[PATCH 2/3] makedumpfile: Introduce vtop4_x86_64_pagetable

[d.hatayama@xxxxxxxxxxxxxx (Hatayama, Daisuke)]

> -----Original Message-----
> From: Takao Indoh [mailto:indou.takao at jp.fujitsu.com]
> Sent: Tuesday, October 10, 2017 6:27 PM
> To: ats-kumagai at wm.jp.nec.com; Hatayama, Daisuke 
> <d.hatayama at jp.fujitsu.com>
> Cc: kexec at lists.infradead.org
> Subject: [PATCH 2/3] makedumpfile: Introduce vtop4_x86_64_pagetable
> 
> This patch introduces new function vtop4_x86_64_pagetable
> to translate virtual address to physical address. Unlike vtop4_x86_64,
> vtop4_x86_64_pagetable need a pointer of top of pagetable like CR3.
> 
> Current vtop4_x86_64 implementation uses symbol value of
> init_level4_pgt, therefore vtop4_x86_64 does not work for sadump
> dumpfile of kaslr enabled kernel because it does not have vmcoreinfo to
> correct address of init_level4_pgt. vtop4_x86_64_pagetable requires
> pagetable address instead of init_level4_pgt and sadump dumpfile can
> pass CR3 value which is included in dump header.
> 
> Signed-off-by: Takao Indoh <indou.takao at jp.fujitsu.com>
> ---
>  arch/x86_64.c  | 30 +++++++++++++++++++++++-------
>  makedumpfile.h |  1 +
>  2 files changed, 24 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86_64.c b/arch/x86_64.c
> index 08dd6b2..33621f1 100644
> --- a/arch/x86_64.c
> +++ b/arch/x86_64.c
> @@ -255,20 +255,15 @@ get_versiondep_info_x86_64(void)
>   * Translate a virtual address to a physical address by using 4 levels paging.
>   */
>  unsigned long long
> -vtop4_x86_64(unsigned long vaddr)
> +__vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>  {
>  	unsigned long page_dir, pml4, pgd_paddr, pgd_pte, pmd_paddr, pmd_pte;
>  	unsigned long pte_paddr, pte;
> 
> -	if (SYMBOL(init_level4_pgt) == NOT_FOUND_SYMBOL) {
> -		ERRMSG("Can't get the symbol of init_level4_pgt.\n");
> -		return NOT_PADDR;
> -	}
> -
>  	/*
>  	 * Get PGD.
>  	 */
> -	page_dir = SYMBOL(init_level4_pgt) - __START_KERNEL_map +
> info->phys_base;
> +	page_dir = pagetable;
>  	if (is_xen_memory()) {
>  		page_dir = ptom_xen(page_dir);
>  		if (page_dir == NOT_PADDR)
> @@ -346,6 +341,27 @@ vtop4_x86_64(unsigned long vaddr)
>  	return (pte & ENTRY_MASK) + PAGEOFFSET(vaddr);
>  }
> 
> +unsigned long long
> +vtop4_x86_64(unsigned long vaddr)
> +{
> +	unsigned long pagetable;
> +
> +	if (SYMBOL(init_level4_pgt) == NOT_FOUND_SYMBOL) {
> +		ERRMSG("Can't get the symbol of init_level4_pgt.\n");
> +		return NOT_PADDR;
> +	}
> +
> +	pagetable = SYMBOL(init_level4_pgt) - __START_KERNEL_map +
> info->phys_base;
> +
> +	return __vtop4_x86_64(vaddr, pagetable);
> +}
> +
> +unsigned long long
> +vtop4_x86_64_pagetable(unsigned long vaddr, unsigned long pagetable)
> +{
> +	return __vtop4_x86_64(vaddr, pagetable);
> +}
> +
>  /*
>   * for Xen extraction
>   */
> diff --git a/makedumpfile.h b/makedumpfile.h
> index 704a6bc..f48dc0b 100644
> --- a/makedumpfile.h
> +++ b/makedumpfile.h
> @@ -978,6 +978,7 @@ int get_phys_base_x86_64(void);
>  int get_machdep_info_x86_64(void);
>  int get_versiondep_info_x86_64(void);
>  unsigned long long vtop4_x86_64(unsigned long vaddr);
> +unsigned long long vtop4_x86_64_pagetable(unsigned long vaddr, unsigned long
> pagetable);
>  #define find_vmemmap()		find_vmemmap_x86_64()
>  #define get_phys_base()		get_phys_base_x86_64()
>  #define get_machdep_info()	get_machdep_info_x86_64()
> --
> 2.9.5

Looks good to me.