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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-01-07 19:42:15 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-01-12 19:34:04 +0100
commit9dd04ec6bc6fa7b310e5595f2ad9bef13eacd3a0 (patch)
tree70ca4c03580209e00d15dc466460b72fdf50a3f9 /drivers/cpufreq
parentLinux 5.11-rc3 (diff)
downloadlinux-9dd04ec6bc6fa7b310e5595f2ad9bef13eacd3a0.tar.xz
linux-9dd04ec6bc6fa7b310e5595f2ad9bef13eacd3a0.zip
cpufreq: intel_pstate: Always read hwp_cap_cached with READ_ONCE()
Because intel_pstate_get_hwp_max() which updates hwp_cap_cached may run in parallel with the readers of it, annotate all of the read accesses to it with READ_ONCE(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Chen Yu <yu.c.chen@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/intel_pstate.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index be05e038d956..74bf54e6c993 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -914,7 +914,7 @@ static void intel_pstate_hwp_offline(struct cpudata *cpu)
}
value &= ~GENMASK_ULL(31, 0);
- min_perf = HWP_LOWEST_PERF(cpu->hwp_cap_cached);
+ min_perf = HWP_LOWEST_PERF(READ_ONCE(cpu->hwp_cap_cached));
/* Set hwp_max = hwp_min */
value |= HWP_MAX_PERF(min_perf);
@@ -1750,6 +1750,7 @@ static int hwp_boost_hold_time_ns = 3 * NSEC_PER_MSEC;
static inline void intel_pstate_hwp_boost_up(struct cpudata *cpu)
{
u64 hwp_req = READ_ONCE(cpu->hwp_req_cached);
+ u64 hwp_cap = READ_ONCE(cpu->hwp_cap_cached);
u32 max_limit = (hwp_req & 0xff00) >> 8;
u32 min_limit = (hwp_req & 0xff);
u32 boost_level1;
@@ -1776,14 +1777,14 @@ static inline void intel_pstate_hwp_boost_up(struct cpudata *cpu)
cpu->hwp_boost_min = min_limit;
/* level at half way mark between min and guranteed */
- boost_level1 = (HWP_GUARANTEED_PERF(cpu->hwp_cap_cached) + min_limit) >> 1;
+ boost_level1 = (HWP_GUARANTEED_PERF(hwp_cap) + min_limit) >> 1;
if (cpu->hwp_boost_min < boost_level1)
cpu->hwp_boost_min = boost_level1;
- else if (cpu->hwp_boost_min < HWP_GUARANTEED_PERF(cpu->hwp_cap_cached))
- cpu->hwp_boost_min = HWP_GUARANTEED_PERF(cpu->hwp_cap_cached);
- else if (cpu->hwp_boost_min == HWP_GUARANTEED_PERF(cpu->hwp_cap_cached) &&
- max_limit != HWP_GUARANTEED_PERF(cpu->hwp_cap_cached))
+ else if (cpu->hwp_boost_min < HWP_GUARANTEED_PERF(hwp_cap))
+ cpu->hwp_boost_min = HWP_GUARANTEED_PERF(hwp_cap);
+ else if (cpu->hwp_boost_min == HWP_GUARANTEED_PERF(hwp_cap) &&
+ max_limit != HWP_GUARANTEED_PERF(hwp_cap))
cpu->hwp_boost_min = max_limit;
else
return;