diff options
| -rw-r--r-- | arch/i386/kernel/tsc.c | 22 | ||||
| -rw-r--r-- | include/asm-i386/bugs.h | 2 |
2 files changed, 15 insertions, 9 deletions
diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c index 12fef14995a..46f752a8bbf 100644 --- a/arch/i386/kernel/tsc.c +++ b/arch/i386/kernel/tsc.c @@ -112,13 +112,10 @@ unsigned long long sched_clock(void) return (*custom_sched_clock)(); /* - * in the NUMA case we dont use the TSC as they are not - * synchronized across all CPUs. + * Fall back to jiffies if there's no TSC available: */ -#ifndef CONFIG_NUMA - if (!cpu_khz || check_tsc_unstable()) -#endif - /* no locking but a rare wrong value is not a big deal */ + if (unlikely(tsc_disable)) + /* No locking but a rare wrong value is not a big deal: */ return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ); /* read the Time Stamp Counter: */ @@ -198,13 +195,13 @@ EXPORT_SYMBOL(recalibrate_cpu_khz); void __init tsc_init(void) { if (!cpu_has_tsc || tsc_disable) - return; + goto out_no_tsc; cpu_khz = calculate_cpu_khz(); tsc_khz = cpu_khz; if (!cpu_khz) - return; + goto out_no_tsc; printk("Detected %lu.%03lu MHz processor.\n", (unsigned long)cpu_khz / 1000, @@ -212,6 +209,15 @@ void __init tsc_init(void) set_cyc2ns_scale(cpu_khz); use_tsc_delay(); + return; + +out_no_tsc: + /* + * Set the tsc_disable flag if there's no TSC support, this + * makes it a fast flag for the kernel to see whether it + * should be using the TSC. + */ + tsc_disable = 1; } #ifdef CONFIG_CPU_FREQ diff --git a/include/asm-i386/bugs.h b/include/asm-i386/bugs.h index 38f1aebbbdb..c90c7c49930 100644 --- a/include/asm-i386/bugs.h +++ b/include/asm-i386/bugs.h @@ -160,7 +160,7 @@ static void __init check_config(void) * If we configured ourselves for a TSC, we'd better have one! */ #ifdef CONFIG_X86_TSC - if (!cpu_has_tsc) + if (!cpu_has_tsc && !tsc_disable) panic("Kernel compiled for Pentium+, requires TSC feature!"); #endif |