[PATCH] gpio: aspeed: fix compile testing warning
From: Alexander Stein <hidden>
Date: 2018-07-09 15:31:33
Also in:
linux-arm-kernel, linux-gpio, lkml
On Monday, July 9, 2018, 4:56:03 PM CEST Arnd Bergmann wrote:
quoted hunk ↗ jump to hunk
Gcc cannot always see that BUG_ON(1) is guaranteed to not return, so we get a warning message in some configurations: drivers/gpio/gpio-aspeed.c: In function 'bank_reg': drivers/gpio/gpio-aspeed.c:244:1: error: control reaches end of non-void function [-Werror=return-type] Using a plain BUG() is easier here and avoids the problem. Fixes: 44ddf559d579 ("gpio: aspeed: Rework register type accessors") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/gpio/gpio-aspeed.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/gpio/gpio-aspeed.c b/drivers/gpio/gpio-aspeed.c index 1e00f4045f9d..2342e154029b 100644 --- a/drivers/gpio/gpio-aspeed.c +++ b/drivers/gpio/gpio-aspeed.c@@ -240,7 +240,7 @@ static inline void __iomem *bank_reg(struct aspeed_gpio*gpio, case reg_cmdsrc1: return gpio->base + bank->cmdsrc_regs + GPIO_CMDSRC_1; } - BUG_ON(1); + BUG(); } #define GPIO_BANK(x) ((x) >> 5)
Is the semantic of BUG() (and BUG_ON as well) to never return? If so, then just an idea: Is it possible to add some macro magic in BUG_ON(x) to fail compiling if x is compile-constant? Giving a hint the passed condition always fails, which indicates a problem, at least to me. From a short search I found this in drivers/gpu/vga/vgaarb.c L630-633:
if (vgadev_find(pdev) != NULL) {
BUG_ON(1);
goto fail;
}You can't fail with a BUG_ON(1) and try to do some error handling after that. Best regards, Alexander