From: Marc Zyngier <maz@kernel.org>
To: Yang Yingliang <yangyingliang@huawei.com>
Cc: linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] KVM: arm64: fix compile error because of shift overflow
Date: Tue, 09 Aug 2022 14:53:51 +0100 [thread overview]
Message-ID: <87wnbhv7yo.wl-maz@kernel.org> (raw)
In-Reply-To: <20220809135127.480285-1-yangyingliang@huawei.com>
On Tue, 09 Aug 2022 14:51:27 +0100,
Yang Yingliang <yangyingliang@huawei.com> wrote:
>
> Using GENMASK() to generate the masks of device type and device id, it makes
> code unambiguous, also it can fix the following fix compile error because of
> shift overflow when using low verison gcc(mine version is 7.5):
>
> In function ‘kvm_vm_ioctl_set_device_addr.isra.38’,
> inlined from ‘kvm_arch_vm_ioctl’ at arch/arm64/kvm/arm.c:1454:10:
> ././include/linux/compiler_types.h:354:38: error: call to ‘__compiletime_assert_599’ \
> declared with attribute error: FIELD_GET: mask is not constant
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>
> Fixes: 9f968c9266aa ("KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
> v2:
> Using GENMASK() to generate the masks.
> ---
> arch/arm64/include/uapi/asm/kvm.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 3bb134355874..5e7dfaf76ec1 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -75,9 +75,9 @@ struct kvm_regs {
>
> /* KVM_ARM_SET_DEVICE_ADDR ioctl id encoding */
> #define KVM_ARM_DEVICE_TYPE_SHIFT 0
> -#define KVM_ARM_DEVICE_TYPE_MASK (0xffff << KVM_ARM_DEVICE_TYPE_SHIFT)
> +#define KVM_ARM_DEVICE_TYPE_MASK GENMASK(15, KVM_ARM_DEVICE_TYPE_SHIFT)
> #define KVM_ARM_DEVICE_ID_SHIFT 16
> -#define KVM_ARM_DEVICE_ID_MASK (0xffff << KVM_ARM_DEVICE_ID_SHIFT)
> +#define KVM_ARM_DEVICE_ID_MASK GENMASK(31, KVM_ARM_DEVICE_ID_SHIFT)
>
> /* Supported device IDs */
> #define KVM_ARM_DEVICE_VGIC_V2 0
This is marginally better, but what I was expecting is something like:
#define KVM_ARM_DEVICE_ID_MASK GENMASK(KVM_ARM_DEVICE_ID_SHIFT + 15, \
KVM_ARM_DEVICE_ID_SHIFT)
which I find a bit more readable.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: Yang Yingliang <yangyingliang@huawei.com>
Cc: <linux-kernel@vger.kernel.org>, <kvmarm@lists.cs.columbia.edu>,
<linux-arm-kernel@lists.infradead.org>, <james.morse@arm.com>,
<alexandru.elisei@arm.com>, <suzuki.poulose@arm.com>,
<oliver.upton@linux.dev>
Subject: Re: [PATCH v2] KVM: arm64: fix compile error because of shift overflow
Date: Tue, 09 Aug 2022 14:53:51 +0100 [thread overview]
Message-ID: <87wnbhv7yo.wl-maz@kernel.org> (raw)
In-Reply-To: <20220809135127.480285-1-yangyingliang@huawei.com>
On Tue, 09 Aug 2022 14:51:27 +0100,
Yang Yingliang <yangyingliang@huawei.com> wrote:
>
> Using GENMASK() to generate the masks of device type and device id, it makes
> code unambiguous, also it can fix the following fix compile error because of
> shift overflow when using low verison gcc(mine version is 7.5):
>
> In function ‘kvm_vm_ioctl_set_device_addr.isra.38’,
> inlined from ‘kvm_arch_vm_ioctl’ at arch/arm64/kvm/arm.c:1454:10:
> ././include/linux/compiler_types.h:354:38: error: call to ‘__compiletime_assert_599’ \
> declared with attribute error: FIELD_GET: mask is not constant
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>
> Fixes: 9f968c9266aa ("KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
> v2:
> Using GENMASK() to generate the masks.
> ---
> arch/arm64/include/uapi/asm/kvm.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 3bb134355874..5e7dfaf76ec1 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -75,9 +75,9 @@ struct kvm_regs {
>
> /* KVM_ARM_SET_DEVICE_ADDR ioctl id encoding */
> #define KVM_ARM_DEVICE_TYPE_SHIFT 0
> -#define KVM_ARM_DEVICE_TYPE_MASK (0xffff << KVM_ARM_DEVICE_TYPE_SHIFT)
> +#define KVM_ARM_DEVICE_TYPE_MASK GENMASK(15, KVM_ARM_DEVICE_TYPE_SHIFT)
> #define KVM_ARM_DEVICE_ID_SHIFT 16
> -#define KVM_ARM_DEVICE_ID_MASK (0xffff << KVM_ARM_DEVICE_ID_SHIFT)
> +#define KVM_ARM_DEVICE_ID_MASK GENMASK(31, KVM_ARM_DEVICE_ID_SHIFT)
>
> /* Supported device IDs */
> #define KVM_ARM_DEVICE_VGIC_V2 0
This is marginally better, but what I was expecting is something like:
#define KVM_ARM_DEVICE_ID_MASK GENMASK(KVM_ARM_DEVICE_ID_SHIFT + 15, \
KVM_ARM_DEVICE_ID_SHIFT)
which I find a bit more readable.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
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: Marc Zyngier <maz@kernel.org>
To: Yang Yingliang <yangyingliang@huawei.com>
Cc: <linux-kernel@vger.kernel.org>, <kvmarm@lists.cs.columbia.edu>,
<linux-arm-kernel@lists.infradead.org>, <james.morse@arm.com>,
<alexandru.elisei@arm.com>, <suzuki.poulose@arm.com>,
<oliver.upton@linux.dev>
Subject: Re: [PATCH v2] KVM: arm64: fix compile error because of shift overflow
Date: Tue, 09 Aug 2022 14:53:51 +0100 [thread overview]
Message-ID: <87wnbhv7yo.wl-maz@kernel.org> (raw)
In-Reply-To: <20220809135127.480285-1-yangyingliang@huawei.com>
On Tue, 09 Aug 2022 14:51:27 +0100,
Yang Yingliang <yangyingliang@huawei.com> wrote:
>
> Using GENMASK() to generate the masks of device type and device id, it makes
> code unambiguous, also it can fix the following fix compile error because of
> shift overflow when using low verison gcc(mine version is 7.5):
>
> In function ‘kvm_vm_ioctl_set_device_addr.isra.38’,
> inlined from ‘kvm_arch_vm_ioctl’ at arch/arm64/kvm/arm.c:1454:10:
> ././include/linux/compiler_types.h:354:38: error: call to ‘__compiletime_assert_599’ \
> declared with attribute error: FIELD_GET: mask is not constant
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>
> Fixes: 9f968c9266aa ("KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
> v2:
> Using GENMASK() to generate the masks.
> ---
> arch/arm64/include/uapi/asm/kvm.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 3bb134355874..5e7dfaf76ec1 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -75,9 +75,9 @@ struct kvm_regs {
>
> /* KVM_ARM_SET_DEVICE_ADDR ioctl id encoding */
> #define KVM_ARM_DEVICE_TYPE_SHIFT 0
> -#define KVM_ARM_DEVICE_TYPE_MASK (0xffff << KVM_ARM_DEVICE_TYPE_SHIFT)
> +#define KVM_ARM_DEVICE_TYPE_MASK GENMASK(15, KVM_ARM_DEVICE_TYPE_SHIFT)
> #define KVM_ARM_DEVICE_ID_SHIFT 16
> -#define KVM_ARM_DEVICE_ID_MASK (0xffff << KVM_ARM_DEVICE_ID_SHIFT)
> +#define KVM_ARM_DEVICE_ID_MASK GENMASK(31, KVM_ARM_DEVICE_ID_SHIFT)
>
> /* Supported device IDs */
> #define KVM_ARM_DEVICE_VGIC_V2 0
This is marginally better, but what I was expecting is something like:
#define KVM_ARM_DEVICE_ID_MASK GENMASK(KVM_ARM_DEVICE_ID_SHIFT + 15, \
KVM_ARM_DEVICE_ID_SHIFT)
which I find a bit more readable.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2022-08-09 13:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-09 13:51 [PATCH v2] KVM: arm64: fix compile error because of shift overflow Yang Yingliang
2022-08-09 13:51 ` Yang Yingliang
2022-08-09 13:51 ` Yang Yingliang
2022-08-09 13:53 ` Marc Zyngier [this message]
2022-08-09 13:53 ` Marc Zyngier
2022-08-09 13:53 ` Marc Zyngier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87wnbhv7yo.wl-maz@kernel.org \
--to=maz@kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=yangyingliang@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.