xref: /openbmc/linux/drivers/acpi/acpica/hwvalid.c (revision 612c2932)

// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: hwvalid - I/O request validation
 *
 * Copyright (C) 2000 - 2023, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"

#define _COMPONENT          ACPI_HARDWARE
ACPI_MODULE_NAME("hwvalid")

/* Local prototypes */
static acpi_status
acpi_hw_validate_io_request(acpi_io_address address, u32 bit_width);

/*
 * Protected I/O ports. Some ports are always illegal, and some are
 * conditionally illegal. This table must remain ordered by port address.
 *
 * The table is used to implement the Microsoft port access rules that
 * first appeared in Windows XP. Some ports are always illegal, and some
 * ports are only illegal if the BIOS calls _OSI with nothing newer than
 * the specific _OSI strings.
 *
 * This provides ACPICA with the desired port protections and
 * Microsoft compatibility.
 *
 * Description of port entries:
 *  DMA:   DMA controller
 *  PIC0:  Programmable Interrupt Controller (8259A)
 *  PIT1:  System Timer 1
 *  PIT2:  System Timer 2 failsafe
 *  RTC:   Real-time clock
 *  CMOS:  Extended CMOS
 *  DMA1:  DMA 1 page registers
 *  DMA1L: DMA 1 Ch 0 low page
 *  DMA2:  DMA 2 page registers
 *  DMA2L: DMA 2 low page refresh
 *  ARBC:  Arbitration control
 *  SETUP: Reserved system board setup
 *  POS:   POS channel select
 *  PIC1:  Cascaded PIC
 *  IDMA:  ISA DMA
 *  ELCR:  PIC edge/level registers
 *  PCI:   PCI configuration space
 */
static const struct acpi_port_info acpi_protected_ports[] = {
	{"DMA", 0x0000, 0x000F, ACPI_OSI_WIN_XP},
	{"PIC0", 0x0020, 0x0021, ACPI_ALWAYS_ILLEGAL},
	{"PIT1", 0x0040, 0x0043, ACPI_OSI_WIN_XP},
	{"PIT2", 0x0048, 0x004B, ACPI_OSI_WIN_XP},
	{"RTC", 0x0070, 0x0071, ACPI_OSI_WIN_XP},
	{"CMOS", 0x0074, 0x0076, ACPI_OSI_WIN_XP},
	{"DMA1", 0x0081, 0x0083, ACPI_OSI_WIN_XP},
	{"DMA1L", 0x0087, 0x0087, ACPI_OSI_WIN_XP},
	{"DMA2", 0x0089, 0x008B, ACPI_OSI_WIN_XP},
	{"DMA2L", 0x008F, 0x008F, ACPI_OSI_WIN_XP},
	{"ARBC", 0x0090, 0x0091, ACPI_OSI_WIN_XP},
	{"SETUP", 0x0093, 0x0094, ACPI_OSI_WIN_XP},
	{"POS", 0x0096, 0x0097, ACPI_OSI_WIN_XP},
	{"PIC1", 0x00A0, 0x00A1, ACPI_ALWAYS_ILLEGAL},
	{"IDMA", 0x00C0, 0x00DF, ACPI_OSI_WIN_XP},
	{"ELCR", 0x04D0, 0x04D1, ACPI_ALWAYS_ILLEGAL},
	{"PCI", 0x0CF8, 0x0CFF, ACPI_OSI_WIN_XP}
};

#define ACPI_PORT_INFO_ENTRIES      ACPI_ARRAY_LENGTH (acpi_protected_ports)

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_validate_io_request
 *
 * PARAMETERS:  Address             Address of I/O port/register
 *              bit_width           Number of bits (8,16,32)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Validates an I/O request (address/length). Certain ports are
 *              always illegal and some ports are only illegal depending on
 *              the requests the BIOS AML code makes to the predefined
 *              _OSI method.
 *
 ******************************************************************************/

static acpi_status
acpi_hw_validate_io_request(acpi_io_address address, u32 bit_width)
{
	u32 i;
	u32 byte_width;
	acpi_io_address last_address;
	const struct acpi_port_info *port_info;

	ACPI_FUNCTION_TRACE(hw_validate_io_request);

	/* Supported widths are 8/16/32 */

	if ((bit_width != 8) && (bit_width != 16) && (bit_width != 32)) {
		ACPI_ERROR((AE_INFO,
			    "Bad BitWidth parameter: %8.8X", bit_width));
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	port_info = acpi_protected_ports;
	byte_width = ACPI_DIV_8(bit_width);
	last_address = address + byte_width - 1;

	ACPI_DEBUG_PRINT((ACPI_DB_IO,
			  "Address %8.8X%8.8X LastAddress %8.8X%8.8X Length %X",
			  ACPI_FORMAT_UINT64(address),
			  ACPI_FORMAT_UINT64(last_address), byte_width));

	/* Maximum 16-bit address in I/O space */

	if (last_address > ACPI_UINT16_MAX) {
		ACPI_ERROR((AE_INFO,
			    "Illegal I/O port address/length above 64K: %8.8X%8.8X/0x%X",
			    ACPI_FORMAT_UINT64(address), byte_width));
		return_ACPI_STATUS(AE_LIMIT);
	}

	/* Exit if requested address is not within the protected port table */

	if (address > acpi_protected_ports[ACPI_PORT_INFO_ENTRIES - 1].end) {
		return_ACPI_STATUS(AE_OK);
	}

	/* Check request against the list of protected I/O ports */

	for (i = 0; i < ACPI_PORT_INFO_ENTRIES; i++, port_info++) {
		/*
		 * Check if the requested address range will write to a reserved
		 * port. There are four cases to consider:
		 *
		 * 1) Address range is contained completely in the port address range
		 * 2) Address range overlaps port range at the port range start
		 * 3) Address range overlaps port range at the port range end
		 * 4) Address range completely encompasses the port range
		 */
		if ((address <= port_info->end)
		    && (last_address >= port_info->start)) {

			/* Port illegality may depend on the _OSI calls made by the BIOS */

			if (port_info->osi_dependency == ACPI_ALWAYS_ILLEGAL ||
			    acpi_gbl_osi_data == port_info->osi_dependency) {
				ACPI_DEBUG_PRINT((ACPI_DB_VALUES,
						  "Denied AML access to port 0x%8.8X%8.8X/%X (%s 0x%.4X-0x%.4X)\n",
						  ACPI_FORMAT_UINT64(address),
						  byte_width, port_info->name,
						  port_info->start,
						  port_info->end));

				return_ACPI_STATUS(AE_AML_ILLEGAL_ADDRESS);
			}
		}

		/* Finished if address range ends before the end of this port */

		if (last_address <= port_info->end) {
			break;
		}
	}

	return_ACPI_STATUS(AE_OK);
}

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_read_port
 *
 * PARAMETERS:  Address             Address of I/O port/register to read
 *              Value               Where value (data) is returned
 *              Width               Number of bits
 *
 * RETURN:      Status and value read from port
 *
 * DESCRIPTION: Read data from an I/O port or register. This is a front-end
 *              to acpi_os_read_port that performs validation on both the port
 *              address and the length.
 *
 *****************************************************************************/

acpi_status acpi_hw_read_port(acpi_io_address address, u32 *value, u32 width)
{
	acpi_status status;
	u32 one_byte;
	u32 i;

	/* Truncate address to 16 bits if requested */

	if (acpi_gbl_truncate_io_addresses) {
		address &= ACPI_UINT16_MAX;
	}

	/* Validate the entire request and perform the I/O */

	status = acpi_hw_validate_io_request(address, width);
	if (ACPI_SUCCESS(status)) {
		status = acpi_os_read_port(address, value, width);
		return (status);
	}

	if (status != AE_AML_ILLEGAL_ADDRESS) {
		return (status);
	}

	/*
	 * There has been a protection violation within the request. Fall
	 * back to byte granularity port I/O and ignore the failing bytes.
	 * This provides compatibility with other ACPI implementations.
	 */
	for (i = 0, *value = 0; i < width; i += 8) {

		/* Validate and read one byte */

		if (acpi_hw_validate_io_request(address, 8) == AE_OK) {
			status = acpi_os_read_port(address, &one_byte, 8);
			if (ACPI_FAILURE(status)) {
				return (status);
			}

			*value |= (one_byte << i);
		}

		address++;
	}

	return (AE_OK);
}

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_write_port
 *
 * PARAMETERS:  Address             Address of I/O port/register to write
 *              Value               Value to write
 *              Width               Number of bits
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Write data to an I/O port or register. This is a front-end
 *              to acpi_os_write_port that performs validation on both the port
 *              address and the length.
 *
 *****************************************************************************/

acpi_status acpi_hw_write_port(acpi_io_address address, u32 value, u32 width)
{
	acpi_status status;
	u32 i;

	/* Truncate address to 16 bits if requested */

	if (acpi_gbl_truncate_io_addresses) {
		address &= ACPI_UINT16_MAX;
	}

	/* Validate the entire request and perform the I/O */

	status = acpi_hw_validate_io_request(address, width);
	if (ACPI_SUCCESS(status)) {
		status = acpi_os_write_port(address, value, width);
		return (status);
	}

	if (status != AE_AML_ILLEGAL_ADDRESS) {
		return (status);
	}

	/*
	 * There has been a protection violation within the request. Fall
	 * back to byte granularity port I/O and ignore the failing bytes.
	 * This provides compatibility with other ACPI implementations.
	 */
	for (i = 0; i < width; i += 8) {

		/* Validate and write one byte */

		if (acpi_hw_validate_io_request(address, 8) == AE_OK) {
			status =
			    acpi_os_write_port(address, (value >> i) & 0xFF, 8);
			if (ACPI_FAILURE(status)) {
				return (status);
			}
		}

		address++;
	}

	return (AE_OK);
}

/******************************************************************************
 *
 * FUNCTION:    acpi_hw_validate_io_block
 *
 * PARAMETERS:  Address             Address of I/O port/register blobk
 *              bit_width           Number of bits (8,16,32) in each register
 *              count               Number of registers in the block
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Validates a block of I/O ports/registers.
 *
 ******************************************************************************/

acpi_status acpi_hw_validate_io_block(u64 address, u32 bit_width, u32 count)
{
	acpi_status status;

	while (count--) {
		status = acpi_hw_validate_io_request((acpi_io_address)address,
						     bit_width);
		if (ACPI_FAILURE(status))
			return_ACPI_STATUS(status);

		address += ACPI_DIV_8(bit_width);
	}

	return_ACPI_STATUS(AE_OK);
}