The following commit has been merged into the ras/core branch of tip:
Commit-ID: 70c459d915e838b7f536b8e26e0b3a6141bd2645
Gitweb: https://git.kernel.org/tip/70c459d915e838b7f536b8e26e0b3a6141bd2645
Author: Carlos Bilbao <carlos.bilbao@xxxxxxx>
AuthorDate: Tue, 05 Apr 2022 13:32:13 -05:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Mon, 25 Apr 2022 12:32:03 +02:00
x86/mce: Simplify AMD severity grading logic
The MCE handler needs to understand the severity of the machine errors to
act accordingly. Simplify the AMD grading logic following a logic that
closely resembles the descriptions of the public PPR documents. This will
help include more fine-grained grading of errors in the future.
[ bp: Touchups. ]
Signed-off-by: Carlos Bilbao <carlos.bilbao@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
Link: https://lore.kernel.org/r/20220405183212.354606-2-carlos.bilbao@xxxxxxx
---
arch/x86/kernel/cpu/mce/severity.c | 101 +++++++++-------------------
1 file changed, 36 insertions(+), 65 deletions(-)
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 1add869..d842148 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -301,85 +301,56 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs)
}
}
-static __always_inline int mce_severity_amd_smca(struct mce *m, enum context err_ctx)
+/* See AMD PPR(s) section Machine Check Error Handling. */
+static noinstr int mce_severity_amd(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
{
- u64 mcx_cfg;
+ int ret;
/*
- * We need to look at the following bits:
- * - "succor" bit (data poisoning support), and
- * - TCC bit (Task Context Corrupt)
- * in MCi_STATUS to determine error severity.
+ * Default return value: Action required, the error must be handled
+ * immediately.
*/
- 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) &&
- (m->status & MCI_STATUS_TCC) &&
- (err_ctx == IN_KERNEL))
- return MCE_PANIC_SEVERITY;
-
- /* ...otherwise invoke hwpoison handler. */
- return MCE_AR_SEVERITY;
-}
-
-/*
- * See AMD Error Scope Hierarchy table in a newer BKDG. For example
- * 49125_15h_Models_30h-3Fh_BKDG.pdf, section "RAS Features"
- */
-static noinstr int mce_severity_amd(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
-{
- enum context ctx = error_context(m, regs);
+ ret = MCE_AR_SEVERITY;
/* Processor Context Corrupt, no need to fumble too much, die! */
- if (m->status & MCI_STATUS_PCC)
- return MCE_PANIC_SEVERITY;
-
- if (m->status & MCI_STATUS_UC) {
-
- if (ctx == IN_KERNEL)
- return MCE_PANIC_SEVERITY;
+ if (m->status & MCI_STATUS_PCC) {
+ ret = MCE_PANIC_SEVERITY;
+ goto out;
+ }
- /*
- * On older systems where overflow_recov flag is not present, we
- * should simply panic if an error overflow occurs. If
- * overflow_recov flag is present and set, then software can try
- * to at least kill process to prolong system operation.
- */
- if (mce_flags.overflow_recov) {
- if (mce_flags.smca)
- return mce_severity_amd_smca(m, ctx);
-
- /* kill current process */
- return MCE_AR_SEVERITY;
- } else {
- /* at least one error was not logged */
- if (m->status & MCI_STATUS_OVER)
- return MCE_PANIC_SEVERITY;
- }
-
- /*
- * For any other case, return MCE_UC_SEVERITY so that we log the
- * error and exit #MC handler.
- */
- return MCE_UC_SEVERITY;
+ if (m->status & MCI_STATUS_DEFERRED) {
+ ret = MCE_DEFERRED_SEVERITY;
+ goto out;
}
/*
- * deferred error: poll handler catches these and adds to mce_ring so
- * memory-failure can take recovery actions.
+ * If the UC bit is not set, the system either corrected or deferred
+ * the error. No action will be required after logging the error.
*/
- if (m->status & MCI_STATUS_DEFERRED)
- return MCE_DEFERRED_SEVERITY;
+ if (!(m->status & MCI_STATUS_UC)) {
+ ret = MCE_KEEP_SEVERITY;
+ goto out;
+ }
/*
- * corrected error: poll handler catches these and passes responsibility
- * of decoding the error to EDAC
+ * On MCA overflow, without the MCA overflow recovery feature the
+ * system will not be able to recover, panic.
*/
- return MCE_KEEP_SEVERITY;
+ if ((m->status & MCI_STATUS_OVER) && !mce_flags.overflow_recov) {
+ ret = MCE_PANIC_SEVERITY;
+ goto out;
+ }
+
+ if (!mce_flags.succor) {
+ ret = MCE_PANIC_SEVERITY;
+ goto out;
+ }
+
+ if (error_context(m, regs) == IN_KERNEL)
+ ret = MCE_PANIC_SEVERITY;
+
+out:
+ return ret;
}
static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
|