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-rw-r--r--arch/x86/kernel/cpu/addon_cpuid_features.c21
-rw-r--r--arch/x86/kernel/cpu/common.c27
-rw-r--r--arch/x86/kernel/setup_64.c9
-rw-r--r--arch/x86/mm/pat.c50
4 files changed, 47 insertions, 60 deletions
diff --git a/arch/x86/kernel/cpu/addon_cpuid_features.c b/arch/x86/kernel/cpu/addon_cpuid_features.c
index 238468ae1993..c2e1ce33c7cb 100644
--- a/arch/x86/kernel/cpu/addon_cpuid_features.c
+++ b/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/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 35b4f6a9c8ef..d0463a946247 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/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/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index 22c14e21c97c..80d80fab7006 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/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/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 277446cd30b6..60adbe22efa0 100644
--- a/arch/x86/mm/pat.c
+++ b/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",
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 17:32:20 +0100