ACPI: SPCR: Check for table version when using precise baudrate

Commit 4d330fe541 ("ACPI: SPCR: Support Precise Baud Rate field")
added support to use the precise baud rate available since SPCR 1.09
(revision 4) but failed to check the version of the table provided by
the firmware.

Accessing an older version of SPCR table causes accesses beyond the
end of the table and can lead to garbage data to be used for the baud
rate.

Check the version of the firmware provided SPCR to ensure that the
precise baudrate is vaild before using it.

Fixes: 4d330fe541 ("ACPI: SPCR: Support Precise Baud Rate field")
Signed-off-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
Link: https://patch.msgid.link/20251024123125.1081612-1-punit.agrawal@oss.qualcomm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Punit Agrawal 2025-10-24 13:31:25 +01:00 committed by Rafael J. Wysocki
parent dc131bcd8d
commit 543d350040
1 changed files with 1 additions and 1 deletions

View File

@ -155,7 +155,7 @@ int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console)
* Baud Rate field. If this field is zero or not present, Configured
* Baud Rate is used.
*/
if (table->precise_baudrate)
if (table->header.revision >= 4 && table->precise_baudrate)
baud_rate = table->precise_baudrate;
else switch (table->baud_rate) {
case 0: