From: Ingo Molnar Date: Mon, 27 Apr 2026 06:07:02 +0000 (+0200) Subject: x86/cpu: Remove unused !CONFIG_X86_TSC code X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5c75b98aa9cd5b1725b76999d794dc72ebd7a54a;p=thirdparty%2Flinux.git x86/cpu: Remove unused !CONFIG_X86_TSC code Now that the Kconfig space always enables CONFIG_X86_TSC (on x86), remove !CONFIG_X86_TSC code from the x86 arch code. We still keep the Kconfig option to catch any eventual code still pending in maintainer or non-mainline trees, plus some drivers have raw TSC timestamping hacks that use CONFIG_X86_TSC. It's also still possible to disable TSC support runtime. Signed-off-by: Ingo Molnar Reviewed-by: Arnd Bergmann Acked-by: Dave Hansen Cc: Ahmed S . Darwish Cc: Andrew Cooper Cc: Ard Biesheuvel Cc: H . Peter Anvin Cc: John Ogness Cc: Linus Torvalds Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250425084216.3913608-13-mingo@kernel.org --- diff --git a/arch/x86/include/asm/timex.h b/arch/x86/include/asm/timex.h index 956e4145311b1..6e57e3c0fdd20 100644 --- a/arch/x86/include/asm/timex.h +++ b/arch/x86/include/asm/timex.h @@ -7,8 +7,7 @@ static inline unsigned long random_get_entropy(void) { - if (!IS_ENABLED(CONFIG_X86_TSC) && - !cpu_feature_enabled(X86_FEATURE_TSC)) + if (!cpu_feature_enabled(X86_FEATURE_TSC)) return random_get_entropy_fallback(); return rdtsc(); } diff --git a/arch/x86/include/asm/trace_clock.h b/arch/x86/include/asm/trace_clock.h index 7061a5650969e..1efab284c32ae 100644 --- a/arch/x86/include/asm/trace_clock.h +++ b/arch/x86/include/asm/trace_clock.h @@ -5,17 +5,9 @@ #include #include -#ifdef CONFIG_X86_TSC - extern u64 notrace trace_clock_x86_tsc(void); # define ARCH_TRACE_CLOCKS \ { trace_clock_x86_tsc, "x86-tsc", .in_ns = 0 }, -#else /* !CONFIG_X86_TSC */ - -#define ARCH_TRACE_CLOCKS - -#endif - #endif /* _ASM_X86_TRACE_CLOCK_H */ diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index 4f7f09f505521..4d2d2f21ff063 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -76,8 +76,7 @@ extern void disable_TSC(void); static inline cycles_t get_cycles(void) { - if (!IS_ENABLED(CONFIG_X86_TSC) && - !cpu_feature_enabled(X86_FEATURE_TSC)) + if (!cpu_feature_enabled(X86_FEATURE_TSC)) return 0; return rdtsc(); } @@ -94,25 +93,15 @@ extern unsigned long native_calibrate_tsc(void); extern unsigned long long native_sched_clock_from_tsc(u64 tsc); extern int tsc_clocksource_reliable; -#ifdef CONFIG_X86_TSC extern bool tsc_async_resets; -#else -# define tsc_async_resets false -#endif /* * Boot-time check whether the TSCs are synchronized across * all CPUs/cores: */ -#ifdef CONFIG_X86_TSC extern bool tsc_store_and_check_tsc_adjust(bool bootcpu); extern void tsc_verify_tsc_adjust(bool resume); extern void check_tsc_sync_target(void); -#else -static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; } -static inline void tsc_verify_tsc_adjust(bool resume) { } -static inline void check_tsc_sync_target(void) { } -#endif extern int notsc_setup(char *); extern void tsc_save_sched_clock_state(void); diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 47a32f5839300..31f46fd005278 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -108,7 +108,7 @@ apm-y := apm_32.o obj-$(CONFIG_APM) += apm.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_SMP) += smpboot.o -obj-$(CONFIG_X86_TSC) += tsc_sync.o +obj-y += tsc_sync.o obj-$(CONFIG_SMP) += setup_percpu.o obj-$(CONFIG_X86_MPPARSE) += mpparse.o obj-y += apic/ @@ -117,7 +117,7 @@ obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o obj-$(CONFIG_FUNCTION_TRACER) += ftrace_$(BITS).o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o -obj-$(CONFIG_X86_TSC) += trace_clock.o +obj-y += trace_clock.o obj-$(CONFIG_TRACING) += trace.o obj-$(CONFIG_RETHOOK) += rethook.o obj-$(CONFIG_VMCORE_INFO) += vmcore_info_$(BITS).o diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c index cb9852ad60989..0b991035f1279 100644 --- a/arch/x86/kernel/i8253.c +++ b/arch/x86/kernel/i8253.c @@ -31,7 +31,7 @@ struct clock_event_device *global_clock_event; */ static bool __init use_pit(void) { - if (!IS_ENABLED(CONFIG_X86_TSC) || !boot_cpu_has(X86_FEATURE_TSC)) + if (!boot_cpu_has(X86_FEATURE_TSC)) return true; /* This also returns true when APIC is disabled */ diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index c5110eb554bcf..ce10ae4b298b7 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -298,30 +298,17 @@ notrace u64 sched_clock(void) preempt_enable_notrace(); return now; } - int check_tsc_unstable(void) { return tsc_unstable; } EXPORT_SYMBOL_GPL(check_tsc_unstable); -#ifdef CONFIG_X86_TSC int __init notsc_setup(char *str) { mark_tsc_unstable("boot parameter notsc"); return 1; } -#else -/* - * disable flag for tsc. Takes effect by clearing the TSC cpu flag - * in cpu/common.c - */ -int __init notsc_setup(char *str) -{ - setup_clear_cpu_cap(X86_FEATURE_TSC); - return 1; -} -#endif __setup("notsc", notsc_setup); enum {