On 12/07/16 06:05, AKASHI Takahiro wrote:
> 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 as
> - "Crash kernel" in /proc/iomem, or
> - "linux,crashkernel-base" and "linux,crashkernel-size" under
> /sys/firmware/devicetree/base/chosen
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> Signed-off-by: Mark Salter <msalter at redhat.com>
> Signed-off-by: Pratyush Anand <panand at redhat.com>
> Reviewed-by: James Morse <james.morse at arm.com>
Minor nits below.
> ---
> arch/arm64/kernel/setup.c | 7 ++-
> arch/arm64/mm/init.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 121 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index c1509e6..cb5eee0 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>
> @@ -222,6 +221,12 @@ static void __init request_standard_resources(void)
> kernel_data.end <= res->end)
> request_resource(res, &kernel_data);
> }
> +
> +#ifdef CONFIG_KEXEC_CORE
> + /* User space tools will find "Crash kernel" region in /proc/iomem. */
> + if (crashk_res.end)
> + insert_resource(&iomem_resource, &crashk_res);
> +#endif
nit: Could we not do this from reserve_crashkernel() ?
>
> #include <asm/boot.h>
> #include <asm/fixmap.h>
> @@ -76,6 +78,117 @@ static int __init early_initrd(char *p)
> early_param("initrd", early_initrd);
> #endif
>
> +#ifdef CONFIG_KEXEC_CORE
> +static unsigned long long crash_size, crash_base;
> +static struct property crash_base_prop = {
> + .name = "linux,crashkernel-base",
> + .length = sizeof(u64),
> + .value = &crash_base
> +};
> +static struct property crash_size_prop = {
> + .name = "linux,crashkernel-size",
> + .length = sizeof(u64),
> + .value = &crash_size,
> +};
> +
> +
> +/*
> + * 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)
> +{
> + 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;
> +
> + if (crash_base == 0) {
...
> + memblock_reserve(crash_base, crash_size);
> +
> + } else {
...
> +
> + memblock_reserve(crash_base, crash_size);
> + }
Nit: you could move the memblock_reserve() here to a single place.
> +
> + 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;
As mentioned above, may be we could move the insert_resource() here, which
would keep the generic setup.c code cleaner and is a bit more reader friendly.
> +}
> +#else
Suzuki
