Re: [PATCH 11/12] kexec: allow architectures to override boot mapping

[Baoquan He <bhe@redhat.com>]

On 04/28/16 at 10:28am, Russell King wrote:
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 52a3a221bcb2..99cb9dac7909 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -318,6 +318,44 @@ int __weak arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr,
>  int __weak arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
>  					unsigned int relsec);
>  
> +#ifndef page_to_boot_pfn
> +static inline unsigned long page_to_boot_pfn(struct page *page)
> +{
> +	return page_to_pfn(page);
> +}
> +#endif

I am thinking if it's appropriate to introduce a new concept which only
exists in a certain system of a certain ARCH. Is it unavoidable? If have
to can we name it as kexec_page_to_pfn/kexec_pfn_to_page, etc? People
might not need to know about boot view physical address and kernel view
physical address things when they just want to understand kexec
implementation related to one ARCH except of ARM, even related to ARM
but not Keystone 2.

> +
> +#ifndef boot_pfn_to_page
> +static inline struct page *boot_pfn_to_page(unsigned long boot_pfn)
> +{
> +	return pfn_to_page(boot_pfn);
> +}
> +#endif
> +
> +#ifndef phys_to_boot_phys
> +static inline unsigned long phys_to_boot_phys(phys_addr_t phys)
> +{
> +	return phys;
> +}
> +#endif
> +
> +#ifndef boot_phys_to_phys
> +static inline phys_addr_t boot_phys_to_phys(unsigned long boot_phys)
> +{
> +	return boot_phys;
> +}
> +#endif
> +
> +static inline unsigned long virt_to_boot_phys(void *addr)
> +{
> +	return phys_to_boot_phys(__pa((unsigned long)addr));
> +}
> +
> +static inline void *boot_phys_to_virt(unsigned long entry)
> +{
> +	return phys_to_virt(boot_phys_to_phys(entry));
> +}
> +
>  #else /* !CONFIG_KEXEC_CORE */
>  struct pt_regs;
>  struct task_struct;
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index ee70aef5cd81..dd49d572a5e2 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -48,7 +48,8 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
>  
>  	if (kexec_on_panic) {
>  		/* Verify we have a valid entry point */
> -		if ((entry < crashk_res.start) || (entry > crashk_res.end))
> +		if ((entry < phys_to_boot_phys(crashk_res.start)) ||
> +		    (entry > phys_to_boot_phys(crashk_res.end)))
>  			return -EADDRNOTAVAIL;
>  	}
>  
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index f9847e5822e6..d04940ccc58d 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -229,8 +229,8 @@ int sanity_check_segment_list(struct kimage *image)
>  			mstart = image->segment[i].mem;
>  			mend = mstart + image->segment[i].memsz - 1;
>  			/* Ensure we are within the crash kernel limits */
> -			if ((mstart < crashk_res.start) ||
> -			    (mend > crashk_res.end))
> +			if ((mstart < phys_to_boot_phys(crashk_res.start)) ||
> +			    (mend > phys_to_boot_phys(crashk_res.end)))
>  				return result;
>  		}
>  	}
> @@ -354,7 +354,7 @@ static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
>  		pages = kimage_alloc_pages(KEXEC_CONTROL_MEMORY_GFP, order);
>  		if (!pages)
>  			break;
> -		pfn   = page_to_pfn(pages);
> +		pfn   = page_to_boot_pfn(pages);
>  		epfn  = pfn + count;
>  		addr  = pfn << PAGE_SHIFT;
>  		eaddr = epfn << PAGE_SHIFT;
> @@ -480,7 +480,7 @@ static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
>  			return -ENOMEM;
>  
>  		ind_page = page_address(page);
> -		*image->entry = virt_to_phys(ind_page) | IND_INDIRECTION;
> +		*image->entry = virt_to_boot_phys(ind_page) | IND_INDIRECTION;
>  		image->entry = ind_page;
>  		image->last_entry = ind_page +
>  				      ((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
> @@ -535,13 +535,13 @@ void kimage_terminate(struct kimage *image)
>  #define for_each_kimage_entry(image, ptr, entry) \
>  	for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
>  		ptr = (entry & IND_INDIRECTION) ? \
> -			phys_to_virt((entry & PAGE_MASK)) : ptr + 1)
> +			boot_phys_to_virt((entry & PAGE_MASK)) : ptr + 1)
>  
>  static void kimage_free_entry(kimage_entry_t entry)
>  {
>  	struct page *page;
>  
> -	page = pfn_to_page(entry >> PAGE_SHIFT);
> +	page = boot_pfn_to_page(entry >> PAGE_SHIFT);
>  	kimage_free_pages(page);
>  }
>  
> @@ -635,7 +635,7 @@ static struct page *kimage_alloc_page(struct kimage *image,
>  	 * have a match.
>  	 */
>  	list_for_each_entry(page, &image->dest_pages, lru) {
> -		addr = page_to_pfn(page) << PAGE_SHIFT;
> +		addr = page_to_boot_pfn(page) << PAGE_SHIFT;
>  		if (addr == destination) {
>  			list_del(&page->lru);
>  			return page;
> @@ -650,12 +650,12 @@ static struct page *kimage_alloc_page(struct kimage *image,
>  		if (!page)
>  			return NULL;
>  		/* If the page cannot be used file it away */
> -		if (page_to_pfn(page) >
> +		if (page_to_boot_pfn(page) >
>  				(KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
>  			list_add(&page->lru, &image->unusable_pages);
>  			continue;
>  		}
> -		addr = page_to_pfn(page) << PAGE_SHIFT;
> +		addr = page_to_boot_pfn(page) << PAGE_SHIFT;
>  
>  		/* If it is the destination page we want use it */
>  		if (addr == destination)
> @@ -678,7 +678,7 @@ static struct page *kimage_alloc_page(struct kimage *image,
>  			struct page *old_page;
>  
>  			old_addr = *old & PAGE_MASK;
> -			old_page = pfn_to_page(old_addr >> PAGE_SHIFT);
> +			old_page = boot_pfn_to_page(old_addr >> PAGE_SHIFT);
>  			copy_highpage(page, old_page);
>  			*old = addr | (*old & ~PAGE_MASK);
>  
> @@ -734,7 +734,7 @@ static int kimage_load_normal_segment(struct kimage *image,
>  			result  = -ENOMEM;
>  			goto out;
>  		}
> -		result = kimage_add_page(image, page_to_pfn(page)
> +		result = kimage_add_page(image, page_to_boot_pfn(page)
>  								<< PAGE_SHIFT);
>  		if (result < 0)
>  			goto out;
> @@ -795,7 +795,7 @@ static int kimage_load_crash_segment(struct kimage *image,
>  		char *ptr;
>  		size_t uchunk, mchunk;
>  
> -		page = pfn_to_page(maddr >> PAGE_SHIFT);
> +		page = boot_pfn_to_page(maddr >> PAGE_SHIFT);
>  		if (!page) {
>  			result  = -ENOMEM;
>  			goto out;
> @@ -922,7 +922,7 @@ void __weak crash_free_reserved_phys_range(unsigned long begin,
>  	unsigned long addr;
>  
>  	for (addr = begin; addr < end; addr += PAGE_SIZE)
> -		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
> +		free_reserved_page(boot_pfn_to_page(addr >> PAGE_SHIFT));
>  }
>  
>  int crash_shrink_memory(unsigned long new_size)
> -- 
> 2.1.0
> 
> 
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