From: Sumit Gupta Date: Wed, 18 Mar 2026 09:50:05 +0000 (+0530) Subject: ACPI: CPPC: Check cpc_read() return values consistently X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0cc24977224a6c7d470860265a4990109f0a32ee;p=thirdparty%2Flinux.git ACPI: CPPC: Check cpc_read() return values consistently Callers of cpc_read() ignore its return value, which can lead to using uninitialized or stale values when the read fails. Fix this by consistently checking cpc_read() return values in cppc_get_perf_caps(), cppc_get_perf_ctrs(), and cppc_get_perf(). Link: https://lore.kernel.org/lkml/48bdf87e-39f1-402f-a7dc-1a0e1e7a819d@nvidia.com/ Suggested-by: Rafael J. Wysocki Signed-off-by: Sumit Gupta Link: https://patch.msgid.link/20260318095005.2437960-1-sumitg@nvidia.com Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 5ad922eb937a9..053fc6765a592 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1394,45 +1394,66 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps) } } - cpc_read(cpunum, highest_reg, &high); + ret = cpc_read(cpunum, highest_reg, &high); + if (ret) + goto out_err; perf_caps->highest_perf = high; - cpc_read(cpunum, lowest_reg, &low); + ret = cpc_read(cpunum, lowest_reg, &low); + if (ret) + goto out_err; perf_caps->lowest_perf = low; - cpc_read(cpunum, nominal_reg, &nom); + ret = cpc_read(cpunum, nominal_reg, &nom); + if (ret) + goto out_err; perf_caps->nominal_perf = nom; /* * If reference perf register is not supported then we should * use the nominal perf value */ - if (CPC_SUPPORTED(reference_reg)) - cpc_read(cpunum, reference_reg, &ref); - else + if (CPC_SUPPORTED(reference_reg)) { + ret = cpc_read(cpunum, reference_reg, &ref); + if (ret) + goto out_err; + } else { ref = nom; + } perf_caps->reference_perf = ref; if (guaranteed_reg->type != ACPI_TYPE_BUFFER || IS_NULL_REG(&guaranteed_reg->cpc_entry.reg)) { perf_caps->guaranteed_perf = 0; } else { - cpc_read(cpunum, guaranteed_reg, &guaranteed); + ret = cpc_read(cpunum, guaranteed_reg, &guaranteed); + if (ret) + goto out_err; perf_caps->guaranteed_perf = guaranteed; } - cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear); + ret = cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear); + if (ret) + goto out_err; perf_caps->lowest_nonlinear_perf = min_nonlinear; - if (!high || !low || !nom || !ref || !min_nonlinear) + if (!high || !low || !nom || !ref || !min_nonlinear) { ret = -EFAULT; + goto out_err; + } /* Read optional lowest and nominal frequencies if present */ - if (CPC_SUPPORTED(low_freq_reg)) - cpc_read(cpunum, low_freq_reg, &low_f); + if (CPC_SUPPORTED(low_freq_reg)) { + ret = cpc_read(cpunum, low_freq_reg, &low_f); + if (ret) + goto out_err; + } - if (CPC_SUPPORTED(nom_freq_reg)) - cpc_read(cpunum, nom_freq_reg, &nom_f); + if (CPC_SUPPORTED(nom_freq_reg)) { + ret = cpc_read(cpunum, nom_freq_reg, &nom_f); + if (ret) + goto out_err; + } perf_caps->lowest_freq = low_f; perf_caps->nominal_freq = nom_f; @@ -1526,16 +1547,25 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs) } } - cpc_read(cpunum, delivered_reg, &delivered); - cpc_read(cpunum, reference_reg, &reference); + ret = cpc_read(cpunum, delivered_reg, &delivered); + if (ret) + goto out_err; + + ret = cpc_read(cpunum, reference_reg, &reference); + if (ret) + goto out_err; + /* * Per spec, if ctr_wrap_time optional register is unsupported, then the * performance counters are assumed to never wrap during the lifetime of * platform */ ctr_wrap_time = (u64)(~((u64)0)); - if (CPC_SUPPORTED(ctr_wrap_reg)) - cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time); + if (CPC_SUPPORTED(ctr_wrap_reg)) { + ret = cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time); + if (ret) + goto out_err; + } if (!delivered || !reference) { ret = -EFAULT; @@ -1811,24 +1841,39 @@ int cppc_get_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls) } /* Read optional elements if present */ - if (CPC_SUPPORTED(max_perf_reg)) - cpc_read(cpu, max_perf_reg, &max); + if (CPC_SUPPORTED(max_perf_reg)) { + ret = cpc_read(cpu, max_perf_reg, &max); + if (ret) + goto out_err; + } perf_ctrls->max_perf = max; - if (CPC_SUPPORTED(min_perf_reg)) - cpc_read(cpu, min_perf_reg, &min); + if (CPC_SUPPORTED(min_perf_reg)) { + ret = cpc_read(cpu, min_perf_reg, &min); + if (ret) + goto out_err; + } perf_ctrls->min_perf = min; - if (CPC_SUPPORTED(desired_perf_reg)) - cpc_read(cpu, desired_perf_reg, &desired_perf); + if (CPC_SUPPORTED(desired_perf_reg)) { + ret = cpc_read(cpu, desired_perf_reg, &desired_perf); + if (ret) + goto out_err; + } perf_ctrls->desired_perf = desired_perf; - if (CPC_SUPPORTED(energy_perf_reg)) - cpc_read(cpu, energy_perf_reg, &energy_perf); + if (CPC_SUPPORTED(energy_perf_reg)) { + ret = cpc_read(cpu, energy_perf_reg, &energy_perf); + if (ret) + goto out_err; + } perf_ctrls->energy_perf = energy_perf; - if (CPC_SUPPORTED(auto_sel_reg)) - cpc_read(cpu, auto_sel_reg, &auto_sel); + if (CPC_SUPPORTED(auto_sel_reg)) { + ret = cpc_read(cpu, auto_sel_reg, &auto_sel); + if (ret) + goto out_err; + } perf_ctrls->auto_sel = (bool)auto_sel; out_err: