linux-kernel - [PATCH 1/2] x86: mce init optimization and signedness fixup

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Message-ID: <1192105075473-git-send-email-joerg.roedel@amd.com>
Date:	Thu, 11 Oct 2007 14:17:53 +0200
From:	"Joerg Roedel" <joerg.roedel@....com>
To:	"Thomas Gleixner" <tglx@...utronix.de>
cc:	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
	"Joerg Roedel" <joerg.roedel@....com>,
	"Christoph Egger" <Christoph.Egger@....com>
Subject: [PATCH 1/2] x86: mce init optimization and signedness fixup

MCG_CAP never reports a negative count of available error-reporting banks.
Therefore, make nr_mce_banks unsigned.
Check for MCA/MCE feature bits as early as possible.

Signed-off-by: Christoph Egger <Christoph.Egger@....com>
Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
 arch/x86/kernel/cpu/mcheck/mce.c |   12 ++++++++++--
 arch/x86/kernel/cpu/mcheck/mce.h |    2 +-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 34c781e..e1ac4f7 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -17,7 +17,7 @@
 #include "mce.h"
 
 int mce_disabled = 0;
-int nr_mce_banks;
+unsigned int nr_mce_banks;
 
 EXPORT_SYMBOL_GPL(nr_mce_banks);	/* non-fatal.o */
 
@@ -33,8 +33,16 @@ void fastcall (*machine_check_vector)(struct pt_regs *, long error_code) = unexp
 /* This has to be run for each processor */
 void mcheck_init(struct cpuinfo_x86 *c)
 {
-	if (mce_disabled==1)
+	if (mce_disabled == 1) {
+		printk(KERN_INFO "MCE support disabled by bootparam\n");
 		return;
+	}
+
+	if (!cpu_has(c, X86_FEATURE_MCA) || !cpu_has(c, X86_FEATURE_MCE)) {
+		printk(KERN_INFO "CPU%i: No machine check support available\n",
+			smp_processor_id());
+		return;
+	}
 
 	switch (c->x86_vendor) {
 		case X86_VENDOR_AMD:
diff --git a/arch/x86/kernel/cpu/mcheck/mce.h b/arch/x86/kernel/cpu/mcheck/mce.h
index 81fb6e2..9cbe812 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.h
+++ b/arch/x86/kernel/cpu/mcheck/mce.h
@@ -10,5 +10,5 @@ void winchip_mcheck_init(struct cpuinfo_x86 *c);
 /* Call the installed machine check handler for this CPU setup. */
 extern fastcall void (*machine_check_vector)(struct pt_regs *, long error_code);
 
-extern int nr_mce_banks;
+extern unsigned int nr_mce_banks;
 
-- 
1.5.2.5



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