f548ccd47d
Make the comments a bit clearer for get_bios_ebda so that it actually tells us what it is returning. Signed-off-by: Mike Waychison <mikew@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
#ifndef _ASM_X86_BIOS_EBDA_H
|
|
#define _ASM_X86_BIOS_EBDA_H
|
|
|
|
#include <asm/io.h>
|
|
|
|
/*
|
|
* Returns physical address of EBDA. Returns 0 if there is no EBDA.
|
|
*/
|
|
static inline unsigned int get_bios_ebda(void)
|
|
{
|
|
/*
|
|
* There is a real-mode segmented pointer pointing to the
|
|
* 4K EBDA area at 0x40E.
|
|
*/
|
|
unsigned int address = *(unsigned short *)phys_to_virt(0x40E);
|
|
address <<= 4;
|
|
return address; /* 0 means none */
|
|
}
|
|
|
|
/*
|
|
* Return the sanitized length of the EBDA in bytes, if it exists.
|
|
*/
|
|
static inline unsigned int get_bios_ebda_length(void)
|
|
{
|
|
unsigned int address;
|
|
unsigned int length;
|
|
|
|
address = get_bios_ebda();
|
|
if (!address)
|
|
return 0;
|
|
|
|
/* EBDA length is byte 0 of the EBDA (stored in KiB) */
|
|
length = *(unsigned char *)phys_to_virt(address);
|
|
length <<= 10;
|
|
|
|
/* Trim the length if it extends beyond 640KiB */
|
|
length = min_t(unsigned int, (640 * 1024) - address, length);
|
|
return length;
|
|
}
|
|
|
|
void reserve_ebda_region(void);
|
|
|
|
#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
|
|
/*
|
|
* This is obviously not a great place for this, but we want to be
|
|
* able to scatter it around anywhere in the kernel.
|
|
*/
|
|
void check_for_bios_corruption(void);
|
|
void start_periodic_check_for_corruption(void);
|
|
#else
|
|
static inline void check_for_bios_corruption(void)
|
|
{
|
|
}
|
|
|
|
static inline void start_periodic_check_for_corruption(void)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
#endif /* _ASM_X86_BIOS_EBDA_H */
|