"crashkernel=" kernel parameter specifies the size (and optionally
the start address) of the system ram to be used by crash dump kernel.
reserve_crashkernel() will allocate and reserve that memory at boot time
of primary kernel.
The memory range will be exposed to userspace as a resource named
"Crash kernel" in /proc/iomem.
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>
Acked-by: Catalin Marinas <catalin.marinas at arm.com>
---
arch/arm64/kernel/setup.c | 7 ++++-
arch/arm64/mm/init.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index b051367e2149..515e9c6696df 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>
@@ -224,6 +223,12 @@ static void __init request_standard_resources(void)
if (kernel_data.start >= res->start &&
kernel_data.end <= res->end)
request_resource(res, &kernel_data);
+#ifdef CONFIG_KEXEC_CORE
+ /* Userspace will find "Crash kernel" region in /proc/iomem. */
+ if (crashk_res.end && crashk_res.start >= res->start &&
+ crashk_res.end <= res->end)
+ request_resource(res, &crashk_res);
+#endif
}
}
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 3c41fd0bbce6..083e8fc9b771 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -30,12 +30,14 @@
#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/vmalloc.h>
+#include <linux/kexec.h>
#include <asm/boot.h>
#include <asm/fixmap.h>
@@ -76,6 +78,67 @@ static int __init early_initrd(char *p)
early_param("initrd", early_initrd);
#endif
+#ifdef CONFIG_KEXEC_CORE
+/*
+ * 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_base, crash_size;
+ 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;
+
+ crash_size = PAGE_ALIGN(crash_size);
+
+ 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("cannot allocate crashkernel (size:0x%llx)\n",
+ crash_size);
+ return;
+ }
+ } else {
+ /* User specifies base address explicitly. */
+ if (!memblock_is_region_memory(crash_base, crash_size)) {
+ pr_warn("cannot reserve crashkernel: region is not memory\n");
+ return;
+ }
+
+ if (memblock_is_region_reserved(crash_base, crash_size)) {
+ pr_warn("cannot reserve crashkernel: region overlaps reserved memory\n");
+ return;
+ }
+
+ if (!IS_ALIGNED(crash_base, SZ_2M)) {
+ pr_warn("cannot reserve crashkernel: base address is not 2MB aligned\n");
+ return;
+ }
+ }
+ memblock_reserve(crash_base, crash_size);
+
+ pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
+ crash_base, crash_base + crash_size, crash_size >> 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
@@ -331,6 +394,9 @@ 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();
--
2.11.1
