diff options
Diffstat (limited to 'arch/x86/mm/physaddr.c')
| -rw-r--r-- | arch/x86/mm/physaddr.c | 40 |
1 files changed, 25 insertions, 15 deletions
diff --git a/arch/x86/mm/physaddr.c b/arch/x86/mm/physaddr.c index d2e2735327b..fd40d75109e 100644 --- a/arch/x86/mm/physaddr.c +++ b/arch/x86/mm/physaddr.c @@ -8,33 +8,43 @@ #ifdef CONFIG_X86_64 +#ifdef CONFIG_DEBUG_VIRTUAL unsigned long __phys_addr(unsigned long x) { - if (x >= __START_KERNEL_map) { - x -= __START_KERNEL_map; - VIRTUAL_BUG_ON(x >= KERNEL_IMAGE_SIZE); - x += phys_base; + unsigned long y = x - __START_KERNEL_map; + + /* use the carry flag to determine if x was < __START_KERNEL_map */ + if (unlikely(x > y)) { + x = y + phys_base; + + VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE); } else { - VIRTUAL_BUG_ON(x < PAGE_OFFSET); - x -= PAGE_OFFSET; - VIRTUAL_BUG_ON(!phys_addr_valid(x)); + x = y + (__START_KERNEL_map - PAGE_OFFSET); + + /* carry flag will be set if starting x was >= PAGE_OFFSET */ + VIRTUAL_BUG_ON((x > y) || !phys_addr_valid(x)); } + return x; } EXPORT_SYMBOL(__phys_addr); +#endif bool __virt_addr_valid(unsigned long x) { - if (x >= __START_KERNEL_map) { - x -= __START_KERNEL_map; - if (x >= KERNEL_IMAGE_SIZE) + unsigned long y = x - __START_KERNEL_map; + + /* use the carry flag to determine if x was < __START_KERNEL_map */ + if (unlikely(x > y)) { + x = y + phys_base; + + if (y >= KERNEL_IMAGE_SIZE) return false; - x += phys_base; } else { - if (x < PAGE_OFFSET) - return false; - x -= PAGE_OFFSET; - if (!phys_addr_valid(x)) + x = y + (__START_KERNEL_map - PAGE_OFFSET); + + /* carry flag will be set if starting x was >= PAGE_OFFSET */ + if ((x > y) || !phys_addr_valid(x)) return false; } |