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Commit 764b51ea authored by AKASHI Takahiro's avatar AKASHI Takahiro Committed by Catalin Marinas
Browse files

arm64: kdump: reserve memory for crash dump kernel 



"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: default avatarAKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: default avatarMark Salter <msalter@redhat.com>
Signed-off-by: default avatarPratyush Anand <panand@redhat.com>
Reviewed-by: default avatarJames Morse <james.morse@arm.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 8f579b1c

arch/arm64/kernel/setup.c

+6 −1
Original line number Diff line number Diff line
@@ -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>
@@ -226,6 +225,12 @@ 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

	}

}

arch/arm64/mm/init.c

+66 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#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>
@@ -37,6 +38,7 @@ 
#include <linux/swiotlb.h>

#include <linux/vmalloc.h>

#include <linux/mm.h>

#include <linux/kexec.h>



#include <asm/boot.h>

#include <asm/fixmap.h>
@@ -77,6 +79,67 @@ 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
@@ -332,6 +395,9 @@ 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();