From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Nathan Chancellor <nathan@kernel.org> Cc: Jiri Slaby <jirislaby@kernel.org>, Shawn Guo <shawnguo@kernel.org>, Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix Kernel Team <kernel@pengutronix.de>, Fabio Estevam <festevam@gmail.com>, NXP Linux Team <linux-imx@nxp.com>, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Andi Shyti <andi.shyti@kernel.org> Subject: Re: [PATCH] serial: mxs-uart: fix Wvoid-pointer-to-enum-cast warning Date: Mon, 14 Aug 2023 08:58:34 +0200 [thread overview] Message-ID: <66cbafc5-f490-511c-df9b-02c2e5e40811@linaro.org> (raw) In-Reply-To: <2023081004-lapped-handbag-0324@gregkh> On 10/08/2023 17:44, Greg Kroah-Hartman wrote: > On Thu, Aug 10, 2023 at 10:50:42AM +0200, Krzysztof Kozlowski wrote: >> `devtype` is enum, thus cast of pointer on 64-bit compile test with W=1 >> causes: >> >> mxs-auart.c:1598:15: error: cast to smaller integer type 'enum mxs_auart_type' from 'const void *' [-Werror,-Wvoid-pointer-to-enum-cast] >> >> Cc: Andi Shyti <andi.shyti@kernel.org> >> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> >> --- >> drivers/tty/serial/mxs-auart.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c >> index 8eeecf8ad359..a9b32722b049 100644 >> --- a/drivers/tty/serial/mxs-auart.c >> +++ b/drivers/tty/serial/mxs-auart.c >> @@ -1595,7 +1595,7 @@ static int mxs_auart_probe(struct platform_device *pdev) >> return -EINVAL; >> } >> >> - s->devtype = (enum mxs_auart_type)of_device_get_match_data(&pdev->dev); >> + s->devtype = (uintptr_t)of_device_get_match_data(&pdev->dev); > > This feels like a compiler issue as devtype is a enum mxs_auart_type > variable, so the cast shoudl be correct. While the cast is obviously safe here, the warning in general is reasonable - people were make too many mistakes by assuming pointers are integers... Just for the record (not saying that others doing is proof of correctness): https://lore.kernel.org/lkml/20230809-cbl-1903-v1-1-df9d66a3ba3e@google.com/T/ But maybe Nathan can share his thoughts whether we should just disable this warning for kernel? > > And if not, unitptr_t isn't a valid kernel type, so that's not a good It is in include/linux/types.h, so do you mean that it is not recommended for in-kernel usage? I can go with kernel_ulong_t - which is a kernel type - if the cast is agreed. > solution either. Worst case, it's how big a pointer is, which is not > going to be what an enum is if you have a sane compiler :( Best regards, Krzysztof _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
WARNING: multiple messages have this Message-ID (diff)
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Nathan Chancellor <nathan@kernel.org> Cc: Jiri Slaby <jirislaby@kernel.org>, Shawn Guo <shawnguo@kernel.org>, Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix Kernel Team <kernel@pengutronix.de>, Fabio Estevam <festevam@gmail.com>, NXP Linux Team <linux-imx@nxp.com>, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Andi Shyti <andi.shyti@kernel.org> Subject: Re: [PATCH] serial: mxs-uart: fix Wvoid-pointer-to-enum-cast warning Date: Mon, 14 Aug 2023 08:58:34 +0200 [thread overview] Message-ID: <66cbafc5-f490-511c-df9b-02c2e5e40811@linaro.org> (raw) In-Reply-To: <2023081004-lapped-handbag-0324@gregkh> On 10/08/2023 17:44, Greg Kroah-Hartman wrote: > On Thu, Aug 10, 2023 at 10:50:42AM +0200, Krzysztof Kozlowski wrote: >> `devtype` is enum, thus cast of pointer on 64-bit compile test with W=1 >> causes: >> >> mxs-auart.c:1598:15: error: cast to smaller integer type 'enum mxs_auart_type' from 'const void *' [-Werror,-Wvoid-pointer-to-enum-cast] >> >> Cc: Andi Shyti <andi.shyti@kernel.org> >> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> >> --- >> drivers/tty/serial/mxs-auart.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c >> index 8eeecf8ad359..a9b32722b049 100644 >> --- a/drivers/tty/serial/mxs-auart.c >> +++ b/drivers/tty/serial/mxs-auart.c >> @@ -1595,7 +1595,7 @@ static int mxs_auart_probe(struct platform_device *pdev) >> return -EINVAL; >> } >> >> - s->devtype = (enum mxs_auart_type)of_device_get_match_data(&pdev->dev); >> + s->devtype = (uintptr_t)of_device_get_match_data(&pdev->dev); > > This feels like a compiler issue as devtype is a enum mxs_auart_type > variable, so the cast shoudl be correct. While the cast is obviously safe here, the warning in general is reasonable - people were make too many mistakes by assuming pointers are integers... Just for the record (not saying that others doing is proof of correctness): https://lore.kernel.org/lkml/20230809-cbl-1903-v1-1-df9d66a3ba3e@google.com/T/ But maybe Nathan can share his thoughts whether we should just disable this warning for kernel? > > And if not, unitptr_t isn't a valid kernel type, so that's not a good It is in include/linux/types.h, so do you mean that it is not recommended for in-kernel usage? I can go with kernel_ulong_t - which is a kernel type - if the cast is agreed. > solution either. Worst case, it's how big a pointer is, which is not > going to be what an enum is if you have a sane compiler :( Best regards, Krzysztof
next prev parent reply other threads:[~2023-08-14 6:59 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-08-10 8:50 [PATCH] serial: mxs-uart: fix Wvoid-pointer-to-enum-cast warning Krzysztof Kozlowski 2023-08-10 8:50 ` Krzysztof Kozlowski 2023-08-10 15:44 ` Greg Kroah-Hartman 2023-08-10 15:44 ` Greg Kroah-Hartman 2023-08-14 6:58 ` Krzysztof Kozlowski [this message] 2023-08-14 6:58 ` Krzysztof Kozlowski 2023-08-14 16:04 ` Greg Kroah-Hartman 2023-08-14 16:04 ` Greg Kroah-Hartman 2023-08-14 16:04 ` Nathan Chancellor 2023-08-14 16:04 ` Nathan Chancellor
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