Hi,
On 17/06/16 00:48, Geoff Levand wrote:
> From: AKASHI Takahiro <takahiro.akashi at linaro.org>
>
> On the startup of primary kernel, the memory region used by crash dump
> kernel must be specified by "crashkernel=" kernel parameter.
> reserve_crashkernel() will allocate and reserve the region for later use.
>
> User space tools, like kexec-tools, will be able to find that region marked
> as "Crash kernel" in /proc/iomem.
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index d45f862..45f1319 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/boot.h>
> #include <asm/fixmap.h>
> @@ -76,6 +77,65 @@ 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_size = 0, crash_base = 0;
> + int ret;
> +
> + ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
> + &crash_size, &crash_base);
> + /* no crashkernel= or invalid value specified */
> + if (!crash_size)
> + return;
Should we check ret too?
> +
> + if (crash_base == 0) {
> + /* Current arm64 boot protocol requires 2MB alignment */
> + crash_base = memblock_find_in_range(0,
> + MEMBLOCK_ALLOC_ACCESSIBLE, crash_size, SZ_2M);
> + if (crash_base == 0) {
> + pr_warn("Unable to allocate crashkernel (size:%llx)\n",
> + crash_size);
> + return;
> + }
> + memblock_reserve(crash_base, crash_size);
What if memblock_reserve() fails?
> +
> + } 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 (IS_ALIGNED(crash_base, SZ_2M)) {
!IS_ALIGNED()...
> + pr_warn("crashkernel base address is not 2MB aligned\n");
> + return;
> + }
> +
> + memblock_reserve(crash_base, crash_size);
What if memblock_reserve() fails?
> + }
> +
> + 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;
> +}
> +#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
> @@ -291,6 +351,8 @@ void __init arm64_memblock_init(void)
> }
> #endif
>
> + reserve_crashkernel();
> +
> early_init_fdt_scan_reserved_mem();
>
> /* 4GB maximum for 32-bit only capable devices */
>
With those,
Reviewed-by: James Morse <james.morse at arm.com>
Thanks,
James
