x86/mce: Pass pointer to saved pt_regs to severity calculation routines

New recovery features require additional information about processor
state when a machine check occurred. Pass pt_regs down to the routines
that need it.

No functional change.

Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201006210910.21062-2-tony.luck@intel.com

Author: youquan-song

arch/x86/kernel/cpu/mce/core.c

@@ -807,7 +807,7 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 			goto clear_it;
 
 		mce_read_aux(&m, i);
-		m.severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);
+		m.severity = mce_severity(&m, NULL, mca_cfg.tolerant, NULL, false);
 		/*
 		 * Don't get the IP here because it's unlikely to
 		 * have anything to do with the actual error location.
@@ -856,7 +856,7 @@ static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
 			quirk_no_way_out(i, m, regs);
 
 		m->bank = i;
-		if (mce_severity(m, mca_cfg.tolerant, &tmp, true) >= MCE_PANIC_SEVERITY) {
+		if (mce_severity(m, regs, mca_cfg.tolerant, &tmp, true) >= MCE_PANIC_SEVERITY) {
 			mce_read_aux(m, i);
 			*msg = tmp;
 			return 1;
@@ -956,7 +956,7 @@ static void mce_reign(void)
 	 */
 	if (m && global_worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3) {
 		/* call mce_severity() to get "msg" for panic */
-		mce_severity(m, mca_cfg.tolerant, &msg, true);
+		mce_severity(m, NULL, mca_cfg.tolerant, &msg, true);
 		mce_panic("Fatal machine check", m, msg);
 	}
 
@@ -1167,7 +1167,7 @@ static noinstr bool mce_check_crashing_cpu(void)
 	return false;
 }
 
-static void __mc_scan_banks(struct mce *m, struct mce *final,
+static void __mc_scan_banks(struct mce *m, struct pt_regs *regs, struct mce *final,
 			    unsigned long *toclear, unsigned long *valid_banks,
 			    int no_way_out, int *worst)
 {
@@ -1202,7 +1202,7 @@ static void __mc_scan_banks(struct mce *m, struct mce *final,
 		/* Set taint even when machine check was not enabled. */
 		add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 
-		severity = mce_severity(m, cfg->tolerant, NULL, true);
+		severity = mce_severity(m, regs, cfg->tolerant, NULL, true);
 
 		/*
 		 * When machine check was for corrected/deferred handler don't
@@ -1354,7 +1354,7 @@ noinstr void do_machine_check(struct pt_regs *regs)
 		order = mce_start(&no_way_out);
 	}
 
-	__mc_scan_banks(&m, final, toclear, valid_banks, no_way_out, &worst);
+	__mc_scan_banks(&m, regs, final, toclear, valid_banks, no_way_out, &worst);
 
 	if (!no_way_out)
 		mce_clear_state(toclear);
@@ -1376,7 +1376,7 @@ noinstr void do_machine_check(struct pt_regs *regs)
 		 * make sure we have the right "msg".
 		 */
 		if (worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3) {
-			mce_severity(&m, cfg->tolerant, &msg, true);
+			mce_severity(&m, regs, cfg->tolerant, &msg, true);
 			mce_panic("Local fatal machine check!", &m, msg);
 		}
 	}

arch/x86/kernel/cpu/mce/internal.h

@@ -38,7 +38,8 @@ int mce_gen_pool_add(struct mce *mce);
 int mce_gen_pool_init(void);
 struct llist_node *mce_gen_pool_prepare_records(void);
 
-extern int (*mce_severity)(struct mce *a, int tolerant, char **msg, bool is_excp);
+extern int (*mce_severity)(struct mce *a, struct pt_regs *regs,
+			   int tolerant, char **msg, bool is_excp);
 struct dentry *mce_get_debugfs_dir(void);
 
 extern mce_banks_t mce_banks_ce_disabled;

arch/x86/kernel/cpu/mce/severity.c

@@ -223,7 +223,7 @@ static struct severity {
  * distinguish an exception taken in user from from one
  * taken in the kernel.
  */
-static int error_context(struct mce *m)
+static int error_context(struct mce *m, struct pt_regs *regs)
 {
 	if ((m->cs & 3) == 3)
 		return IN_USER;
@@ -267,9 +267,10 @@ static int mce_severity_amd_smca(struct mce *m, enum context err_ctx)
  * See AMD Error Scope Hierarchy table in a newer BKDG. For example
  * 49125_15h_Models_30h-3Fh_BKDG.pdf, section "RAS Features"
  */
-static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_excp)
+static int mce_severity_amd(struct mce *m, struct pt_regs *regs, int tolerant,
+			    char **msg, bool is_excp)
 {
-	enum context ctx = error_context(m);
+	enum context ctx = error_context(m, regs);
 
 	/* Processor Context Corrupt, no need to fumble too much, die! */
 	if (m->status & MCI_STATUS_PCC)
@@ -319,10 +320,11 @@ static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_exc
 	return MCE_KEEP_SEVERITY;
 }
 
-static int mce_severity_intel(struct mce *m, int tolerant, char **msg, bool is_excp)
+static int mce_severity_intel(struct mce *m, struct pt_regs *regs,
+			      int tolerant, char **msg, bool is_excp)
 {
 	enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP);
-	enum context ctx = error_context(m);
+	enum context ctx = error_context(m, regs);
 	struct severity *s;
 
 	for (s = severities;; s++) {
@@ -356,7 +358,7 @@ static int mce_severity_intel(struct mce *m, int tolerant, char **msg, bool is_e
 }
 
 /* Default to mce_severity_intel */
-int (*mce_severity)(struct mce *m, int tolerant, char **msg, bool is_excp) =
+int (*mce_severity)(struct mce *m, struct pt_regs *regs, int tolerant, char **msg, bool is_excp) =
 		    mce_severity_intel;
 
 void __init mcheck_vendor_init_severity(void)