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| author | Alexey Starikovskiy <astarikovskiy@suse.de> | 2010-04-16 15:36:40 -0400 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2010-04-16 15:36:54 -0400 |
| commit | 2060c44576c79086ff24718878d7edaa7384a985 (patch) | |
| tree | 6753da133e11ba121902d0dd3d71da466b9094de /drivers | |
| parent | dadf28a10c3eb29421837a2e413ab869ebd9e168 (diff) | |
| download | linux-stable-2060c44576c79086ff24718878d7edaa7384a985.tar.gz linux-stable-2060c44576c79086ff24718878d7edaa7384a985.tar.bz2 linux-stable-2060c44576c79086ff24718878d7edaa7384a985.zip | |
ACPI: EC: Limit burst to 64 bits
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>
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 a610ebe18edd..2fbfe51fb141 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, |