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Groups > linux.kernel > #1320604
| From | Torsten Duwe <duwe@lst.de> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v6 1/9] ppc64 (le): prepare for -mprofile-kernel |
| Date | 2016-01-28 13:00 +0100 |
| Message-ID | <qVTp0-2RX-5@gated-at.bofh.it> (permalink) |
| References | <qUSOm-7cE-23@gated-at.bofh.it> <qUSOm-7cE-21@gated-at.bofh.it> <qVvmG-1Z6-23@gated-at.bofh.it> <qVvPH-2dw-13@gated-at.bofh.it> <qVMnw-6eG-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Jan 28, 2016 at 03:26:59PM +1100, Michael Ellerman wrote: > > That raises an interesting question, how does it work *without* DYNAMIC_FTRACE? > > It looks like you haven't updated that version of _mcount at all? Or maybe I'm > missing an #ifdef somewhere? You didn't, I did. I haven't considered that combination. > It doesn't look like that will work right with the -mprofile-kernel ABI. And > indeed it doesn't boot. The lean _mcount should handle it and boot, had I not misplaced it in the #ifdefs, but then of course profiling wouldn't work. > So we'll need to work that out. I guess the minimum would be to disable > -mprofile-kernel if DYNAMIC_FTRACE is disabled. I feel that supporting all combinations of ABIv1/ABIv2, FTRACE/DYNAMIC_FTRACE, -p/-mprofile-kernel will get us into #ifdef hell, and at least one kernel developer will go insane. That will probably be the one porting this to ppc64be (ABIv1). > Frankly I think we'd be happy to *only* support DYNAMIC_FTRACE, but the generic > code doesn't let us do that at the moment. Seconded. I'll have a look at the Kconfigs. > But it's better than the previous version which didn't boot :) That's your fault, you picked the wrong compiler ;-) > Also ftracetest fails at step 8: > ... > [8] ftrace - function graph filters with stack tracer > Unable to handle kernel paging request for data at address 0xd0000000033d7f70 [...] > That doesn't happen without your series applied, though that doesn't 100% mean > it's your bug. I haven't had time to dig any deeper. Will check as well... Torsten
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Re: [PATCH v6 1/9] ppc64 (le): prepare for -mprofile-kernel Michael Ellerman <mpe@ellerman.id.au> - 2016-01-28 05:30 +0100 Re: [PATCH v6 1/9] ppc64 (le): prepare for -mprofile-kernel Torsten Duwe <duwe@lst.de> - 2016-01-28 13:00 +0100
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