Re: [PATCH 00/15] Backport 8xx TLB to 2.4
Willy Tarreau w...@1wt.eu wrote on 2011/06/14 21:31:06: Hi Joakim, On Tue, Jun 14, 2011 at 03:54:45PM +0200, Joakim Tjernlund wrote: This is a backport from 2.6 which I did to overcome 8xx CPU bugs. 8xx does not update the DAR register when taking a TLB error caused by dcbX and icbi insns which makes it very tricky to use these insns. Also the dcbst wrongly sets the the store bit when faulting into DTLB error. A few more bugs very found during development. I know 2.4 is in strict maintenance mode and 8xx is obsolete but as it is still in use I wanted 8xx to age with grace. OK, I'm not opposed to merge these patches and I really welcome your work and want to thank you for having done it. However, I have absolutely *zero* skills on ppc, so I want to ensure that someone (possibly you) will be able to back me up in case of reported regressions once these patches are merged. Since you say that the code works on your board, I'm not much worried but at least Dan's comment about the risk of performance regression has to be considered. If we all agree that it's a tradeoff between performance and stability or security, then that's a different matter of course ! Yes, I will still be here :) If there are any regressions I will help out. If we can't fix it, we can easily back these changes out. I guess I and Dan will come to some agreement soon and I will post additional, if needed, patches on top of what I already sent once Dan is happy. Jocke ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
[PATCH 00/15] Backport 8xx TLB to 2.4
This is a backport from 2.6 which I did to overcome 8xx CPU bugs. 8xx does not update the DAR register when taking a TLB error caused by dcbX and icbi insns which makes it very tricky to use these insns. Also the dcbst wrongly sets the the store bit when faulting into DTLB error. A few more bugs very found during development. I know 2.4 is in strict maintenance mode and 8xx is obsolete but as it is still in use I wanted 8xx to age with grace. Addendum: I have now ported our 8xx custom board to 2.4.37.11 and tested these patches there. Joakim Tjernlund (15): 8xx: Use a macro to simpliy CPU6 errata code. 8xx: Tag DAR with 0x00f0 to catch buggy instructions. 8xx: invalidate non present TLBs 8xx: Fix CONFIG_PIN_TLB 8xx: Update TLB asm so it behaves as linux mm expects. 8xx: Always pin kernel instruction TLB 8xx: Fixup DAR from buggy dcbX instructions. 8xx: CPU6 errata make DTLB error too big to fit. 8xx: Add missing Guarded setting in DTLB Error. 8xx: Restore _PAGE_WRITETHRU 8xx: Set correct HW pte flags in DTLB Error too 8xx: start using dcbX instructions in various copy routines 8xx: Use symbolic constants in TLB asm 8xx: Optimize ITLBMiss handler. 8xx: Optimize TLB Miss handlers arch/ppc/kernel/head_8xx.S | 381 ++- arch/ppc/kernel/misc.S | 18 -- arch/ppc/lib/string.S | 17 -- include/asm-ppc/pgtable.h | 16 +- 4 files changed, 274 insertions(+), 158 deletions(-) -- 1.7.3.4 ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 00/15] Backport 8xx TLB to 2.4
Hi Joakim. On Jun 14, 2011, at 6:54 AM, Joakim Tjernlund wrote: I know 2.4 is in strict maintenance mode and 8xx is obsolete but as it is still in use I wanted 8xx to age with grace. Thanks for your continued support. I have recently become involved in some 8xx development again, and have noticed it is still used more than some may realize. -- Dan ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 00/15] Backport 8xx TLB to 2.4
Dan Malek digitald...@digitaldans.com wrote on 2011/06/14 18:11:51: Hi Joakim. On Jun 14, 2011, at 6:54 AM, Joakim Tjernlund wrote: I know 2.4 is in strict maintenance mode and 8xx is obsolete but as it is still in use I wanted 8xx to age with grace. Thanks for your continued support. I have recently become involved in some 8xx development again, and have noticed it is still used more than some may realize. hehe, 8xx is still hanging on here to. The app. is still in development. I hope you will give these patches a go and let us know how it went? Jocke ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 00/15] Backport 8xx TLB to 2.4
Hi Joakim, On Tue, Jun 14, 2011 at 03:54:45PM +0200, Joakim Tjernlund wrote: This is a backport from 2.6 which I did to overcome 8xx CPU bugs. 8xx does not update the DAR register when taking a TLB error caused by dcbX and icbi insns which makes it very tricky to use these insns. Also the dcbst wrongly sets the the store bit when faulting into DTLB error. A few more bugs very found during development. I know 2.4 is in strict maintenance mode and 8xx is obsolete but as it is still in use I wanted 8xx to age with grace. OK, I'm not opposed to merge these patches and I really welcome your work and want to thank you for having done it. However, I have absolutely *zero* skills on ppc, so I want to ensure that someone (possibly you) will be able to back me up in case of reported regressions once these patches are merged. Since you say that the code works on your board, I'm not much worried but at least Dan's comment about the risk of performance regression has to be considered. If we all agree that it's a tradeoff between performance and stability or security, then that's a different matter of course ! Thanks ! Willy ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
