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SubjectRe: [v2 1/5] arm64: kdump: reserve memory for crash dump kernel
> +#ifdef CONFIG_CRASH_DUMP
> +/*
> + * reserve_elfcorehdr() - reserves memory for elf core header
> + *
> + * This function reserves memory area given in "elfcorehdr=" kernel command
> + * line parameter. The memory reserved is used by a dump capture kernel to
> + * identify the memory used by primary kernel.
> + */

Hi AKASHI,

May I know why elfcorehdr need be reserved separately but not locate a
memory region in crashkernel reserved region like all other ARCHs? Is
there any special reason?

Thanks
Baoquan

> +static void __init reserve_elfcorehdr(void)
> +{
> + if (!elfcorehdr_size)
> + return;
> +
> + if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
> + pr_warn("elfcorehdr reservation failed - memory is in use (0x%llx)\n",
> + elfcorehdr_addr);
> + return;
> + }
> +
> + if (memblock_reserve(elfcorehdr_addr, elfcorehdr_size)) {
> + pr_warn("elfcorehdr reservation failed - out of memory\n");
> + return;
> + }
> +
> + pr_info("Reserving %lldKB of memory at %lldMB for elfcorehdr\n",
> + elfcorehdr_size >> 10, elfcorehdr_addr >> 20);
> +}
> +#endif /* CONFIG_CRASH_DUMP */
> /*
> * 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 +247,13 @@ void __init arm64_memblock_init(void)
> memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
> #endif
>
> +#ifdef CONFIG_KEXEC
> + reserve_crashkernel(memory_limit);
> +#endif
> +#ifdef CONFIG_CRASH_DUMP
> + reserve_elfcorehdr();
> +#endif
> +
> early_init_fdt_scan_reserved_mem();
>
> /* 4GB maximum for 32-bit only capable devices */
> --
> 1.7.9.5
>
> --
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