linux-kernel - Re: [PATCH] RISC-V: uaccess: Wrap the get_user

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Message-ID: <de5e9d8d-c620-4371-8c74-7ef804d97d53@ghiti.fr>
Date: Wed, 11 Jun 2025 09:31:18 +0200
From: Alexandre Ghiti <alex@...ti.fr>
To: Palmer Dabbelt <palmer@...belt.com>, linux-riscv@...ts.infradead.org
Cc: Paul Walmsley <paul.walmsley@...ive.com>, aou@...s.berkeley.edu,
 cyrilbur@...storrent.com, jszhang@...nel.org, cleger@...osinc.com,
 samuel.holland@...ive.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] RISC-V: uaccess: Wrap the get_user_8 uaccess macro

On 6/10/25 23:30, Palmer Dabbelt wrote:
> From: Palmer Dabbelt <palmer@...belt.com>
>
> I must have lost this rebasing things during the merge window, I know I
> got it at some point but it's not here now.  Without this I get warnings
> along the lines of
>
>      include/linux/fs.h:3975:15: warning: label followed by a declaration is a C23 extension [-Wc23-extensions]
>       3975 |         if (unlikely(get_user(c, path)))
>            |                      ^
>      arch/riscv/include/asm/uaccess.h:274:3: note: expanded from macro 'get_user'
>        274 |                 __get_user((x), __p) :                          \
>            |                 ^
>      arch/riscv/include/asm/uaccess.h:244:2: note: expanded from macro '__get_user'
>        244 |         __get_user_error(__gu_val, __gu_ptr, __gu_err);         \
>            |         ^
>      arch/riscv/include/asm/uaccess.h:207:2: note: expanded from macro '__get_user_error'
>        207 |         __ge  LD [M]  net/802/psnap.ko
>      t_user_nocheck(x, ptr, __gu_failed);                        \
>            |         ^
>      arch/riscv/include/asm/uaccess.h:196:3: note: expanded from macro '__get_user_nocheck'
>        196 |                 __get_user_8((x), __gu_ptr, label);             \
>            |                 ^
>      arch/riscv/include/asm/uaccess.h:130:2: note: expanded from macro '__get_user_8'
>        130 |         u32 __user *__ptr = (u32 __user *)(ptr);                \
>            |         ^
>
> Signed-off-by: Palmer Dabbelt <palmer@...belt.com>
> ---
>   arch/riscv/include/asm/uaccess.h | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
> index d472da4450e6..525e50db24f7 100644
> --- a/arch/riscv/include/asm/uaccess.h
> +++ b/arch/riscv/include/asm/uaccess.h
> @@ -127,6 +127,7 @@ do {								\
>   
>   #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
>   #define __get_user_8(x, ptr, label)				\
> +do {								\
>   	u32 __user *__ptr = (u32 __user *)(ptr);		\
>   	u32 __lo, __hi;						\
>   	asm_goto_output(					\
> @@ -141,7 +142,7 @@ do {								\
>   		: : label);                                     \
>   	(x) = (__typeof__(x))((__typeof__((x) - (x)))(		\
>   		(((u64)__hi << 32) | __lo)));			\
> -
> +} while (0)
>   #else /* !CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
>   #define __get_user_8(x, ptr, label)				\
>   do {								\


I had come up with the same fix so:

Reviewed-by: Alexandre Ghiti <alexghiti@...osinc.com>