CVE-2024-26721
Assigner: Linux
Published: 2024-04-03T14:55:20.995Z
State: PUBLISHED
descriptions: value: In the Linux kernel, the following vulnerability has been resolved:

drm/i915/dsc: Fix the macro that calculates DSCC_/DSCA_ PPS reg address

Commit bd077259d0a9 ("drm/i915/vdsc: Add function to read any PPS
register") defines a new macro to calculate the DSC PPS register
addresses with PPS number as an input. This macro correctly calculates
the addresses till PPS 11 since the addresses increment by 4. So in that
case the following macro works correctly to give correct register
address:

_MMIO(_DSCA_PPS_0 + (pps) * 4)

However after PPS 11, the register address for PPS 12 increments by 12
because of RC Buffer memory allocation in between. Because of this
discontinuity in the address space, the macro calculates wrong addresses
for PPS 12 - 16 resulting into incorrect DSC PPS parameter value
read/writes causing DSC corruption.

This fixes it by correcting this macro to add the offset of 12 for PPS
>=12.

v3: Add correct paranthesis for pps argument (Jani Nikula)

(cherry picked from commit 6074be620c31dc2ae11af96a1a5ea95580976fb5)
affected: product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions: version: bd077259d0a9
lessThan: ff5999fb03f4
status: affected
versionType: git
version: bd077259d0a9
lessThan: 962ac2dce56b
status: affected
versionType: git
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions: version: 6.7
status: affected
version: 0
lessThan: 6.7
status: unaffected
versionType: custom
version: 6.7.6
lessThanOrEqual: 6.7.*
status: unaffected
versionType: custom
version: 6.8
lessThanOrEqual: *
status: unaffected
versionType: original_commit_for_fix
title: drm/i915/dsc: Fix the macro that calculates DSCC_/DSCA_ PPS reg address
x_generator: engine: bippy-d3b290d2becc