--- /dev/null
+From 44b82b7700d05a52cd983799d3ecde1a976b3bed Mon Sep 17 00:00:00 2001
+From: Mark Rutland <mark.rutland@arm.com>
+Date: Fri, 24 Oct 2014 14:56:40 +0100
+Subject: arm64: Fix up /proc/cpuinfo
+
+From: Mark Rutland <mark.rutland@arm.com>
+
+commit 44b82b7700d05a52cd983799d3ecde1a976b3bed upstream.
+
+Commit d7a49086f263164a (arm64: cpuinfo: print info for all CPUs)
+attempted to clean up /proc/cpuinfo, but due to concerns regarding
+further changes was reverted in commit 5e39977edf6500fd (Revert "arm64:
+cpuinfo: print info for all CPUs").
+
+There are two major issues with the arm64 /proc/cpuinfo format
+currently:
+
+* The "Features" line describes (only) the 64-bit hwcaps, which is
+ problematic for some 32-bit applications which attempt to parse it. As
+ the same names are used for analogous ISA features (e.g. aes) despite
+ these generally being architecturally unrelated, it is not possible to
+ simply append the 64-bit and 32-bit hwcaps in a manner that might not
+ be misleading to some applications.
+
+ Various potential solutions have appeared in vendor kernels. Typically
+ the format of the Features line varies depending on whether the task
+ is 32-bit.
+
+* Information is only printed regarding a single CPU. This does not
+ match the ARM format, and does not provide sufficient information in
+ big.LITTLE systems where CPUs are heterogeneous. The CPU information
+ printed is queried from the current CPU's registers, which is racy
+ w.r.t. cross-cpu migration.
+
+This patch attempts to solve these issues. The following changes are
+made:
+
+* When a task with a LINUX32 personality attempts to read /proc/cpuinfo,
+ the "Features" line contains the decoded 32-bit hwcaps, as with the
+ arm port. Otherwise, the decoded 64-bit hwcaps are shown. This aligns
+ with the behaviour of COMPAT_UTS_MACHINE and COMPAT_ELF_PLATFORM. In
+ the absense of compat support, the Features line is empty.
+
+ The set of hwcaps injected into a task's auxval are unaffected.
+
+* Properties are printed per-cpu, as with the ARM port. The per-cpu
+ information is queried from pre-recorded cpu information (as used by
+ the sanity checks).
+
+* As with the previous attempt at fixing up /proc/cpuinfo, the hardware
+ field is removed. The only users so far are 32-bit applications tied
+ to particular boards, so no portable applications should be affected,
+ and this should prevent future tying to particular boards.
+
+The following differences remain:
+
+* No model_name is printed, as this cannot be queried from the hardware
+ and cannot be provided in a stable fashion. Use of the CPU
+ {implementor,variant,part,revision} fields is sufficient to identify a
+ CPU and is portable across arm and arm64.
+
+* The following system-wide properties are not provided, as they are not
+ possible to provide generally. Programs relying on these are already
+ tied to particular (32-bit only) boards:
+ - Hardware
+ - Revision
+ - Serial
+
+No software has yet been identified for which these remaining
+differences are problematic.
+
+Cc: Greg Hackmann <ghackmann@google.com>
+Cc: Ian Campbell <ijc@hellion.org.uk>
+Cc: Serban Constantinescu <serban.constantinescu@arm.com>
+Cc: Will Deacon <will.deacon@arm.com>
+Cc: cross-distro@lists.linaro.org
+Cc: linux-api@vger.kernel.org
+Cc: linux-arm-kernel@lists.infradead.org
+Cc: linux-kernel@vger.kernel.org
+Acked-by: Catalin Marinas <catalin.marinas@arm.com>
+[Mark: backport to v3.10.x]
+Signed-off-by: Mark Rutland <mark.rutland@arm.com>
+Signed-off-by: Will Deacon <will.deacon@arm.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/arm64/include/asm/cputype.h | 2
+ arch/arm64/kernel/setup.c | 100 +++++++++++++++++++++++++++++----------
+ arch/arm64/kernel/smp.c | 5 +
+ 3 files changed, 82 insertions(+), 25 deletions(-)
+
+--- a/arch/arm64/include/asm/cputype.h
++++ b/arch/arm64/include/asm/cputype.h
+@@ -74,6 +74,8 @@ static inline u32 __attribute_const__ re
+ return read_cpuid(ID_CTR_EL0);
+ }
+
++void cpuinfo_store_cpu(void);
++
+ #endif /* __ASSEMBLY__ */
+
+ #endif
+--- a/arch/arm64/kernel/setup.c
++++ b/arch/arm64/kernel/setup.c
+@@ -41,6 +41,7 @@
+ #include <linux/memblock.h>
+ #include <linux/of_fdt.h>
+ #include <linux/of_platform.h>
++#include <linux/personality.h>
+
+ #include <asm/cputype.h>
+ #include <asm/elf.h>
+@@ -97,6 +98,19 @@ void __init early_print(const char *str,
+ printk("%s", buf);
+ }
+
++struct cpuinfo_arm64 {
++ struct cpu cpu;
++ u32 reg_midr;
++};
++
++static DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data);
++
++void cpuinfo_store_cpu(void)
++{
++ struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data);
++ info->reg_midr = read_cpuid_id();
++}
++
+ static void __init setup_processor(void)
+ {
+ struct cpu_info *cpu_info;
+@@ -127,6 +141,8 @@ static void __init setup_machine_fdt(phy
+ struct boot_param_header *devtree;
+ unsigned long dt_root;
+
++ cpuinfo_store_cpu();
++
+ /* Check we have a non-NULL DT pointer */
+ if (!dt_phys) {
+ early_print("\n"
+@@ -290,14 +306,12 @@ static int __init arm64_device_init(void
+ }
+ arch_initcall(arm64_device_init);
+
+-static DEFINE_PER_CPU(struct cpu, cpu_data);
+-
+ static int __init topology_init(void)
+ {
+ int i;
+
+ for_each_possible_cpu(i) {
+- struct cpu *cpu = &per_cpu(cpu_data, i);
++ struct cpu *cpu = &per_cpu(cpu_data.cpu, i);
+ cpu->hotpluggable = 1;
+ register_cpu(cpu, i);
+ }
+@@ -312,14 +326,41 @@ static const char *hwcap_str[] = {
+ NULL
+ };
+
++#ifdef CONFIG_COMPAT
++static const char *compat_hwcap_str[] = {
++ "swp",
++ "half",
++ "thumb",
++ "26bit",
++ "fastmult",
++ "fpa",
++ "vfp",
++ "edsp",
++ "java",
++ "iwmmxt",
++ "crunch",
++ "thumbee",
++ "neon",
++ "vfpv3",
++ "vfpv3d16",
++ "tls",
++ "vfpv4",
++ "idiva",
++ "idivt",
++ "vfpd32",
++ "lpae",
++ "evtstrm"
++};
++#endif /* CONFIG_COMPAT */
++
+ 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);
++ int i, j;
+
+ 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
+@@ -328,27 +369,36 @@ static int c_show(struct seq_file *m, vo
+ #ifdef CONFIG_SMP
+ seq_printf(m, "processor\t: %d\n", i);
+ #endif
+- seq_printf(m, "BogoMIPS\t: %lu.%02lu\n\n",
++ seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
+ loops_per_jiffy / (500000UL/HZ),
+ loops_per_jiffy / (5000UL/HZ) % 100);
+- }
+-
+- /* 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);
++ /*
++ * 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 (personality(current->personality) == PER_LINUX32) {
++#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]);
++#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 >> 24));
++ seq_printf(m, "CPU architecture: 8\n");
++ seq_printf(m, "CPU variant\t: 0x%x\n", ((midr >> 20) & 0xf));
++ seq_printf(m, "CPU part\t: 0x%03x\n", ((midr >> 4) & 0xfff));
++ seq_printf(m, "CPU revision\t: %d\n\n", (midr & 0xf));
++ }
+
+ return 0;
+ }
+--- a/arch/arm64/kernel/smp.c
++++ b/arch/arm64/kernel/smp.c
+@@ -200,6 +200,11 @@ asmlinkage void __cpuinit secondary_star
+ raw_spin_unlock(&boot_lock);
+
+ /*
++ * Log the CPU info before it is marked online and might get read.
++ */
++ cpuinfo_store_cpu();
++
++ /*
+ * OK, now it's safe to let the boot CPU continue. Wait for
+ * the CPU migration code to notice that the CPU is online
+ * before we continue.
projects / thirdparty / kernel / stable-queue.git / commitdiff
