diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-i386/system.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h index 772f85da120..88b4d5c6f37 100644 --- a/include/asm-i386/system.h +++ b/include/asm-i386/system.h @@ -140,6 +140,19 @@ static inline unsigned long _get_base(char * addr) :"=r" (__dummy)); \ __dummy; \ }) + +#define read_cr4_safe() ({ \ + unsigned int __dummy; \ + /* This could fault if %cr4 does not exist */ \ + __asm__("1: movl %%cr4, %0 \n" \ + "2: \n" \ + ".section __ex_table,\"a\" \n" \ + ".long 1b,2b \n" \ + ".previous \n" \ + : "=r" (__dummy): "0" (0)); \ + __dummy; \ +}) + #define write_cr4(x) \ __asm__ __volatile__("movl %0,%%cr4": :"r" (x)); #define stts() write_cr0(8 | read_cr0()) |