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authorMark Rutland <mark.rutland@arm.com>2014-07-18 14:57:38 +0100
committerWill Deacon <will.deacon@arm.com>2014-07-18 18:33:23 +0100
commitd7a49086f263164a2c4c178eb76412d48cd671d7 (patch)
treeca28bf83df063497d8e55e76834efa2e39d7563e /arch/arm64
parent127161aaf0fcd37680984f79e1451b870b3e310a (diff)
downloadlinux-d7a49086f263164a2c4c178eb76412d48cd671d7.tar.gz
arm64: cpuinfo: print info for all CPUs
Currently reading /proc/cpuinfo will result in information being read out of the MIDR_EL1 of the current CPU, and the information is not associated with any particular logical CPU number. This is problematic for systems with heterogeneous CPUs (i.e. big.LITTLE) where MIDR fields will vary across CPUs, and the output will differ depending on the executing CPU. This patch reorganises the code responsible for /proc/cpuinfo to print information per-cpu. In the process, we perform several cleanups: * Property names are coerced to lower-case (to match "processor" as per glibc's expectations). * Property names are simplified and made to match the MIDR field names. * Revision is changed to hex as with every other field. * The meaningless Architecture property is removed. * The ripe-for-abuse Machine field is removed. The features field (a human-readable representation of the hwcaps) remains printed once, as this is expected to remain in use as the globally support CPU features. To enable the possibility of the addition of per-cpu HW feature information later, this is printed before any CPU-specific information. Comments are added to guide userspace developers in the right direction (using the hwcaps provided in auxval). Hopefully where userspace applications parse /proc/cpuinfo rather than using the readily available hwcaps, they limit themselves to reading said first line. If CPU features differ from each other, the previously installed sanity checks will give us some advance notice with warnings and TAINT_CPU_OUT_OF_SPEC. If we are lucky, we will never see such systems. Rework will be required in many places to support such systems anyway. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marcus Shawcroft <marcus.shawcroft@arm.com> Cc: Peter Maydell <peter.maydell@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> [catalin.marinas@arm.com: remove machine_name as it is no longer reported] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/kernel/setup.c40
1 files changed, 18 insertions, 22 deletions
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index edb146d01857..f6f0ccf35ae6 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -78,7 +78,6 @@ unsigned int compat_elf_hwcap2 __read_mostly;
#endif
static const char *cpu_name;
-static const char *machine_name;
phys_addr_t __fdt_pointer __initdata;
/*
@@ -310,8 +309,6 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys)
while (true)
cpu_relax();
}
-
- machine_name = of_flat_dt_get_machine_name();
}
/*
@@ -450,10 +447,21 @@ static int c_show(struct seq_file *m, void *v)
{
int i;
- seq_printf(m, "Processor\t: %s rev %d (%s)\n",
- cpu_name, read_cpuid_id() & 15, ELF_PLATFORM);
+ /*
+ * 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.
+ */
+ seq_puts(m, "features\t:");
+ for (i = 0; hwcap_str[i]; i++)
+ if (elf_hwcap & (1 << i))
+ seq_printf(m, " %s", hwcap_str[i]);
+ seq_puts(m, "\n\n");
for_each_online_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
@@ -462,25 +470,13 @@ static int c_show(struct seq_file *m, void *v)
#ifdef CONFIG_SMP
seq_printf(m, "processor\t: %d\n", i);
#endif
+ seq_printf(m, "implementer\t: 0x%02x\n",
+ MIDR_IMPLEMENTOR(midr));
+ seq_printf(m, "variant\t\t: 0x%x\n", MIDR_VARIANT(midr));
+ seq_printf(m, "partnum\t\t: 0x%03x\n", MIDR_PARTNUM(midr));
+ seq_printf(m, "revision\t: 0x%x\n\n", MIDR_REVISION(midr));
}
- /* dump out the processor features */
- seq_puts(m, "Features\t: ");
-
- for (i = 0; hwcap_str[i]; i++)
- if (elf_hwcap & (1 << i))
- seq_printf(m, "%s ", hwcap_str[i]);
-
- seq_printf(m, "\nCPU implementer\t: 0x%02x\n", read_cpuid_id() >> 24);
- seq_printf(m, "CPU architecture: AArch64\n");
- seq_printf(m, "CPU variant\t: 0x%x\n", (read_cpuid_id() >> 20) & 15);
- seq_printf(m, "CPU part\t: 0x%03x\n", (read_cpuid_id() >> 4) & 0xfff);
- seq_printf(m, "CPU revision\t: %d\n", read_cpuid_id() & 15);
-
- seq_puts(m, "\n");
-
- seq_printf(m, "Hardware\t: %s\n", machine_name);
-
return 0;
}