Re: [PATCH] Arm64: fix build with gcc 10

[Jan Beulich <jbeulich@xxxxxxxx>]

On 08.09.2020 15:05, Bertrand Marquis wrote:
>> On 8 Sep 2020, at 13:53, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>
>> With gcc10 inlining is (no longer?) the default for certain atomics.
>>
>> Suggested-by: Julien Grall <jgrall@xxxxxxxxxx>
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>> --- a/xen/arch/arm/arch.mk
>> +++ b/xen/arch/arm/arch.mk
>> @@ -12,6 +12,7 @@ CFLAGS-$(CONFIG_ARM_32) += -mcpu=cortex-
>>
>> CFLAGS-$(CONFIG_ARM_64) += -mcpu=generic
>> CFLAGS-$(CONFIG_ARM_64) += -mgeneral-regs-only # No fp registers etc
>> +$(call cc-option-add,CFLAGS-$(CONFIG_ARM_64),CC,-mno-outline-atomics)
> 
> Why not adding this before with the other “call cc-option” ?

I elected to group it with the other Arm64 specific ones.

> Also it might be a good idea to have a sentence in the commit message with the
> error happening when this is not added:
> undefined reference to `__aarch64_ldadd4_acq_rel’
> 
> Because some might need to backport this to other Xen releases if they switch 
> to
> a new compiler (although i could not reproduce that with Xen 4.14).

I guess I'll go with Julien's suggested description (with some
minor adjustments perhaps).

Jan