Le 20/04/2022 à 05:04, Tong Tiangen a écrit :
> x86/powerpc has it's implementation of copy_mc_to_user but not use #define
> to declare.
>
> This may cause problems, for example, if other architectures open
> CONFIG_ARCH_HAS_COPY_MC, but want to use copy_mc_to_user() outside the
> architecture, the code add to include/linux/uaddess.h is as follows:
>
> #ifndef copy_mc_to_user
> static inline unsigned long __must_check
> copy_mc_to_user(void *dst, const void *src, size_t cnt)
> {
> ...
> }
> #endif
>
> Then this definition will conflict with the implementation of x86/powerpc
> and cause compilation errors as follow:
>
> Fixes: ec6347bb4339 ("x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()")
I don't understand, what does it fix really ? What was the
(existing/real) bug introduced by that patch and that your are fixing ?
If those defined had been expected and missing, we would have had a
build failure. If you have one, can you describe it ?
> Signed-off-by: Tong Tiangen <[email protected]>
> ---
> arch/powerpc/include/asm/uaccess.h | 1 +
> arch/x86/include/asm/uaccess.h | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
> index 9b82b38ff867..58dbe8e2e318 100644
> --- a/arch/powerpc/include/asm/uaccess.h
> +++ b/arch/powerpc/include/asm/uaccess.h
> @@ -358,6 +358,7 @@ copy_mc_to_user(void __user *to, const void *from, unsigned long n)
>
> return n;
> }
> +#define copy_mc_to_user copy_mc_to_user
> #endif
>
> extern long __copy_from_user_flushcache(void *dst, const void __user *src,
> diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
> index f78e2b3501a1..e18c5f098025 100644
> --- a/arch/x86/include/asm/uaccess.h
> +++ b/arch/x86/include/asm/uaccess.h
> @@ -415,6 +415,7 @@ copy_mc_to_kernel(void *to, const void *from, unsigned len);
>
> unsigned long __must_check
> copy_mc_to_user(void *to, const void *from, unsigned len);
> +#define copy_mc_to_user copy_mc_to_user
> #endif
>
> /*
在 2022/5/2 22:24, Christophe Leroy 写道:
>
>
> Le 20/04/2022 à 05:04, Tong Tiangen a écrit :
>> x86/powerpc has it's implementation of copy_mc_to_user but not use #define
>> to declare.
>>
>> This may cause problems, for example, if other architectures open
>> CONFIG_ARCH_HAS_COPY_MC, but want to use copy_mc_to_user() outside the
>> architecture, the code add to include/linux/uaddess.h is as follows:
>>
>> #ifndef copy_mc_to_user
>> static inline unsigned long __must_check
>> copy_mc_to_user(void *dst, const void *src, size_t cnt)
>> {
>> ...
>> }
>> #endif
>>
>> Then this definition will conflict with the implementation of x86/powerpc
>> and cause compilation errors as follow:
>>
>> Fixes: ec6347bb4339 ("x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()")
>
> I don't understand, what does it fix really ? What was the
> (existing/real) bug introduced by that patch and that your are fixing ?
>
> If those defined had been expected and missing, we would have had a
> build failure. If you have one, can you describe it ?
There will be build failure after patch 3 is added, there is a little
confusing for a reader of this commit in isolation.
In the next version, I will put this patch after patch 3.
Thanks,
Tong.
>
>> Signed-off-by: Tong Tiangen <[email protected]>
>> ---
>> arch/powerpc/include/asm/uaccess.h | 1 +
>> arch/x86/include/asm/uaccess.h | 1 +
>> 2 files changed, 2 insertions(+)
>>
>> diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
>> index 9b82b38ff867..58dbe8e2e318 100644
>> --- a/arch/powerpc/include/asm/uaccess.h
>> +++ b/arch/powerpc/include/asm/uaccess.h
>> @@ -358,6 +358,7 @@ copy_mc_to_user(void __user *to, const void *from, unsigned long n)
>>
>> return n;
>> }
>> +#define copy_mc_to_user copy_mc_to_user
>> #endif
>>
>> extern long __copy_from_user_flushcache(void *dst, const void __user *src,
>> diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
>> index f78e2b3501a1..e18c5f098025 100644
>> --- a/arch/x86/include/asm/uaccess.h
>> +++ b/arch/x86/include/asm/uaccess.h
>> @@ -415,6 +415,7 @@ copy_mc_to_kernel(void *to, const void *from, unsigned len);
>>
>> unsigned long __must_check
>> copy_mc_to_user(void *to, const void *from, unsigned len);
>> +#define copy_mc_to_user copy_mc_to_user
>> #endif
>>
>> /*
On 2022/5/3 9:06, Tong Tiangen wrote:
>
>
> 在 2022/5/2 22:24, Christophe Leroy 写道:
>>
>>
>> Le 20/04/2022 à 05:04, Tong Tiangen a écrit :
>>> x86/powerpc has it's implementation of copy_mc_to_user but not use
>>> #define
>>> to declare.
>>>
>>> This may cause problems, for example, if other architectures open
>>> CONFIG_ARCH_HAS_COPY_MC, but want to use copy_mc_to_user() outside the
>>> architecture, the code add to include/linux/uaddess.h is as follows:
>>>
>>> #ifndef copy_mc_to_user
>>> static inline unsigned long __must_check
>>> copy_mc_to_user(void *dst, const void *src, size_t cnt)
>>> {
>>> ...
>>> }
>>> #endif
>>>
>>> Then this definition will conflict with the implementation of
>>> x86/powerpc
>>> and cause compilation errors as follow:
>>>
>>> Fixes: ec6347bb4339 ("x86, powerpc: Rename memcpy_mcsafe() to
>>> copy_mc_to_{user, kernel}()")
>>
>> I don't understand, what does it fix really ? What was the
>> (existing/real) bug introduced by that patch and that your are fixing ?
>>
>> If those defined had been expected and missing, we would have had a
>> build failure. If you have one, can you describe it ?
>
It could prevent future problems when patch3 is introduced， and yes，for
now，
this patch won't fix any issue，we could drop the fix tag, and update the
changelog.
> There will be build failure after patch 3 is added, there is a little
> confusing for a reader of this commit in isolation.
> In the next version, I will put this patch after patch 3.
This is an alternative.
>
> Thanks,
> Tong.
> .