Android cpu信息获取/修改

CPU信息查看

通过 cat proc/cpuinfo 查看

processor       : 7BogoMIPS        : 38.40Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuidCPU implementer : 0x51CPU architecture: 8CPU variant     : 0xaCPU part        : 0x800CPU revision    : 2Hardware        : Qualcomm Technologies, Inc

应用端，类似某兔兔中CPU信息应该也是从这里获取的

CPU信息修改 

 cpuinfo 文件内容是在 kernel/msm-4.19/arch/arm64/kernel/cpuinfo.c 中 c_show 函数中写入的

static int c_show(struct seq_file *m, void *v){int i, j;bool compat = personality(current->personality) == PER_LINUX32;seq_printf(m, "Processor\t: AArch64 Processor rev %d (%s)\n",read_cpuid_id() & 15, ELF_PLATFORM);for_each_present_cpu(i) {struct cpuinfo_arm64 *cpuinfo = &per_cpu(cpu_data, i);u32 midr = cpuinfo->reg_midr;seq_printf(m, "processor\t: %d\n", i);if (compat)seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n",   MIDR_REVISION(midr), COMPAT_ELF_PLATFORM);seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",   loops_per_jiffy / (500000UL/HZ),   loops_per_jiffy / (5000UL/HZ) % 100);seq_puts(m, "Features\t:");if (compat) {#ifdef CONFIG_COMPATfor (j = 0; compat_hwcap_str[j]; j++)if (compat_elf_hwcap & (1 << j))seq_printf(m, " %s", compat_hwcap_str[j]);for (j = 0; compat_hwcap2_str[j]; j++)if (compat_elf_hwcap2 & (1 << j))seq_printf(m, " %s", compat_hwcap2_str[j]);#endif } else {for (j = 0; hwcap_str[j]; j++)if (elf_hwcap & (1 << j))seq_printf(m, " %s", hwcap_str[j]);}seq_puts(m, "\n");seq_printf(m, "CPU implementer\t: 0x%02x\n",   MIDR_IMPLEMENTOR(midr));seq_printf(m, "CPU architecture: 8\n");seq_printf(m, "CPU variant\t: 0x%x\n", MIDR_VARIANT(midr));seq_printf(m, "CPU part\t: 0x%03x\n", MIDR_PARTNUM(midr));seq_printf(m, "CPU revision\t: %d\n\n", MIDR_REVISION(midr));}if (!arch_read_hardware_id)seq_printf(m, "Hardware\t: %s\n", machine_name);elseseq_printf(m, "Hardware\t: %s\n", arch_read_hardware_id());return 0;}

注：上面 arch_read_hardware_id 函数，高通平台是在 kernel/msm-4.19/drivers/soc/qcom/socinfo.c 文件中，等于 msm_read_hardware_id 函数

static char *msm_read_hardware_id(void){static char msm_soc_str[256] = "Qualcomm Technologies, Inc ";static bool string_generated;int ret = 0;if (string_generated)return msm_soc_str;if (!socinfo)goto err_path;if (!cpu_of_id[socinfo->v0_1.id].soc_id_string)goto err_path;ret = strlcat(msm_soc_str, cpu_of_id[socinfo->v0_1.id].soc_id_string,sizeof(msm_soc_str));if (ret > sizeof(msm_soc_str))goto err_path;string_generated = true;return msm_soc_str;err_path:return "UNKNOWN SOC TYPE";}

这里就是将高通和芯片名称 soc_id_string 进行拼接下。上面 msm_soc_info cpu_of_id[] 中枚举了相关芯片信息

static struct msm_soc_info cpu_of_id[] = {[0]  = {MSM_CPU_UNKNOWN, "Unknown CPU"},[87] = {MSM_CPU_8960, "MSM8960"},[109] = {MSM_CPU_8064, "APQ8064"},[122] = {MSM_CPU_8960, "MSM8960"},... ...

根据 socinfo->v0_1.id 进行匹配，这个 id 等于项目的 dtsi 中配置的 qcom,msm-id 

/ {model = "Qualcomm Technologies, Inc. xxx";compatible = "xxx";qcom,msm-id = , ;

注意：

高Android版本，修改 cpu_of_id 可能会影响CTS testConfigHardwareMitigations 此项。相关源码cts/hostsidetests/security/class="lazy" data-src/android/security/cts/KernelConfigTest.java

    private Map hardwareMitigations = new HashMap() {    {        put("EXYNOS990", null);        put("EXYNOS980", null);        put("EXYNOS850", null);        put("EXYNOS3830", null);        put("EXYNOS9630", null);        put("EXYNOS9830", null);        put("EXYNOS7870", null);        put("EXYNOS7880", null);        put("EXYNOS7570", null);        put("EXYNOS7872", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("EXYNOS7885", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("EXYNOS9610", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("Kirin980", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("Kirin970", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("Kirin810", null);        put("Kirin710", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("SDMMAGPIE", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("SM6150", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("SM7150", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("LITO", null);        put("SM8150", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("SM8150P", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("KONA", null);        put("SDM429", null);        put("SDM439", null);        put("QM215", null);        put("BENGAL", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y"});        put("DEFAULT", new String[]{"CONFIG_HARDEN_BRANCH_PREDICTOR=y",            "CONFIG_UNMAP_KERNEL_AT_EL0=y"});    }};    private String[] lookupMitigations() throws Exception {        return hardwareMitigations.get(getHardware());    }        @CddTest(requirement="9.7")    public void testConfigHardwareMitigations() throws Exception {        String mitigations[];        if (PropertyUtil.getFirstApiLevel(mDevice) < 28) {            return;        }        if (CpuFeatures.isArm64(mDevice) && !CpuFeatures.kernelVersionLessThan(mDevice, 4, 4)) {            mitigations = lookupMitigations();            if (mitigations != null) {                for (String mitigation : mitigations) {                    assertTrue("Linux kernel must have " + mitigation + " enabled.",configSet.contains(mitigation));                }            }        } else if (CpuFeatures.isX86(mDevice)) {            assertTrue("Linux kernel must have KPTI enabled: CONFIG_PAGE_TABLE_ISOLATION=y",                    configSet.contains("CONFIG_PAGE_TABLE_ISOLATION=y"));        }    }

测试会根据 hardwareMitigations 中CPU型号，确认需要开启的宏，所以修改CPU名称后需要确认相关宏是否开启。

来源地址：https://blog.csdn.net/tq501501/article/details/131514655