Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 6 Jul 2015 11:39:29 -0700 | Subject | Re: [PATCH] x86/asm/entry/64: Clean up entry_64.S |
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On Mon, Jul 6, 2015 at 11:35 AM, Andy Lutomirski <luto@amacapital.net> wrote: > On Mon, Jul 6, 2015 at 10:41 AM, Ingo Molnar <mingo@kernel.org> wrote: >> >> * Sasha Levin <sasha.levin@oracle.com> wrote: >> >>> On 07/06/2015 01:20 PM, Andy Lutomirski wrote: >>> > On Mon, Jul 6, 2015 at 8:00 AM, Sasha Levin <sasha.levin@oracle.com> wrote: >>> >> > >>> >> > --- entry.before.o.cmd 2015-07-06 10:48:32.110189938 -0400 >>> >> > +++ entry.after.o.cmd 2015-07-06 10:48:23.509645442 -0400 >>> >> > @@ -1,5 +1,5 @@ >>> >> > >>> >> > -entry.before.o: file format elf64-x86-64 >>> >> > +entry.after.o: file format elf64-x86-64 >>> >> > >>> >> > >>> >> > Disassembly of section .entry.text: >>> >> > @@ -3961,8 +3961,8 @@ >>> >> > 3b: 09 02 or %eax,(%rdx) >>> >> > ... >>> >> > 3d: R_X86_64_64 .entry.text >>> >> > - 45: 03 3a add (%rdx),%edi >>> >> > - 47: 01 3d 03 d6 00 c8 add %edi,-0x37ff29fd(%rip) # ffffffffc800d650 <ignore_sysret+0xffffffffc800b1f0> >>> >> > + 45: 03 33 add (%rbx),%esi >>> >> > + 47: 01 3d 03 d5 00 c8 add %edi,-0x37ff2afd(%rip) # ffffffffc800d550 <ignore_sysret+0xffffffffc800b0f0> >>> > What exactly are you doing to generate this diff? This all looks really weird. >>> > >>> >> > 4d: 44 91 rex.R xchg %eax,%ecx >>> >> > 4f: 93 xchg %eax,%ebx >>> >> > 50: 2f (bad) >>> > For example: what on earth is the asm above? >>> >>> objdump... >> >> Oh, so I'm using 'objdump -d' to compare - but you probably used 'objdump >> --disassemble-all', to disassemble .data sections as well? >> > > I can reproduce the difference now. Give me a few minutes to see if I > can figure out what's causing it.
It's debug info. If I strip the two .o files, the results are identical. I think the differences are just line numbers.
Why would this matter? Sasha, can you double-check that this patch really introduced the problem?
--Andy
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