On Tue, Nov 24, 2015 at 10:25:34PM +0000, Geoff Levand wrote:
> From: AKASHI Takahiro <takahiro.akashi at linaro.org>
>
> On primary kernel, the memory region used by crash dump kernel must be
> specified by "crashkernel=" boot parameter. reserve_crashkernel()
> will allocate and reserve the region for later use.
>
> User space tools will be able to find the region marked as "Crash kernel"
> in /proc/iomem.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
> arch/arm64/kernel/setup.c | 7 +++++-
> arch/arm64/mm/init.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 60 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index 8119479..f9fffc9 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>
> @@ -221,6 +220,12 @@ static void __init request_standard_resources(void)
> kernel_data.end <= res->end)
> request_resource(res, &kernel_data);
> }
> +
> +#ifdef CONFIG_KEXEC
> + /* User space tools will find "Crash kernel" region in /proc/iomem. */
> + if (crashk_res.end)
> + insert_resource(&iomem_resource, &crashk_res);
> +#endif
Why can't this bit be moved into reserved_crashkernel, at the end?
> }
>
> #ifdef CONFIG_BLK_DEV_INITRD
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 17bf39a..24f0a1c 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/fixmap.h>
> #include <asm/memory.h>
> @@ -66,6 +67,55 @@ static int __init early_initrd(char *p)
> early_param("initrd", early_initrd);
> #endif
>
> +#ifdef CONFIG_KEXEC
> +/*
> + * 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);
> + if (ret)
> + return;
What's the point in ret?
> +
> + if (crash_base == 0) {
> + crash_base = memblock_alloc(crash_size, 1 << 21);
What is this magic number? How about SZ_2M and a comment mentioning the
arm64 boot protocol?
> + if (crash_base == 0) {
> + pr_warn("Unable to allocate crashkernel (size:%llx)\n",
> + crash_size);
> + return;
> + }
> + } 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 (crash_base & ((1 << 21) - 1)) {
IS_ALIGNED
> + pr_warn("crashkernel base address is not 2MB aligned\n");
> + return;
> + }
> +
> + memblock_reserve(crash_base, crash_size);
> + }
> +
> + 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) {};
Will
