Peter Zijlstra wrote:
On Sat, May 21, 2022 at 09:38:35AM +0000, Christophe Leroy wrote:
I gave it a try this morning, I selected HAVE_OBJTOOL and
HAVE_OBJTOOL_MCOUNT from arch/powerpc/Kconfig
Seems like there are still some x86 arch specific stuff in common common
code and I get the following errors.
I'm assuming there's a metric ton of x86 specific stuff in there.
That'll take a while to clean out.
Mostly Josh's rewrite was centered around splitting out the runtime
options, but objtool is still always build with all options included,
even the ones you're not using for your arch, which is what's triggering
the problems you see here, I suppose...
Also, is it normal to get those functions built allthough I have not
selected HAVE_STACK_VALIDATION ?
CC /home/chleroy/linux-powerpc/tools/objtool/check.o
check.c: In function 'has_valid_stack_frame':
check.c:2369:30: error: 'CFI_BP' undeclared (first use in this
function); did you mean 'CFI_SP'?
2369 | if (cfi->cfa.base == CFI_BP &&
| ^~~~~~
| CFI_SP
check.c:2369:30: note: each undeclared identifier is reported only once
for each function it appears in
check.c:2371:44: error: 'CFI_RA' undeclared (first use in this
function); did you mean 'CFI_R3'?
2371 | check_reg_frame_pos(&cfi->regs[CFI_RA],
-cfi->cfa.offset + 8))
| ^~~~~~
| CFI_R3
check.c: In function 'update_cfi_state':
check.c:2499:70: error: 'CFI_BP' undeclared (first use in this
function); did you mean 'CFI_SP'?
2499 | if (op->src.reg == CFI_SP &&
op->dest.reg == CFI_BP &&
|
^~~~~~
|
CFI_SP
make[3]: *** [/home/chleroy/linux-powerpc/tools/build/Makefile.build:97:
/home/chleroy/linux-powerpc/tools/objtool/check.o] Error 1
make[2]: *** [Makefile:54:
/home/chleroy/linux-powerpc/tools/objtool/objtool-in.o] Error 2
make[1]: *** [Makefile:69: objtool] Error 2
make: *** [Makefile:1337: tools/objtool] Error 2
What would be the best approach to fix that ?
Define CFI_BP to your frame register (r2, afaict) I suppose. If you're
only using OBJTOOL_MCOUNT this code will never run, so all you have to
ensure is that it compiles, not that it makes sense (-:
Sathvika has been looking into this.
The very long and complicated way would be to propagate the various
CONFIG_HAVE_* build time things to the objtool build and librally
sprinkle a lot of #ifdef around.
I think there were just a couple of unrelated checks/warnings that were
causing problems on powerpc. So, we likely won't need too many #ifdefs,
at least for mcount purposes.
Sathvika,
Can you post what you have?
- Naveen
