 486 if we can modify the AC flag - */ - if (flag_is_changeable_p(X86_EFLAGS_AC)) - c->x86 = 4; - else - c->x86 = 3; - } - generic_identify(c); if (this_cpu->c_identify) -- 2.39.2