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Date:   Wed, 19 Jan 2022 16:23:06 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Eric DeVolder <eric.devolder@oracle.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        kexec@lists.infradead.org, ebiederm@xmission.com,
        dyoung@redhat.com, vgoyal@redhat.com, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
        hpa@zytor.com, nramas@linux.microsoft.com, thomas.lendacky@amd.com,
        robh@kernel.org, efault@gmx.de, rppt@kernel.org,
        konrad.wilk@oracle.com, boris.ostrovsky@oracle.com
Subject: Re: [RFC v2 3/6] crash hp: definitions and prototype changes
Message-ID: <20220119082306.GA5158@MiWiFi-R3L-srv>
References: <20211207195204.1582-1-eric.devolder@oracle.com>
 <20211207195204.1582-4-eric.devolder@oracle.com>
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On 12/07/21 at 02:52pm, Eric DeVolder wrote:
> This change adds members to struct kimage to facilitate crash
> hotplug support.
> 
> This change also defines crash hotplug events and associated
> prototypes.
> 
> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
> ---
>  include/linux/kexec.h | 21 +++++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 0c994ae37729..068f853f1c65 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -221,8 +221,9 @@ struct crash_mem {
>  extern int crash_exclude_mem_range(struct crash_mem *mem,
>  				   unsigned long long mstart,
>  				   unsigned long long mend);
> -extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
> -				       void **addr, unsigned long *sz);
> +extern int crash_prepare_elf64_headers(struct kimage *image,
> +					struct crash_mem *mem, int kernel_map,
> +					void **addr, unsigned long *sz);
>  #endif /* CONFIG_KEXEC_FILE */
>  
>  #ifdef CONFIG_KEXEC_ELF
> @@ -299,6 +300,13 @@ struct kimage {
>  
>  	/* Information for loading purgatory */
>  	struct purgatory_info purgatory_info;
> +
> +#ifdef CONFIG_CRASH_HOTPLUG
> +	bool hotplug_event;
> +	int offlinecpu;
> +	bool elf_index_valid;
> +	int elf_index;

Do we really need elf_index_valid? Can we initialize elf_index to , e.g '-1',
then check if the value is valid?

> +#endif
>  #endif
>  
>  #ifdef CONFIG_IMA_KEXEC
> @@ -315,6 +323,15 @@ struct kimage {
>  	unsigned long elf_load_addr;
>  };
>  
> +#ifdef CONFIG_CRASH_HOTPLUG
> +void arch_crash_hotplug_handler(struct kimage *image,
> +	unsigned int hp_action, unsigned long a, unsigned long b);
> +#define KEXEC_CRASH_HP_REMOVE_CPU   0
> +#define KEXEC_CRASH_HP_ADD_CPU      1
> +#define KEXEC_CRASH_HP_REMOVE_MEMORY 2
> +#define KEXEC_CRASH_HP_ADD_MEMORY   3
> +#endif /* CONFIG_CRASH_HOTPLUG */
> +
>  /* kexec interface functions */
>  extern void machine_kexec(struct kimage *image);
>  extern int machine_kexec_prepare(struct kimage *image);
> -- 
> 2.27.0
>