Accumulate the entire 64-bit value before updating the return_value.
Previously, it was possible to update the low 32 bits, then return
failure if reading the upper 32 bits failed, leaving a half-updated
return_value.
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/acpi/acpica/hwxface.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/acpi/acpica/hwxface.c b/drivers/acpi/acpica/hwxface.c
index c2793a8..12b5c57 100644
--- a/drivers/acpi/acpica/hwxface.c
+++ b/drivers/acpi/acpica/hwxface.c
@@ -123,6 +123,7 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
u32 value;
u32 width;
u64 address;
+ u64 complete_value;
acpi_status status;
ACPI_FUNCTION_NAME(acpi_read);
@@ -146,6 +147,7 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
/* Initialize entire 64-bit return value to zero */
*return_value = 0;
+ complete_value = 0;
value = 0;
/*
@@ -158,7 +160,7 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
if (ACPI_FAILURE(status)) {
return (status);
}
- *return_value = value;
+ complete_value = value;
if (reg->bit_width == 64) {
@@ -169,7 +171,7 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
if (ACPI_FAILURE(status)) {
return (status);
}
- *return_value |= ((u64)value << 32);
+ complete_value |= ((u64)value << 32);
}
} else { /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
@@ -178,7 +180,7 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
if (ACPI_FAILURE(status)) {
return (status);
}
- *return_value = value;
+ complete_value = value;
if (reg->bit_width == 64) {
@@ -189,10 +191,11 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
if (ACPI_FAILURE(status)) {
return (status);
}
- *return_value |= ((u64)value << 32);
+ complete_value |= ((u64)value << 32);
}
}
+ *return_value = complete_value;
ACPI_DEBUG_PRINT((ACPI_DB_IO,
"Read: %8.8X%8.8X width %2d from %8.8X%8.8X (%s)\n",
ACPI_FORMAT_UINT64(*return_value), reg->bit_width,
--
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