* [RFC][PATCH] ACPI: EC: Allow limited large burst reads
@ 2010-04-14 21:11 Alexey Starikovskiy
0 siblings, 0 replies; only message in thread
From: Alexey Starikovskiy @ 2010-04-14 21:11 UTC (permalink / raw)
To: Len Brown; +Cc: Linux-acpi
access_bit_width field is u8 in ACPICA, thus 256 value written to it
becomes 0, causing divide by zero later.
Proper fix would be to remove access_bit_width at all, just because
we already have access_byte_width, which is access_bit_width / 8.
Limit access width to 64 bit for in general, but allow larger reads
if they are aligned with access_byte_width.
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
---
drivers/acpi/acpica/acobject.h | 3 +--
drivers/acpi/acpica/exfldio.c | 24 ++++++++++++------------
drivers/acpi/acpica/exprep.c | 16 +++++-----------
3 files changed, 18 insertions(+), 25 deletions(-)
diff --git a/drivers/acpi/acpica/acobject.h b/drivers/acpi/acpica/acobject.h
index cde18ea..8ef1a08 100644
--- a/drivers/acpi/acpica/acobject.h
+++ b/drivers/acpi/acpica/acobject.h
@@ -243,12 +243,11 @@ ACPI_OBJECT_COMMON_HEADER ACPI_COMMON_NOTIFY_INFO};
u8 field_flags; /* Access, update, and lock bits */\
u8 attribute; /* From access_as keyword */\
u8 access_byte_width; /* Read/Write size in bytes */\
+ u8 start_field_bit_offset;/* Bit offset within first field datum (0-63) */\
struct acpi_namespace_node *node; /* Link back to parent node */\
u32 bit_length; /* Length of field in bits */\
u32 base_byte_offset; /* Byte offset within containing object */\
u32 value; /* Value to store into the Bank or Index register */\
- u8 start_field_bit_offset;/* Bit offset within first field datum (0-63) */\
- u8 access_bit_width; /* Read/Write size in bits (8-64) */
struct acpi_object_field_common { /* COMMON FIELD (for BUFFER, REGION, BANK, and INDEX fields) */
ACPI_OBJECT_COMMON_HEADER ACPI_COMMON_FIELD_INFO union acpi_operand_object *region_obj; /* Parent Operation Region object (REGION/BANK fields only) */
diff --git a/drivers/acpi/acpica/exfldio.c b/drivers/acpi/acpica/exfldio.c
index f68a216..a05cef5 100644
--- a/drivers/acpi/acpica/exfldio.c
+++ b/drivers/acpi/acpica/exfldio.c
@@ -699,12 +699,12 @@ acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
/* Compute the number of datums (access width data items) */
datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
- obj_desc->common_field.access_bit_width);
+ obj_desc->common_field.access_byte_width * 8);
field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
obj_desc->common_field.
start_field_bit_offset,
obj_desc->common_field.
- access_bit_width);
+ access_byte_width * 8);
/* Priming read from the field */
@@ -738,12 +738,12 @@ acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
* This avoids the differences in behavior between different compilers
* concerning shift values larger than the target data width.
*/
- if ((obj_desc->common_field.access_bit_width -
+ if ((obj_desc->common_field.access_byte_width * 8 -
obj_desc->common_field.start_field_bit_offset) <
ACPI_INTEGER_BIT_SIZE) {
merged_datum |=
raw_datum << (obj_desc->common_field.
- access_bit_width -
+ access_byte_width * 8 -
obj_desc->common_field.
start_field_bit_offset);
}
@@ -766,7 +766,7 @@ acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
/* Mask off any extra bits in the last datum */
buffer_tail_bits = obj_desc->common_field.bit_length %
- obj_desc->common_field.access_bit_width;
+ (obj_desc->common_field.access_byte_width * 8);
if (buffer_tail_bits) {
merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
}
@@ -849,12 +849,12 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
* Note: This if/else is used to bypass compiler differences with the
* shift operator
*/
- if (obj_desc->common_field.access_bit_width == ACPI_INTEGER_BIT_SIZE) {
+ if (obj_desc->common_field.access_byte_width * 8 == ACPI_INTEGER_BIT_SIZE) {
width_mask = ACPI_UINT64_MAX;
} else {
width_mask =
ACPI_MASK_BITS_ABOVE(obj_desc->common_field.
- access_bit_width);
+ access_byte_width * 8);
}
mask = width_mask &
@@ -863,13 +863,13 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
/* Compute the number of datums (access width data items) */
datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
- obj_desc->common_field.access_bit_width);
+ obj_desc->common_field.access_byte_width * 8);
field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
obj_desc->common_field.
start_field_bit_offset,
obj_desc->common_field.
- access_bit_width);
+ access_byte_width * 8);
/* Get initial Datum from the input buffer */
@@ -905,12 +905,12 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
* This avoids the differences in behavior between different compilers
* concerning shift values larger than the target data width.
*/
- if ((obj_desc->common_field.access_bit_width -
+ if ((obj_desc->common_field.access_byte_width * 8 -
obj_desc->common_field.start_field_bit_offset) <
ACPI_INTEGER_BIT_SIZE) {
merged_datum =
raw_datum >> (obj_desc->common_field.
- access_bit_width -
+ access_byte_width * 8 -
obj_desc->common_field.
start_field_bit_offset);
} else {
@@ -937,7 +937,7 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
buffer_tail_bits = (obj_desc->common_field.bit_length +
obj_desc->common_field.start_field_bit_offset) %
- obj_desc->common_field.access_bit_width;
+ (obj_desc->common_field.access_byte_width * 8);
if (buffer_tail_bits) {
mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
}
diff --git a/drivers/acpi/acpica/exprep.c b/drivers/acpi/acpica/exprep.c
index a610ebe..b401c50 100644
--- a/drivers/acpi/acpica/exprep.c
+++ b/drivers/acpi/acpica/exprep.c
@@ -360,8 +360,6 @@ acpi_ex_prep_common_field_object(union acpi_operand_object *obj_desc,
obj_desc->common_field.access_byte_width = (u8)
ACPI_DIV_8(access_bit_width); /* 1, 2, 4, 8 */
- obj_desc->common_field.access_bit_width = (u8) access_bit_width;
-
/*
* base_byte_offset is the address of the start of the field within the
* region. It is the byte address of the first *datum* (field-width data
@@ -470,15 +468,11 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
/* allow full data read from EC address space */
if (obj_desc->field.region_obj->region.space_id ==
- ACPI_ADR_SPACE_EC) {
- if (obj_desc->common_field.bit_length > 8)
- obj_desc->common_field.access_bit_width =
- ACPI_ROUND_UP(obj_desc->common_field.
- bit_length, 8);
- obj_desc->common_field.access_byte_width =
- ACPI_DIV_8(obj_desc->common_field.
- access_bit_width);
- }
+ ACPI_ADR_SPACE_EC &&
+ obj_desc->common_field.bit_length > 8)
+ obj_desc->common_field.access_byte_width =
+ ACPI_ROUND_BITS_UP_TO_BYTES(
+ obj_desc->common_field.bit_length);
ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
"RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",
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2010-04-14 21:11 [RFC][PATCH] ACPI: EC: Allow limited large burst reads Alexey Starikovskiy
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