Re: Missing operand for tlbie instruction on Power7

[Denis Kirjanov]

On 10/2/15, Peter Bergner <bergner@xxxxxxxxxxxx> wrote:
> On Fri, 2015-10-02 at 22:03 +0300, Denis Kirjanov wrote:
>> arch/powerpc/kernel/swsusp_asm64.S: Assembler messages:
>>> arch/powerpc/kernel/swsusp_asm64.S:188: Error: missing operand
>>> scripts/Makefile.build:294: recipe for target
>>> 'arch/powerpc/kernel/swsusp_asm64.o' failed
>>> make[1]: *** [arch/powerpc/kernel/swsusp_asm64.o] Error 1
>>> Makefile:941: recipe for target 'arch/powerpc/kernel' failed
>>> make: *** [arch/powerpc/kernel] Error 2
> [snip]
>>> I don't know enough ppc assembly to properly fix this but I can test.
>>
>> Could you please test the patch attached?
> [snip]
>> -0:     tlbie   r4;                             \
>> +0:     tlbie   r4, 0;                          \
>
> This isn't correct.  With POWER7 and later (which this compile
> is, since it's on LE), the tlbie instruction takes two register
> operands:
>
>     tlbie RB, RS
>
> The tlbie instruction on pre POWER7 cpus had one required register
> operand (RB) and an optional second L operand, where if you omitted
> it, it was the same as using "0":
>
>     tlbie RB, L
>
> This is a POWER7 and later build, so your change which adds the "0"
> above is really adding r0 for RS.  The new tlbie instruction doesn't
> treat r0 specially, so you'll be using whatever random bits which
> happen to be in r0 which I don't think that is what you want.

Ok, than we can just zero out r5 for example and use it in tlbie as RS,
right?


>
>
> Peter
>
>
>
>
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index dd0fc18..cb0f627 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -443,9 +443,10 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,945)
 #if !defined(CONFIG_4xx) && !defined(CONFIG_8xx)
 #define tlbia					\
 	li	r4,1024;			\
+	li  r5,0;				\
 	mtctr	r4;				\
 	lis	r4,KERNELBASE@h;		\
-0:	tlbie	r4;				\
+0:	tlbie	r4, r5;				\
 	addi	r4,r4,0x1000;			\
 	bdnz	0b
 #endif