* [PATCH 06/12] mmc: meson-mx-sdio: Fix misuse of GENMASK macro
2019-07-10 5:04 ` [PATCH 00/12] treewide: Fix GENMASK misuses Joe Perches
@ 2019-07-10 5:04 ` Joe Perches
2019-07-22 7:23 ` Neil Armstrong
2019-07-22 13:43 ` Ulf Hansson
2019-07-10 9:17 ` [PATCH 00/12] treewide: Fix GENMASK misuses Johannes Berg
` (2 subsequent siblings)
3 siblings, 2 replies; 10+ messages in thread
From: Joe Perches @ 2019-07-10 5:04 UTC (permalink / raw)
To: Andrew Morton, Kevin Hilman
Cc: Ulf Hansson, linux-mmc, linux-arm-kernel, linux-amlogic,
linux-kernel
Arguments are supposed to be ordered high then low.
Signed-off-by: Joe Perches <joe@perches.com>
---
drivers/mmc/host/meson-mx-sdio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mmc/host/meson-mx-sdio.c b/drivers/mmc/host/meson-mx-sdio.c
index 2d736e416775..ba9a63db73da 100644
--- a/drivers/mmc/host/meson-mx-sdio.c
+++ b/drivers/mmc/host/meson-mx-sdio.c
@@ -73,7 +73,7 @@
#define MESON_MX_SDIO_IRQC_IF_CONFIG_MASK GENMASK(7, 6)
#define MESON_MX_SDIO_IRQC_FORCE_DATA_CLK BIT(8)
#define MESON_MX_SDIO_IRQC_FORCE_DATA_CMD BIT(9)
- #define MESON_MX_SDIO_IRQC_FORCE_DATA_DAT_MASK GENMASK(10, 13)
+ #define MESON_MX_SDIO_IRQC_FORCE_DATA_DAT_MASK GENMASK(13, 10)
#define MESON_MX_SDIO_IRQC_SOFT_RESET BIT(15)
#define MESON_MX_SDIO_IRQC_FORCE_HALT BIT(30)
#define MESON_MX_SDIO_IRQC_HALT_HOLE BIT(31)
--
2.15.0
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH 06/12] mmc: meson-mx-sdio: Fix misuse of GENMASK macro
2019-07-10 5:04 ` [PATCH 06/12] mmc: meson-mx-sdio: Fix misuse of GENMASK macro Joe Perches
@ 2019-07-22 7:23 ` Neil Armstrong
2019-07-22 13:43 ` Ulf Hansson
1 sibling, 0 replies; 10+ messages in thread
From: Neil Armstrong @ 2019-07-22 7:23 UTC (permalink / raw)
To: Joe Perches, Andrew Morton, Kevin Hilman
Cc: linux-amlogic, Ulf Hansson, linux-mmc, linux-kernel,
linux-arm-kernel
On 10/07/2019 07:04, Joe Perches wrote:
> Arguments are supposed to be ordered high then low.
>
> Signed-off-by: Joe Perches <joe@perches.com>
> ---
> drivers/mmc/host/meson-mx-sdio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/meson-mx-sdio.c b/drivers/mmc/host/meson-mx-sdio.c
> index 2d736e416775..ba9a63db73da 100644
> --- a/drivers/mmc/host/meson-mx-sdio.c
> +++ b/drivers/mmc/host/meson-mx-sdio.c
> @@ -73,7 +73,7 @@
> #define MESON_MX_SDIO_IRQC_IF_CONFIG_MASK GENMASK(7, 6)
> #define MESON_MX_SDIO_IRQC_FORCE_DATA_CLK BIT(8)
> #define MESON_MX_SDIO_IRQC_FORCE_DATA_CMD BIT(9)
> - #define MESON_MX_SDIO_IRQC_FORCE_DATA_DAT_MASK GENMASK(10, 13)
> + #define MESON_MX_SDIO_IRQC_FORCE_DATA_DAT_MASK GENMASK(13, 10)
> #define MESON_MX_SDIO_IRQC_SOFT_RESET BIT(15)
> #define MESON_MX_SDIO_IRQC_FORCE_HALT BIT(30)
> #define MESON_MX_SDIO_IRQC_HALT_HOLE BIT(31)
>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 06/12] mmc: meson-mx-sdio: Fix misuse of GENMASK macro
2019-07-10 5:04 ` [PATCH 06/12] mmc: meson-mx-sdio: Fix misuse of GENMASK macro Joe Perches
2019-07-22 7:23 ` Neil Armstrong
@ 2019-07-22 13:43 ` Ulf Hansson
1 sibling, 0 replies; 10+ messages in thread
From: Ulf Hansson @ 2019-07-22 13:43 UTC (permalink / raw)
To: Joe Perches
Cc: Andrew Morton, Kevin Hilman, linux-mmc@vger.kernel.org, Linux ARM,
open list:ARM/Amlogic Meson..., Linux Kernel Mailing List
On Wed, 10 Jul 2019 at 07:04, Joe Perches <joe@perches.com> wrote:
>
> Arguments are supposed to be ordered high then low.
>
> Signed-off-by: Joe Perches <joe@perches.com>
Applied for fixes by adding a fixes+stable tag, thanks!
Kind regards
Uffe
> ---
> drivers/mmc/host/meson-mx-sdio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/meson-mx-sdio.c b/drivers/mmc/host/meson-mx-sdio.c
> index 2d736e416775..ba9a63db73da 100644
> --- a/drivers/mmc/host/meson-mx-sdio.c
> +++ b/drivers/mmc/host/meson-mx-sdio.c
> @@ -73,7 +73,7 @@
> #define MESON_MX_SDIO_IRQC_IF_CONFIG_MASK GENMASK(7, 6)
> #define MESON_MX_SDIO_IRQC_FORCE_DATA_CLK BIT(8)
> #define MESON_MX_SDIO_IRQC_FORCE_DATA_CMD BIT(9)
> - #define MESON_MX_SDIO_IRQC_FORCE_DATA_DAT_MASK GENMASK(10, 13)
> + #define MESON_MX_SDIO_IRQC_FORCE_DATA_DAT_MASK GENMASK(13, 10)
> #define MESON_MX_SDIO_IRQC_SOFT_RESET BIT(15)
> #define MESON_MX_SDIO_IRQC_FORCE_HALT BIT(30)
> #define MESON_MX_SDIO_IRQC_HALT_HOLE BIT(31)
> --
> 2.15.0
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 00/12] treewide: Fix GENMASK misuses
2019-07-10 5:04 ` [PATCH 00/12] treewide: Fix GENMASK misuses Joe Perches
2019-07-10 5:04 ` [PATCH 06/12] mmc: meson-mx-sdio: Fix misuse of GENMASK macro Joe Perches
@ 2019-07-10 9:17 ` Johannes Berg
2019-07-10 9:43 ` Russell King - ARM Linux admin
2019-07-11 21:30 ` David Miller
2019-07-12 12:54 ` Andrzej Hajda
3 siblings, 1 reply; 10+ messages in thread
From: Johannes Berg @ 2019-07-10 9:17 UTC (permalink / raw)
To: Joe Perches, Andrew Morton, Patrick Venture, Nancy Yuen,
Benjamin Fair, Andrew Jeffery, openbmc, linux-kernel,
linux-aspeed, linux-arm-kernel, linux-amlogic, netdev,
linux-mediatek, linux-stm32, linux-wireless, linux-media
Cc: dri-devel, linux-iio, linux-mmc, devel, alsa-devel
On Tue, 2019-07-09 at 22:04 -0700, 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
IMHO this doesn't make a lot of sense as a checkpatch test - just throw
in a BUILD_BUG_ON()?
johannes
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 00/12] treewide: Fix GENMASK misuses
2019-07-10 9:17 ` [PATCH 00/12] treewide: Fix GENMASK misuses Johannes Berg
@ 2019-07-10 9:43 ` Russell King - ARM Linux admin
2019-07-10 15:45 ` Joe Perches
0 siblings, 1 reply; 10+ messages in thread
From: Russell King - ARM Linux admin @ 2019-07-10 9:43 UTC (permalink / raw)
To: Johannes Berg
Cc: devel, linux-mmc, alsa-devel, Benjamin Fair, linux-aspeed,
Andrew Jeffery, Patrick Venture, openbmc, linux-wireless,
linux-kernel, linux-iio, Nancy Yuen, linux-mediatek, dri-devel,
netdev, Joe Perches, linux-amlogic, Andrew Morton, linux-stm32,
linux-arm-kernel, linux-media
On Wed, Jul 10, 2019 at 11:17:31AM +0200, Johannes Berg wrote:
> On Tue, 2019-07-09 at 22:04 -0700, 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
>
> IMHO this doesn't make a lot of sense as a checkpatch test - just throw
> in a BUILD_BUG_ON()?
My personal take on this is that GENMASK() is really not useful, it's
just pure obfuscation and leads to exactly these kinds of mistakes.
Yes, I fully understand the argument that you can just specify the
start and end bits, and it _in theory_ makes the code more readable.
However, the problem is when writing code. GENMASK(a, b). Is a the
starting bit or ending bit? Is b the number of bits? It's confusing
and causes mistakes resulting in incorrect code. A BUILD_BUG_ON()
can catch some of the cases, but not all of them.
For example:
GENMASK(6, 2)
would satisify the requirement that a > b, so a BUILD_BUG_ON() will
not trigger, but was the author meaning 0x3c or 0xc0?
Personally, I've decided I am _not_ going to use GENMASK() in my code
because I struggle to get the macro arguments correct - I'm _much_
happier, and it is way more reliable for me to write the mask in hex
notation.
I think this is where use of a ternary operator would come in use. The
normal way of writing a number of bits tends to be "a:b", so if GENMASK
took something like GENMASK(6:2), then I'd have less issue with it,
because it's argument is then in a familiar notation.
Yes, I'm sure that someone will point out that the GENMASK arguments
are just in the same order, but that doesn't prevent _me_ frequently
getting it wrong - and that's the point. The macro seems to me to
cause more problems than it solves.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 00/12] treewide: Fix GENMASK misuses
2019-07-10 9:43 ` Russell King - ARM Linux admin
@ 2019-07-10 15:45 ` Joe Perches
2019-07-10 16:01 ` Joe Perches
0 siblings, 1 reply; 10+ messages in thread
From: Joe Perches @ 2019-07-10 15:45 UTC (permalink / raw)
To: Russell King - ARM Linux admin, Johannes Berg
Cc: Andrew Morton, Patrick Venture, Nancy Yuen, Benjamin Fair,
Andrew Jeffery, openbmc, linux-kernel, linux-aspeed,
linux-arm-kernel, linux-amlogic, netdev, linux-mediatek,
linux-stm32, linux-wireless, linux-media, linux-iio, devel,
alsa-devel, linux-mmc, dri-devel
On Wed, 2019-07-10 at 10:43 +0100, Russell King - ARM Linux admin wrote:
> On Wed, Jul 10, 2019 at 11:17:31AM +0200, Johannes Berg wrote:
> > On Tue, 2019-07-09 at 22:04 -0700, 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
> >
> > IMHO this doesn't make a lot of sense as a checkpatch test - just throw
> > in a BUILD_BUG_ON()?
I tried that.
It'd can't be done as it's used in declarations
and included in asm files and it uses the UL()
macro.
I also tried just making it do the right thing
whatever the argument order.
Oh well.
> My personal take on this is that GENMASK() is really not useful, it's
> just pure obfuscation and leads to exactly these kinds of mistakes.
>
> Yes, I fully understand the argument that you can just specify the
> start and end bits, and it _in theory_ makes the code more readable.
>
> However, the problem is when writing code. GENMASK(a, b). Is a the
> starting bit or ending bit? Is b the number of bits? It's confusing
> and causes mistakes resulting in incorrect code. A BUILD_BUG_ON()
> can catch some of the cases, but not all of them.
It's a horrid little macro and I agree with Russell.
I also think if it existed at all it should have been
GENMASK(low, high) not GENMASK(high, low).
I
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 00/12] treewide: Fix GENMASK misuses
2019-07-10 15:45 ` Joe Perches
@ 2019-07-10 16:01 ` Joe Perches
0 siblings, 0 replies; 10+ messages in thread
From: Joe Perches @ 2019-07-10 16:01 UTC (permalink / raw)
To: Russell King - ARM Linux admin, Johannes Berg
Cc: devel, linux-mmc, alsa-devel, Benjamin Fair, linux-aspeed,
Andrew Jeffery, Patrick Venture, openbmc, linux-wireless,
linux-kernel, linux-iio, Nancy Yuen, linux-mediatek, dri-devel,
netdev, linux-amlogic, Andrew Morton, linux-stm32,
linux-arm-kernel, linux-media
On Wed, 2019-07-10 at 08:45 -0700, Joe Perches wrote:
> On Wed, 2019-07-10 at 10:43 +0100, Russell King - ARM Linux admin wrote:
> > On Wed, Jul 10, 2019 at 11:17:31AM +0200, Johannes Berg wrote:
> > > On Tue, 2019-07-09 at 22:04 -0700, 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
> > >
> > > IMHO this doesn't make a lot of sense as a checkpatch test - just throw
> > > in a BUILD_BUG_ON()?
>
> I tried that.
>
> It'd can't be done as it's used in declarations
> and included in asm files and it uses the UL()
> macro.
>
> I also tried just making it do the right thing
> whatever the argument order.
I forgot.
I also made all those arguments when it was
introduced in 2013.
https://lore.kernel.org/patchwork/patch/414248/
> Oh well.
yeah.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 00/12] treewide: Fix GENMASK misuses
2019-07-10 5:04 ` [PATCH 00/12] treewide: Fix GENMASK misuses Joe Perches
2019-07-10 5:04 ` [PATCH 06/12] mmc: meson-mx-sdio: Fix misuse of GENMASK macro Joe Perches
2019-07-10 9:17 ` [PATCH 00/12] treewide: Fix GENMASK misuses Johannes Berg
@ 2019-07-11 21:30 ` David Miller
2019-07-12 12:54 ` Andrzej Hajda
3 siblings, 0 replies; 10+ messages in thread
From: David Miller @ 2019-07-11 21:30 UTC (permalink / raw)
To: joe
Cc: akpm, venture, yuenn, benjaminfair, andrew, openbmc, linux-kernel,
linux-aspeed, linux-arm-kernel, linux-amlogic, netdev,
linux-mediatek, linux-stm32, linux-wireless, linux-media,
dri-devel, linux-iio, linux-mmc, devel, alsa-devel
From: Joe Perches <joe@perches.com>
Date: Tue, 9 Jul 2019 22:04:13 -0700
> 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.
Patches #7 and #8 applied to 'net', with appropriate Fixes tags
added to #8.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH 00/12] treewide: Fix GENMASK misuses
2019-07-10 5:04 ` [PATCH 00/12] treewide: Fix GENMASK misuses Joe Perches
` (2 preceding siblings ...)
2019-07-11 21:30 ` David Miller
@ 2019-07-12 12:54 ` Andrzej Hajda
3 siblings, 0 replies; 10+ messages in thread
From: Andrzej Hajda @ 2019-07-12 12:54 UTC (permalink / raw)
To: Joe Perches, Andrew Morton, Patrick Venture, Nancy Yuen,
Benjamin Fair, Andrew Jeffery, openbmc, linux-kernel,
linux-aspeed, linux-arm-kernel, linux-amlogic, netdev,
linux-mediatek, linux-stm32, linux-wireless, linux-media
Cc: linux-iio, devel, alsa-devel, linux-mmc, dri-devel
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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^ permalink raw reply related [flat|nested] 10+ messages in thread