x86: if we cannot calibrate the TSC, we panic.
authorRusty Russell <rusty@rustcorp.com.au>
Tue, 4 Mar 2008 12:07:50 +0000 (23:07 +1100)
committerIngo Molnar <mingo@elte.hu>
Thu, 17 Apr 2008 15:40:52 +0000 (17:40 +0200)
commit3c2047cd32b1a8c782d7efab72707e7daa251625
tree79a3481d5f7b637626d0cf346dc1f1042d68c07f
parent9fc34113f6880b215cbea4e7017fc818700384c2
x86: if we cannot calibrate the TSC, we panic.

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>
arch/x86/kernel/tsc_32.c