Messages in this thread Patch in this message | | | Date | Thu, 22 Apr 2010 12:54:58 -0700 | From | Greg KH <> | Subject | [121/139] ACPI: EC: Limit burst to 64 bits |
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2.6.33-stable review patch. If anyone has any objections, please let us know.
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From: Alexey Starikovskiy <astarikovskiy@suse.de>
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>
--- drivers/acpi/acpica/exprep.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)
--- a/drivers/acpi/acpica/exprep.c +++ b/drivers/acpi/acpica/exprep.c @@ -471,13 +471,18 @@ acpi_status acpi_ex_prep_field_value(str /* 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,
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