xen/arm: Detect silicon revision and set cap bits accordingly

After each CPU has been started, we iterate through a list of CPU
errata to detect CPUs which need from hypervisor code patches.

For each bug there is a function which checks if that a particular CPU is
affected. This needs to be done on every CPU to cover heterogenous
systems properly.

If a certain erratum has been detected, the capability bit will be set.
In the case the erratum requires code patching, this will be triggered
by the call to apply_alternatives.

The code is based on the file arch/arm64/kernel/cpu_errata.c in Linux
v4.6-rc3.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 8b01f6364f50f3b416105cc5f1ee2ca4f13d43eb)

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 48613206d4230d738c0be498901f08f086b96b86..c0c3cb9164bb9389bafc52b0cad6da3a59a1a855 100644 (file)
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -6,6 +6,7 @@ subdir-$(CONFIG_ACPI) += acpi
 
 obj-$(EARLY_PRINTK) += early_printk.o
 obj-y += cpu.o
+obj-y += cpuerrata.o
 obj-y += cpufeature.o
 obj-y += domain.o
 obj-y += psci.o

diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
new file mode 100644 (file)
index 0000000..03ae7b4
--- /dev/null
+++ b/xen/arch/arm/cpuerrata.c
@@ -0,0 +1,34 @@
+#include <xen/config.h>
+#include <asm/cpufeature.h>
+#include <asm/cpuerrata.h>
+
+#define MIDR_RANGE(model, min, max)     \
+    .matches = is_affected_midr_range,  \
+    .midr_model = model,                \
+    .midr_range_min = min,              \
+    .midr_range_max = max
+
+static bool_t __maybe_unused
+is_affected_midr_range(const struct arm_cpu_capabilities *entry)
+{
+    return MIDR_IS_CPU_MODEL_RANGE(boot_cpu_data.midr.bits, entry->midr_model,
+                                   entry->midr_range_min,
+                                   entry->midr_range_max);
+}
+
+static const struct arm_cpu_capabilities arm_errata[] = {
+    {},
+};
+
+void check_local_cpu_errata(void)
+{
+    update_cpu_capabilities(arm_errata, "enabled workaround for");
+}
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 38b1a795376fc877d11e39bfcdcb7a4d38c7d56d..e9ec4f4b79ed78148a3dfd6de759e3d8766984c7 100644 (file)
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -42,6 +42,7 @@
 #include <asm/current.h>
 #include <asm/setup.h>
 #include <asm/gic.h>
+#include <asm/cpuerrata.h>
 #include <asm/cpufeature.h>
 #include <asm/platform.h>
 #include <asm/procinfo.h>
@@ -170,6 +171,8 @@ static void __init processor_id(void)
     }
 
     processor_setup();
+
+    check_local_cpu_errata();
 }
 
 void dt_unreserved_regions(paddr_t s, paddr_t e,

diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 81f3a59b1afa1f7f24b20067bb931d7ff453e21c..ae7ac45e7899a396d49b6cdc91129ce06b8113b5 100644 (file)
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -29,6 +29,7 @@
 #include <xen/timer.h>
 #include <xen/irq.h>
 #include <xen/console.h>
+#include <asm/cpuerrata.h>
 #include <asm/gic.h>
 #include <asm/psci.h>
 #include <asm/acpi.h>
@@ -320,6 +321,8 @@ void start_secondary(unsigned long boot_phys_offset,
     local_irq_enable();
     local_abort_enable();
 
+    check_local_cpu_errata();
+
     printk(XENLOG_DEBUG "CPU %u booted.\n", smp_processor_id());
 
     startup_cpu_idle_loop();

diff --git a/xen/include/asm-arm/cpuerrata.h b/xen/include/asm-arm/cpuerrata.h
new file mode 100644 (file)
index 0000000..c495ee5
--- /dev/null
+++ b/xen/include/asm-arm/cpuerrata.h
@@ -0,0 +1,14 @@
+#ifndef __ARM_CPUERRATA_H__
+#define __ARM_CPUERRATA_H__
+
+void check_local_cpu_errata(void);
+
+#endif /* __ARM_CPUERRATA_H__ */
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */

diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
index 9c21a0e043b9495828f5e4291db15379c2ac483f..6ae90b4d693f73f4ec6a76a8c99c8b43376180ac 100644 (file)
--- a/xen/include/asm-arm/cpufeature.h
+++ b/xen/include/asm-arm/cpufeature.h
@@ -66,6 +66,12 @@ struct arm_cpu_capabilities {
     const char *desc;
     u16 capability;
     bool_t (*matches)(const struct arm_cpu_capabilities *);
+    union {
+        struct {    /* To be used for eratum handling only */
+            u32 midr_model;
+            u32 midr_range_min, midr_range_max;
+        };
+    };
 };
 
 void update_cpu_capabilities(const struct arm_cpu_capabilities *caps,