Re: [PATCH 2/5] mce: mask out undefined bits from MCi_ADDR

From: Chen Gong
Date: Mon Sep 05 2011 - 05:19:38 EST


ä 2011/9/1 6:25, Luck, Tony åé:
From: Tony Luck<tony.luck@xxxxxxxxx>

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@xxxxxxxxx>
---

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;

According to SDM, here it should be "m->misc & 0x3f"

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