[PATCH RFC] riscv: Allow to build only with LLVM >= 17.0.0

[Alexandre Ghiti]

Hi Conor,

On 17/07/2024 13:32, Conor Dooley wrote:
> On Wed, Jul 17, 2024 at 01:17:16PM +0200, Alexandre Ghiti wrote:
>> The following build failure happens when using LLVM < 17.0.0:
>>
>> kernel/sched/core.c:11873:7: error: cannot jump from this asm goto statement to one of its possible targets
>>
>> This is a known issue [1] so let's upgrade the minimal requirement for
>> LLVM to the version 17.0.0, which is the first version to contain the
>> fix.
> I think doing this unilaterally is kinda insane, LLVM 17 isn't even a
> year old. Debian testing doesn't have anything later than 16.


Debian will very likely select the qspinlocks when available anyway, so 
they'll need llvm >= 17. And Debian won't ship a kernel >= 6.11 until 
some time right? So they'll probably update their infra to llvm >= 17 
(and they'll probably do to take advantages of the new extensions).


> Why does
> it need to be done unilaterally rather than just when the qspinlock
> stuff is built?


We can do that indeed, it may happen again and we can keep requiring 
llvm 17 on a per-config basis.


>> Link: https://github.com/ClangBuiltLinux/linux/issues/1886#issuecomment-1645979992 [1]
>> Reported-by: kernel test robot <lkp at intel.com>
>> Closes: https://lore.kernel.org/oe-kbuild-all/202407041157.odTZAYZ6-lkp@intel.com/
>> Signed-off-by: Nathan Chancellor <nathan at kernel.org>
> If Nathan wrote the patch, you need to set him as the author of the
> patch :)


I thought I did, how should I do that then?


>
>> Signed-off-by: Alexandre Ghiti <alexghiti at rivosinc.com>
>> ---
>>
>> This patch was done by Nathan, I'm just sending it as an RFC to get quicker
>> feedbacks.
>>
>> I tested it successfully.
>>
>> Note that the build failure happens on the not-yet merged qspinlock
>> patchset.
>>
>>   scripts/min-tool-version.sh | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
>> index 91c91201212c..e81eb7ed257d 100755
>> --- a/scripts/min-tool-version.sh
>> +++ b/scripts/min-tool-version.sh
>> @@ -28,6 +28,8 @@ llvm)
>>   		echo 15.0.0
>>   	elif [ "$SRCARCH" = loongarch ]; then
>>   		echo 18.0.0
>> +	elif [ "$SRCARCH" = riscv ]; then
>> +		echo 17.0.0
>>   	else
>>   		echo 13.0.1
>>   	fi
>> -- 
>> 2.39.2
>>
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv