[PATCH v5 15/51] x86/tsc: Kill off x86_platform_ops.calibrate_{cpu,tsc}() hooks
From: Sean Christopherson <seanjc@google.com>
Date: 2026-07-01 19:32:45
Also in:
kvm, linux-coco, linux-doc, lkml, virtualization, xen-devel
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Now that getting the CPU and/or TSC frequencies from the hypervisor uses
dedicated hooks, drop x86_platform_ops.calibrate_{cpu,tsc}() and instead
directly invoke the correct helper at each phase of (re)calibration. In
addition to eliminating unnecessary code, this makes it a bit more obvious
when the "late" path invokes pit_hpet_ptimer_calibrate_cpu() instead of
x86_platform_ops.calibrate_cpu().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/include/asm/tsc.h | 2 --
arch/x86/include/asm/x86_init.h | 4 ----
arch/x86/kernel/tsc.c | 28 ++++++++++++----------------
arch/x86/kernel/x86_init.c | 2 --
4 files changed, 12 insertions(+), 24 deletions(-)
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index b6b86e24e1bf..c09ec485abcd 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h@@ -95,8 +95,6 @@ extern void mark_tsc_unstable(char *reason); extern int unsynchronized_tsc(void); extern int check_tsc_unstable(void); extern void mark_tsc_async_resets(char *reason); -extern unsigned long native_calibrate_cpu_early(void); -extern unsigned long native_calibrate_tsc(void); extern unsigned long long native_sched_clock_from_tsc(u64 tsc); extern int tsc_clocksource_reliable;
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 0c89bf40f507..e879e6e83428 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h@@ -295,8 +295,6 @@ struct x86_hyper_runtime { /** * struct x86_platform_ops - platform specific runtime functions - * @calibrate_cpu: calibrate CPU - * @calibrate_tsc: calibrate TSC, if different from CPU * @get_wallclock: get time from HW clock like RTC etc. * @set_wallclock: set time back to HW clock * @iommu_shutdown: set by an IOMMU driver for shutdown if necessary
@@ -320,8 +318,6 @@ struct x86_hyper_runtime { * @guest: guest incarnations callbacks */ struct x86_platform_ops { - unsigned long (*calibrate_cpu)(void); - unsigned long (*calibrate_tsc)(void); void (*get_wallclock)(struct timespec64 *ts); int (*set_wallclock)(const struct timespec64 *ts); void (*iommu_shutdown)(void);
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 676910292af7..a877b82d0991 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c@@ -672,7 +672,7 @@ int cpuid_get_tsc_info(struct cpuid_tsc_info *info) * native_calibrate_tsc - determine TSC frequency * Determine TSC frequency via CPUID, else return 0. */ -unsigned long native_calibrate_tsc(void) +static unsigned long native_calibrate_tsc(void) { struct cpuid_tsc_info info;
@@ -904,7 +904,7 @@ static unsigned long pit_hpet_ptimer_calibrate_cpu(void) /** * native_calibrate_cpu_early - can calibrate the cpu early in boot */ -unsigned long native_calibrate_cpu_early(void) +static unsigned long native_calibrate_cpu_early(void) { unsigned long flags, fast_calibrate = cpu_khz_from_cpuid();
@@ -918,7 +918,7 @@ unsigned long native_calibrate_cpu_early(void) return fast_calibrate; } - +#ifndef CONFIG_SMP /** * native_calibrate_cpu - calibrate the cpu */
@@ -931,6 +931,7 @@ static unsigned long native_calibrate_cpu(void) return tsc_freq; } +#endif void recalibrate_cpu_khz(void) {
@@ -943,8 +944,8 @@ void recalibrate_cpu_khz(void) if (WARN_ON_ONCE(cpu_feature_enabled(X86_FEATURE_TSC_KNOWN_FREQ))) return; - cpu_khz = x86_platform.calibrate_cpu(); - tsc_khz = x86_platform.calibrate_tsc(); + cpu_khz = native_calibrate_cpu(); + tsc_khz = native_calibrate_tsc(); if (tsc_khz == 0) tsc_khz = cpu_khz; else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz)
@@ -1458,17 +1459,19 @@ static bool __init determine_cpu_tsc_frequencies(bool early, WARN_ON(cpu_khz || tsc_khz); if (early) { + /* + * Early CPU calibration can only use methods that are available + * early in boot (obviously). + */ if (known_cpu_khz) cpu_khz = known_cpu_khz; else - cpu_khz = x86_platform.calibrate_cpu(); + cpu_khz = native_calibrate_cpu_early(); if (known_tsc_khz) tsc_khz = known_tsc_khz; else - tsc_khz = x86_platform.calibrate_tsc(); + tsc_khz = native_calibrate_tsc(); } else { - /* We should not be here with non-native cpu calibration */ - WARN_ON(x86_platform.calibrate_cpu != native_calibrate_cpu); cpu_khz = pit_hpet_ptimer_calibrate_cpu(); }
@@ -1571,13 +1574,6 @@ void __init tsc_init(void) return; } - /* - * native_calibrate_cpu_early can only calibrate using methods that are - * available early in boot. - */ - if (x86_platform.calibrate_cpu == native_calibrate_cpu_early) - x86_platform.calibrate_cpu = native_calibrate_cpu; - if (!tsc_khz) { /* We failed to determine frequencies earlier, try again */ if (!determine_cpu_tsc_frequencies(false, 0, 0)) {
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index 252c5827d063..b7a48e622f48 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c@@ -147,8 +147,6 @@ static void enc_kexec_finish_noop(void) {} static bool is_private_mmio_noop(u64 addr) {return false; } struct x86_platform_ops x86_platform __ro_after_init = { - .calibrate_cpu = native_calibrate_cpu_early, - .calibrate_tsc = native_calibrate_tsc, .get_wallclock = mach_get_cmos_time, .set_wallclock = mach_set_cmos_time, .iommu_shutdown = iommu_shutdown_noop,
--
2.55.0.rc0.799.gd6f94ed593-goog