[PATCH AUTOSEL 5.15 41/41] perf/imx_ddr: Fix undefined behavior due to shift overflowing the constant

Sasha Levin
2022-04-12T00:55:05Z

From: Borislav Petkov <bp@suse.de>

[ Upstream commit d02b4dd84e1a90f7f1444d027c0289bf355b0d5a ]

Fix:

In file included from <command-line>:0:0:
In function ‘ddr_perf_counter_enable’,
inlined from ‘ddr_perf_irq_handler’ at drivers/perf/fsl_imx8_ddr_perf.c:651:2:
././include/linux/compiler_types.h:352:38: error: call to ‘__compiletime_assert_729’ \
declared with attribute error: FIELD_PREP: mask is not constant
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
...

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

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Frank Li <Frank.li@nxp.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220405151517.29753-10-bp@alien8.de
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/perf/fsl_imx8_ddr_perf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/perf/fsl_imx8_ddr_perf.c b/drivers/perf/fsl_imx8_ddr_perf.c
index 94ebc1ecace7..b1b2a55de77f 100644
--- a/drivers/perf/fsl_imx8_ddr_perf.c
+++ b/drivers/perf/fsl_imx8_ddr_perf.c
@@ -29,7 +29,7 @@
#define CNTL_OVER_MASK 0xFFFFFFFE

#define CNTL_CSV_SHIFT 24
-#define CNTL_CSV_MASK (0xFF << CNTL_CSV_SHIFT)
+#define CNTL_CSV_MASK (0xFFU << CNTL_CSV_SHIFT)

#define EVENT_CYCLES_ID 0
#define EVENT_CYCLES_COUNTER 0
--
2.35.1