From: Dhananjay Ugwekar Date: Sat, 22 Feb 2025 03:32:22 +0000 (+0000) Subject: cpufreq/amd-pstate: Fix the clamping of perf values X-Git-Tag: v6.15-rc1~191^2~4^2~2^2~19 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a1d1d8fb653532638cfb3ee0b7e67ebd5327a3d6;p=thirdparty%2Fkernel%2Flinux.git cpufreq/amd-pstate: Fix the clamping of perf values The clamping in freq_to_perf() is broken right now, as we first typecast (read wraparound) the overflowing value into a u8 and then clamp it down. So, use a u32 to store the >255 value in certain edge cases and then clamp it down into a u8. Also, use a "explicit typecast + clamp" instead of just a "clamp_t" as the latter typecasts first and then clamps between the limits, which defeats our purpose. Fixes: 620136ced35a ("cpufreq/amd-pstate: Modularize perf<->freq conversion") Signed-off-by: Dhananjay Ugwekar Reviewed-by: Mario Limonciello Link: https://lore.kernel.org/r/20250222033221.554976-1-dhananjay.ugwekar@amd.com Signed-off-by: Mario Limonciello --- diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 08ae480768120..56930424c9fad 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -144,10 +144,10 @@ static struct quirk_entry quirk_amd_7k62 = { static inline u8 freq_to_perf(struct amd_cpudata *cpudata, unsigned int freq_val) { - u8 perf_val = DIV_ROUND_UP_ULL((u64)freq_val * cpudata->nominal_perf, + u32 perf_val = DIV_ROUND_UP_ULL((u64)freq_val * cpudata->nominal_perf, cpudata->nominal_freq); - return clamp_t(u8, perf_val, cpudata->lowest_perf, cpudata->highest_perf); + return (u8)clamp(perf_val, cpudata->lowest_perf, cpudata->highest_perf); } static inline u32 perf_to_freq(struct amd_cpudata *cpudata, u8 perf_val)