linux-kernel - Re: [PATCH] watchdog: aspeed: fix 64-bit division

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Message-ID: <9ff3ba59-be59-4a2e-ac1a-5ce23b1b3fba@roeck-us.net>
Date: Fri, 14 Mar 2025 10:37:17 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Arnd Bergmann <arnd@...nel.org>, Wim Van Sebroeck
 <wim@...ux-watchdog.org>, Joel Stanley <joel@....id.au>,
 Andrew Jeffery <andrew@...econstruct.com.au>,
 Chin-Ting Kuo <chin-ting_kuo@...eedtech.com>
Cc: Arnd Bergmann <arnd@...db.de>, linux-watchdog@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-aspeed@...ts.ozlabs.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] watchdog: aspeed: fix 64-bit division

On 3/14/25 09:02, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> On 32-bit architectures, the new calculation causes a build failure:
> 
> ld.lld-21: error: undefined symbol: __aeabi_uldivmod
> 
> Since neither value is ever larger than a register, cast both
> sides into a uintptr_t.
> 
> Fixes: 5c03f9f4d362 ("watchdog: aspeed: Update bootstatus handling")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>   drivers/watchdog/aspeed_wdt.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
> index 369635b38ca0..837e15701c0e 100644
> --- a/drivers/watchdog/aspeed_wdt.c
> +++ b/drivers/watchdog/aspeed_wdt.c
> @@ -254,7 +254,7 @@ static void aspeed_wdt_update_bootstatus(struct platform_device *pdev,
>   
>   	if (!of_device_is_compatible(pdev->dev.of_node, "aspeed,ast2400-wdt")) {
>   		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -		idx = ((intptr_t)wdt->base & 0x00000fff) / resource_size(res);
> +		idx = ((intptr_t)wdt->base & 0x00000fff) / (uintptr_t)resource_size(res);
>   	}
>   
>   	scu_base = syscon_regmap_lookup_by_compatible(scu.compatible);
Does that help if the pointers are 64-bit on a 32-bit platform (multi_v7_lpae_defconfig) ?

Guenter