Re: [PATCH] selftests/powerpc: Fix build failures with GCC 9

On Thu, Aug 01, 2019 at 10:26:28PM +1000, Michael Ellerman wrote:

GCC 9 fails to build some of the ptrace TM tests, with errors such as:

  ptrace-tm-spd-vsx.c: In function 'tm_spd_vsx':
  ptrace-tm-spd-vsx.c:51:2: error: listing the stack pointer register 'r1' in a clobber list is deprecated [-Werror=deprecated]
     51 |  asm __volatile__(
        |  ^~~
  ptrace-tm-spd-vsx.c:51:2: note: the value of the stack pointer after an 'asm' statement must be the same as it was before the statement

Which is probably fair enough.

Maybe you shouldn't build the tests with -Werror though?  (And you could
include the much more useful -Wextra while you're at it ;-) ).

Some of these inline asm blocks are doing quite a lot and are probably
pushing the boundaries of what's sane to do with inline asm,

These are just testcases, you sometimes need to do evil things there.
But yeah :-)

but they shouldn't actually be returning with r1 modified.

But they *do* modify lr, and that one isnt't listed; I guess the r1
clobber was there because of the call in the asm, but that needs an
lr clobber, instead.

(Or it was because of the "or 1,1,1")?


Segher