[PATCH 3/3] kexec: arrange for paddr_vmcoreinfo_note() to return phys_addr_t

[Baoquan He]

On 04/14/16 at 09:00pm, Russell King wrote:
> On PAE systems (eg, ARM LPAE) the vmcore note may be located above
> 4GB physical on 32-bit architectures, so we need a wider type than
> "unsigned long" here.  Arrange for paddr_vmcoreinfo_note() to return
> a phys_addr_t, thereby allowing it to be located above 4GB.

At first glance, it sounds great. But I can't imagine a scenario where
on pae system kernel can be located above 4G. As far as I know i386 and
its pae can't do this because the current linux VM implementation can't
allow that. I am not familiar with arm system. So please correct me if
I was wrong.

Thanks
Baoquan

> 
> This makes no difference for kexec-tools, as they already assume a
> 64-bit type when reading from this file.
> 
> Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
> ---
>  arch/ia64/kernel/machine_kexec.c | 2 +-
>  include/linux/kexec.h            | 2 +-
>  kernel/kexec_core.c              | 2 +-
>  kernel/ksysfs.c                  | 4 ++--
>  4 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/ia64/kernel/machine_kexec.c b/arch/ia64/kernel/machine_kexec.c
> index b72cd7a07222..599507bcec91 100644
> --- a/arch/ia64/kernel/machine_kexec.c
> +++ b/arch/ia64/kernel/machine_kexec.c
> @@ -163,7 +163,7 @@ void arch_crash_save_vmcoreinfo(void)
>  #endif
>  }
>  
> -unsigned long paddr_vmcoreinfo_note(void)
> +phys_addr_t paddr_vmcoreinfo_note(void)
>  {
>  	return ia64_tpa((unsigned long)(char *)&vmcoreinfo_note);
>  }
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 1b32ab587f66..52a3a221bcb2 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -235,7 +235,7 @@ void crash_unmap_reserved_pages(void);
>  void arch_crash_save_vmcoreinfo(void);
>  __printf(1, 2)
>  void vmcoreinfo_append_str(const char *fmt, ...);
> -unsigned long paddr_vmcoreinfo_note(void);
> +phys_addr_t paddr_vmcoreinfo_note(void);
>  
>  #define VMCOREINFO_OSRELEASE(value) \
>  	vmcoreinfo_append_str("OSRELEASE=%s\n", value)
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index d719a4d0ef55..f9847e5822e6 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -1377,7 +1377,7 @@ void vmcoreinfo_append_str(const char *fmt, ...)
>  void __weak arch_crash_save_vmcoreinfo(void)
>  {}
>  
> -unsigned long __weak paddr_vmcoreinfo_note(void)
> +phys_addr_t __weak paddr_vmcoreinfo_note(void)
>  {
>  	return __pa((unsigned long)(char *)&vmcoreinfo_note);
>  }
> diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
> index 152da4a48867..9f1920d2d0c6 100644
> --- a/kernel/ksysfs.c
> +++ b/kernel/ksysfs.c
> @@ -128,8 +128,8 @@ KERNEL_ATTR_RW(kexec_crash_size);
>  static ssize_t vmcoreinfo_show(struct kobject *kobj,
>  			       struct kobj_attribute *attr, char *buf)
>  {
> -	return sprintf(buf, "%lx %x\n",
> -		       paddr_vmcoreinfo_note(),
> +	phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
> +	return sprintf(buf, "%pa %x\n", &vmcore_base,
>  		       (unsigned int)sizeof(vmcoreinfo_note));
>  }
>  KERNEL_ATTR_RO(vmcoreinfo);
> -- 
> 2.1.0
> 
> 
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