diff options
| author | Alexey Starikovskiy <astarikovskiy@suse.de> | 2010-04-16 15:36:40 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-04-26 07:48:03 -0700 |
| commit | f7c3b8d3f3bce2c0972165fc65721b735e60de6d (patch) | |
| tree | e1909983ccbb8281049b68ac17f4086e8b80623f /drivers | |
| parent | 3064d4245eecba89cc2eb2ce3cf89fd5ffe060de (diff) | |
ACPI: EC: Limit burst to 64 bits
commit 2060c44576c79086ff24718878d7edaa7384a985 upstream.
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 now.
https://bugzilla.kernel.org/show_bug.cgi?id=15749
fixes regression caused by the fix for:
https://bugzilla.kernel.org/show_bug.cgi?id=14667
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/acpi/acpica/exprep.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/acpi/acpica/exprep.c b/drivers/acpi/acpica/exprep.c index c02d543a2601..83b62521d8d3 100644 --- a/drivers/acpi/acpica/exprep.c +++ b/drivers/acpi/acpica/exprep.c @@ -471,13 +471,18 @@ 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); + if (obj_desc->common_field.bit_length > 8) { + unsigned width = + ACPI_ROUND_BITS_UP_TO_BYTES( + obj_desc->common_field.bit_length); + // access_bit_width is u8, don't overflow it + if (width > 8) + width = 8; obj_desc->common_field.access_byte_width = - ACPI_DIV_8(obj_desc->common_field. - access_bit_width); + width; + obj_desc->common_field.access_bit_width = + 8 * width; + } } ACPI_DEBUG_PRINT((ACPI_DB_BFIELD, |