cpufreq: intel_pstate: Read global.no_turbo under READ_ONCE()
[ Upstream commit 9558fae8ce97b3b320b387dd7c88309df2c36d4d ]
Because global.no_turbo is generally not read under intel_pstate_driver_lock
make store_no_turbo() use WRITE_ONCE() for updating it (this is the only
place at which it is updated except for the initialization) and make the
majority of places reading it use READ_ONCE().
Also remove redundant global.turbo_disabled checks from places that
depend on the 'true' value of global.no_turbo because it can only be
'true' if global.turbo_disabled is also 'true'.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Stable-dep-of: 350cbb5d2f67 ("cpufreq: intel_pstate: Check turbo_is_disabled() in store_no_turbo()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 0395bc0..7570d6d 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -1264,7 +1264,7 @@ static ssize_t store_no_turbo(struct kobject *a, struct kobj_attribute *b,
goto unlock_driver;
}
- global.no_turbo = no_turbo;
+ WRITE_ONCE(global.no_turbo, no_turbo);
mutex_lock(&intel_pstate_limits_lock);
@@ -1730,7 +1730,7 @@ static u64 atom_get_val(struct cpudata *cpudata, int pstate)
u32 vid;
val = (u64)pstate << 8;
- if (global.no_turbo && !global.turbo_disabled)
+ if (READ_ONCE(global.no_turbo) && !global.turbo_disabled)
val |= (u64)1 << 32;
vid_fp = cpudata->vid.min + mul_fp(
@@ -1900,7 +1900,7 @@ static u64 core_get_val(struct cpudata *cpudata, int pstate)
u64 val;
val = (u64)pstate << 8;
- if (global.no_turbo && !global.turbo_disabled)
+ if (READ_ONCE(global.no_turbo) && !global.turbo_disabled)
val |= (u64)1 << 32;
return val;
@@ -2186,7 +2186,7 @@ static inline int32_t get_target_pstate(struct cpudata *cpu)
sample->busy_scaled = busy_frac * 100;
- target = global.no_turbo || global.turbo_disabled ?
+ target = READ_ONCE(global.no_turbo) ?
cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
target += target >> 2;
target = mul_fp(target, busy_frac);
@@ -2455,7 +2455,7 @@ static void intel_pstate_clear_update_util_hook(unsigned int cpu)
static int intel_pstate_get_max_freq(struct cpudata *cpu)
{
- return global.turbo_disabled || global.no_turbo ?
+ return READ_ONCE(global.no_turbo) ?
cpu->pstate.max_freq : cpu->pstate.turbo_freq;
}
@@ -2592,7 +2592,7 @@ static void intel_pstate_verify_cpu_policy(struct cpudata *cpu,
if (hwp_active) {
intel_pstate_get_hwp_cap(cpu);
- max_freq = global.no_turbo || global.turbo_disabled ?
+ max_freq = READ_ONCE(global.no_turbo) ?
cpu->pstate.max_freq : cpu->pstate.turbo_freq;
} else {
max_freq = intel_pstate_get_max_freq(cpu);
