On the startup of primary kernel, the memory region used by crash dump
kernel must be specified by "crashkernel=" kernel parameter.
reserve_crashkernel() will allocate and reserve the region for later use.
User space tools, like kexec-tools, will be able to find that region as
- "Crash kernel" in /proc/iomem, or
- "linux,crashkernel-base" and "linux,crashkernel-size" under
/sys/firmware/devicetree/base/chosen
Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
Signed-off-by: Mark Salter <msalter at redhat.com>
Signed-off-by: Pratyush Anand <panand at redhat.com>
Reviewed-by: James Morse <james.morse at arm.com>
---
arch/arm64/kernel/setup.c | 7 ++-
arch/arm64/mm/init.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 119 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 514b4e3..38589b5 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -31,7 +31,6 @@
#include <linux/screen_info.h>
#include <linux/init.h>
#include <linux/kexec.h>
-#include <linux/crash_dump.h>
#include <linux/root_dev.h>
#include <linux/cpu.h>
#include <linux/interrupt.h>
@@ -225,6 +224,12 @@ static void __init request_standard_resources(void)
kernel_data.end <= res->end)
request_resource(res, &kernel_data);
}
+
+#ifdef CONFIG_KEXEC_CORE
+ /* User space tools will find "Crash kernel" region in /proc/iomem. */
+ if (crashk_res.end)
+ insert_resource(&iomem_resource, &crashk_res);
+#endif
}
u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID };
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index bbb7ee7..dd273ec 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -29,11 +29,13 @@
#include <linux/gfp.h>
#include <linux/memblock.h>
#include <linux/sort.h>
+#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/dma-mapping.h>
#include <linux/dma-contiguous.h>
#include <linux/efi.h>
#include <linux/swiotlb.h>
+#include <linux/kexec.h>
#include <asm/boot.h>
#include <asm/fixmap.h>
@@ -76,6 +78,114 @@ static int __init early_initrd(char *p)
early_param("initrd", early_initrd);
#endif
+#ifdef CONFIG_KEXEC_CORE
+static unsigned long long crash_size, crash_base;
+static struct property crash_base_prop = {
+ .name = "linux,crashkernel-base",
+ .length = sizeof(u64),
+ .value = &crash_base
+};
+static struct property crash_size_prop = {
+ .name = "linux,crashkernel-size",
+ .length = sizeof(u64),
+ .value = &crash_size,
+};
+
+static int __init export_crashkernel(void)
+{
+ struct device_node *node;
+ int ret;
+
+ if (!crashk_res.end)
+ return 0;
+
+ crash_base = cpu_to_be64(crashk_res.start);
+ crash_size = cpu_to_be64(crashk_res.end - crashk_res.start + 1);
+
+ /* Add /chosen/linux,crashkernel-* properties */
+ node = of_find_node_by_path("/chosen");
+ if (!node)
+ return -ENOENT;
+
+ /*
+ * There might be existing crash kernel properties, but we can't
+ * be sure what's in them, so remove them.
+ */
+ of_remove_property(node, of_find_property(node,
+ "linux,crashkernel-base", NULL));
+ of_remove_property(node, of_find_property(node,
+ "linux,crashkernel-size", NULL));
+
+ ret = of_add_property(node, &crash_base_prop);
+ if (ret)
+ goto ret_err;
+
+ ret = of_add_property(node, &crash_size_prop);
+ if (ret)
+ goto ret_err;
+
+ return 0;
+
+ret_err:
+ pr_warn("Exporting crashkernel region to device tree failed\n");
+ return ret;
+}
+late_initcall(export_crashkernel);
+
+/*
+ * reserve_crashkernel() - reserves memory for crash kernel
+ *
+ * This function reserves memory area given in "crashkernel=" kernel command
+ * line parameter. The memory reserved is used by dump capture kernel when
+ * primary kernel is crashing.
+ */
+static void __init reserve_crashkernel(void)
+{
+ int ret;
+
+ ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
+ &crash_size, &crash_base);
+ /* no crashkernel= or invalid value specified */
+ if (ret || !crash_size)
+ return;
+
+ if (crash_base == 0) {
+ /* Current arm64 boot protocol requires 2MB alignment */
+ crash_base = memblock_find_in_range(0, ARCH_LOW_ADDRESS_LIMIT,
+ crash_size, SZ_2M);
+ if (crash_base == 0) {
+ pr_warn("Unable to allocate crashkernel (size:%llx)\n",
+ crash_size);
+ return;
+ }
+ } else {
+ /* User specifies base address explicitly. */
+ if (!memblock_is_region_memory(crash_base, crash_size) ||
+ memblock_is_region_reserved(crash_base, crash_size)) {
+ pr_warn("crashkernel has wrong address or size\n");
+ return;
+ }
+
+ if (!IS_ALIGNED(crash_base, SZ_2M)) {
+ pr_warn("crashkernel base address is not 2MB aligned\n");
+ return;
+ }
+ }
+ memblock_reserve(crash_base, crash_size);
+
+ pr_info("Reserving %lldMB of memory at %lldMB for crashkernel\n",
+ crash_size >> 20, crash_base >> 20);
+
+ crashk_res.start = crash_base;
+ crashk_res.end = crash_base + crash_size - 1;
+}
+#else
+static void __init reserve_crashkernel(void)
+{
+ ;
+}
+#endif /* CONFIG_KEXEC_CORE */
+
/*
* Return the maximum physical address for ZONE_DMA (DMA_BIT_MASK(32)). It
* currently assumes that for memory starting above 4G, 32-bit devices will
@@ -296,6 +406,9 @@ void __init arm64_memblock_init(void)
arm64_dma_phys_limit = max_zone_dma_phys();
else
arm64_dma_phys_limit = PHYS_MASK + 1;
+
+ reserve_crashkernel();
+
dma_contiguous_reserve(arm64_dma_phys_limit);
memblock_allow_resize();
--
2.9.0
