[PATCH v2 4/4] x86/mce: Add AMD SMCA support to SRAO notifier

[Yazen Ghannam]

From: Yazen Ghannam <yazen.ghannam@xxxxxxx>

Deferred errors on AMD systems may get an Action Optional severity with the
goal of being handled by the SRAO notifier block. However, the process of
determining if an address is usable is different between Intel and AMD. So
define vendor-specific functions for this.

Also, check for the AO severity before determining if an address is usable
to possibly save some cycles.

Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
---
Link: http://lkml.kernel.org/r/1486760120-60944-3-git-send-email-Yazen.Ghannam@xxxxxxx

v1->v2:
- New in v2. Based on v1 patch 3.
- Update SRAO notifier block to handle errors from SMCA systems.

 arch/x86/kernel/cpu/mcheck/mce.c | 52 ++++++++++++++++++++++++++++++----------
 1 file changed, 40 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 5e365a2..1a2669d 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -547,19 +547,49 @@ static void mce_report_event(struct pt_regs *regs)
  * be somewhat complicated (e.g. segment offset would require an instruction
  * parser). So only support physical addresses up to page granuality for now.
  */
-static int mce_usable_address(struct mce *m)
+static int mce_usable_address_intel(struct mce *m, unsigned long *pfn)
 {
-	if (!(m->status & MCI_STATUS_MISCV) || !(m->status & MCI_STATUS_ADDRV))
+	if (!(m->status & MCI_STATUS_MISCV))
 		return 0;
-
-	/* Checks after this one are Intel-specific: */
-	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
-		return 1;
-
 	if (MCI_MISC_ADDR_LSB(m->misc) > PAGE_SHIFT)
 		return 0;
 	if (MCI_MISC_ADDR_MODE(m->misc) != MCI_MISC_ADDR_PHYS)
 		return 0;
+
+	*pfn = m->addr >> PAGE_SHIFT;
+	return 1;
+}
+
+/* Only support this on SMCA systems and errors logged from a UMC. */
+static int mce_usable_address_amd(struct mce *m, unsigned long *pfn)
+{
+	u8 umc;
+	u16 nid = cpu_to_node(m->extcpu);
+	u64 addr;
+
+	if (!mce_flags.smca)
+		return 0;
+
+	umc = find_umc_channel(m);
+
+	if (umc < 0 || umc_normaddr_to_sysaddr(m->addr, nid, umc, &addr))
+		return 0;
+
+	*pfn = addr >> PAGE_SHIFT;
+	return 1;
+}
+
+static int mce_usable_address(struct mce *m, unsigned long *pfn)
+{
+	if (!(m->status & MCI_STATUS_ADDRV))
+		return 0;
+
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+		return mce_usable_address_intel(m, pfn);
+
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+		return mce_usable_address_amd(m, pfn);
+
 	return 1;
 }
 
@@ -567,15 +597,13 @@ static int srao_decode_notifier(struct notifier_block *nb, unsigned long val,
 				void *data)
 {
 	struct mce *mce = (struct mce *)data;
-	unsigned long pfn;
+	unsigned long pfn = 0;
 
 	if (!mce)
 		return NOTIFY_DONE;
 
-	if (mce_usable_address(mce) && (mce->severity == MCE_AO_SEVERITY)) {
-		pfn = mce->addr >> PAGE_SHIFT;
+	if ((mce->severity == MCE_AO_SEVERITY) && mce_usable_address(mce, &pfn))
 		memory_failure(pfn, MCE_VECTOR, 0);
-	}
 
 	return NOTIFY_OK;
 }
@@ -750,7 +778,7 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 		 */
 		if (!(flags & MCP_DONTLOG) && !mca_cfg.dont_log_ce)
 			mce_log(&m);
-		else if (mce_usable_address(&m)) {
+		else if (mce_usable_address(&m, NULL)) {
 			/*
 			 * Although we skipped logging this, we still want
 			 * to take action. Add to the pool so the registered
-- 
2.7.4