Re: [PATCH v2] powerpc/8xx: Fix do_mtspr_cpu6 build on older compilers

From: Scott Wood
Date: Tue Mar 15 2016 - 13:41:49 EST


On Tue, 2016-03-15 at 14:07 +0100, Christophe Leroy wrote:
> Some versions of GCC, reportedly before 4.8, fail with
> arch/powerpc/mm/8xx_mmu.c:139:2: error: memory input 1 is not directly
> addressable

"before 4.8" means "< 4.8", not "<= 4.8" -- did you mean "before 4.9"?

> Change the one-element array into a simple variable to avoid this.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> Cc: Scott Wood <oss@xxxxxxxxxxxx>
> ---
> Verified with GCC 4.4.4 and GCC 4.8.3
>
> v2: compilation result is compliant with CPU6 ERRATA
> (using stw/lwz and not stwx/lwzx)
>
> arch/powerpc/include/asm/reg_8xx.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/include/asm/reg_8xx.h
> b/arch/powerpc/include/asm/reg_8xx.h
> index d41412c..94d01f8 100644
> --- a/arch/powerpc/include/asm/reg_8xx.h
> +++ b/arch/powerpc/include/asm/reg_8xx.h
> @@ -53,7 +53,7 @@
> #ifdef CONFIG_8xx_CPU6
> #define do_mtspr_cpu6(rn, rn_addr, v) \
> do {
> \
> - int _reg_cpu6 = rn_addr, _tmp_cpu6[1]; \
> + int _reg_cpu6 = rn_addr, _tmp_cpu6; \
> asm volatile("stw %0, %1;" \
> "lwz %0, %1;" \
> "mtspr " __stringify(rn) ",%2" :
> \

I thought I tried this with 4.7.2 without success, but now it seems to be
working...

-Scott