[patch 02/43] Fix misreporting of #cores as #hyperthreads for Q9550

From: Greg KH
Date: Fri Mar 20 2009 - 19:26:40 EST


2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: Joe Korty <joe.korty@xxxxxxxx>

For the Q9550, in x86_64 mode, /proc/cpuinfo mistakenly
thinks the #cores present is the #hyperthreads present.
i386 mode was not examined but is assumed to have the
same problem.

A backport of the following three 2.6.29-rc1 patches
fixes the problem:

066941bd4eeb159307a5d7d795100d0887c00442:
[PATCH] x86: unmask CPUID levels on Intel CPUs
99fb4d349db7e7dacb2099c5cc320a9e2d31c1ef:
[PATCH] x86: unmask CPUID levels on Intel CPUs, fix
bdf21a49bab28f0d9613e8d8724ef9c9168b61b9:
[PATCH] x86: add MSR_IA32_MISC_ENABLE bits to <asm/msr-index.h>

>From the first patch: "If the CPUID limit bit in
MSR_IA32_MISC_ENABLE is set, clear it to make all CPUID
information available. This is required for some features
to work, in particular XSAVE."

Originally-Developed-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Backported-by: Joe Korty <joe.korty@xxxxxxxx>
Signed-off-by: Joe Korty <joe.korty@xxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
arch/x86/include/asm/msr-index.h | 29 +++++++++++++++++++++++++++++
arch/x86/kernel/cpu/intel.c | 13 +++++++++++++
2 files changed, 42 insertions(+)

--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -200,6 +200,35 @@
#define MSR_IA32_THERM_STATUS 0x0000019c
#define MSR_IA32_MISC_ENABLE 0x000001a0

+/* MISC_ENABLE bits: architectural */
+#define MSR_IA32_MISC_ENABLE_FAST_STRING (1ULL << 0)
+#define MSR_IA32_MISC_ENABLE_TCC (1ULL << 1)
+#define MSR_IA32_MISC_ENABLE_EMON (1ULL << 7)
+#define MSR_IA32_MISC_ENABLE_BTS_UNAVAIL (1ULL << 11)
+#define MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL (1ULL << 12)
+#define MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP (1ULL << 16)
+#define MSR_IA32_MISC_ENABLE_MWAIT (1ULL << 18)
+#define MSR_IA32_MISC_ENABLE_LIMIT_CPUID (1ULL << 22)
+#define MSR_IA32_MISC_ENABLE_XTPR_DISABLE (1ULL << 23)
+#define MSR_IA32_MISC_ENABLE_XD_DISABLE (1ULL << 34)
+
+/* MISC_ENABLE bits: model-specific, meaning may vary from core to core */
+#define MSR_IA32_MISC_ENABLE_X87_COMPAT (1ULL << 2)
+#define MSR_IA32_MISC_ENABLE_TM1 (1ULL << 3)
+#define MSR_IA32_MISC_ENABLE_SPLIT_LOCK_DISABLE (1ULL << 4)
+#define MSR_IA32_MISC_ENABLE_L3CACHE_DISABLE (1ULL << 6)
+#define MSR_IA32_MISC_ENABLE_SUPPRESS_LOCK (1ULL << 8)
+#define MSR_IA32_MISC_ENABLE_PREFETCH_DISABLE (1ULL << 9)
+#define MSR_IA32_MISC_ENABLE_FERR (1ULL << 10)
+#define MSR_IA32_MISC_ENABLE_FERR_MULTIPLEX (1ULL << 10)
+#define MSR_IA32_MISC_ENABLE_TM2 (1ULL << 13)
+#define MSR_IA32_MISC_ENABLE_ADJ_PREF_DISABLE (1ULL << 19)
+#define MSR_IA32_MISC_ENABLE_SPEEDSTEP_LOCK (1ULL << 20)
+#define MSR_IA32_MISC_ENABLE_L1D_CONTEXT (1ULL << 24)
+#define MSR_IA32_MISC_ENABLE_DCU_PREF_DISABLE (1ULL << 37)
+#define MSR_IA32_MISC_ENABLE_TURBO_DISABLE (1ULL << 38)
+#define MSR_IA32_MISC_ENABLE_IP_PREF_DISABLE (1ULL << 39)
+
/* Intel Model 6 */
#define MSR_P6_EVNTSEL0 0x00000186
#define MSR_P6_EVNTSEL1 0x00000187
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -30,6 +30,19 @@

static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
{
+ /* Unmask CPUID levels if masked: */
+ if (c->x86 == 6 && c->x86_model >= 15) {
+ u64 misc_enable;
+
+ rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
+
+ if (misc_enable & MSR_IA32_MISC_ENABLE_LIMIT_CPUID) {
+ misc_enable &= ~MSR_IA32_MISC_ENABLE_LIMIT_CPUID;
+ wrmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
+ c->cpuid_level = cpuid_eax(0);
+ }
+ }
+
if ((c->x86 == 0xf && c->x86_model >= 0x03) ||
(c->x86 == 0x6 && c->x86_model >= 0x0e))
set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);


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