Messages in this thread Patch in this message | | | Subject | [PATCH 2/6] lguest tsc fix | From | Rusty Russell <> | Date | Wed, 06 Jun 2007 00:56:36 +1000 |
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In recent -mm kernels, the TSC capability cannot be disabled, resulting in a divide by zero error in the normal sched_clock.
The correct fix is to have a special lguest sched_clock implementation: this is as simple as it gets.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> --- drivers/lguest/lguest.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
=================================================================== --- a/drivers/lguest/lguest.c +++ b/drivers/lguest/lguest.c @@ -351,11 +351,18 @@ static void lguest_time_irq(unsigned int update_process_times(user_mode_vm(get_irq_regs())); } +static u64 sched_clock_base; static void lguest_time_init(void) { set_irq_handler(0, lguest_time_irq); hcall(LHCALL_TIMER_READ, 0, 0, 0); + sched_clock_base = jiffies_64; enable_lguest_irq(0); +} + +static unsigned long long lguest_sched_clock(void) +{ + return (jiffies_64 - sched_clock_base) * (1000000000 / HZ); } static void lguest_load_esp0(struct tss_struct *tss, @@ -494,6 +501,7 @@ __init void lguest_init(void *boot) paravirt_ops.time_init = lguest_time_init; paravirt_ops.set_lazy_mode = lguest_lazy_mode; paravirt_ops.wbinvd = lguest_wbinvd; + paravirt_ops.sched_clock = lguest_sched_clock; hcall(LHCALL_LGUEST_INIT, __pa(&lguest_data), 0, 0); @@ -507,8 +515,6 @@ __init void lguest_init(void *boot) cpu_detect(&new_cpu_data); /* Math is always hard! */ new_cpu_data.hard_math = 1; - - tsc_disable = 1; #ifdef CONFIG_X86_MCE mce_disabled = 1;
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