#include <linux/cpuidle.h>
#include <linux/numa.h>
#include <linux/pgtable.h>
+#include <linux/overflow.h>
#include <asm/acpi.h>
#include <asm/desc.h>
#endif
+#ifdef CONFIG_X86_64
/*
* APERF/MPERF frequency ratio computation.
*
}
}
+static void disable_freq_invariance_workfn(struct work_struct *work)
+{
+ static_branch_disable(&arch_scale_freq_key);
+}
+
+static DECLARE_WORK(disable_freq_invariance_work,
+ disable_freq_invariance_workfn);
+
DEFINE_PER_CPU(unsigned long, arch_freq_scale) = SCHED_CAPACITY_SCALE;
void arch_scale_freq_tick(void)
{
- u64 freq_scale;
+ u64 freq_scale = SCHED_CAPACITY_SCALE;
u64 aperf, mperf;
u64 acnt, mcnt;
acnt = aperf - this_cpu_read(arch_prev_aperf);
mcnt = mperf - this_cpu_read(arch_prev_mperf);
- if (!mcnt)
- return;
this_cpu_write(arch_prev_aperf, aperf);
this_cpu_write(arch_prev_mperf, mperf);
- acnt <<= 2*SCHED_CAPACITY_SHIFT;
- mcnt *= arch_max_freq_ratio;
+ if (check_shl_overflow(acnt, 2*SCHED_CAPACITY_SHIFT, &acnt))
+ goto error;
+
+ if (check_mul_overflow(mcnt, arch_max_freq_ratio, &mcnt) || !mcnt)
+ goto error;
freq_scale = div64_u64(acnt, mcnt);
+ if (!freq_scale)
+ goto error;
if (freq_scale > SCHED_CAPACITY_SCALE)
freq_scale = SCHED_CAPACITY_SCALE;
this_cpu_write(arch_freq_scale, freq_scale);
+ return;
+
+error:
+ pr_warn("Scheduler frequency invariance went wobbly, disabling!\n");
+ schedule_work(&disable_freq_invariance_work);
+}
+#else
+static inline void init_freq_invariance(bool secondary)
+{
}
+#endif /* CONFIG_X86_64 */