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Subject: Re: [PATCH v3 3/9] crash_core: change parse_crashkernel() to support
 crashkernel=,high|low parsing
To:     Baoquan He <bhe@redhat.com>, linux-kernel@vger.kernel.org
Cc:     akpm@linux-foundation.org, thunder.leizhen@huawei.com,
        catalin.marinas@arm.com, chenjiahao16@huawei.com,
        kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
        linux-riscv@lists.infradead.org, x86@kernel.org
References: <20230914033142.676708-1-bhe@redhat.com>
 <20230914033142.676708-4-bhe@redhat.com>
From:   "Leizhen (ThunderTown)" <thunder.leizhen@huaweicloud.com>
Message-ID: <69917722-0788-30f4-b28e-cb0a41881f35@huaweicloud.com>
Date:   Mon, 18 Sep 2023 20:41:20 +0800
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On 2023/9/14 11:31, 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.

Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>

> 
> Signed-off-by: Baoquan He <bhe@redhat.com>
> ---
>  include/linux/crash_core.h |  6 ++++++
>  kernel/crash_core.c        | 36 +++++++++++++++++++++++++++++++++---
>  2 files changed, 39 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
> index 6156355ef831..d8050a7eab01 100644
> --- a/include/linux/crash_core.h
> +++ b/include/linux/crash_core.h
> @@ -79,6 +79,12 @@ 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 cca1d76e8255..dce2f5874fea 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -283,6 +283,9 @@ 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,
> @@ -296,10 +299,37 @@ int __init parse_crashkernel(char *cmdline,
>  	/* crashkernel=X[@offset] */
>  	ret = __parse_crashkernel(cmdline, system_ram, crash_size,
>  				crash_base, NULL);
> -	if (!high)
> -		return ret;
> +#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
> +	/*
> +	 * If non-NULL 'high' passed in and no normal crashkernel
> +	 * setting detected, try parsing crashkernel=,high|low.
> +	 */
> +	if (high && ret == -ENOENT) {
> +		ret = __parse_crashkernel(cmdline, 0, crash_size,
> +				crash_base, suffix_tbl[SUFFIX_HIGH]);
> +		if (ret || !*crash_size)
> +			return -EINVAL;
>  
> -	return 0;
> +		/*
> +		 * 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;
> +			ret = 0;
> +		} else if (ret) {
> +			return ret;
> +		}
> +
> +		*high = true;
> +	}
> +#endif
> +	if (!*crash_size)
> +		ret = -EINVAL;
> +
> +	return ret;
>  }
>  
>  int __init parse_crashkernel_high(char *cmdline,
> 

-- 
Regards,
  Zhen Lei