H. Peter Anvin | 1965aae | 2008-10-22 22:26:29 -0700 | [diff] [blame] | 1 | #ifndef _ASM_X86_BIOS_EBDA_H |
| 2 | #define _ASM_X86_BIOS_EBDA_H |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | |
Akinobu Mita | 2c0903f | 2008-04-19 23:55:18 +0900 | [diff] [blame] | 4 | #include <asm/io.h> |
| 5 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | /* |
| 7 | * there is a real-mode segmented pointer pointing to the |
| 8 | * 4K EBDA area at 0x40E. |
| 9 | */ |
| 10 | static inline unsigned int get_bios_ebda(void) |
| 11 | { |
| 12 | unsigned int address = *(unsigned short *)phys_to_virt(0x40E); |
| 13 | address <<= 4; |
| 14 | return address; /* 0 means none */ |
| 15 | } |
| 16 | |
Mike Waychison | 57d5f9f | 2011-03-14 23:58:45 -0700 | [diff] [blame^] | 17 | /* |
| 18 | * Return the sanitized length of the EBDA in bytes, if it exists. |
| 19 | */ |
| 20 | static inline unsigned int get_bios_ebda_length(void) |
| 21 | { |
| 22 | unsigned int address; |
| 23 | unsigned int length; |
| 24 | |
| 25 | address = get_bios_ebda(); |
| 26 | if (!address) |
| 27 | return 0; |
| 28 | |
| 29 | /* EBDA length is byte 0 of the EBDA (stored in KiB) */ |
| 30 | length = *(unsigned char *)phys_to_virt(address); |
| 31 | length <<= 10; |
| 32 | |
| 33 | /* Trim the length if it extends beyond 640KiB */ |
| 34 | length = min_t(unsigned int, (640 * 1024) - address, length); |
| 35 | return length; |
| 36 | } |
| 37 | |
Huang, Ying | 0c51a96 | 2008-06-02 14:26:23 +0800 | [diff] [blame] | 38 | void reserve_ebda_region(void); |
| 39 | |
Ingo Molnar | 46eaa67 | 2008-10-12 15:06:29 +0200 | [diff] [blame] | 40 | #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION |
| 41 | /* |
| 42 | * This is obviously not a great place for this, but we want to be |
| 43 | * able to scatter it around anywhere in the kernel. |
| 44 | */ |
| 45 | void check_for_bios_corruption(void); |
| 46 | void start_periodic_check_for_corruption(void); |
| 47 | #else |
| 48 | static inline void check_for_bios_corruption(void) |
| 49 | { |
| 50 | } |
| 51 | |
| 52 | static inline void start_periodic_check_for_corruption(void) |
| 53 | { |
| 54 | } |
| 55 | #endif |
| 56 | |
H. Peter Anvin | 1965aae | 2008-10-22 22:26:29 -0700 | [diff] [blame] | 57 | #endif /* _ASM_X86_BIOS_EBDA_H */ |