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Commit 920de6eb authored by Lv Zheng's avatar Lv Zheng Committed by Rafael J. Wysocki
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ACPICA: Hardware: Enhance acpi_hw_validate_register() with access_width/bit_offset awareness 

ACPICA commit 997a90f810a4cb78604ef2e187611a181b498286

This patch enhances acpi_hw_validate_register() to sanitize register
accesses with awareness of access_width and bit_offset. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/997a90f8
Link: https://bugs.acpica.org/show_bug.cgi?id=1240


Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 0461f34e

drivers/acpi/acpica/hwregs.c

+15 −10
Original line number Diff line number Diff line
@@ -83,6 +83,8 @@ acpi_status 
acpi_hw_validate_register(struct acpi_generic_address *reg,

			  u8 max_bit_width, u64 *address)

{

	u8 bit_width;

	u8 access_width;



	/* Must have a valid pointer to a GAS structure */
@@ -109,23 +111,26 @@ acpi_hw_validate_register(struct acpi_generic_address *reg, 
		return (AE_SUPPORT);

	}



	/* Validate the bit_width */

	/* Validate the access_width */



	if ((reg->bit_width != 8) &&

	    (reg->bit_width != 16) &&

	    (reg->bit_width != 32) && (reg->bit_width != max_bit_width)) {

	if (reg->access_width > 4) {

		ACPI_ERROR((AE_INFO,

			    "Unsupported register bit width: 0x%X",

			    reg->bit_width));

			    "Unsupported register access width: 0x%X",

			    reg->access_width));

		return (AE_SUPPORT);

	}



	/* Validate the bit_offset. Just a warning for now. */

	/* Validate the bit_width, convert access_width into number of bits */



	if (reg->bit_offset != 0) {

	access_width = reg->access_width ? reg->access_width : 1;

	access_width = 1 << (access_width + 2);

	bit_width =

	    ACPI_ROUND_UP(reg->bit_offset + reg->bit_width, access_width);

	if (max_bit_width < bit_width) {

		ACPI_WARNING((AE_INFO,

			      "Unsupported register bit offset: 0x%X",

			      reg->bit_offset));

			      "Requested bit width 0x%X is smaller than register bit width 0x%X",

			      max_bit_width, bit_width));

		return (AE_SUPPORT);

	}



	return (AE_OK);