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authorVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>2005-10-30 14:59:35 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-30 17:37:12 -0800
commit434440a2804639f11858d9d384c9505927feb186 (patch)
tree60bb584d535aa6ff3b632025facd167e844c6009
parent251e6912df43df54570ed68aade703b329c6cd5b (diff)
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[PATCH] x86: bug fix in P6 Machine check initialization
Make P6 MCA initialization code complaint with guidelines in IA-32 SDM Vol3. Bank 0 control register should not be set by OS and clear status registers on all banks on reset. This will prevent false MCE alarms on the systems that has some non-MCE information left-over in MC0_STATUS on reboot. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/i386/kernel/cpu/mcheck/p6.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/i386/kernel/cpu/mcheck/p6.c b/arch/i386/kernel/cpu/mcheck/p6.c
index 3c035b8fa3d..979b18bc95c 100644
--- a/arch/i386/kernel/cpu/mcheck/p6.c
+++ b/arch/i386/kernel/cpu/mcheck/p6.c
@@ -102,11 +102,16 @@ void __devinit intel_p6_mcheck_init(struct cpuinfo_x86 *c)
wrmsr(MSR_IA32_MCG_CTL, 0xffffffff, 0xffffffff);
nr_mce_banks = l & 0xff;
- /* Don't enable bank 0 on intel P6 cores, it goes bang quickly. */
- for (i=1; i<nr_mce_banks; i++) {
+ /*
+ * Following the example in IA-32 SDM Vol 3:
+ * - MC0_CTL should not be written
+ * - Status registers on all banks should be cleared on reset
+ */
+ for (i=1; i<nr_mce_banks; i++)
wrmsr (MSR_IA32_MC0_CTL+4*i, 0xffffffff, 0xffffffff);
+
+ for (i=0; i<nr_mce_banks; i++)
wrmsr (MSR_IA32_MC0_STATUS+4*i, 0x0, 0x0);
- }
set_in_cr4 (X86_CR4_MCE);
printk (KERN_INFO "Intel machine check reporting enabled on CPU#%d.\n",