Re: [PATCH v2 3/8] crash_core: change parse_crashkernel() to support crashkernel=,high|low parsing

From: Leizhen (ThunderTown)
Date: Wed Aug 30 2023 - 22:57:13 EST




On 2023/8/29 20:16, Baoquan He wrote:
> Now parse_crashkernel() is a real entry point for all kinds of
> crahskernel parsing on any architecture.
>
> And wrap the crahskernel=,high|low handling inside
> CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION ifdeffery scope.
>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
> include/linux/crash_core.h | 6 ++++++
> kernel/crash_core.c | 28 +++++++++++++++++++++++++++-
> 2 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
> index 2e76289699ff..85260bf4a734 100644
> --- a/include/linux/crash_core.h
> +++ b/include/linux/crash_core.h
> @@ -77,6 +77,12 @@ Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
> void *data, size_t data_len);
> void final_note(Elf_Word *buf);
>
> +#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
> +#ifndef DEFAULT_CRASH_KERNEL_LOW_SIZE
> +#define DEFAULT_CRASH_KERNEL_LOW_SIZE (128UL << 20)
> +#endif
> +#endif
> +
> int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
> unsigned long long *crash_size, unsigned long long *crash_base,
> unsigned long long *low_size, bool *high);
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index f6a5c219e2e1..355b0ab5189c 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -276,6 +276,9 @@ static int __init __parse_crashkernel(char *cmdline,
> /*
> * That function is the entry point for command line parsing and should be
> * called from the arch-specific code.
> + *
> + * If crashkernel=,high|low is supported on architecture, non-NULL values
> + * should be passed to parameters 'low_size' and 'high'.
> */
> int __init parse_crashkernel(char *cmdline,
> unsigned long long system_ram,
> @@ -291,7 +294,30 @@ int __init parse_crashkernel(char *cmdline,
> crash_base, NULL);
> if (!high)
> return ret;
> -
> +#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
> + else if (ret == -ENOENT) {
> + ret = __parse_crashkernel(cmdline, 0, crash_size,
> + crash_base, suffix_tbl[SUFFIX_HIGH]);
> + if (ret || !*crash_size)
> + return -1;

Change -1 to -EINVAL?

> +
> + /*
> + * crashkernel=Y,low can be specified or not, but invalid value
> + * is not allowed.
> + */
> + ret = __parse_crashkernel(cmdline, 0, low_size,
> + crash_base, suffix_tbl[SUFFIX_LOW]);
> + if (ret == -ENOENT)
> + *low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
> + else if (ret)
> + return -1;

return ret;

> +
> + *high = true;
> + } else if (ret || !*crash_size) {

This check can be moved outside of #ifdef. Because even '!high', it's completely
applicable. The overall adjustment is as follows:

- if (!high)
- return ret;

#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
if (high && ret == -ENOENT) {
... ...
if (ret || !*crash_size) //parse HIGH
... ...
}

//At this point, *crash_size is not 0 and ret is 0.
//We can also delete if (!*crash_size) above because it will be checked later.
#endif

if (!*crash_size)
ret = -EINVAL;

return ret;

- return 0;

> + /* The specified value is invalid */
> + return -1;
> + }
> +#endif
> return 0;
> }
>
>

--
Regards,
Zhen Lei