From: AKASHI Takahiro <takahiro.aka...@linaro.org>
On primary kernel, the memory region used by crash dump kernel must be
specified by "crashkernel=" boot parameter. reserve_crashkernel()
will allocate and reserve the region for later use.
User space tools will be able to find the region marked as "Crash kernel"
in /proc/iomem.
Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
---
arch/arm64/kernel/setup.c | 6 ++++++
arch/arm64/mm/init.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 60 insertions(+)
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index bbdb53b..d4d1f49 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -366,6 +366,12 @@ static void __init request_standard_resources(void)
kernel_data.end <= res->end)
request_resource(res, &kernel_data);
}
+
+ #ifdef CONFIG_KEXEC
+ /* 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 ae8f940..3220251 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -34,6 +34,7 @@
#include <linux/dma-contiguous.h>
#include <linux/efi.h>
#include <linux/swiotlb.h>
+#include <linux/kexec.h>
#include <asm/fixmap.h>
#include <asm/memory.h>
@@ -66,6 +67,55 @@ static int __init early_initrd(char *p)
early_param("initrd", early_initrd);
#endif
+#ifdef CONFIG_KEXEC
+/*
+ * 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)
+{
+ unsigned long long crash_size = 0, crash_base = 0;
+ int ret;
+
+ ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
+ &crash_size, &crash_base);
+ if (ret)
+ return;
+
+ if (crash_base == 0) {
+ crash_base = memblock_alloc(crash_size, 1 << 21);
+ 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 (crash_base & ((1 << 21) - 1)) {
+ 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;
+}
+#endif /* CONFIG_KEXEC */
+
/*
* 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
@@ -170,6 +220,10 @@ void __init arm64_memblock_init(void)
memblock_reserve(__virt_to_phys(initrd_start), initrd_end -
initrd_start);
#endif
+#ifdef CONFIG_KEXEC
+ reserve_crashkernel();
+#endif
+
early_init_fdt_scan_reserved_mem();
/* 4GB maximum for 32-bit only capable devices */
--
2.7.4
--
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