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authorBjorn Helgaas <bjorn.helgaas@hp.com>2013-09-23 01:51:22 (GMT)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-09-23 23:46:23 (GMT)
commitc3faedcdb41a2fedbec8ca8f8612d67b012b44a2 (patch)
treed287953ff51e44e7f3be93d42f9d7d825b69a5ad
parentf28eb9f5009abdc74d4052ae05c01795e254a6fc (diff)
downloadlinux-c3faedcdb41a2fedbec8ca8f8612d67b012b44a2.tar.xz
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: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Lv Zheng <lv.zheng@intel.com> Reviewed-by: Len Brown <len.brown@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/acpi/acpica/hwxface.c26
1 files changed, 14 insertions, 12 deletions
diff --git a/drivers/acpi/acpica/hwxface.c b/drivers/acpi/acpica/hwxface.c
index 5ee7a814..f81fb06 100644
--- a/drivers/acpi/acpica/hwxface.c
+++ b/drivers/acpi/acpica/hwxface.c
@@ -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)