Android cpu信息获取/修改_qt android 获得cpu信息

CPU信息查看

通过 cat proc/cpuinfo 查看

processor       : 7
BogoMIPS        : 38.40
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x51
CPU architecture: 8
CPU variant     : 0xa
CPU part        : 0x800
CPU revision    : 2
 
Hardware        : 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;
		/*
		 * glibc reads /proc/cpuinfo to determine the number of
		 * online processors, looking for lines beginning with
		 * "processor".  Give glibc what it expects.
		 */
		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);
		/*
		 * Dump out the common processor features in a single line.
		 * Userspace should read the hwcaps with getauxval(AT_HWCAP)
		 * rather than attempting to parse this, but there's a body of
		 * software which does already (at least for 32-bit).
		 */
		seq_puts(m, "Features\t:");
		if (compat) {
#ifdef CONFIG_COMPAT
			for (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 /* CONFIG_COMPAT */
		} 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);
	else
		seq_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"},
	/* 8960 IDs */
	[87] = {MSM_CPU_8960, "MSM8960"},
	/* 8064 IDs */
	[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 = <xxx 0x10000>, <xxx 0x10000>;

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/src/android/security/cts/KernelConfigTest.java

    private Map<String, String[]> hardwareMitigations = new HashMap<String, String[]>() {
    {
        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());
    }
    /**
     * Test that the kernel has Spectre/Meltdown mitigations for architectures and kernel versions
     * that support it. Exempt platforms which are known to not be vulnerable.
     *
     * @throws Exception
     */
    @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。