---

yaml --- r: 96347 b: refs/heads/master c: 8d4a430 h: refs/heads/master i: 96345: 9258bbe 96343: a3a99ef v: v3
git-mirror · May 8, 2008 · 9cb607e · 9cb607e
1 parent 1456ed1
commit 9cb607e
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Showing 6 changed files with 56 additions and 61 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: cb3f43b22bbb5ddbf6ce3e2bac40ce6eba30aba0
+refs/heads/master: 8d4a4300854f3971502e81dacd930704cb88f606
diff --git a/trunk/arch/x86/kernel/cpu/addon_cpuid_features.c b/trunk/arch/x86/kernel/cpu/addon_cpuid_features.c
@@ -6,6 +6,7 @@
 
 #include <linux/cpu.h>
 
+#include <asm/pat.h>
 #include <asm/processor.h>
 
 struct cpuid_bit {
@@ -48,3 +49,23 @@ void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
 			set_cpu_cap(c, cb->feature);
 	}
 }
+
+#ifdef CONFIG_X86_PAT
+void __cpuinit validate_pat_support(struct cpuinfo_x86 *c)
+{
+	switch (c->x86_vendor) {
+	case X86_VENDOR_AMD:
+		if (c->x86 >= 0xf && c->x86 <= 0x11)
+			return;
+		break;
+	case X86_VENDOR_INTEL:
+		if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15))
+			return;
+		break;
+	}
+
+	pat_disable(cpu_has_pat ?
+		    "PAT disabled. Not yet verified on this CPU type." :
+		    "PAT not supported by CPU.");
+}
+#endif
diff --git a/trunk/arch/x86/kernel/cpu/common.c b/trunk/arch/x86/kernel/cpu/common.c
@@ -12,6 +12,7 @@
 #include <asm/mmu_context.h>
 #include <asm/mtrr.h>
 #include <asm/mce.h>
+#include <asm/pat.h>
 #ifdef CONFIG_X86_LOCAL_APIC
 #include <asm/mpspec.h>
 #include <asm/apic.h>
@@ -308,19 +309,6 @@ static void __cpuinit early_get_cap(struct cpuinfo_x86 *c)
 
 	}
 
-	clear_cpu_cap(c, X86_FEATURE_PAT);
-
-	switch (c->x86_vendor) {
-	case X86_VENDOR_AMD:
-		if (c->x86 >= 0xf && c->x86 <= 0x11)
-			set_cpu_cap(c, X86_FEATURE_PAT);
-		break;
-	case X86_VENDOR_INTEL:
-		if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15))
-			set_cpu_cap(c, X86_FEATURE_PAT);
-		break;
-	}
-
 }
 
 /*
@@ -409,18 +397,6 @@ static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
 		init_scattered_cpuid_features(c);
 	}
 
-	clear_cpu_cap(c, X86_FEATURE_PAT);
-
-	switch (c->x86_vendor) {
-	case X86_VENDOR_AMD:
-		if (c->x86 >= 0xf && c->x86 <= 0x11)
-			set_cpu_cap(c, X86_FEATURE_PAT);
-		break;
-	case X86_VENDOR_INTEL:
-		if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15))
-			set_cpu_cap(c, X86_FEATURE_PAT);
-		break;
-	}
 }
 
 static void __cpuinit squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
@@ -651,6 +627,7 @@ void __init early_cpu_init(void)
 		cpu_devs[cvdev->vendor] = cvdev->cpu_dev;
 
 	early_cpu_detect();
+	validate_pat_support(&boot_cpu_data);
 }
 
 /* Make sure %fs is initialized properly in idle threads */

diff --git a/trunk/arch/x86/kernel/setup_64.c b/trunk/arch/x86/kernel/setup_64.c
@@ -70,6 +70,7 @@
 #include <asm/ds.h>
 #include <asm/topology.h>
 #include <asm/trampoline.h>
+#include <asm/pat.h>
 
 #include <mach_apic.h>
 #ifdef CONFIG_PARAVIRT
@@ -1063,25 +1064,19 @@ static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c)
 	if (c->extended_cpuid_level >= 0x80000007)
 		c->x86_power = cpuid_edx(0x80000007);
 
-
-	clear_cpu_cap(c, X86_FEATURE_PAT);
-
 	switch (c->x86_vendor) {
 	case X86_VENDOR_AMD:
 		early_init_amd(c);
-		if (c->x86 >= 0xf && c->x86 <= 0x11)
-			set_cpu_cap(c, X86_FEATURE_PAT);
 		break;
 	case X86_VENDOR_INTEL:
 		early_init_intel(c);
-		if (c->x86 == 0xF || (c->x86 == 6 && c->x86_model >= 15))
-			set_cpu_cap(c, X86_FEATURE_PAT);
 		break;
 	case X86_VENDOR_CENTAUR:
 		early_init_centaur(c);
 		break;
 	}
 
+	validate_pat_support(c);
 }
 
 /*

diff --git a/trunk/arch/x86/mm/pat.c b/trunk/arch/x86/mm/pat.c
@@ -25,31 +25,24 @@
 #include <asm/mtrr.h>
 #include <asm/io.h>
 
-int pat_wc_enabled = 1;
+#ifdef CONFIG_X86_PAT
+int __read_mostly pat_wc_enabled = 1;
 
-static u64 __read_mostly boot_pat_state;
-
-static int nopat(char *str)
+void __init pat_disable(char *reason)
 {
 	pat_wc_enabled = 0;
-	printk(KERN_INFO "x86: PAT support disabled.\n");
-
-	return 0;
+	printk(KERN_INFO "%s\n", reason);
 }
-early_param("nopat", nopat);
 
-static int pat_known_cpu(void)
+static int nopat(char *str)
 {
-	if (!pat_wc_enabled)
-		return 0;
-
-	if (cpu_has_pat)
-		return 1;
-
-	pat_wc_enabled = 0;
-	printk(KERN_INFO "CPU and/or kernel does not support PAT.\n");
+	pat_disable("PAT support disabled.");
 	return 0;
 }
+early_param("nopat", nopat);
+#endif
+
+static u64 __read_mostly boot_pat_state;
 
 enum {
 	PAT_UC = 0,		/* uncached */
@@ -66,17 +59,19 @@ void pat_init(void)
 {
 	u64 pat;
 
-#ifndef CONFIG_X86_PAT
-	nopat(NULL);
-#endif
-
-	/* Boot CPU enables PAT based on CPU feature */
-	if (!smp_processor_id() && !pat_known_cpu())
+	if (!pat_wc_enabled)
 		return;
 
-	/* APs enable PAT iff boot CPU has enabled it before */
-	if (smp_processor_id() && !pat_wc_enabled)
-		return;
+	/* Paranoia check. */
+	if (!cpu_has_pat) {
+		printk(KERN_ERR "PAT enabled, but CPU feature cleared\n");
+		/*
+		 * Panic if this happens on the secondary CPU, and we
+		 * switched to PAT on the boot CPU. We have no way to
+		 * undo PAT.
+		*/
+		BUG_ON(boot_pat_state);
+	}
 
 	/* Set PWT to Write-Combining. All other bits stay the same */
 	/*
@@ -95,9 +90,8 @@ void pat_init(void)
 	      PAT(4,WB) | PAT(5,WC) | PAT(6,UC_MINUS) | PAT(7,UC);
 
 	/* Boot CPU check */
-	if (!smp_processor_id()) {
+	if (!boot_pat_state)
 		rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
-	}
 
 	wrmsrl(MSR_IA32_CR_PAT, pat);
 	printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n",

diff --git a/trunk/include/asm-x86/pat.h b/trunk/include/asm-x86/pat.h
@@ -4,13 +4,21 @@
 
 #include <linux/types.h>
 
+#ifdef CONFIG_X86_PAT
 extern int pat_wc_enabled;
+extern void validate_pat_support(struct cpuinfo_x86 *c);
+#else
+static const int pat_wc_enabled = 0;
+static inline void validate_pat_support(struct cpuinfo_x86 *c) { }
+#endif
 
 extern void pat_init(void);
 
 extern int reserve_memtype(u64 start, u64 end,
 		unsigned long req_type, unsigned long *ret_type);
 extern int free_memtype(u64 start, u64 end);
 
+extern void pat_disable(char *reason);
+
 #endif