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create-diff-object: ppc64le - Fix wrong addend value for switch labels

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Commit f0518ef58a ("create-diff-object: fix ppc64le
kpatch_replace_sections_syms() bundling assumption"), subtracted
sym.st_value for all bundled symbols on ppc64le and GCC6+ irrespective
of function or switch label.

As a side effect the addend for switch labels were incorrect and call
to local function executed TOC setup code. Fallback to the original
behaviour of subtracting sym.st_value only for the dynrela.

Example of wrong switch label:
------------------------------
0000000000000008 <register_netdevice>:
...
 31c:   05 00 85 2b     cmplwi  cr7,r5,5
 320:   7c 02 9d 41     bgt     cr7,59c <register_netdevice+0x594>
 324:   00 00 e2 3c     addis   r7,r2,0
                        324: R_PPC64_TOC16_HA   .toc+0x580
 328:   64 17 a5 78     rldicr  r5,r5,2,61
 32c:   00 00 47 e9     ld      r10,0(r7)
                        32c: R_PPC64_TOC16_LO_DS        .toc+0x580
 330:   aa 2a 2a 7d     lwax    r9,r10,r5
 334:   14 52 29 7d     add     r9,r9,r10
 338:   a6 03 29 7d     mtctr   r9
 33c:   20 04 80 4e     bctr
 340:   44 02 00 00     .long 0x244
 344:   f0 01 00 00     .long 0x1f0
 348:   20 02 00 00     .long 0x220
 34c:   38 02 00 00     .long 0x238
 350:   2c 02 00 00     .long 0x22c
 354:   50 02 00 00     .long 0x250
 358:   00 00 00 60     nop

Before Patch (.toc section):
Offset Info             Type           Symbol's Value  Symbol's Name + Addend
...
0x580  0000008200000026 R_PPC64_ADDR64 0000000000000008 register_netdevice + 338

After Patch (.toc section):
Offset Info             Type           Symbol's Value  Symbol's Name + Addend
...
0x580  0000008200000026 R_PPC64_ADDR64 0000000000000008 register_netdevice + 340

Example of localentry addend removed:
------------------------------------
Before Patch (.toc section):
Offset Info             Type           Symbol's Value  Symbol's Name + Addend
...
0x48   0000002c00000026 R_PPC64_ADDR64 0000000000000008 cmdline_proc_show + 0

After Patch (.toc section):
Offset Info             Type           Symbol's Value   Symbol's Name + Addend
...
0x48   0000002c00000026 R_PPC64_ADDR64 0000000000000008 cmdline_proc_show + 8

Fixes: f0518ef58a ("create-diff-object: fix ppc64le kpatch_replace_sections_syms() bundling assumption")
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
This commit is contained in:
Kamalesh Babulal 2018-03-06 16:16:51 +05:30
parent 07c7200cc9
commit 7b4efd1509
1 changed files with 3 additions and 6 deletions
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9
kpatch-build/create-diff-object.c
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@ -1114,12 +1114,6 @@ static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
if (rela->sym->sec && rela->sym->sec->sym) {
rela->sym = rela->sym->sec->sym;
/*
* ppc64le: a GCC 6+ bundled function is at
* offset 8 in its section.
*/
rela->addend -= rela->sym->sym.st_value;
continue;
}
@ -2514,6 +2508,9 @@ static void kpatch_create_intermediate_sections(struct kpatch_elf *kelf,
offsetof(struct kpatch_symbol, objname);
/* Fill in krelas[index] */
if (is_gcc6_localentry_bundled_sym(rela->sym) &&
rela->addend == rela->sym->sym.st_value)
rela->addend -= rela->sym->sym.st_value;
krelas[index].addend = rela->addend;
krelas[index].type = rela->type;
krelas[index].external = external;