linux-kernel - [PATCH 4.9 42/94] x86/MCE: Export memory

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Date:   Mon,  5 Jun 2017 18:17:18 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Borislav Petkov <bp@...e.de>,
        Tony Luck <tony.luck@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 4.9 42/94] x86/MCE: Export memory_error()

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Borislav Petkov <bp@...e.de>

commit 2d1f406139ec20320bf38bcd2461aa8e358084b5 upstream.

Export the function which checks whether an MCE is a memory error to
other users so that we can reuse the logic. Drop the boot_cpu_data use,
while at it, as mce.cpuvendor already has the CPU vendor in there.

Integrate a piece from a patch from Vishal Verma
<vishal.l.verma@...el.com> to export it for modules (nfit).

The main reason we're exporting it is that the nfit handler
nfit_handle_mce() needs to detect a memory error properly before doing
its recovery actions.

Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Tony Luck <tony.luck@...el.com>
Cc: Vishal Verma <vishal.l.verma@...el.com>
Link: http://lkml.kernel.org/r/20170519093915.15413-2-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/include/asm/mce.h       |    1 +
 arch/x86/kernel/cpu/mcheck/mce.c |   11 +++++------
 2 files changed, 6 insertions(+), 6 deletions(-)

--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -257,6 +257,7 @@ static inline void mce_amd_feature_init(
 #endif
 
 int mce_available(struct cpuinfo_x86 *c);
+bool mce_is_memory_error(struct mce *m);
 
 DECLARE_PER_CPU(unsigned, mce_exception_count);
 DECLARE_PER_CPU(unsigned, mce_poll_count);
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -598,16 +598,14 @@ static void mce_read_aux(struct mce *m,
 	}
 }
 
-static bool memory_error(struct mce *m)
+bool mce_is_memory_error(struct mce *m)
 {
-	struct cpuinfo_x86 *c = &boot_cpu_data;
-
-	if (c->x86_vendor == X86_VENDOR_AMD) {
+	if (m->cpuvendor == X86_VENDOR_AMD) {
 		/* ErrCodeExt[20:16] */
 		u8 xec = (m->status >> 16) & 0x1f;
 
 		return (xec == 0x0 || xec == 0x8);
-	} else if (c->x86_vendor == X86_VENDOR_INTEL) {
+	} else if (m->cpuvendor == X86_VENDOR_INTEL) {
 		/*
 		 * Intel SDM Volume 3B - 15.9.2 Compound Error Codes
 		 *
@@ -628,6 +626,7 @@ static bool memory_error(struct mce *m)
 
 	return false;
 }
+EXPORT_SYMBOL_GPL(mce_is_memory_error);
 
 DEFINE_PER_CPU(unsigned, mce_poll_count);
 
@@ -691,7 +690,7 @@ bool machine_check_poll(enum mcp_flags f
 
 		severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);
 
-		if (severity == MCE_DEFERRED_SEVERITY && memory_error(&m))
+		if (severity == MCE_DEFERRED_SEVERITY && mce_is_memory_error(&m))
 			if (m.status & MCI_STATUS_ADDRV)
 				m.severity = severity;