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ACPI: make some IO ports off-limits to AML 

ACPICA exports acpi_os_validate_address() so the OS
can prevent BIOS AML from accessing specified addresses.

Start using this interface to prevent AML from accessing
some well known IO addresses that the OS "owns".

Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Len Brown 2009-02-03 22:52:12 -05:00
parent 3e0676a9b6
commit 5ec5d38a1c
1 changed files with 50 additions and 0 deletions
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50
drivers/acpi/osl.c
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@ -1317,6 +1317,54 @@ acpi_os_validate_interface (char *interface)
return AE_SUPPORT; return AE_SUPPORT;
} }
#ifdef CONFIG_X86
struct aml_port_desc {
uint start;
uint end;
char* name;
char warned;
};
static struct aml_port_desc aml_invalid_port_list[] = {
{0x20, 0x21, "PIC0", 0},
{0xA0, 0xA1, "PIC1", 0},
{0x4D0, 0x4D1, "ELCR", 0}
};
/*
* valid_aml_io_address()
*
* if valid, return true
* else invalid, warn once, return false
*/
static bool valid_aml_io_address(uint address, uint length)
{
int i;
int entries = sizeof(aml_invalid_port_list) / sizeof(struct aml_port_desc);
for (i = 0; i < entries; ++i) {
if ((address >= aml_invalid_port_list[i].start &&
address <= aml_invalid_port_list[i].end) ||
(address + length >= aml_invalid_port_list[i].start &&
address + length <= aml_invalid_port_list[i].end))
{
if (!aml_invalid_port_list[i].warned)
{
printk(KERN_ERR "ACPI: Denied BIOS AML access"
" to invalid port 0x%x+0x%x (%s)\n",
address, length,
aml_invalid_port_list[i].name);
aml_invalid_port_list[i].warned = 1;
}
return false; /* invalid */
}
}
return true; /* valid */
}
#else
static inline bool valid_aml_io_address(uint address, uint length) { return true; }
#endif
/****************************************************************************** /******************************************************************************
* *
* FUNCTION: acpi_os_validate_address * FUNCTION: acpi_os_validate_address
@ -1346,6 +1394,8 @@ acpi_os_validate_address (
switch (space_id) { switch (space_id) {
case ACPI_ADR_SPACE_SYSTEM_IO: case ACPI_ADR_SPACE_SYSTEM_IO:
if (!valid_aml_io_address(address, length))
return AE_AML_ILLEGAL_ADDRESS;
case ACPI_ADR_SPACE_SYSTEM_MEMORY: case ACPI_ADR_SPACE_SYSTEM_MEMORY:
/* Only interference checks against SystemIO and SytemMemory /* Only interference checks against SystemIO and SytemMemory
are needed */ are needed */