[PATCH 2/4] x86/mce/AMD: Fix logic to obtain block address

[Aravind Gopalakrishnan]

In upcoming processors, the BLKPTR field is no longer used
to indicate the MSR number of the additional register.
Insted, it simply indicates the prescence of additional MSRs.

Fixing the logic here to gather MSR address from
MSR_AMD64_SMCA_MCx_MISC() for newer processors
and we fall back to existing logic for older processors.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
---
 arch/x86/include/asm/msr-index.h     |  4 ++
 arch/x86/kernel/cpu/mcheck/mce_amd.c | 94 +++++++++++++++++++++++++-----------
 2 files changed, 69 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 93bccbc..ca49e928e 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -265,10 +265,14 @@
 #define MSR_IA32_MCx_CTL2(x)		(MSR_IA32_MC0_CTL2 + (x))
 
 /* 'SMCA': AMD64 Scalable MCA */
+#define MSR_AMD64_SMCA_MC0_MISC0	0xc0002003
 #define MSR_AMD64_SMCA_MC0_CONFIG	0xc0002004
 #define MSR_AMD64_SMCA_MC0_IPID		0xc0002005
+#define MSR_AMD64_SMCA_MC0_MISC1	0xc000200a
+#define MSR_AMD64_SMCA_MCx_MISC(x)	(MSR_AMD64_SMCA_MC0_MISC0 + 0x10*(x))
 #define MSR_AMD64_SMCA_MCx_CONFIG(x)	(MSR_AMD64_SMCA_MC0_CONFIG + 0x10*(x))
 #define MSR_AMD64_SMCA_MCx_IPID(x)	(MSR_AMD64_SMCA_MC0_IPID + 0x10*(x))
+#define MSR_AMD64_SMCA_MCx_MISCy(x, y)	((MSR_AMD64_SMCA_MC0_MISC1 + y) + (0x10*(x)))
 
 #define MSR_P6_PERFCTR0			0x000000c1
 #define MSR_P6_PERFCTR1			0x000000c2
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index 8169103..4bdc836 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -286,6 +286,58 @@ static void deferred_error_interrupt_enable(struct cpuinfo_x86 *c)
 	wrmsr(MSR_CU_DEF_ERR, low, high);
 }
 
+static u32 get_block_address(u32 current_addr,
+			     u32 low,
+			     u32 high,
+			     unsigned int bank,
+			     unsigned int block)
+{
+	u32 addr = 0, offset = 0;
+
+	if (mce_flags.smca) {
+		if (!block) {
+			addr = MSR_AMD64_SMCA_MCx_MISC(bank);
+		} else {
+			/*
+			 * For SMCA enabled processors, BLKPTR field
+			 * of the first MISC register (MCx_MISC0) indicates
+			 * presence of additional MISC register set (MISC1-4)
+			 */
+			u32 smca_low, smca_high;
+
+			if (rdmsr_safe(MSR_AMD64_SMCA_MCx_CONFIG(bank),
+				       &smca_low, &smca_high) ||
+			    !(smca_low & MCI_CONFIG_MCAX))
+				goto nextaddr_out;
+
+			if (!rdmsr_safe(MSR_AMD64_SMCA_MCx_MISC(bank),
+					&smca_low, &smca_high) &&
+			    (smca_low & MASK_BLKPTR_LO))
+				addr = MSR_AMD64_SMCA_MCx_MISCy(bank,
+								block - 1);
+		}
+
+		goto nextaddr_out;
+	}
+
+	/* Fall back to method we used for older processors */
+	switch (block) {
+	case 0:
+		addr = MSR_IA32_MCx_MISC(bank);
+		break;
+	case 1:
+		offset = ((low & MASK_BLKPTR_LO) >> 21);
+		if (offset)
+			addr = MCG_XBLK_ADDR + offset;
+		break;
+	default:
+		addr = current_addr++;
+	}
+
+nextaddr_out:
+		return addr;
+}
+
 static int
 prepare_threshold_block(unsigned int bank, unsigned int block, u32 addr,
 			int offset, u32 misc_high)
@@ -348,16 +400,10 @@ void mce_amd_feature_init(struct cpuinfo_x86 *c)
 
 	for (bank = 0; bank < mca_cfg.banks; ++bank) {
 		for (block = 0; block < NR_BLOCKS; ++block) {
-			if (block == 0)
-				address = MSR_IA32_MCx_MISC(bank);
-			else if (block == 1) {
-				address = (low & MASK_BLKPTR_LO) >> 21;
-				if (!address)
-					break;
-
-				address += MCG_XBLK_ADDR;
-			} else
-				++address;
+			address = get_block_address(address, high, low,
+						    bank, block);
+			if (!address)
+				break;
 
 			if (rdmsr_safe(address, &low, &high))
 				break;
@@ -462,16 +508,10 @@ static void amd_threshold_interrupt(void)
 		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
 			continue;
 		for (block = 0; block < NR_BLOCKS; ++block) {
-			if (block == 0) {
-				address = MSR_IA32_MCx_MISC(bank);
-			} else if (block == 1) {
-				address = (low & MASK_BLKPTR_LO) >> 21;
-				if (!address)
-					break;
-				address += MCG_XBLK_ADDR;
-			} else {
-				++address;
-			}
+			address = get_block_address(address, high, low,
+						    bank, block);
+			if (!address)
+				break;
 
 			if (rdmsr_safe(address, &low, &high))
 				break;
@@ -691,16 +731,12 @@ static int allocate_threshold_blocks(unsigned int cpu, unsigned int bank,
 	if (err)
 		goto out_free;
 recurse:
-	if (!block) {
-		address = (low & MASK_BLKPTR_LO) >> 21;
-		if (!address)
-			return 0;
-		address += MCG_XBLK_ADDR;
-	} else {
-		++address;
-	}
+	address = get_block_address(address, high, low, bank, ++block);
+
+	if (!address)
+		return 0;
 
-	err = allocate_threshold_blocks(cpu, bank, ++block, address);
+	err = allocate_threshold_blocks(cpu, bank, block, address);
 	if (err)
 		goto out_free;
 
-- 
2.7.0