Re: [PATCH V2 4/5] x86/mcheck/AMD: Fix LVT offset configuration for thresholding

[Borislav Petkov]

On Fri, Jan 15, 2016 at 05:50:35PM -0600, Aravind Gopalakrishnan wrote:
> For processor families with  SMCA feature, the LVT offset
> for threshold interrupts is configured only in MSR 0xC0000410
> and not in each per bank MISC register as was done in earlier
> families.
> 
> Fixing the code here to obtain the LVT offset from the correct
> MSR for those families which have SMCA feature enabled.
> 
> Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
> ---
>  arch/x86/kernel/cpu/mcheck/mce_amd.c | 34 +++++++++++++++++++++++++++++++++-
>  1 file changed, 33 insertions(+), 1 deletion(-)

Did a small cleanup ontop:

---
From: Borislav Petkov <bp@xxxxxxx>
Subject: [PATCH] x86/mce/AMD: Carve out threshold block preparation

mce_amd_feature_init() was getting pretty fat, carve out the
threshold_block setup into a separate function on order to simplify
flow and make it more understandable.

No functionality change.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
---
 arch/x86/kernel/cpu/mcheck/mce_amd.c | 88 ++++++++++++++++++++----------------
 1 file changed, 50 insertions(+), 38 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index b9739b9b9341..57c7b296d1c5 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -267,14 +267,60 @@ static void deferred_error_interrupt_enable(struct cpuinfo_x86 *c)
 	wrmsr(MSR_CU_DEF_ERR, low, high);
 }
 
+static int
+prepare_threshold_block(unsigned int bank, unsigned int block, u32 addr,
+			int offset, u32 misc_high)
+{
+	unsigned int cpu = smp_processor_id();
+	struct threshold_block b;
+	int new;
+
+	if (!block)
+		per_cpu(bank_map, cpu) |= (1 << bank);
+
+	memset(&b, 0, sizeof(b));
+	b.cpu			= cpu;
+	b.bank			= bank;
+	b.block			= block;
+	b.address		= addr;
+	b.interrupt_capable	= lvt_interrupt_supported(bank, misc_high);
+
+	if (!b.interrupt_capable)
+		goto done;
+
+	b.interrupt_enable = 1;
+
+	if (mce_flags.smca) {
+		u32 smca_low = 0, smca_high = 0;
+
+		/* Gather LVT offset for thresholding */
+		if (rdmsr_safe(MSR_CU_DEF_ERR, &smca_low, &smca_high))
+			goto out;
+
+		new = (smca_low & SMCA_THR_LVT_OFF) >> 12;
+	} else {
+		new = (misc_high & MASK_LVTOFF_HI) >> 20;
+	}
+
+	offset = setup_APIC_mce_threshold(offset, new);
+
+	if ((offset == new) &&
+	    (mce_threshold_vector != amd_threshold_interrupt))
+		mce_threshold_vector = amd_threshold_interrupt;
+
+done:
+	mce_threshold_block_init(&b, offset);
+
+out:
+	return offset;
+}
+
 /* cpu init entry point, called from mce.c with preempt off */
 void mce_amd_feature_init(struct cpuinfo_x86 *c)
 {
-	struct threshold_block b;
-	unsigned int cpu = smp_processor_id();
 	u32 low = 0, high = 0, address = 0;
 	unsigned int bank, block;
-	int offset = -1, new;
+	int offset = -1;
 
 	for (bank = 0; bank < mca_cfg.banks; ++bank) {
 		for (block = 0; block < NR_BLOCKS; ++block) {
@@ -299,41 +345,7 @@ void mce_amd_feature_init(struct cpuinfo_x86 *c)
 			     (high & MASK_LOCKED_HI))
 				continue;
 
-			if (!block)
-				per_cpu(bank_map, cpu) |= (1 << bank);
-
-			memset(&b, 0, sizeof(b));
-			b.cpu			= cpu;
-			b.bank			= bank;
-			b.block			= block;
-			b.address		= address;
-			b.interrupt_capable	= lvt_interrupt_supported(bank, high);
-
-			if (!b.interrupt_capable)
-				goto init;
-
-			b.interrupt_enable = 1;
-
-			if (mce_flags.smca) {
-				u32 smca_low = 0, smca_high = 0;
-
-				/* Gather LVT offset for thresholding */
-				if (rdmsr_safe(MSR_CU_DEF_ERR, &smca_low, &smca_high))
-					break;
-
-				new = (smca_low & SMCA_THR_LVT_OFF) >> 12;
-			} else {
-				new = (high & MASK_LVTOFF_HI) >> 20;
-			}
-
-			offset  = setup_APIC_mce_threshold(offset, new);
-
-			if ((offset == new) &&
-			    (mce_threshold_vector != amd_threshold_interrupt))
-				mce_threshold_vector = amd_threshold_interrupt;
-
-init:
-			mce_threshold_block_init(&b, offset);
+			offset = prepare_threshold_block(bank, block, address, offset, high);
 		}
 	}
 
-- 
2.3.5

-- 
Regards/Gruss,
    Boris.

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