[PATCH v6 03/15] x86/mce: Define BSP-only SMCA init

[Yazen Ghannam <yazen.ghannam@amd.com>]

Currently on AMD systems, MCA interrupt handler functions are set during
CPU init. However, the functions only need to be set once for the whole
system.

Assign the handlers only during BSP init. Do so only for SMCA systems to
maintain the old behavior for legacy systems.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---

Notes:
    Link:
    https://lore.kernel.org/r/20250825-wip-mca-updates-v5-9-865768a2eef8@amd.com
    
    v5->v6:
    * No change.
    
    v4->v5:
    * No change.
    
    v3->v4:
    * Change mce_smca_cpu_init() to smca_bsp_init().
    
    v2->v3:
    * No change.
    
    v1->v2:
    * New in v2.

 arch/x86/kernel/cpu/mce/amd.c      | 6 ++++++
 arch/x86/kernel/cpu/mce/core.c     | 3 +++
 arch/x86/kernel/cpu/mce/internal.h | 2 ++
 3 files changed, 11 insertions(+)

diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c
index 3c6c19eb0a18..7345e24bf658 100644
--- a/arch/x86/kernel/cpu/mce/amd.c
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -684,6 +684,12 @@ void mce_amd_feature_init(struct cpuinfo_x86 *c)
 		deferred_error_interrupt_enable(c);
 }
 
+void smca_bsp_init(void)
+{
+	mce_threshold_vector	  = amd_threshold_interrupt;
+	deferred_error_int_vector = amd_deferred_error_interrupt;
+}
+
 /*
  * DRAM ECC errors are reported in the Northbridge (bank 4) with
  * Extended Error Code 8.
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 79f3dd7f7851..a8cb7ff53e32 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -2244,6 +2244,9 @@ void mca_bsp_init(struct cpuinfo_x86 *c)
 	mce_flags.succor	 = cpu_feature_enabled(X86_FEATURE_SUCCOR);
 	mce_flags.smca		 = cpu_feature_enabled(X86_FEATURE_SMCA);
 
+	if (mce_flags.smca)
+		smca_bsp_init();
+
 	rdmsrq(MSR_IA32_MCG_CAP, cap);
 
 	/* Use accurate RIP reporting if available. */
diff --git a/arch/x86/kernel/cpu/mce/internal.h b/arch/x86/kernel/cpu/mce/internal.h
index 64ac25b95360..6cb2995f0ec1 100644
--- a/arch/x86/kernel/cpu/mce/internal.h
+++ b/arch/x86/kernel/cpu/mce/internal.h
@@ -294,12 +294,14 @@ static __always_inline void smca_extract_err_addr(struct mce *m)
 	m->addr &= GENMASK_ULL(55, lsb);
 }
 
+void smca_bsp_init(void);
 #else
 static inline void mce_threshold_create_device(unsigned int cpu)	{ }
 static inline void mce_threshold_remove_device(unsigned int cpu)	{ }
 static inline bool amd_filter_mce(struct mce *m) { return false; }
 static inline bool amd_mce_usable_address(struct mce *m) { return false; }
 static inline void smca_extract_err_addr(struct mce *m) { }
+static inline void smca_bsp_init(void) { }
 #endif
 
 #ifdef CONFIG_X86_ANCIENT_MCE

-- 
2.51.0