From d554d9a4295dd0595d12eeccbc55d1f495b15176 Mon Sep 17 00:00:00 2001 From: Marcin Slusarz Date: Mon, 11 Aug 2008 00:07:44 +0200 Subject: x86, tsc: fix section mismatch warning WARNING: vmlinux.o(.text+0x7950): Section mismatch in reference from the function native_calibrate_tsc() to the function .init.text:tsc_read_refs() The function native_calibrate_tsc() references the function __init tsc_read_refs(). This is often because native_calibrate_tsc lacks a __init annotation or the annotation of tsc_read_refs is wrong. tsc_read_refs is called from native_calibrate_tsc which is not __init and native_calibrate_tsc cannot be marked __init Signed-off-by: Marcin Slusarz Signed-off-by: H. Peter Anvin Signed-off-by: Ingo Molnar --- arch/x86/kernel/tsc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/tsc.c') diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 7603c0553909..46af71676738 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -104,7 +104,7 @@ __setup("notsc", notsc_setup); /* * Read TSC and the reference counters. Take care of SMI disturbance */ -static u64 __init tsc_read_refs(u64 *pm, u64 *hpet) +static u64 tsc_read_refs(u64 *pm, u64 *hpet) { u64 t1, t2; int i; -- cgit v1.2.3 From 060700b571717c997a2ea5e2049b848fa248ee13 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 24 Aug 2008 11:52:06 -0700 Subject: x86: do not enable TSC notifier if we don't need it Impact: crash on non-TSC-equipped CPUs Don't enable the TSC notifier if we *either*: 1. don't have a CPU, or 2. have a CPU with constant TSC. In either of those cases, the notifier is either damaging (1) or useless(2). From: Linus Torvalds Signed-off-by: H. Peter Anvin --- arch/x86/kernel/tsc.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/kernel/tsc.c') diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 46af71676738..9bed5cae4bdc 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -325,6 +325,10 @@ static struct notifier_block time_cpufreq_notifier_block = { static int __init cpufreq_tsc(void) { + if (!cpu_has_tsc) + return 0; + if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) + return 0; cpufreq_register_notifier(&time_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); return 0; -- cgit v1.2.3 From 52a8968ce95da8469ba0a9b3e4010fe31caf77a3 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 25 Aug 2008 13:35:06 +0200 Subject: x86: fix cpufreq + sched_clock() regression I noticed that my sched_clock() was slow on a number of machine, so I started looking at cpufreq. The below seems to fix the problem for me. Signed-off-by: Ingo Molnar --- arch/x86/kernel/tsc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/tsc.c') diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 9bed5cae4bdc..8e786b0d665a 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -314,7 +314,7 @@ static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, mark_tsc_unstable("cpufreq changes"); } - set_cyc2ns_scale(tsc_khz_ref, freq->cpu); + set_cyc2ns_scale(tsc_khz, freq->cpu); return 0; } -- cgit v1.2.3