linux-kernel - [PATCH 2/5] mce: mask out undefined bits from MCi

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Date:	Wed, 31 Aug 2011 15:25:49 -0700
From:	"Luck, Tony" <tony.luck@...el.com>
To:	linux-kernel@...r.kernel.org
Cc:	"Ingo Molnar" <mingo@...e.hu>, "Borislav Petkov" <bp@...64.org>,
	"Hidetoshi Seto" <seto.hidetoshi@...fujitsu.com>
Subject: [PATCH 2/5] mce: mask out undefined bits from MCi_ADDR

From:	"Luck, Tony" <tony.luck@...el.com>

From: Tony Luck <tony.luck@...el.com>

Move duplicate copies of the code that reads ADDR/MISC registers
to a function. Add masking code for systems that have undefined
low-order bits in the MCi_ADDR register.

Based on original code by Andi Kleen

Signed-off-by: Tony Luck <tony.luck@...el.com>
---

Andi originally posted this as two patches - one to move the common
code to the new function "mce_read_aux()", the second to add the
masking.
Seto-san objected to the masking on the grounds that the bits might
contain something useful - but after some thought, I agree with Andi
that it is better to drop undefined bits.

 arch/x86/kernel/cpu/mcheck/mce.c |   31 +++++++++++++++++++++++--------
 1 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 91bb983..1ce64c3 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -490,6 +490,27 @@ static void mce_report_event(struct pt_regs *regs)
 	irq_work_queue(&__get_cpu_var(mce_irq_work));
 }
 
+/*
+ * Read ADDR and MISC registers.
+ */
+static void mce_read_aux(struct mce *m, int i)
+{
+	if (m->status & MCI_STATUS_MISCV)
+		m->misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
+	if (m->status & MCI_STATUS_ADDRV) {
+		m->addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
+
+		/*
+		 * Mask the reported address by the reported granuality.
+		 */
+		if (mce_ser && (m->status & MCI_STATUS_MISCV)) {
+			u8 shift = m->misc & 0x1f;
+			m->addr >>= shift;
+			m->addr <<= shift;
+		}
+	}
+}
+
 DEFINE_PER_CPU(unsigned, mce_poll_count);
 
 /*
@@ -540,10 +561,7 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 		    (m.status & (mce_ser ? MCI_STATUS_S : MCI_STATUS_UC)))
 			continue;
 
-		if (m.status & MCI_STATUS_MISCV)
-			m.misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
-		if (m.status & MCI_STATUS_ADDRV)
-			m.addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
+		mce_read_aux(&m, i);
 
 		if (!(flags & MCP_TIMESTAMP))
 			m.tsc = 0;
@@ -984,10 +1002,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 		if (severity == MCE_AR_SEVERITY)
 			kill_it = 1;
 
-		if (m.status & MCI_STATUS_MISCV)
-			m.misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
-		if (m.status & MCI_STATUS_ADDRV)
-			m.addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
+		mce_read_aux(&m, i);
 
 		/*
 		 * Action optional error. Queue address for later processing.
-- 
1.7.3.1

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