Commit | Line | Data |
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1965aae3 PA |
1 | #ifndef _ASM_X86_BIOS_EBDA_H |
2 | #define _ASM_X86_BIOS_EBDA_H | |
1da177e4 | 3 | |
2c0903f2 AM |
4 | #include <asm/io.h> |
5 | ||
1da177e4 | 6 | /* |
f548ccd4 | 7 | * Returns physical address of EBDA. Returns 0 if there is no EBDA. |
1da177e4 LT |
8 | */ |
9 | static inline unsigned int get_bios_ebda(void) | |
10 | { | |
f548ccd4 MW |
11 | /* |
12 | * There is a real-mode segmented pointer pointing to the | |
13 | * 4K EBDA area at 0x40E. | |
14 | */ | |
1da177e4 LT |
15 | unsigned int address = *(unsigned short *)phys_to_virt(0x40E); |
16 | address <<= 4; | |
17 | return address; /* 0 means none */ | |
18 | } | |
19 | ||
57d5f9f8 MW |
20 | /* |
21 | * Return the sanitized length of the EBDA in bytes, if it exists. | |
22 | */ | |
23 | static inline unsigned int get_bios_ebda_length(void) | |
24 | { | |
25 | unsigned int address; | |
26 | unsigned int length; | |
27 | ||
28 | address = get_bios_ebda(); | |
29 | if (!address) | |
30 | return 0; | |
31 | ||
32 | /* EBDA length is byte 0 of the EBDA (stored in KiB) */ | |
33 | length = *(unsigned char *)phys_to_virt(address); | |
34 | length <<= 10; | |
35 | ||
36 | /* Trim the length if it extends beyond 640KiB */ | |
37 | length = min_t(unsigned int, (640 * 1024) - address, length); | |
38 | return length; | |
39 | } | |
40 | ||
0c51a965 HY |
41 | void reserve_ebda_region(void); |
42 | ||
46eaa670 IM |
43 | #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION |
44 | /* | |
45 | * This is obviously not a great place for this, but we want to be | |
46 | * able to scatter it around anywhere in the kernel. | |
47 | */ | |
48 | void check_for_bios_corruption(void); | |
49 | void start_periodic_check_for_corruption(void); | |
50 | #else | |
51 | static inline void check_for_bios_corruption(void) | |
52 | { | |
53 | } | |
54 | ||
55 | static inline void start_periodic_check_for_corruption(void) | |
56 | { | |
57 | } | |
58 | #endif | |
59 | ||
1965aae3 | 60 | #endif /* _ASM_X86_BIOS_EBDA_H */ |