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[CPUFREQ] cpumask: avoid cpumask games in arch/x86/kernel/cpu/cpufreq/speedstep-centrino.c

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Impact: don't play with current's cpumask

It's generally a very bad idea to mug some process's cpumask: it could
legitimately and reasonably be changed by root, which could break us
(if done before our code) or them (if we restore the wrong value).

Use rdmsr_on_cpu and wrmsr_on_cpu instead.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
To: cpufreq@vger.kernel.org
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Dave Jones <davej@redhat.com>
This commit is contained in:
Rusty Russell 2009-06-11 22:59:58 +09:30 committed by Dave Jones
parent 394122ab14
commit e3f996c26f
1 changed files with 17 additions and 43 deletions
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60
arch/x86/kernel/cpu/cpufreq/speedstep-centrino.c
View file

@ -323,14 +323,8 @@ static unsigned int get_cur_freq(unsigned int cpu)
{
unsigned l, h;
unsigned clock_freq;
cpumask_t saved_mask;
saved_mask = current->cpus_allowed;
set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
if (smp_processor_id() != cpu)
return 0;
rdmsr(MSR_IA32_PERF_STATUS, l, h);
rdmsr_on_cpu(cpu, MSR_IA32_PERF_STATUS, &l, &h);
clock_freq = extract_clock(l, cpu, 0);
if (unlikely(clock_freq == 0)) {
@ -340,11 +334,9 @@ static unsigned int get_cur_freq(unsigned int cpu)
* P-state transition (like TM2). Get the last freq set
* in PERF_CTL.
*/
rdmsr(MSR_IA32_PERF_CTL, l, h);
rdmsr_on_cpu(cpu, MSR_IA32_PERF_CTL, &l, &h);
clock_freq = extract_clock(l, cpu, 1);
}
set_cpus_allowed_ptr(current, &saved_mask);
return clock_freq;
}
@ -467,15 +459,10 @@ static int centrino_target (struct cpufreq_policy *policy,
struct cpufreq_freqs freqs;
int retval = 0;
unsigned int j, k, first_cpu, tmp;
cpumask_var_t saved_mask, covered_cpus;
cpumask_var_t covered_cpus;
if (unlikely(!alloc_cpumask_var(&saved_mask, GFP_KERNEL)))
if (unlikely(!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL)))
return -ENOMEM;
if (unlikely(!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))) {
free_cpumask_var(saved_mask);
return -ENOMEM;
}
cpumask_copy(saved_mask, &current->cpus_allowed);
if (unlikely(per_cpu(centrino_model, cpu) == NULL)) {
retval = -ENODEV;
@ -493,7 +480,7 @@ static int centrino_target (struct cpufreq_policy *policy,
first_cpu = 1;
for_each_cpu(j, policy->cpus) {
const struct cpumask *mask;
int good_cpu;
/* cpufreq holds the hotplug lock, so we are safe here */
if (!cpu_online(j))
@ -504,32 +491,30 @@ static int centrino_target (struct cpufreq_policy *policy,
* Make sure we are running on CPU that wants to change freq
*/
if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
mask = policy->cpus;
good_cpu = cpumask_any_and(policy->cpus,
cpu_online_mask);
else
mask = cpumask_of(j);
good_cpu = j;
set_cpus_allowed_ptr(current, mask);
preempt_disable();
if (unlikely(!cpu_isset(smp_processor_id(), *mask))) {
if (good_cpu >= nr_cpu_ids) {
dprintk("couldn't limit to CPUs in this domain\n");
retval = -EAGAIN;
if (first_cpu) {
/* We haven't started the transition yet. */
goto migrate_end;
goto out;
}
preempt_enable();
break;
}
msr = per_cpu(centrino_model, cpu)->op_points[newstate].index;
if (first_cpu) {
rdmsr(MSR_IA32_PERF_CTL, oldmsr, h);
rdmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, &oldmsr, &h);
if (msr == (oldmsr & 0xffff)) {
dprintk("no change needed - msr was and needs "
"to be %x\n", oldmsr);
retval = 0;
goto migrate_end;
goto out;
}
freqs.old = extract_clock(oldmsr, cpu, 0);
@ -553,14 +538,11 @@ static int centrino_target (struct cpufreq_policy *policy,
oldmsr |= msr;
}
wrmsr(MSR_IA32_PERF_CTL, oldmsr, h);
if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
preempt_enable();
wrmsr_on_cpu(good_cpu, MSR_IA32_PERF_CTL, oldmsr, h);
if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
break;
}
cpu_set(j, *covered_cpus);
preempt_enable();
cpumask_set_cpu(j, covered_cpus);
}
for_each_cpu(k, policy->cpus) {
@ -578,10 +560,8 @@ static int centrino_target (struct cpufreq_policy *policy,
* Best effort undo..
*/
for_each_cpu_mask_nr(j, *covered_cpus) {
set_cpus_allowed_ptr(current, &cpumask_of_cpu(j));
wrmsr(MSR_IA32_PERF_CTL, oldmsr, h);
}
for_each_cpu(j, covered_cpus)
wrmsr_on_cpu(j, MSR_IA32_PERF_CTL, oldmsr, h);
tmp = freqs.new;
freqs.new = freqs.old;
@ -593,15 +573,9 @@ static int centrino_target (struct cpufreq_policy *policy,
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
}
set_cpus_allowed_ptr(current, saved_mask);
retval = 0;
goto out;
migrate_end:
preempt_enable();
set_cpus_allowed_ptr(current, saved_mask);
out:
free_cpumask_var(saved_mask);
free_cpumask_var(covered_cpus);
return retval;
}