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From:   Yazen Ghannam <yazen.ghannam@amd.com>
To:     <linux-edac@vger.kernel.org>
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        "Yazen Ghannam" <yazen.ghannam@amd.com>
Subject: [PATCH 02/20] x86/mce: Define mce_setup() helpers for global and per-CPU fields
Date:   Sat, 18 Nov 2023 13:32:30 -0600
Message-ID: <20231118193248.1296798-3-yazen.ghannam@amd.com>
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Generally, MCA information for an error is gathered on the CPU that
reported the error. In this case, CPU-specific information from the
running CPU will be correct.

However, this will be incorrect if the MCA information is gathered while
running on a CPU that didn't report the error. One example is creating
an MCA record using mce_setup() for errors reported from ACPI.

Split mce_setup() so that there is a helper function to gather global,
i.e. not CPU-specific, information and another helper for CPU-specific
information.

Don't set the CPU number in either helper function. This will be set
appropriately for each call site of the helpers.

Leave mce_setup() defined as-is for the common case when running on the
reporting CPU.

Get MCG_CAP in the global helper even though the register is per-CPU.
This value is not already cached per-CPU like other values. And it does
not assist with any per-CPU decoding or handling.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
 arch/x86/kernel/cpu/mce/core.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 1642018dd6c9..7e86086aa19c 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -115,20 +115,31 @@ static struct irq_work mce_irq_work;
  */
 BLOCKING_NOTIFIER_HEAD(x86_mce_decoder_chain);
 
+void mce_setup_global(struct mce *m)
+{
+	memset(m, 0, sizeof(struct mce));
+
+	m->cpuid	= cpuid_eax(1);
+	m->cpuvendor	= boot_cpu_data.x86_vendor;
+	m->mcgcap	= __rdmsr(MSR_IA32_MCG_CAP);
+	/* need the internal __ version to avoid deadlocks */
+	m->time		= __ktime_get_real_seconds();
+}
+
+void mce_setup_per_cpu(struct mce *m)
+{
+	m->apicid		= cpu_data(m->extcpu).topo.initial_apicid;
+	m->microcode		= cpu_data(m->extcpu).microcode;
+	m->ppin			= cpu_data(m->extcpu).ppin;
+	m->socketid		= cpu_data(m->extcpu).topo.pkg_id;
+}
+
 /* Do initial initialization of a struct mce */
 void mce_setup(struct mce *m)
 {
-	memset(m, 0, sizeof(struct mce));
+	mce_setup_global(m);
 	m->cpu = m->extcpu = smp_processor_id();
-	/* need the internal __ version to avoid deadlocks */
-	m->time = __ktime_get_real_seconds();
-	m->cpuvendor = boot_cpu_data.x86_vendor;
-	m->cpuid = cpuid_eax(1);
-	m->socketid = cpu_data(m->extcpu).topo.pkg_id;
-	m->apicid = cpu_data(m->extcpu).topo.initial_apicid;
-	m->mcgcap = __rdmsr(MSR_IA32_MCG_CAP);
-	m->ppin = cpu_data(m->extcpu).ppin;
-	m->microcode = boot_cpu_data.microcode;
+	mce_setup_per_cpu(m);
 }
 
 DEFINE_PER_CPU(struct mce, injectm);
-- 
2.34.1