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Commit c3faedcd authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by Rafael J. Wysocki
Browse files

ACPICA: acpi_read: On error, do not modify the return value target location. 



If an error happens in the middle of a split 32/32 64-bit I/O
operation, do not modify the target of the return value pointer.
Makes the code consistent with the rest of ACPICA. Bjorn Helgaas.

Signed-off-by: default avatarBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
Reviewed-by: default avatarLen Brown <len.brown@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent f28eb9f5

drivers/acpi/acpica/hwxface.c

+14 −12
Original line number Diff line number Diff line
@@ -119,7 +119,8 @@ ACPI_EXPORT_SYMBOL(acpi_reset) 
 ******************************************************************************/

acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)

{

	u32 value;

	u32 value_lo;

	u32 value_hi;

	u32 width;

	u64 address;

	acpi_status status;
@@ -137,13 +138,8 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg) 
		return (status);

	}



	/* Initialize entire 64-bit return value to zero */



	*return_value = 0;

	value = 0;



	/*

	 * Two address spaces supported: Memory or IO. PCI_Config is

	 * Two address spaces supported: Memory or I/O. PCI_Config is

	 * not supported here because the GAS structure is insufficient

	 */

	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
@@ -155,29 +151,35 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg) 
		}

	} else {		/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */



		value_lo = 0;

		value_hi = 0;



		width = reg->bit_width;

		if (width == 64) {

			width = 32;	/* Break into two 32-bit transfers */

		}



		status = acpi_hw_read_port((acpi_io_address)

					   address, &value, width);

					   address, &value_lo, width);

		if (ACPI_FAILURE(status)) {

			return (status);

		}

		*return_value = value;



		if (reg->bit_width == 64) {



			/* Read the top 32 bits */



			status = acpi_hw_read_port((acpi_io_address)

						   (address + 4), &value, 32);

						   (address + 4), &value_hi,

						   32);

			if (ACPI_FAILURE(status)) {

				return (status);

			}

			*return_value |= ((u64)value << 32);

		}



		/* Set the return value only if status is AE_OK */



		*return_value = (value_lo | ((u64)value_hi << 32));

	}



	ACPI_DEBUG_PRINT((ACPI_DB_IO,
@@ -186,7 +188,7 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg) 
			  ACPI_FORMAT_UINT64(address),

			  acpi_ut_get_region_name(reg->space_id)));



	return (status);

	return (AE_OK);

}



ACPI_EXPORT_SYMBOL(acpi_read)