Re: [PATCH] RISC-V: fix barrier() use in <vdso/processor.h>

[Randy Dunlap]

On 11/17/20 11:00 AM, Nick Desaulniers wrote:
> On Mon, Nov 16, 2020 at 5:40 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>>
>> riscv's <vdso/processor.h> uses barrier() so it should
>> #include <asm/barrier.h> to prevent build errors.
>>
>> Fixes this build error:
>>   CC [M]  drivers/net/ethernet/emulex/benet/be_main.o
>> In file included from ./include/vdso/processor.h:10,
>>                  from ./arch/riscv/include/asm/processor.h:11,
>>                  from ./include/linux/prefetch.h:15,
>>                  from drivers/net/ethernet/emulex/benet/be_main.c:14:
>> ./arch/riscv/include/asm/vdso/processor.h: In function 'cpu_relax':
>> ./arch/riscv/include/asm/vdso/processor.h:14:2: error: implicit declaration of function 'barrier' [-Werror=implicit-function-declaration]
>>    14 |  barrier();
>>
>> This happens with a total of 5 networking drivers -- they all use
>> <linux/prefetch.h>.
>>
>> rv64 allmodconfig now builds cleanly after this patch.
>>
>> Fixes fallout from:
>> 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive")
>>
>> Fixes: ad5d1122b82f ("riscv: use vDSO common flow to reduce the latency of the time-related functions")
> 
> Hi Randy,
> Thanks for the patch, it looks good to me.  I only had a question on
> the commit message.
> 
> Is this also related to:
> commit 3347acc6fcd4 ("compiler.h: fix barrier_data() on clang")

Hi Nick,
Yes, it looks like I tagged the wrong commit in Fixes:
Thanks for noticing that.


> I plan to backport 3347acc6fcd4, so it would be good if all of the
> follow ups are all tagged accordingly with fixes tags, so that I don't
> break anything backporting 3347acc6fcd4 because I forgot or missed any
> follow ups that also needed to be backported.
> 
>> Reported-by: Andreas Schwab <schwab@xxxxxxxxxxxxxx>
>> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
>> Cc: Arvind Sankar <nivedita@xxxxxxxxxxxx>
>> Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
>> Cc: clang-built-linux@xxxxxxxxxxxxxxxx
>> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
>> Cc: Nathan Chancellor <natechancellor@xxxxxxxxx>
>> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
>> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
>> Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
>> ---
>>  arch/riscv/include/asm/vdso/processor.h |    2 ++
>>  1 file changed, 2 insertions(+)
>>
>> --- lnx-510-rc4.orig/arch/riscv/include/asm/vdso/processor.h
>> +++ lnx-510-rc4/arch/riscv/include/asm/vdso/processor.h
>> @@ -4,6 +4,8 @@
>>
>>  #ifndef __ASSEMBLY__
>>
>> +#include <asm/barrier.h>
>> +
>>  static inline void cpu_relax(void)
>>  {
>>  #ifdef __riscv_muldiv
> 
> 
> 


-- 
~Randy