diff options
Diffstat (limited to 'include/asm-powerpc/page.h')
| -rw-r--r-- | include/asm-powerpc/page.h | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/include/asm-powerpc/page.h b/include/asm-powerpc/page.h index 18c1e5ee81a38c..76d7cb4b4ffc3f 100644 --- a/include/asm-powerpc/page.h +++ b/include/asm-powerpc/page.h @@ -37,8 +37,30 @@ */ #define PAGE_MASK (~((1 << PAGE_SHIFT) - 1)) +/* + * KERNELBASE is the virtual address of the start of the kernel, it's often + * the same as PAGE_OFFSET, but _might not be_. + * + * The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET. + * + * To get a physical address from a virtual one you subtract PAGE_OFFSET, + * _not_ KERNELBASE. + * + * If you want to know something's offset from the start of the kernel you + * should subtract KERNELBASE. + * + * If you want to test if something's a kernel address, use is_kernel_addr(). + */ + +#ifdef CONFIG_CRASH_DUMP +/* Kdump kernel runs at 32 MB, change at your peril. */ +#define PHYSICAL_START 0x2000000 +#else +#define PHYSICAL_START 0x0 +#endif + #define PAGE_OFFSET ASM_CONST(CONFIG_KERNEL_START) -#define KERNELBASE PAGE_OFFSET +#define KERNELBASE (PAGE_OFFSET + PHYSICAL_START) #ifdef CONFIG_DISCONTIGMEM #define page_to_pfn(page) discontigmem_page_to_pfn(page) @@ -56,7 +78,7 @@ #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) #define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT) -#define __va(x) ((void *)((unsigned long)(x) + KERNELBASE)) +#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET)) #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET) /* @@ -86,6 +108,12 @@ /* to align the pointer to the (next) page boundary */ #define PAGE_ALIGN(addr) _ALIGN(addr, PAGE_SIZE) +/* + * Don't compare things with KERNELBASE or PAGE_OFFSET to test for + * "kernelness", use is_kernel_addr() - it should do what you want. + */ +#define is_kernel_addr(x) ((x) >= PAGE_OFFSET) + #ifndef __ASSEMBLY__ #undef STRICT_MM_TYPECHECKS |