[Patch V1 3/7] x86/microcode/core: Move microcode_check() to cpu/microcode/core.c

From: Ashok Raj
Date: Tue Nov 29 2022 - 16:09:34 EST


microcode_check() is only called from microcode/core.c. Move it and make
it static to prepare for upcoming fix of false negative when checking CPU
features after a microcode update. Also move get_cpu_cap() to processor.h
for general use outside of kernel/cpu.h

No functional change.

Suggested-by: Alison Schofield <alison.schofield@xxxxxxxxx>
Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
---
Tony
Add movement of get_cpu_cap() to commit log
Reinette
Avoid including ../cpu.h and move to more general header.
Alison
Split patch to just move the function before use inside microcode
files.
---
arch/x86/include/asm/processor.h | 3 +--
arch/x86/kernel/cpu/cpu.h | 1 -
arch/x86/kernel/cpu/common.c | 32 ----------------------------
arch/x86/kernel/cpu/microcode/core.c | 31 +++++++++++++++++++++++++++
4 files changed, 32 insertions(+), 35 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 67c9d73b31fa..f5380806f3fa 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -192,8 +192,8 @@ extern const struct seq_operations cpuinfo_op;

#define cache_line_size() (boot_cpu_data.x86_cache_alignment)

+extern void get_cpu_cap(struct cpuinfo_x86 *c);
extern void cpu_detect(struct cpuinfo_x86 *c);
-
static inline unsigned long long l1tf_pfn_limit(void)
{
return BIT_ULL(boot_cpu_data.x86_cache_bits - 1 - PAGE_SHIFT);
@@ -835,7 +835,6 @@ bool xen_set_default_idle(void);
#endif

void __noreturn stop_this_cpu(void *dummy);
-void microcode_check(void);

enum l1tf_mitigations {
L1TF_MITIGATION_OFF,
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index 7c9b5893c30a..a142b8d543a3 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -63,7 +63,6 @@ static inline void tsx_ap_init(void) { }

extern void init_spectral_chicken(struct cpuinfo_x86 *c);

-extern void get_cpu_cap(struct cpuinfo_x86 *c);
extern void get_cpu_address_sizes(struct cpuinfo_x86 *c);
extern void cpu_detect_cache_sizes(struct cpuinfo_x86 *c);
extern void init_scattered_cpuid_features(struct cpuinfo_x86 *c);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 3e508f239098..bbd362ead043 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2305,38 +2305,6 @@ void cpu_init_secondary(void)
}
#endif

-#ifdef CONFIG_MICROCODE_LATE_LOADING
-/*
- * The microcode loader calls this upon late microcode load to recheck features,
- * only when microcode has been updated. Caller holds microcode_mutex and CPU
- * hotplug lock.
- */
-void microcode_check(void)
-{
- struct cpuinfo_x86 info;
-
- perf_check_microcode();
-
- /* Reload CPUID max function as it might've changed. */
- info.cpuid_level = cpuid_eax(0);
-
- /*
- * Copy all capability leafs to pick up the synthetic ones so that
- * memcmp() below doesn't fail on that. The ones coming from CPUID will
- * get overwritten in get_cpu_cap().
- */
- memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability));
-
- get_cpu_cap(&info);
-
- if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability)))
- return;
-
- pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n");
- pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n");
-}
-#endif
-
/*
* Invoked from core CPU hotplug code after hotplug operations
*/
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 712aafff96e0..ef24e1d228d0 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -431,6 +431,37 @@ static int __reload_late(void *info)
return ret;
}

+/*
+ * The microcode loader calls this upon late microcode load to recheck features,
+ * only when microcode has been updated. Caller holds microcode_mutex and CPU
+ * hotplug lock.
+ */
+static void microcode_check(void)
+{
+ struct cpuinfo_x86 info;
+
+ perf_check_microcode();
+
+ /* Reload CPUID max function as it might've changed. */
+ info.cpuid_level = cpuid_eax(0);
+
+ /*
+ * Copy all capability leafs to pick up the synthetic ones so that
+ * memcmp() below doesn't fail on that. The ones coming from CPUID will
+ * get overwritten in get_cpu_cap().
+ */
+ memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability));
+
+ get_cpu_cap(&info);
+
+ if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability,
+ sizeof(info.x86_capability)))
+ return;
+
+ pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n");
+ pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n");
+}
+
/*
* Reload microcode late on all CPUs. Wait for a sec until they
* all gather together.
--
2.34.1