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arm64: kdump: reserve memory for crash dump kernel

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"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@linaro.org>
Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Pratyush Anand <panand@redhat.com>
Reviewed-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
AKASHI Takahiro 2017-04-03 11:24:32 +09:00 committed by Catalin Marinas
parent 8f579b1c4e
commit 764b51ead1
2 changed files with 72 additions and 1 deletions
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7
arch/arm64/kernel/setup.c
View File

@ -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
}
}

66
arch/arm64/mm/init.c
View File

@ -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();