New version of early CPU detect

diff -u linux-2.6.5-i386/arch/i386/kernel/cpu/common.c-o linux-2.6.5-i386/arch/i386/kernel/cpu/common.c
@@ -137,8 +137,7 @@
 }
 
 
-
-void __init get_cpu_vendor(struct cpuinfo_x86 *c)
+void __init get_cpu_vendor(struct cpuinfo_x86 *c, int early)
 {
 	char *v = c->x86_vendor_id;
 	int i;

@@ -149,7 +148,8 @@
 			    (cpu_devs[i]->c_ident[1] && 
 			     !strcmp(v,cpu_devs[i]->c_ident[1]))) {
 				c->x86_vendor = i;
-				this_cpu = cpu_devs[i];
+				if (!early) 
+					this_cpu = cpu_devs[i];
 				break;
 			}
 		}

@@ -193,6 +193,44 @@
 	return flag_is_changeable_p(X86_EFLAGS_ID);
 }
 
+/* Do minimum CPU detection early. 
+   Fields really needed: vendor, cpuid_level, family, model, mask, cache alignment.
+   The others are not touched to avoid unwanted side effects. */
+void __init early_cpu_detect(void) 
+{ 
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	if (!have_cpuid_p())
+		return;
+
+	/* Get vendor name */
+	cpuid(0x00000000, &c->cpuid_level,
+	      (int *)&c->x86_vendor_id[0],
+	      (int *)&c->x86_vendor_id[8],
+	      (int *)&c->x86_vendor_id[4]);
+	
+	get_cpu_vendor(c, 1);
+
+	c->x86 = 4;
+	c->x86_cache_alignment = 32;
+
+	if (c->cpuid_level >= 0x00000001) {
+		u32 junk, tfms, cap0, misc;
+		cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
+		c->x86 = (tfms >> 8) & 15;
+		c->x86_model = (tfms >> 4) & 15;
+		if (c->x86 == 0xf) {
+			c->x86 += (tfms >> 20) & 0xff;
+			c->x86_model += ((tfms >> 16) & 0xF) << 4;
+		} 
+		c->x86_mask = tfms & 15;
+		if (cap0 & (1<<19)) 
+			c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8;
+	}
+
+	early_intel_workaround(c); 
+} 
+
 void __init generic_identify(struct cpuinfo_x86 * c)
 {
 	u32 tfms, xlvl;

@@ -205,7 +243,7 @@
 		      (int *)&c->x86_vendor_id[8],
 		      (int *)&c->x86_vendor_id[4]);
 		
-		get_cpu_vendor(c);
+		get_cpu_vendor(c, 0);
 		/* Initialize the standard set of capabilities */
 		/* Note that the vendor-specific code below might override */
 	

@@ -383,7 +421,6 @@
  
 void __init dodgy_tsc(void)
 {
-	get_cpu_vendor(&boot_cpu_data);
 	if (( boot_cpu_data.x86_vendor == X86_VENDOR_CYRIX ) ||
 	    ( boot_cpu_data.x86_vendor == X86_VENDOR_NSC   ))
 		cpu_devs[X86_VENDOR_CYRIX]->c_init(&boot_cpu_data);

@@ -431,9 +468,11 @@
 extern int rise_init_cpu(void);
 extern int nexgen_init_cpu(void);
 extern int umc_init_cpu(void);
+void early_cpu_detect(void);
 
 void __init early_cpu_init(void)
 {
+	early_cpu_detect();
 	intel_cpu_init();
 	cyrix_init_cpu();
 	nsc_init_cpu();

diff -u linux-2.6.5-i386/arch/i386/kernel/cpu/cpu.h-o linux-2.6.5-i386/arch/i386/kernel/cpu/cpu.h
@@ -26,3 +26,6 @@
 
 extern void generic_identify(struct cpuinfo_x86 * c);
 extern int have_cpuid_p(void);
+
+extern void early_intel_workaround(struct cpuinfo_x86 *c);
+

62 lines not on this page · raw message

diff -u linux-2.6.7-work/arch/i386/kernel/cpu/common.c-o linux-2.6.7-work/arch/i386/kernel/cpu/common.c
@@ -143,8 +143,9 @@
 	char *v = c->x86_vendor_id;
 	int i;
 
+	c->x86_vendor = X86_VENDOR_UNKNOWN;
 	for (i = 0; i < X86_VENDOR_NUM; i++) {
-		if (cpu_devs[i]) {
+		if (cpu_devs[i] || early) {
 			if (!strcmp(v,cpu_devs[i]->c_ident[0]) ||
 			    (cpu_devs[i]->c_ident[1] && 
 			     !strcmp(v,cpu_devs[i]->c_ident[1]))) {

diff -u linux-2.6.7-work/arch/i386/kernel/cpu/common.c-o linux-2.6.7-work/arch/i386/kernel/cpu/common.c
@@ -473,7 +473,6 @@
 
 void __init early_cpu_init(void)
 {
-	early_cpu_detect();
 	intel_cpu_init();
 	cyrix_init_cpu();
 	nsc_init_cpu();

@@ -483,6 +482,7 @@
 	rise_init_cpu();
 	nexgen_init_cpu();
 	umc_init_cpu();
+	early_cpu_detect();
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
 	/* pse is not compatible with on-the-fly unmapping,