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authorAndre Przywara <andre.przywara@arm.com>2015-04-24 10:30:47 -0700
committerSasha Levin <sasha.levin@oracle.com>2015-04-27 17:13:44 -0400
commitda767e54e365f4816ffbbf1403e5f7735d363bc3 (patch)
treec7b3281aefff769b47be835fc62595a8e0826e41
parent6a5a8112e8423ce3b941427b823107765ea7ce6a (diff)
downloadlinux-linaro-stable-da767e54e365f4816ffbbf1403e5f7735d363bc3.tar.gz
arm64: detect silicon revisions and set cap bits accordingly
After each CPU has been started, we iterate through a list of CPU features or bugs to detect CPUs which need (or could benefit from) kernel code patches. For each feature/bug there is a function which checks if that particular CPU is affected. We will later provide some more generic functions for common things like testing for certain MIDR ranges. We do this for every CPU to cover big.LITTLE systems properly as well. If a certain feature/bug has been detected, the capability bit will be set, so that later the call to apply_alternatives() will trigger the actual code patching. Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: <stable@vger.kernel.org> # v3.18.y (cherry picked from commit e116a375423393cdb94714e90a96857005d58428) Signed-off-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--arch/arm64/include/asm/cpufeature.h2
-rw-r--r--arch/arm64/kernel/Makefile2
-rw-r--r--arch/arm64/kernel/cpu_errata.c59
-rw-r--r--arch/arm64/kernel/cpuinfo.c3
4 files changed, 65 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 20b2b3d6b702..744eaf7fab0f 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -46,4 +46,6 @@ static inline void cpus_set_cap(unsigned int num)
__set_bit(num, cpu_hwcaps);
}
+void check_local_cpu_errata(void);
+
#endif
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 65b5a8e87ea5..da2272811a31 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -15,7 +15,7 @@ arm64-obj-y := cputable.o debug-monitors.o entry.o irq.o fpsimd.o \
entry-fpsimd.o process.o ptrace.o setup.o signal.o \
sys.o stacktrace.o time.o traps.o io.o vdso.o \
hyp-stub.o psci.o cpu_ops.o insn.o return_address.o \
- cpuinfo.o alternative.o
+ cpuinfo.o cpu_errata.o alternative.o
arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \
sys_compat.o
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
new file mode 100644
index 000000000000..9332cf7c0826
--- /dev/null
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -0,0 +1,59 @@
+/*
+ * Contains CPU specific errata definitions
+ *
+ * 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/>.
+ */
+
+#define pr_fmt(fmt) "alternative: " fmt
+
+#include <linux/types.h>
+#include <asm/cpu.h>
+#include <asm/cputype.h>
+#include <asm/cpufeature.h>
+
+/*
+ * Add a struct or another datatype to the union below if you need
+ * different means to detect an affected CPU.
+ */
+struct arm64_cpu_capabilities {
+ const char *desc;
+ u16 capability;
+ bool (*is_affected)(struct arm64_cpu_capabilities *);
+ union {
+ struct {
+ u32 midr_model;
+ u32 midr_range_min, midr_range_max;
+ };
+ };
+};
+
+struct arm64_cpu_capabilities arm64_errata[] = {
+ {}
+};
+
+void check_local_cpu_errata(void)
+{
+ struct arm64_cpu_capabilities *cpus = arm64_errata;
+ int i;
+
+ for (i = 0; cpus[i].desc; i++) {
+ if (!cpus[i].is_affected(&cpus[i]))
+ continue;
+
+ if (!cpus_have_cap(cpus[i].capability))
+ pr_info("enabling workaround for %s\n", cpus[i].desc);
+ cpus_set_cap(cpus[i].capability);
+ }
+}
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 504fdaa8367e..16d6d032ecf1 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -18,6 +18,7 @@
#include <asm/cachetype.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
+#include <asm/cpufeature.h>
#include <linux/bitops.h>
#include <linux/bug.h>
@@ -186,6 +187,8 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
cpuinfo_detect_icache_policy(info);
+
+ check_local_cpu_errata();
}
void cpuinfo_store_cpu(void)