On Wed, Apr 03, 2019 at 08:02:43AM -0700, Randy Dunlap wrote:
> On 4/3/19 1:24 AM, Stephen Rothwell wrote:
> > Hi all,
> >
> > Changes since 20190402:
> >
>
> on x86_64:
>
> arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x909: unreachable instruction
Your .o file looks odd. I can't recreate the issue when I build the
same object.
Did the issue only just now show up? Can you bisect it? What version
of binutils are you using?
Here's the disassembly:
------------------
903: e8 00 00 00 00 callq 908 <interrupt_entry+0xc8>
904: R_X86_64_PC32 trace_hardirqs_off_thunk-0x4
908: c3 retq
909: eb 75 jmp 980 <common_interrupt>
90b: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
912: 00 00 00 00
916: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
91d: 00 00 00 00
921: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
928: 00 00 00 00
92c: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
933: 00 00 00 00
937: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
93e: 00 00 00 00
942: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
949: 00 00 00 00
94d: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
954: 00 00 00 00
958: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
95f: 00 00 00 00
963: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
96a: 00 00 00 00
96e: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
975: 00 00 00 00
979: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
0000000000000980 <common_interrupt>:
------------------
Where the heck does that "jmp 980" come from? I don't see it in the
code:
------------------
ENTRY(interrupt_entry)
....
TRACE_IRQS_OFF
ret
END(interrupt_entry)
_ASM_NOKPROBE(interrupt_entry)
/* Interrupt entry/exit. */
/*
* The interrupt stubs push (~vector+0x80) onto the stack and
* then jump to common_interrupt.
*/
.p2align CONFIG_X86_L1_CACHE_SHIFT
common_interrupt:
------------------
Hopefully gas isn't inserting stray jumps for code alignments...
--
Josh
