diff options
Diffstat (limited to 'include/asm-sh/page.h')
| -rw-r--r-- | include/asm-sh/page.h | 50 |
1 files changed, 37 insertions, 13 deletions
diff --git a/include/asm-sh/page.h b/include/asm-sh/page.h index bff635a078c8..002e64a4f049 100644 --- a/include/asm-sh/page.h +++ b/include/asm-sh/page.h @@ -5,6 +5,8 @@ * Copyright (C) 1999 Niibe Yutaka */ +#include <linux/const.h> + #ifdef __KERNEL__ /* PAGE_SHIFT determines the page size */ @@ -18,15 +20,13 @@ # error "Bogus kernel page size?" #endif -#ifdef __ASSEMBLY__ -#define PAGE_SIZE (1 << PAGE_SHIFT) -#else -#define PAGE_SIZE (1UL << PAGE_SHIFT) -#endif - +#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT) #define PAGE_MASK (~(PAGE_SIZE-1)) #define PTE_MASK PAGE_MASK +/* to align the pointer to the (next) page boundary */ +#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK) + #if defined(CONFIG_HUGETLB_PAGE_SIZE_64K) #define HPAGE_SHIFT 16 #elif defined(CONFIG_HUGETLB_PAGE_SIZE_256K) @@ -104,20 +104,44 @@ typedef struct { unsigned long pgd; } pgd_t; #endif /* !__ASSEMBLY__ */ -/* to align the pointer to the (next) page boundary */ -#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK) - +/* + * __MEMORY_START and SIZE are the physical addresses and size of RAM. + */ #define __MEMORY_START CONFIG_MEMORY_START #define __MEMORY_SIZE CONFIG_MEMORY_SIZE +/* + * PAGE_OFFSET is the virtual address of the start of kernel address + * space. + */ #define PAGE_OFFSET CONFIG_PAGE_OFFSET -#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET) -#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET)) -#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) +/* + * Virtual to physical RAM address translation. + * + * In 29 bit mode, the physical offset of RAM from address 0 is visible in + * the kernel virtual address space, and thus we don't have to take + * this into account when translating. However in 32 bit mode this offset + * is not visible (it is part of the PMB mapping) and so needs to be + * added or subtracted as required. + */ +#ifdef CONFIG_32BIT +#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET+__MEMORY_START) +#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET-__MEMORY_START)) +#else +#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET) +#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET)) +#endif + +#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) #define page_to_phys(page) (page_to_pfn(page) << PAGE_SHIFT) -/* PFN start number, because of __MEMORY_START */ +/* + * PFN = physical frame number (ie PFN 0 == physical address 0) + * PFN_START is the PFN of the first page of RAM. By defining this we + * don't have struct page entries for the portion of address space + * between physical address 0 and the start of RAM. + */ #define PFN_START (__MEMORY_START >> PAGE_SHIFT) #define ARCH_PFN_OFFSET (PFN_START) #define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT) |
