[PATCH v2 2/6] x86/cpu: Merge Intel and AMD ppin_init() functions

From: Tony Luck
Date: Fri Jan 21 2022 - 12:47:59 EST


The code to decide whether a system supports the PPIN (Protected
Processor Inventory Number) MSR was cloned from the Intel
implementation. Apart from the X86_FEATURE bit and the MSR numbers it is
identical.

Merge the two functions into common x86 code, but use x86_match_cpu()
instead of the switch (c->x86_model) that was used by the old Intel
code.

No functional change.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
arch/x86/kernel/cpu/amd.c | 30 -------------
arch/x86/kernel/cpu/common.c | 76 +++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/mce/intel.c | 42 ------------------
3 files changed, 76 insertions(+), 72 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 4edb6f0f628c..bad0fa4c1779 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -394,35 +394,6 @@ static void amd_detect_cmp(struct cpuinfo_x86 *c)
per_cpu(cpu_llc_id, cpu) = c->cpu_die_id = c->phys_proc_id;
}

-static void amd_detect_ppin(struct cpuinfo_x86 *c)
-{
- unsigned long long val;
-
- if (!cpu_has(c, X86_FEATURE_AMD_PPIN))
- return;
-
- /* When PPIN is defined in CPUID, still need to check PPIN_CTL MSR */
- if (rdmsrl_safe(MSR_AMD_PPIN_CTL, &val))
- goto clear_ppin;
-
- /* PPIN is locked in disabled mode, clear feature bit */
- if ((val & 3UL) == 1UL)
- goto clear_ppin;
-
- /* If PPIN is disabled, try to enable it */
- if (!(val & 2UL)) {
- wrmsrl_safe(MSR_AMD_PPIN_CTL, val | 2UL);
- rdmsrl_safe(MSR_AMD_PPIN_CTL, &val);
- }
-
- /* If PPIN_EN bit is 1, return from here; otherwise fall through */
- if (val & 2UL)
- return;
-
-clear_ppin:
- clear_cpu_cap(c, X86_FEATURE_AMD_PPIN);
-}
-
u32 amd_get_nodes_per_socket(void)
{
return nodes_per_socket;
@@ -947,7 +918,6 @@ static void init_amd(struct cpuinfo_x86 *c)
amd_detect_cmp(c);
amd_get_topology(c);
srat_detect_node(c);
- amd_detect_ppin(c);

init_amd_cacheinfo(c);

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 7b8382c11788..b7700a47eadd 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -88,6 +88,80 @@ EXPORT_SYMBOL_GPL(get_llc_id);
/* L2 cache ID of each logical CPU */
DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id) = BAD_APICID;

+static struct ppin_info {
+ int feature;
+ int msr_ppin_ctl;
+} ppin_info[] = {
+ [X86_VENDOR_INTEL] = {
+ .feature = X86_FEATURE_INTEL_PPIN,
+ .msr_ppin_ctl = MSR_PPIN_CTL,
+ .msr_ppin = MSR_PPIN
+ },
+ [X86_VENDOR_AMD] = {
+ .feature = X86_FEATURE_AMD_PPIN,
+ .msr_ppin_ctl = MSR_AMD_PPIN_CTL,
+ .msr_ppin = MSR_AMD_PPIN
+ },
+};
+
+static const struct x86_cpu_id ppin_cpuids[] = {
+ X86_MATCH_FEATURE(X86_FEATURE_AMD_PPIN, &ppin_info[X86_VENDOR_AMD]),
+
+ /* Legacy models without CPUID enumeration */
+ X86_MATCH_INTEL_FAM6_MODEL(IVYBRIDGE_X, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_D, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_X, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNL, &ppin_info[X86_VENDOR_INTEL]),
+ X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNM, &ppin_info[X86_VENDOR_INTEL]),
+
+ {}
+};
+
+static void ppin_init(struct cpuinfo_x86 *c)
+{
+ const struct x86_cpu_id *id;
+ unsigned long long val;
+ struct ppin_info *info;
+
+ id = x86_match_cpu(ppin_cpuids);
+ if (!id)
+ return;
+
+ /*
+ * Testing the presence of the MSR is not enough. Need to check
+ * that the PPIN_CTL allows reading of the PPIN.
+ */
+ info = (struct ppin_info *)id->driver_data;
+
+ if (rdmsrl_safe(info->msr_ppin_ctl, &val))
+ goto clear_ppin;
+
+ if ((val & 3UL) == 1UL) {
+ /* PPIN locked in disabled mode */
+ goto clear_ppin;
+ }
+
+ /* If PPIN is disabled, try to enable */
+ if (!(val & 2UL)) {
+ wrmsrl_safe(info->msr_ppin_ctl, val | 2UL);
+ rdmsrl_safe(info->msr_ppin_ctl, &val);
+ }
+
+ /* Is the enable bit set? */
+ if (val & 2UL) {
+ set_cpu_cap(c, info->feature);
+ return;
+ }
+
+clear_ppin:
+ clear_cpu_cap(c, info->feature);
+}
+
/* correctly size the local cpu masks */
void __init setup_cpu_local_masks(void)
{
@@ -1655,6 +1729,8 @@ static void identify_cpu(struct cpuinfo_x86 *c)
c->x86_capability[i] |= boot_cpu_data.x86_capability[i];
}

+ ppin_init(c);
+
/* Init Machine Check Exception if available. */
mcheck_cpu_init(c);

diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c
index baafbb37be67..95275a5e57e0 100644
--- a/arch/x86/kernel/cpu/mce/intel.c
+++ b/arch/x86/kernel/cpu/mce/intel.c
@@ -470,47 +470,6 @@ void intel_clear_lmce(void)
wrmsrl(MSR_IA32_MCG_EXT_CTL, val);
}

-static void intel_ppin_init(struct cpuinfo_x86 *c)
-{
- unsigned long long val;
-
- /*
- * Even if testing the presence of the MSR would be enough, we don't
- * want to risk the situation where other models reuse this MSR for
- * other purposes.
- */
- switch (c->x86_model) {
- case INTEL_FAM6_IVYBRIDGE_X:
- case INTEL_FAM6_HASWELL_X:
- case INTEL_FAM6_BROADWELL_D:
- case INTEL_FAM6_BROADWELL_X:
- case INTEL_FAM6_SKYLAKE_X:
- case INTEL_FAM6_ICELAKE_X:
- case INTEL_FAM6_ICELAKE_D:
- case INTEL_FAM6_SAPPHIRERAPIDS_X:
- case INTEL_FAM6_XEON_PHI_KNL:
- case INTEL_FAM6_XEON_PHI_KNM:
-
- if (rdmsrl_safe(MSR_PPIN_CTL, &val))
- return;
-
- if ((val & 3UL) == 1UL) {
- /* PPIN locked in disabled mode */
- return;
- }
-
- /* If PPIN is disabled, try to enable */
- if (!(val & 2UL)) {
- wrmsrl_safe(MSR_PPIN_CTL, val | 2UL);
- rdmsrl_safe(MSR_PPIN_CTL, &val);
- }
-
- /* Is the enable bit set? */
- if (val & 2UL)
- set_cpu_cap(c, X86_FEATURE_INTEL_PPIN);
- }
-}
-
/*
* Enable additional error logs from the integrated
* memory controller on processors that support this.
@@ -535,7 +494,6 @@ void mce_intel_feature_init(struct cpuinfo_x86 *c)
{
intel_init_cmci();
intel_init_lmce();
- intel_ppin_init(c);
intel_imc_init(c);
}

--
2.31.1