Re: arm64 build failure with CONFIG_ARM64_LSE_ATOMICS=y

[Suzuki K Poulose <Suzuki.Poulose@arm.com>]

On 02/11/16 23:28, Will Deacon wrote:
> Hi Artem,
>
> On Wed, Nov 02, 2016 at 05:44:27PM +0100, Artem Savkov wrote:
>> Hello Catalin,
>>
>> Looks like your patch "efd9e03 arm64: Use static keys for CPU features"
>> breaks arm64 build with "CONFIG_ARM64_LSE_ATOMICS=y" because it creates a
>> circular dependency for asm/lse.h through jump_label.h:
>>
>>   CC      arch/arm64/kernel/asm-offsets.s
>> In file included from ./arch/arm64/include/asm/atomic.h:34:0,
>>                  from ./include/linux/atomic.h:4,
>>                  from ./include/linux/jump_label.h:169,
>>                  from ./arch/arm64/include/asm/cpufeature.h:12,
>>                  from ./arch/arm64/include/asm/alternative.h:4,
>>                  from ./arch/arm64/include/asm/lse.h:7,
>>                  from ./arch/arm64/include/asm/spinlock.h:19,
>>                  from ./include/linux/spinlock.h:87,
>>                  from ./include/linux/seqlock.h:35,
>>                  from ./include/linux/time.h:5,
>>                  from ./include/uapi/linux/timex.h:56,
>>                  from ./include/linux/timex.h:56,
>>                  from ./include/linux/sched.h:19,
>>                  from arch/arm64/kernel/asm-offsets.c:21:
>> ./arch/arm64/include/asm/atomic_lse.h: In function ‘atomic_andnot’:
>> ./arch/arm64/include/asm/atomic_lse.h:35:15: error: expected string literal before ‘	’
>>   asm volatile(ARM64_LSE_ATOMIC_INSN(__LL_SC_ATOMIC(op),  \
>>
>> ...
>>
>> ./arch/arm64/include/asm/cmpxchg.h: In function ‘__xchg_case_1’:
>> ./arch/arm64/include/asm/cmpxchg.h:38:15: error: expected string literal before ‘ARM64_LSE_ATOMIC_INSN’
>>   asm volatile(ARM64_LSE_ATOMIC_INSN(    \
>
> I'm unable to reproduce this. I've tried enabling LSE with defconfig and
> mainline, using compilers that both do and don't support the instructions.

I am not able to reproduce it either. One minor problem I see with the commit could
be fixed with the following change : Does it help ?

----8>-----

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 758d74f..62db988 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -9,7 +9,6 @@
  #ifndef __ASM_CPUFEATURE_H
  #define __ASM_CPUFEATURE_H
  
-#include <linux/jump_label.h>
  
  #include <asm/hwcap.h>
  #include <asm/sysreg.h>
@@ -45,6 +44,7 @@
  
  #ifndef __ASSEMBLY__
  
+#include <linux/jump_label.h>
  #include <linux/kernel.h>
  
  /* CPU feature register tracking */



Suzuki