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From:   Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
To:     <x86@kernel.org>, <linux-edac@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     Tony Luck <tony.luck@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H . Peter Anvin" <hpa@zytor.com>,
        James Morse <james.morse@arm.com>,
        Robert Richter <rric@kernel.org>,
        Yazen Ghannam <yazen.ghannam@amd.com>,
        Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Subject: [PATCH v3 3/4] x86/mce, EDAC/mce_amd: Cache MCA_CONFIG[McaX] in struct mce_bank
Date:   Fri, 11 Feb 2022 16:34:41 -0600
Message-ID: <20220211223442.254489-4-Smita.KoralahalliChannabasappa@amd.com>
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Cache the value of MCA_CONFIG[McaX] in the existing mce_bank struct
similar to MCA_CONFIG[McaLsbInStatusSupported].

This simplifies and eliminates the need to read MCA_CONFIG register each
time to check McaX.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
 arch/x86/include/asm/mce.h         | 10 ++--------
 arch/x86/kernel/cpu/mce/amd.c      | 24 ++++++++++++++++++++----
 arch/x86/kernel/cpu/mce/internal.h | 13 ++++++++++++-
 arch/x86/kernel/cpu/mce/severity.c |  6 +-----
 drivers/edac/mce_amd.c             |  5 +----
 5 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index cc67c74e8b46..bb2d45b0bb89 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -50,14 +50,6 @@
 #define MCI_STATUS_POISON	BIT_ULL(43)  /* access poisonous data */
 #define MCI_STATUS_SCRUB	BIT_ULL(40)  /* Error detected during scrub operation */
 
-/*
- * McaX field if set indicates a given bank supports MCA extensions:
- *  - Deferred error interrupt type is specifiable by bank.
- *  - MCx_MISC0[BlkPtr] field indicates presence of extended MISC registers,
- *    But should not be used to determine MSR numbers.
- *  - TCC bit is present in MCx_STATUS.
- */
-#define MCI_CONFIG_MCAX		0x1
 #define MCI_IPID_MCATYPE	0xFFFF0000
 #define MCI_IPID_HWID		0xFFF
 
@@ -339,6 +331,7 @@ void mce_amd_feature_init(struct cpuinfo_x86 *c);
 enum smca_bank_types smca_get_bank_type(unsigned int cpu, unsigned int bank);
 void smca_extract_err_addr(struct mce *m);
 void smca_feature_init(void);
+bool smca_config_get_mcax(struct mce *m);
 #else
 
 static inline int mce_threshold_create_device(unsigned int cpu)		{ return 0; };
@@ -347,6 +340,7 @@ static inline bool amd_mce_is_memory_error(struct mce *m)		{ return false; };
 static inline void mce_amd_feature_init(struct cpuinfo_x86 *c)		{ }
 static inline void smca_extract_err_addr(struct mce *m) { }
 static inline void smca_feature_init(void) { }
+static inline bool smca_config_get_mcax(struct mce *m) { return false; };
 #endif
 
 static inline void mce_hygon_feature_init(struct cpuinfo_x86 *c)	{ return mce_amd_feature_init(c); }
diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c
index ed75d4bd2aff..4ec644611f33 100644
--- a/arch/x86/kernel/cpu/mce/amd.c
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -257,10 +257,7 @@ static void smca_set_misc_banks_map(unsigned int bank, unsigned int cpu)
 	 * For SMCA enabled processors, BLKPTR field of the first MISC register
 	 * (MCx_MISC0) indicates presence of additional MISC regs set (MISC1-4).
 	 */
-	if (rdmsr_safe(MSR_AMD64_SMCA_MCx_CONFIG(bank), &low, &high))
-		return;
-
-	if (!(low & MCI_CONFIG_MCAX))
+	if (!(this_cpu_ptr(mce_banks_array)[bank].mcax))
 		return;
 
 	if (rdmsr_safe(MSR_AMD64_SMCA_MCx_MISC(bank), &low, &high))
@@ -735,6 +732,24 @@ void smca_extract_err_addr(struct mce *m)
 	}
 }
 
+bool smca_config_get_mcax(struct mce *m)
+{
+	struct mce_bank *mce_banks;
+
+	/*
+	 * Check if the bank number is valid. It could be possible for the
+	 * user to input unavailable bank number when doing SW error injection
+	 * or to get an invalid bank number like with APEI memory handling.
+	 */
+	if (m->bank >= per_cpu(mce_num_banks, m->extcpu))
+		return false;
+
+	mce_banks = per_cpu_ptr(mce_banks_array, m->extcpu);
+
+	return mce_banks[m->bank].mcax;
+}
+EXPORT_SYMBOL_GPL(smca_config_get_mcax);
+
 void smca_feature_init(void)
 {
 	unsigned int bank;
@@ -743,6 +758,7 @@ void smca_feature_init(void)
 	for (bank = 0; bank < this_cpu_read(mce_num_banks); ++bank) {
 		rdmsrl(MSR_AMD64_SMCA_MCx_CONFIG(bank), mca_cfg);
 		this_cpu_ptr(mce_banks_array)[bank].lsb_in_status = !!(mca_cfg & BIT(8));
+		this_cpu_ptr(mce_banks_array)[bank].mcax          = !!(mca_cfg & BIT(0));
 	}
 }
 
diff --git a/arch/x86/kernel/cpu/mce/internal.h b/arch/x86/kernel/cpu/mce/internal.h
index 39dc37052cb9..422387f8699d 100644
--- a/arch/x86/kernel/cpu/mce/internal.h
+++ b/arch/x86/kernel/cpu/mce/internal.h
@@ -184,7 +184,18 @@ struct mce_bank {
 	 * the LSB field is found in MCA_STATUS, when set.
 	 */
 	__u64 lsb_in_status		: 1,
-	      __reserved_1		: 63;
+
+	/*
+	 * (AMD) MCA_CONFIG[McaX]: This bit when set indicates a given
+	 * bank supports MCA extensions:
+	 *  - Deferred error interrupt type is specifiable by bank.
+	 *  - MCx_MISC0[BlkPtr] field indicates presence of extended MISC registers,
+	 *    But should not be used to determine MSR numbers.
+	 *  - TCC bit is present in MCx_STATUS.
+	 */
+	      mcax			: 1,
+
+	      __reserved_1		: 62;
 };
 
 DECLARE_PER_CPU_READ_MOSTLY(struct mce_bank[MAX_NR_BANKS], mce_banks_array);
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 7aa2bda93cbb..95030a162f61 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -303,8 +303,6 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs)
 
 static int mce_severity_amd_smca(struct mce *m, enum context err_ctx)
 {
-	u64 mcx_cfg;
-
 	/*
 	 * We need to look at the following bits:
 	 * - "succor" bit (data poisoning support), and
@@ -314,10 +312,8 @@ static int mce_severity_amd_smca(struct mce *m, enum context err_ctx)
 	if (!mce_flags.succor)
 		return MCE_PANIC_SEVERITY;
 
-	mcx_cfg = mce_rdmsrl(MSR_AMD64_SMCA_MCx_CONFIG(m->bank));
-
 	/* TCC (Task context corrupt). If set and if IN_KERNEL, panic. */
-	if ((mcx_cfg & MCI_CONFIG_MCAX) &&
+	if ((smca_config_get_mcax(m)) &&
 	    (m->status & MCI_STATUS_TCC) &&
 	    (err_ctx == IN_KERNEL))
 		return MCE_PANIC_SEVERITY;
diff --git a/drivers/edac/mce_amd.c b/drivers/edac/mce_amd.c
index cc5c63feb26a..415201ce35c7 100644
--- a/drivers/edac/mce_amd.c
+++ b/drivers/edac/mce_amd.c
@@ -1254,11 +1254,8 @@ amd_decode_mce(struct notifier_block *nb, unsigned long val, void *data)
 		((m->status & MCI_STATUS_PCC)	? "PCC"	  : "-"));
 
 	if (boot_cpu_has(X86_FEATURE_SMCA)) {
-		u32 low, high;
-		u32 addr = MSR_AMD64_SMCA_MCx_CONFIG(m->bank);
 
-		if (!rdmsr_safe(addr, &low, &high) &&
-		    (low & MCI_CONFIG_MCAX))
+		if (smca_config_get_mcax(m))
 			pr_cont("|%s", ((m->status & MCI_STATUS_TCC) ? "TCC" : "-"));
 
 		pr_cont("|%s", ((m->status & MCI_STATUS_SYNDV) ? "SyndV" : "-"));
-- 
2.17.1