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60 lines
1.3 KiB
60 lines
1.3 KiB
#ifndef _ASM_X86_BIOS_EBDA_H |
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#define _ASM_X86_BIOS_EBDA_H |
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#include <asm/io.h> |
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/* |
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* Returns physical address of EBDA. Returns 0 if there is no EBDA. |
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*/ |
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static inline unsigned int get_bios_ebda(void) |
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{ |
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/* |
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* There is a real-mode segmented pointer pointing to the |
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* 4K EBDA area at 0x40E. |
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*/ |
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unsigned int address = *(unsigned short *)phys_to_virt(0x40E); |
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address <<= 4; |
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return address; /* 0 means none */ |
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} |
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/* |
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* Return the sanitized length of the EBDA in bytes, if it exists. |
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*/ |
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static inline unsigned int get_bios_ebda_length(void) |
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{ |
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unsigned int address; |
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unsigned int length; |
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address = get_bios_ebda(); |
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if (!address) |
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return 0; |
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/* EBDA length is byte 0 of the EBDA (stored in KiB) */ |
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length = *(unsigned char *)phys_to_virt(address); |
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length <<= 10; |
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/* Trim the length if it extends beyond 640KiB */ |
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length = min_t(unsigned int, (640 * 1024) - address, length); |
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return length; |
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} |
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void reserve_ebda_region(void); |
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#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION |
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/* |
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* This is obviously not a great place for this, but we want to be |
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* able to scatter it around anywhere in the kernel. |
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*/ |
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void check_for_bios_corruption(void); |
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void start_periodic_check_for_corruption(void); |
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#else |
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static inline void check_for_bios_corruption(void) |
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{ |
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} |
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static inline void start_periodic_check_for_corruption(void) |
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{ |
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} |
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#endif |
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#endif /* _ASM_X86_BIOS_EBDA_H */
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