# \[PATCH\] gpio: uniphier: Replace zero-length array with flexible-array member - Subsystems: ARM/UNIPHIER ARCHITECTURE, GPIO SUBSYSTEM, THE REST - Maintainers: Kunihiko Hayashi, Masami Hiramatsu, Linus Walleij, Bartosz Golaszewski, Linus Torvalds - List: linux-arm-kernel - 3 messages, 3 authors - Page: https://ratatoskr.run/linux-arm-kernel/2020/02/5857708/t ## \[PATCH\] gpio: uniphier: Replace zero-length array with flexible-array member - From: Gustavo A. R. Silva \ - Date: 2020-02-11 21:03:48 - Message: https://ratatoskr.run/linux-arm-kernel/2020/02/5857708.md ```text The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertenly introduced[3] to the codebase from now on. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- drivers/gpio/gpio-uniphier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpio/gpio-uniphier.c b/drivers/gpio/gpio-uniphier.c index 0f662b297a95..9843638d99d0 100644 --- a/drivers/gpio/gpio-uniphier.c +++ b/drivers/gpio/gpio-uniphier.c @@ -33,7 +33,7 @@ struct uniphier_gpio_priv { struct irq_domain *domain; void __iomem *regs; spinlock_t lock; - u32 saved_vals[0]; + u32 saved_vals[]; }; static unsigned int uniphier_gpio_bank_to_reg(unsigned int bank) -- 2.25.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ``` ## Re: \[PATCH\] gpio: uniphier: Replace zero-length array with flexible-array member - From: Bartosz Golaszewski \ - Date: 2020-02-17 09:38:56 - Message: https://ratatoskr.run/linux-arm-kernel/2020/02/5864892.md ```text wt., 11 lut 2020 o 22:03 Gustavo A. R. Silva [ref] napisał(a): > > The current codebase makes use of the zero-length array language > extension to the C90 standard, but the preferred mechanism to declare > variable-length types such as these ones is a flexible array member[1][2], > introduced in C99: > > struct foo { > int stuff; > struct boo array[]; > }; > > By making use of the mechanism above, we will get a compiler warning > in case the flexible array does not occur last in the structure, which > will help us prevent some kind of undefined behavior bugs from being > inadvertenly introduced[3] to the codebase from now on. > > This issue was found with the help of Coccinelle. > > [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html > [2] https://github.com/KSPP/linux/issues/21 > [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") > > Signed-off-by: Gustavo A. R. Silva Patch applied, thanks! Bartosz _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ``` ## Re: \[PATCH\] gpio: uniphier: Replace zero-length array with flexible-array member - From: Masahiro Yamada \ - Date: 2020-02-18 01:25:50 - Message: https://ratatoskr.run/linux-arm-kernel/2020/02/5865614.md ```text On Wed, Feb 12, 2020 at 6:03 AM Gustavo A. R. Silva [ref] wrote: > > The current codebase makes use of the zero-length array language > extension to the C90 standard, but the preferred mechanism to declare > variable-length types such as these ones is a flexible array member[1][2], > introduced in C99: > > struct foo { > int stuff; > struct boo array[]; > }; > > By making use of the mechanism above, we will get a compiler warning > in case the flexible array does not occur last in the structure, which > will help us prevent some kind of undefined behavior bugs from being > inadvertenly introduced[3] to the codebase from now on. > > This issue was found with the help of Coccinelle. > > [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html > [2] https://github.com/KSPP/linux/issues/21 > [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") > > Signed-off-by: Gustavo A. R. Silva Acked-by: Masahiro Yamada > --- > drivers/gpio/gpio-uniphier.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpio/gpio-uniphier.c b/drivers/gpio/gpio-uniphier.c > index 0f662b297a95..9843638d99d0 100644 > --- a/drivers/gpio/gpio-uniphier.c > +++ b/drivers/gpio/gpio-uniphier.c > @@ -33,7 +33,7 @@ struct uniphier_gpio_priv { > struct irq_domain *domain; > void __iomem *regs; > spinlock_t lock; > - u32 saved_vals[0]; > + u32 saved_vals[]; > }; > > static unsigned int uniphier_gpio_bank_to_reg(unsigned int bank) > -- > 2.25.0 > -- Best Regards Masahiro Yamada _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ```