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Commit 5ec5d38a authored by Len Brown's avatar Len Brown
Browse files

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: default avatarLen Brown <len.brown@intel.com>
parent 3e0676a9

drivers/acpi/osl.c

+50 −0
Original line number Diff line number Diff line
@@ -1317,6 +1317,54 @@ acpi_os_validate_interface (char *interface) 
	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
@@ -1346,6 +1394,8 @@ acpi_os_validate_address ( 


	switch (space_id) {

	case ACPI_ADR_SPACE_SYSTEM_IO:

		if (!valid_aml_io_address(address, length))

			return AE_AML_ILLEGAL_ADDRESS;

	case ACPI_ADR_SPACE_SYSTEM_MEMORY:

		/* Only interference checks against SystemIO and SytemMemory

		   are needed */