Re: Missing operand for tlbie instruction on Power7

On 10/05/2015 08:35 PM, Michael Ellerman wrote:

On Fri, 2015-10-02 at 08:43 -0700, Laura Abbott wrote:

quoted

Hi,

We received a report (https://bugzilla.redhat.com/show_bug.cgi?id=1267395) of bad assembly
when compiling on powerpc with little endian

...

quoted

After some discussion with the binutils folks, it turns out that the tlbie
instruction actually requires another operand and binutils was updated to
check for this https://sourceware.org/ml/binutils/2015-05/msg00133.html .

The code sequence in arch/powerpc/include/asm/ppc_asm.h now needs to be updated:

#if !defined(CONFIG_4xx) && !defined(CONFIG_8xx)
#define tlbia                                   \
          li      r4,1024;                        \
          mtctr   r4;                             \
          lis     r4,KERNELBASE@h;                \
0:      tlbie   r4;                             \
          addi    r4,r4,0x1000;                   \
          bdnz    0b
#endif

I don't know enough ppc assembly to properly fix this but I can test.

How are you testing? This code is fairly old and I'm dubious if it still works.

These days we have a ppc_md hook for flushing the TLB, ppc_md.flush_tlb().
Ideally the swsusp code would use that.

cheers

Testing would probably just be compile and maybe boot. I don't have regular
access to the hardware. This problem just showed up for me when someone
tried to compile Fedora rawhide with the latest binutils.

 From what I can tell, it looks like the .flush_tlb of the cpu_spec is only
defined for power7 and power8 and I don't see a ppc_md.flush_tlb on the
master branch. It's not clear what to do for the case where there is no
flush_tlb function. Would filling in a .flush_tlb for all the PPC_BOOK3S_64
with the existing tlbia sequence work? It's also worth noting that the
__flush_power7 uses tlbiel instead of tlbie.

Thanks,
Laura