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authorRusty Russell <rusty@rustcorp.com.au>2008-03-04 23:07:50 +1100
committerChris Wright <chrisw@sous-sol.org>2008-06-09 11:27:02 -0700
commitcf8ec9fd81d2be5cdcd978ca7ca1977d0548d7cb (patch)
treee6719049a6d19a5de693c63c83f810da64a22118
parent611a6f01f6cf797604dea042a0b64a868fd3170b (diff)
x86: if we cannot calibrate the TSC, we panic.
upstream commit: 3c2047cd32b1a8c782d7efab72707e7daa251625 The current tsc_init() clears the TSC feature bit if the TSC khz cannot be calculated, causing us to panic in arch/x86/kernel/cpu/bugs.c check_config(). We should simply mark it unstable. Frankly, someone should take an axe to this code. mark_tsc_unstable() not only marks it unstable, but sets tsc_enabled to 0, which seems redundant but is actually important here because means it won't be used by sched_clock() either. Perhaps a tristate enum "UNUSABLE, UNSTABLE, OK" would be clearer, and separate mark_tsc_unstable() and mark_tsc_broken() functions? Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
-rw-r--r--arch/x86/kernel/tsc_32.c13
1 files changed, 5 insertions, 8 deletions
diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c
index c2241e04ea5f..68657d8526fb 100644
--- a/arch/x86/kernel/tsc_32.c
+++ b/arch/x86/kernel/tsc_32.c
@@ -392,13 +392,15 @@ void __init tsc_init(void)
int cpu;
if (!cpu_has_tsc)
- goto out_no_tsc;
+ return;
cpu_khz = calculate_cpu_khz();
tsc_khz = cpu_khz;
- if (!cpu_khz)
- goto out_no_tsc;
+ if (!cpu_khz) {
+ mark_tsc_unstable("could not calculate TSC khz");
+ return;
+ }
printk("Detected %lu.%03lu MHz processor.\n",
(unsigned long)cpu_khz / 1000,
@@ -431,9 +433,4 @@ void __init tsc_init(void)
tsc_enabled = 1;
clocksource_register(&clocksource_tsc);
-
- return;
-
-out_no_tsc:
- setup_clear_cpu_cap(X86_FEATURE_TSC);
}