Re: [RFC PATCH v3 11/12] powerpc: Remove unreachable() from WARN_ON()
From: Christophe Leroy <hidden>
Date: 2022-06-25 06:47:04
Also in:
lkml
Le 24/06/2022 à 20:32, Sathvika Vasireddy a écrit :
objtool is throwing *unannotated intra-function call* warnings with a few instructions that are marked unreachable. Remove unreachable() from WARN_ON() to fix these warnings, as the codegen remains same with and without unreachable() in WARN_ON().
Did you try the two exemples described in commit 1e688dd2a3d6
("powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with
asm goto") ?
Without your patch:
00000640 <test>:
640: 81 23 00 84 lwz r9,132(r3)
644: 71 29 40 00 andi. r9,r9,16384
648: 40 82 00 0c bne 654 <test+0x14>
64c: 80 63 00 0c lwz r3,12(r3)
650: 4e 80 00 20 blr
654: 0f e0 00 00 twui r0,0
00000658 <test9w>:
658: 2c 04 00 00 cmpwi r4,0
65c: 41 82 00 0c beq 668 <test9w+0x10>
660: 7c 63 23 96 divwu r3,r3,r4
664: 4e 80 00 20 blr
668: 0f e0 00 00 twui r0,0
66c: 38 60 00 00 li r3,0
670: 4e 80 00 20 blr
With your patch:
00000640 <test>:
640: 81 23 00 84 lwz r9,132(r3)
644: 71 29 40 00 andi. r9,r9,16384
648: 40 82 00 0c bne 654 <test+0x14>
64c: 80 63 00 0c lwz r3,12(r3)
650: 4e 80 00 20 blr
654: 0f e0 00 00 twui r0,0
658: 4b ff ff f4 b 64c <test+0xc> <==
0000065c <test9w>:
65c: 2c 04 00 00 cmpwi r4,0
660: 41 82 00 0c beq 66c <test9w+0x10>
664: 7c 63 23 96 divwu r3,r3,r4
668: 4e 80 00 20 blr
66c: 0f e0 00 00 twui r0,0
670: 38 60 00 00 li r3,0 <==
674: 4e 80 00 20 blr <==
678: 38 60 00 00 li r3,0
67c: 4e 80 00 20 blr
Christophe
quoted hunk ↗ jump to hunk
Signed-off-by: Sathvika Vasireddy <redacted> --- arch/powerpc/include/asm/bug.h | 1 - 1 file changed, 1 deletion(-)diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index ecbae1832de3..df6c11e008b9 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h@@ -97,7 +97,6 @@ __label__ __label_warn_on; \ \ WARN_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags), __label_warn_on); \ - unreachable(); \ \ __label_warn_on: \ break; \