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Subject[tip:x86/core] x86/mce: Add infrastructure to support Local MCE
Commit-ID:  88d538672ea26223bca08225bc49f4e65e71683d
Gitweb: http://git.kernel.org/tip/88d538672ea26223bca08225bc49f4e65e71683d
Author: Ashok Raj <ashok.raj@intel.com>
AuthorDate: Thu, 4 Jun 2015 18:55:23 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 7 Jun 2015 15:33:14 +0200

x86/mce: Add infrastructure to support Local MCE

Initialize and prepare for handling LMCEs. Add a boot-time
option to disable LMCEs.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
[ Simplify stuff, align statements for better readability, reflow comments; kill
unused lmce_clear(); save us an MSR write if LMCE is already enabled. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1433436928-31903-16-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
Documentation/x86/x86_64/boot-options.txt | 3 +++
arch/x86/include/asm/mce.h | 5 ++++
arch/x86/kernel/cpu/mcheck/mce.c | 3 +++
arch/x86/kernel/cpu/mcheck/mce_intel.c | 43 +++++++++++++++++++++++++++++++
4 files changed, 54 insertions(+)

diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
index 5223479..68ed311 100644
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -31,6 +31,9 @@ Machine check
(e.g. BIOS or hardware monitoring applications), conflicting
with OS's error handling, and you cannot deactivate the agent,
then this option will be a help.
+ mce=no_lmce
+ Do not opt-in to Local MCE delivery. Use legacy method
+ to broadcast MCEs.
mce=bootlog
Enable logging of machine checks left over from booting.
Disabled by default on AMD because some BIOS leave bogus ones.
diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index ae2bfb8..982dfc3 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -109,6 +109,7 @@ struct mce_log {
struct mca_config {
bool dont_log_ce;
bool cmci_disabled;
+ bool lmce_disabled;
bool ignore_ce;
bool disabled;
bool ser;
@@ -184,12 +185,16 @@ void cmci_clear(void);
void cmci_reenable(void);
void cmci_rediscover(void);
void cmci_recheck(void);
+void lmce_clear(void);
+void lmce_enable(void);
#else
static inline void mce_intel_feature_init(struct cpuinfo_x86 *c) { }
static inline void cmci_clear(void) {}
static inline void cmci_reenable(void) {}
static inline void cmci_rediscover(void) {}
static inline void cmci_recheck(void) {}
+static inline void lmce_clear(void) {}
+static inline void lmce_enable(void) {}
#endif

#ifdef CONFIG_X86_MCE_AMD
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 0cbcd31..c8c6577 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1982,6 +1982,7 @@ void mce_disable_bank(int bank)
/*
* mce=off Disables machine check
* mce=no_cmci Disables CMCI
+ * mce=no_lmce Disables LMCE
* mce=dont_log_ce Clears corrected events silently, no log created for CEs.
* mce=ignore_ce Disables polling and CMCI, corrected events are not cleared.
* mce=TOLERANCELEVEL[,monarchtimeout] (number, see above)
@@ -2005,6 +2006,8 @@ static int __init mcheck_enable(char *str)
cfg->disabled = true;
else if (!strcmp(str, "no_cmci"))
cfg->cmci_disabled = true;
+ else if (!strcmp(str, "no_lmce"))
+ cfg->lmce_disabled = true;
else if (!strcmp(str, "dont_log_ce"))
cfg->dont_log_ce = true;
else if (!strcmp(str, "ignore_ce"))
diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c b/arch/x86/kernel/cpu/mcheck/mce_intel.c
index b4a41cf..2d872de 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_intel.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c
@@ -91,6 +91,36 @@ static int cmci_supported(int *banks)
return !!(cap & MCG_CMCI_P);
}

+static bool lmce_supported(void)
+{
+ u64 tmp;
+
+ if (mca_cfg.lmce_disabled)
+ return false;
+
+ rdmsrl(MSR_IA32_MCG_CAP, tmp);
+
+ /*
+ * LMCE depends on recovery support in the processor. Hence both
+ * MCG_SER_P and MCG_LMCE_P should be present in MCG_CAP.
+ */
+ if ((tmp & (MCG_SER_P | MCG_LMCE_P)) !=
+ (MCG_SER_P | MCG_LMCE_P))
+ return false;
+
+ /*
+ * BIOS should indicate support for LMCE by setting bit 20 in
+ * IA32_FEATURE_CONTROL without which touching MCG_EXT_CTL will
+ * generate a #GP fault.
+ */
+ rdmsrl(MSR_IA32_FEATURE_CONTROL, tmp);
+ if ((tmp & (FEATURE_CONTROL_LOCKED | FEATURE_CONTROL_LMCE)) ==
+ (FEATURE_CONTROL_LOCKED | FEATURE_CONTROL_LMCE))
+ return true;
+
+ return false;
+}
+
bool mce_intel_cmci_poll(void)
{
if (__this_cpu_read(cmci_storm_state) == CMCI_STORM_NONE)
@@ -405,6 +435,19 @@ static void intel_init_cmci(void)
cmci_recheck();
}

+void intel_init_lmce(void)
+{
+ u64 val;
+
+ if (!lmce_supported())
+ return;
+
+ rdmsrl(MSR_IA32_MCG_EXT_CTL, val);
+
+ if (!(val & MCG_EXT_CTL_LMCE_EN))
+ wrmsrl(MSR_IA32_MCG_EXT_CTL, val | MCG_EXT_CTL_LMCE_EN);
+}
+
void mce_intel_feature_init(struct cpuinfo_x86 *c)
{
intel_init_thermal(c);

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