arm64: cpuinfo: record cpu system register values

Several kernel subsystems need to know details about CPU system register
values, sometimes for CPUs other than that they are executing on. Rather
than hard-coding system register accesses and cross-calls for these
cases, this patch adds logic to record various system register values at
boot-time. This may be used for feature reporting, firmware bug
detection, etc.

Separate hooks are added for the boot and hotplug paths to enable
one-time intialisation and cold/warm boot value mismatch detection in
later patches.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
new file mode 100644
index 000000000000..1f350fe5b318
--- /dev/null
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -0,0 +1,73 @@
+/*
+ * Record and handle CPU attributes.
+ *
+ * Copyright (C) 2014 ARM Ltd.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <asm/arch_timer.h>
+#include <asm/cachetype.h>
+#include <asm/cpu.h>
+#include <asm/cputype.h>
+
+#include <linux/init.h>
+#include <linux/smp.h>
+
+/*
+ * In case the boot CPU is hotpluggable, we record its initial state and
+ * current state separately. Certain system registers may contain different
+ * values depending on configuration at or after reset.
+ */
+DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data);
+static struct cpuinfo_arm64 boot_cpu_data;
+
+static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
+{
+	info->reg_cntfrq = arch_timer_get_cntfrq();
+	info->reg_ctr = read_cpuid_cachetype();
+	info->reg_dczid = read_cpuid(DCZID_EL0);
+	info->reg_midr = read_cpuid_id();
+
+	info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1);
+	info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1);
+	info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
+	info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);
+	info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
+	info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
+
+	info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1);
+	info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1);
+	info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1);
+	info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
+	info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
+	info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
+	info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
+	info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
+	info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
+	info->reg_id_mmfr3 = read_cpuid(ID_MMFR3_EL1);
+	info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1);
+	info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
+}
+
+void cpuinfo_store_cpu(void)
+{
+	struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data);
+	__cpuinfo_store_cpu(info);
+}
+
+void __init cpuinfo_store_boot_cpu(void)
+{
+	struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0);
+	__cpuinfo_store_cpu(info);
+
+	boot_cpu_data = *info;
+}