x86: c_p_a clflush_cache_range fix

Because in i386 early boot stage, boot_cpu_data may be not available,
which makes clflush_cach_range() into infinite loop, which is called
by change_page_attr(). This patch fixes this by setting
boot_cpu_data.x86_clflush_size in early_cpu_detect().

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index db28aa9e2f694b7f14669d3c66df8cc712cfab48..d608c9ebbfe242fb2e0f8cd9db7133515e941dfc 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -274,8 +274,10 @@ void __init cpu_detect(struct cpuinfo_x86 *c)
                if (c->x86 >= 0x6)
                        c->x86_model += ((tfms >> 16) & 0xF) << 4;
                c->x86_mask = tfms & 15;
-               if (cap0 & (1<<19))
+               if (cap0 & (1<<19)) {
                        c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8;
+                       c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
+               }
        }
 }
 static void __cpuinit early_get_cap(struct cpuinfo_x86 *c)
@@ -317,6 +319,7 @@ static void __init early_cpu_detect(void)
        struct cpuinfo_x86 *c = &boot_cpu_data;
 
        c->x86_cache_alignment = 32;
+       c->x86_clflush_size = 32;
 
        if (!have_cpuid_p())
                return;