[PATCH v6 02/51] x86/apic: Add CONFIG_X86_LOCAL_APIC=n stubs for APIC timer frequency APIs

Sean Christopherson <[email protected]> Thu, 6 Aug 2026 16:35:19 -0700
Newsgroups org.kernel.vger.linux-hyperv,dev.linux.lists.linux-coco,dev.linux.lists.virtualization,org.kernel.vger.kvm,org.kernel.vger.linux-kernel,org.xenproject.lists.xen-devel
Message-ID <[email protected]>
Add stubs for the apic_set_timer_frequency_{,k}hz() APIs when the kernel is
built without support for a local APIC, and drop #ifdefs in callers that
don't need to check CONFIG_X86_LOCAL_APIC for other reasons.

No functional change intended.

Signed-off-by: Sean Christopherson <[email protected]>
---
 arch/x86/include/asm/apic.h  | 2 ++
 arch/x86/kernel/cpu/vmware.c | 2 --
 arch/x86/kernel/tsc.c        | 2 --
 arch/x86/kernel/tsc_msr.c    | 2 --
 4 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 6946220a6008..9c5084f3317f 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -189,6 +189,8 @@ static inline void disable_local_APIC(void) { }
 # define setup_boot_APIC_clock x86_init_noop
 # define setup_secondary_APIC_clock x86_init_noop
 static inline void lapic_update_tsc_freq(void) { }
+static inline void apic_set_timer_frequency_hz(u64 freq_hz, const char *source) { }
+static inline void apic_set_timer_frequency_khz(u64 freq_khz, const char *source) { }
 static inline void init_bsp_APIC(void) { }
 static inline void apic_intr_mode_select(void) { }
 static inline void apic_intr_mode_init(void) { }
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 22842bf5b59e..2225df67d45f 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -422,10 +422,8 @@ static void __init vmware_platform_setup(void)
 		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
 		x86_platform.calibrate_cpu = vmware_get_tsc_khz;
 
-#ifdef CONFIG_X86_LOCAL_APIC
 		/* Skip lapic calibration since we know the bus frequency. */
 		apic_set_timer_frequency_hz(ecx, "VMware hypervisor");
-#endif
 	} else {
 		pr_warn("Failed to get TSC freq from the hypervisor\n");
 	}
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 63e26805f8dd..4392fddd616e 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -710,7 +710,6 @@ unsigned long native_calibrate_tsc(void)
 	if (boot_cpu_data.x86_vfm == INTEL_ATOM_GOLDMONT)
 		setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
 
-#ifdef CONFIG_X86_LOCAL_APIC
 	/*
 	 * The local APIC appears to be fed by the core crystal clock
 	 * (which sounds entirely sensible). We can set the global
@@ -718,7 +717,6 @@ unsigned long native_calibrate_tsc(void)
 	 * timer later.
 	 */
 	apic_set_timer_frequency_khz(crystal_khz, "CPUID 0x15/0x16");
-#endif
 
 	return crystal_khz * ebx_numerator / eax_denominator;
 }
diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c
index 4bd5f2ae656b..179e3a331ef9 100644
--- a/arch/x86/kernel/tsc_msr.c
+++ b/arch/x86/kernel/tsc_msr.c
@@ -211,9 +211,7 @@ unsigned long cpu_khz_from_msr(void)
 	if (freq == 0)
 		pr_err("Error MSR_FSB_FREQ index %d is unknown\n", index);
 
-#ifdef CONFIG_X86_LOCAL_APIC
 	apic_set_timer_frequency_khz(freq, "MSR_FSB_FREQ");
-#endif
 
 	/*
 	 * TSC frequency determined by MSR is always considered "known"
-- 
2.55.0.679.g6767b8d81c-goog