From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> mainline inclusion from mainline-v5.1-rc3 commit edef1ef134180149694b86386277076f566d165c category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=44 CVE: NA ----------------------------------------------- As per the ACPI specification, "Guaranteed Performance Register" is a "Buffer" field and it cannot be "Integer", so treat the "Integer" type for "Guaranteed Performance Register" field as invalid and ignore its value in that case. Also save one cpc_read() call when "Guaranteed Performance Register" is not present, which means a register defined as: "Register(SystemMemory, 0, 0, 0, 0)". Fixes: 29523f095397 ("ACPI / CPPC: Add support for guaranteed performance") Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: 4.20+ <stable@vger.kernel.org> # 4.20+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/acpi/cppc_acpi.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index ccd0e851a3d02..13d64dd4cfe0f 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -1153,8 +1153,13 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps) cpc_read(cpunum, nominal_reg, &nom); perf_caps->nominal_perf = nom; - cpc_read(cpunum, guaranteed_reg, &guaranteed); - perf_caps->guaranteed_perf = guaranteed; + 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); + perf_caps->guaranteed_perf = guaranteed; + } cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear); perf_caps->lowest_nonlinear_perf = min_nonlinear; -- 2.25.1