Re: [PATCH -next v2 1/2] riscv: uaccess: rename __get/put_user_nocheck to __get/put_mem_nocheck

[Tong Tiangen]

在 2022/8/25 18:56, Andrew Jones 写道:
> On Mon, Aug 15, 2022 at 03:20:24AM +0000, Tong Tiangen wrote:
> > Current, The helpers __get/put_user_nocheck() is used by get/put_user() and
> > __get/put_kernel_nofault(), which is not always uaccess, so the name with
> > *user* is not appropriate.
> >
> > Also rename xxx_user_xxx to xxx_mem_xx  on the call path of
> > __get/put_user_nocheck()
> >
> > Only refactor code without any functional changes.
> >
> > Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx>
> > ---
> >   arch/riscv/include/asm/uaccess.h | 48 ++++++++++++++++----------------
> >   1 file changed, 24 insertions(+), 24 deletions(-)
> >
> > diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
> > index 855450bed9f5..1370da055b44 100644
> > --- a/arch/riscv/include/asm/uaccess.h
> > +++ b/arch/riscv/include/asm/uaccess.h
> > @@ -50,7 +50,7 @@
> >    * call.
> >    */
> >   
> > -#define __get_user_asm(insn, x, ptr, err)			\
> > +#define __get_mem_asm(insn, x, ptr, err)			\
> >   do {								\
> >   	__typeof__(x) __x;					\
> >   	__asm__ __volatile__ (					\
> > @@ -64,12 +64,12 @@ do {								\
> >   } while (0)
> >   
> >   #ifdef CONFIG_64BIT
> > -#define __get_user_8(x, ptr, err) \
> > -	__get_user_asm("ld", x, ptr, err)
> > +#define __get_mem_8(x, ptr, err) \
> > +	__get_mem_asm("ld", x, ptr, err)
> >   #else /* !CONFIG_64BIT */
> > -#define __get_user_8(x, ptr, err)				\
> > +#define __get_mem_8(x, ptr, err)				\
> >   do {								\
> > -	u32 __user *__ptr = (u32 __user *)(ptr);		\
> > +	u32 *__ptr = (u32 *)(ptr);				\
>
> Doesn't casting away __user reduce sparse's utility?

From the call logic[1], the address passed into this macro is not 
necessarily __user. I understand that no problem will be introduced for 
sparse's utility.

In addition, there is no need to do a pointer conversion here, will be 
fixed next version.

[1] __get_kernel_nofault -> __get_mem_nocheck -> __get_mem_8
> >   	u32 __lo, __hi;						\
> >   	__asm__ __volatile__ (					\
> >   		"1:\n"						\
> > @@ -88,20 +88,20 @@ do {								\
> >   } while (0)
> >   #endif /* CONFIG_64BIT */
> >   
> > -#define __get_user_nocheck(x, __gu_ptr, __gu_err)		\
> > +#define __get_mem_nocheck(x, __gu_ptr, __gu_err)		\
>
> The patch replaces all get/put_user instances with get/put_mem,
> but what about 'gu' and 'pu' instances (which are presumably short
> for get/put_user)?

ok, missing that, It is not appropriate to use __gu_xxx，will be fixed 
next version.

Thanks,
Tong.

> Thanks,
> drew
> .