linux-kernel - Re: [PATCH v3 5/9] crash_core: move crashk_*res definition into crash

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Message-ID: <69346bd7-1dc6-8202-f5d1-dbcf4ccac096@huaweicloud.com>
Date:   Mon, 18 Sep 2023 20:58:57 +0800
From:   "Leizhen (ThunderTown)" <thunder.leizhen@...weicloud.com>
To:     Baoquan He <bhe@...hat.com>, linux-kernel@...r.kernel.org
Cc:     akpm@...ux-foundation.org, thunder.leizhen@...wei.com,
        catalin.marinas@....com, chenjiahao16@...wei.com,
        kexec@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, x86@...nel.org
Subject: Re: [PATCH v3 5/9] crash_core: move crashk_*res definition into
 crash_core.c



On 2023/9/14 11:31, Baoquan He wrote:
> Both crashk_res and crashk_low_res are used to mark the reserved
> crashkernel regions in iomem_resource tree. And later the generic
> crashkernel resrvation will be added into crash_core.c. So move
> crashk_res and crashk_low_res definition into crash_core.c to avoid
> compiling error if CONFIG_CRASH_CORE=on while CONFIG_KEXEC_CORE is
> unset.
> 
> Meanwhile include <asm/crash_core.h> in <linux/crash_core.h> if generic
> reservation is needed. In that case, <asm/crash_core.h> need be added
> by ARCH. In asm/crash_core.h, ARCH can provide its own macro definitions
> to override macros in <linux/crash_core.h> if needed. Wrap the including
> into CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION ifdeffery scope to
> avoid compiling error in other ARCH-es which don't take the generic
> reservation way yet.

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

> 
> Signed-off-by: Baoquan He <bhe@...hat.com>
> ---
>  include/linux/crash_core.h |  8 ++++++++
>  include/linux/kexec.h      |  4 ----
>  kernel/crash_core.c        | 16 ++++++++++++++++
>  kernel/kexec_core.c        | 17 -----------------
>  4 files changed, 24 insertions(+), 21 deletions(-)
> 
> diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
> index 4dbd6565e0ff..3c735a7e33fb 100644
> --- a/include/linux/crash_core.h
> +++ b/include/linux/crash_core.h
> @@ -5,6 +5,14 @@
>  #include <linux/linkage.h>
>  #include <linux/elfcore.h>
>  #include <linux/elf.h>
> +#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
> +#include <asm/crash_core.h>
> +#endif
> +
> +/* Location of a reserved region to hold the crash kernel.
> + */
> +extern struct resource crashk_res;
> +extern struct resource crashk_low_res;
>  
>  #define CRASH_CORE_NOTE_NAME	   "CORE"
>  #define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 32c78078552c..8227455192b7 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -22,10 +22,6 @@
>  #include <uapi/linux/kexec.h>
>  #include <linux/verification.h>
>  
> -/* Location of a reserved region to hold the crash kernel.
> - */
> -extern struct resource crashk_res;
> -extern struct resource crashk_low_res;
>  extern note_buf_t __percpu *crash_notes;
>  
>  #ifdef CONFIG_KEXEC_CORE
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index ca66b5f41dc7..ad7dc03f3993 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -35,6 +35,22 @@ u32 *vmcoreinfo_note;
>  /* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
>  static unsigned char *vmcoreinfo_data_safecopy;
>  
> +/* Location of the reserved area for the crash kernel */
> +struct resource crashk_res = {
> +	.name  = "Crash kernel",
> +	.start = 0,
> +	.end   = 0,
> +	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
> +	.desc  = IORES_DESC_CRASH_KERNEL
> +};
> +struct resource crashk_low_res = {
> +	.name  = "Crash kernel",
> +	.start = 0,
> +	.end   = 0,
> +	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
> +	.desc  = IORES_DESC_CRASH_KERNEL
> +};
> +
>  /*
>   * parsing the "crashkernel" commandline
>   *
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index 9dc728982d79..be5642a4ec49 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -52,23 +52,6 @@ atomic_t __kexec_lock = ATOMIC_INIT(0);
>  /* Flag to indicate we are going to kexec a new kernel */
>  bool kexec_in_progress = false;
>  
> -
> -/* Location of the reserved area for the crash kernel */
> -struct resource crashk_res = {
> -	.name  = "Crash kernel",
> -	.start = 0,
> -	.end   = 0,
> -	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
> -	.desc  = IORES_DESC_CRASH_KERNEL
> -};
> -struct resource crashk_low_res = {
> -	.name  = "Crash kernel",
> -	.start = 0,
> -	.end   = 0,
> -	.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
> -	.desc  = IORES_DESC_CRASH_KERNEL
> -};
> -
>  int kexec_should_crash(struct task_struct *p)
>  {
>  	/*
> 

-- 
Regards,
  Zhen Lei