[PATCH AUTOSEL 5.18 02/93] drm/r128: Fix undefined behavior due to shift overflowing the constant

Sasha Levin
2022-08-11T15:51:43Z

From: Borislav Petkov <bp@suse.de>

[ Upstream commit 6556551f8848f98eff356c8aacae42c8dd65b2df ]

Fix:

drivers/gpu/drm/r128/r128_cce.c: In function ‘r128_do_init_cce’:
drivers/gpu/drm/r128/r128_cce.c:417:2: error: case label does not reduce to an integer constant
case R128_PM4_64BM_64VCBM_64INDBM:
^~~~
drivers/gpu/drm/r128/r128_cce.c:418:2: error: case label does not reduce to an integer constant
case R128_PM4_64PIO_64VCPIO_64INDPIO:
^~~~

See https://lore.kernel.org/r/YkwQ6%2BtIH8GQpuct@zn.tnic for the gory
details as to why it triggers with older gccs only.

Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405151517.29753-5-bp@alien8.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/r128/r128_drv.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/r128/r128_drv.h b/drivers/gpu/drm/r128/r128_drv.h
index 2e1bc01aa5c9..970e192b0d51 100644
--- a/drivers/gpu/drm/r128/r128_drv.h
+++ b/drivers/gpu/drm/r128/r128_drv.h
@@ -300,8 +300,8 @@ extern long r128_compat_ioctl(struct file *filp, unsigned int cmd,
# define R128_PM4_64PIO_128INDBM (5 << 28)
# define R128_PM4_64BM_128INDBM (6 << 28)
# define R128_PM4_64PIO_64VCBM_64INDBM (7 << 28)
-# define R128_PM4_64BM_64VCBM_64INDBM (8 << 28)
-# define R128_PM4_64PIO_64VCPIO_64INDPIO (15 << 28)
+# define R128_PM4_64BM_64VCBM_64INDBM (8U << 28)
+# define R128_PM4_64PIO_64VCPIO_64INDPIO (15U << 28)
# define R128_PM4_BUFFER_CNTL_NOUPDATE (1 << 27)

#define R128_PM4_BUFFER_WM_CNTL 0x0708
--
2.35.1