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Use the correct location of the EBDA for searching for the RSDP.

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The EBDA is the 1 KB area addressed by the 16 bit pointer at 0x40E.

Pointed out by:	robert.moore AT intel.com
This commit is contained in:
Nate Lawson 2004-05-25 05:52:48 +00:00
parent 3ffbc0cd8e
commit 2c0d74e8e8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=129702
3 changed files with 40 additions and 26 deletions
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16
sys/boot/i386/libi386/biosacpi.c
View File

@ -84,22 +84,24 @@ biosacpi_detect(void)
}
/*
* Find the RSDP in low memory.
* Find the RSDP in low memory. See section 5.2.2 of the ACPI spec.
*/
static RSDP_DESCRIPTOR *
biosacpi_find_rsdp(void)
{
RSDP_DESCRIPTOR *rsdp;
uint16_t *addr;
/* search the EBDA */
if ((rsdp = biosacpi_search_rsdp((char *)0, 0x400)) != NULL)
return(rsdp);
/* EBDA is the 1 KB addressed by the 16 bit pointer at 0x40E. */
addr = (uint16_t *)0x40E;
if ((rsdp = biosacpi_search_rsdp((char *)(*addr << 4), 0x400)) != NULL)
return (rsdp);
/* search the BIOS space */
/* Check the upper memory BIOS space, 0xe0000 - 0xfffff. */
if ((rsdp = biosacpi_search_rsdp((char *)0xe0000, 0x20000)) != NULL)
return(rsdp);
return (rsdp);
return(NULL);
return (NULL);
}
static RSDP_DESCRIPTOR *

46
usr.sbin/acpi/acpidump/acpi_user.c
View File

@ -121,6 +121,34 @@ acpi_get_rsdp(u_long addr)
return (acpi_map_physical(addr, len));
}
static struct ACPIrsdp *
acpi_scan_rsd_ptr(void)
{
#if defined(__i386__)
struct ACPIrsdp *rsdp;
u_long addr, end;
/*
* On ia32, scan physical memory for the RSD PTR if above failed.
* According to section 5.2.2 of the ACPI spec, we only consider
* two regions for the base address:
* 1. EBDA (1 KB area addressed by the 16 bit pointer at 0x40E
* 2. High memory (0xE0000 - 0xFFFFF)
*/
addr = RSDP_EBDA_PTR;
pread(acpi_mem_fd, &addr, sizeof(uint16_t), addr);
addr <<= 4;
end = addr + RSDP_EBDA_SIZE;
for (; addr < end; addr += 16)
if ((rsdp = acpi_get_rsdp(addr)) != NULL)
return (rsdp);
for (addr = RSDP_HI_START; addr < RSDP_HI_END; addr += 16)
if ((rsdp = acpi_get_rsdp(addr)) != NULL)
return (rsdp);
#endif /* __i386__ */
return (NULL);
}
/*
* Public interfaces
*/
@ -143,23 +171,7 @@ acpi_find_rsd_ptr(void)
machdep_acpi_root);
}
#if defined(__i386__)
/*
* On ia32, scan physical memory for the RSD PTR if above failed.
* According to section 5.2.2 of the ACPI spec, we only consider
* two regions for the base address:
* 1. EBDA (0x0 - 0x3FF)
* 2. High memory (0xE0000 - 0xFFFFF)
*/
for (addr = RSDP_EBDA_START; addr < RSDP_EBDA_END; addr += 16)
if ((rsdp = acpi_get_rsdp(addr)) != NULL)
return (rsdp);
for (addr = RSDP_HI_START; addr < RSDP_HI_END; addr += 16)
if ((rsdp = acpi_get_rsdp(addr)) != NULL)
return (rsdp);
#endif
return (NULL);
return (acpi_scan_rsd_ptr());
}
void *

4
usr.sbin/acpi/acpidump/acpidump.h
View File

@ -299,8 +299,8 @@ struct ECDTbody {
* 1. EBDA (0x0 - 0x3FF)
* 2. High memory (0xE0000 - 0xFFFFF)
*/
#define RSDP_EBDA_START 0
#define RSDP_EBDA_END (0x400 - sizeof(struct ACPIrsdp))
#define RSDP_EBDA_PTR 0x40E
#define RSDP_EBDA_SIZE (1024 - sizeof(struct ACPIrsdp))
#define RSDP_HI_START 0xE0000
#define RSDP_HI_END (0x100000 - sizeof(struct ACPIrsdp))