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Message-ID: <469b0d3d-9466-b287-5ca3-27f3d01ff3cd@samsung.com>
Date: Fri, 12 Jul 2019 14:54:09 +0200
From: Andrzej Hajda <a.hajda@...sung.com>
To: Joe Perches <joe@...ches.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Patrick Venture <venture@...gle.com>,
Nancy Yuen <yuenn@...gle.com>,
Benjamin Fair <benjaminfair@...gle.com>,
Andrew Jeffery <andrew@...id.au>, openbmc@...ts.ozlabs.org,
linux-kernel@...r.kernel.org, linux-aspeed@...ts.ozlabs.org,
linux-arm-kernel@...ts.infradead.org,
linux-amlogic@...ts.infradead.org, netdev@...r.kernel.org,
linux-mediatek@...ts.infradead.org,
linux-stm32@...md-mailman.stormreply.com,
linux-wireless@...r.kernel.org, linux-media@...r.kernel.org
Cc: linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
alsa-devel@...a-project.org, linux-mmc@...r.kernel.org,
dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 00/12] treewide: Fix GENMASK misuses
Hi Joe,
On 10.07.2019 07:04, Joe Perches wrote:
> These GENMASK uses are inverted argument order and the
> actual masks produced are incorrect. Fix them.
>
> Add checkpatch tests to help avoid more misuses too.
>
> Joe Perches (12):
> checkpatch: Add GENMASK tests
> clocksource/drivers/npcm: Fix misuse of GENMASK macro
> drm: aspeed_gfx: Fix misuse of GENMASK macro
> iio: adc: max9611: Fix misuse of GENMASK macro
> irqchip/gic-v3-its: Fix misuse of GENMASK macro
> mmc: meson-mx-sdio: Fix misuse of GENMASK macro
> net: ethernet: mediatek: Fix misuses of GENMASK macro
> net: stmmac: Fix misuses of GENMASK macro
> rtw88: Fix misuse of GENMASK macro
> phy: amlogic: G12A: Fix misuse of GENMASK macro
> staging: media: cedrus: Fix misuse of GENMASK macro
> ASoC: wcd9335: Fix misuse of GENMASK macro
>
> drivers/clocksource/timer-npcm7xx.c | 2 +-
> drivers/gpu/drm/aspeed/aspeed_gfx.h | 2 +-
> drivers/iio/adc/max9611.c | 2 +-
> drivers/irqchip/irq-gic-v3-its.c | 2 +-
> drivers/mmc/host/meson-mx-sdio.c | 2 +-
> drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 +-
> drivers/net/ethernet/mediatek/mtk_sgmii.c | 2 +-
> drivers/net/ethernet/stmicro/stmmac/descs.h | 2 +-
> drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c | 4 ++--
> drivers/net/wireless/realtek/rtw88/rtw8822b.c | 2 +-
> drivers/phy/amlogic/phy-meson-g12a-usb2.c | 2 +-
> drivers/staging/media/sunxi/cedrus/cedrus_regs.h | 2 +-
> scripts/checkpatch.pl | 15 +++++++++++++++
> sound/soc/codecs/wcd-clsh-v2.c | 2 +-
> 14 files changed, 29 insertions(+), 14 deletions(-)
>
After adding following compile time check:
------
diff --git a/Makefile b/Makefile
index 5102b2bbd224..ac4ea5f443a9 100644
--- a/Makefile
+++ b/Makefile
@@ -457,7 +457,7 @@ KBUILD_AFLAGS := -D__ASSEMBLY__ -fno-PIE
KBUILD_CFLAGS := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
-fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE \
-Werror=implicit-function-declaration
-Werror=implicit-int \
- -Wno-format-security \
+ -Wno-format-security -Werror=div-by-zero \
-std=gnu89
KBUILD_CPPFLAGS := -D__KERNEL__
KBUILD_AFLAGS_KERNEL :=
diff --git a/include/linux/bits.h b/include/linux/bits.h
index 669d69441a62..61d74b103055 100644
--- a/include/linux/bits.h
+++ b/include/linux/bits.h
@@ -19,11 +19,11 @@
* GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
*/
#define GENMASK(h, l) \
- (((~UL(0)) - (UL(1) << (l)) + 1) & \
+ (((~UL(0)) - (UL(1) << (l)) + 1 + 0/((h) >= (l))) & \
(~UL(0) >> (BITS_PER_LONG - 1 - (h))))
#define GENMASK_ULL(h, l) \
- (((~ULL(0)) - (ULL(1) << (l)) + 1) & \
+ (((~ULL(0)) - (ULL(1) << (l)) + 1 + 0/((h) >= (l))) & \
(~ULL(0) >> (BITS_PER_LONG_LONG - 1 - (h))))
#endif /* __LINUX_BITS_H */
-------
I was able to detect one more GENMASK misue (AARCH64, allyesconfig):
CC drivers/phy/rockchip/phy-rockchip-inno-hdmi.o
In file included from ../include/linux/bitops.h:5:0,
from ../include/linux/kernel.h:12,
from ../include/linux/clk.h:13,
from ../drivers/phy/rockchip/phy-rockchip-inno-hdmi.c:9:
../drivers/phy/rockchip/phy-rockchip-inno-hdmi.c: In function
‘inno_hdmi_phy_rk3328_power_on’:
../include/linux/bits.h:22:37: error: division by zero [-Werror=div-by-zero]
(((~UL(0)) - (UL(1) << (l)) + 1 + 0/((h) >= (l))) & \
^
../drivers/phy/rockchip/phy-rockchip-inno-hdmi.c:24:42: note: in
expansion of macro ‘GENMASK’
#define UPDATE(x, h, l) (((x) << (l)) & GENMASK((h), (l)))
^~~~~~~
../drivers/phy/rockchip/phy-rockchip-inno-hdmi.c:201:50: note: in
expansion of macro ‘UPDATE’
#define RK3328_TERM_RESISTOR_CALIB_SPEED_7_0(x) UPDATE(x, 7, 9)
^~~~~~
../drivers/phy/rockchip/phy-rockchip-inno-hdmi.c:1046:26: note: in
expansion of macro ‘RK3328_TERM_RESISTOR_CALIB_SPEED_7_0’
inno_write(inno, 0xc6, RK3328_TERM_RESISTOR_CALIB_SPEED_7_0(v));
Of course I do not advise to add the check as is to Kernel - it is
undefined behavior area AFAIK.
Regards
Andrzej
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