From: "Maciej W. Rozycki" <macro@mips.com> To: Fredrik Noring <noring@nocrew.org> Cc: <linux-mips@linux-mips.org> Subject: Re: [PATCH v2] MIPS: Add basic R5900 support Date: Mon, 23 Oct 2017 17:10:27 +0100 [thread overview] Message-ID: <alpine.DEB.2.00.1710231659060.3886@tp.orcam.me.uk> (raw) In-Reply-To: <20171021180040.GC10522@localhost.localdomain> On Sat, 21 Oct 2017, Fredrik Noring wrote: > > > Still left to explain is why the kernel stumbles on registers during > > > initialisation, before user applications are invoked. > > > > Good luck! > > The problem was with the inq and outq macros in the Graphics Synthesizer > driver. A 32-bit kernel now works with 32-bit register save/restore and o32 > applications, as intended. Many thanks for all your help in finding this! Great, and you are welcome! > I've found an unrelated curiosity. With CONFIG_CPU_HAS_MSA undefined, > handle_msa_fpe_int, do_msa_fpe, etc. are still generated with nonsensical > instructions: > > 80025128 <handle_msa_fpe_int>: > 80025128: 787e0859 lq s8,2137(v1) <<<----- > 8002512c: 00202821 move a1,at > 80025130: 0000040f sync.p > 80025134: 40086000 mfc0 t0,c0_sr > ... > > 80030f08 <do_msa_fpe>: > 80030f08: 27bdffd8 addiu sp,sp,-40 > 80030f0c: afb0001c sw s0,28(sp) > 80030f10: 00808021 move s0,a0 > ... > 80030f70: 02228824 and s1,s1,v0 > 80030f74: 02200821 move at,s1 > 80030f78: 783e0859 lq s8,2137(at) <<<----- > 80030f7c: 0000040f sync.p > 80030f80: 40016000 mfc0 at,c0_sr > ... > > I disabled both with the patch below (there seems to be more opportunities > for size reductions overall). Perhaps the MSA and the MSAFPE exception handlers could be improved somehow for configurations known not to support the MSA ASE, however your change as it stands will make the MSA exception handler default to `do_reserved', which in turn will cause MSA software to cause a kernel panic rather than sending SIGILL if run with CPU_HAS_MSA disabled on MSA hardware. This would be rather nasty IMO. Maciej
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From: "Maciej W. Rozycki" <macro@mips.com> To: Fredrik Noring <noring@nocrew.org> Cc: linux-mips@linux-mips.org Subject: Re: [PATCH v2] MIPS: Add basic R5900 support Date: Mon, 23 Oct 2017 17:10:27 +0100 [thread overview] Message-ID: <alpine.DEB.2.00.1710231659060.3886@tp.orcam.me.uk> (raw) Message-ID: <20171023161027.tVxdK-Ml1HZ4GZq-QusgXa9tt-J1ne5fYUrRankyDYM@z> (raw) In-Reply-To: <20171021180040.GC10522@localhost.localdomain> On Sat, 21 Oct 2017, Fredrik Noring wrote: > > > Still left to explain is why the kernel stumbles on registers during > > > initialisation, before user applications are invoked. > > > > Good luck! > > The problem was with the inq and outq macros in the Graphics Synthesizer > driver. A 32-bit kernel now works with 32-bit register save/restore and o32 > applications, as intended. Many thanks for all your help in finding this! Great, and you are welcome! > I've found an unrelated curiosity. With CONFIG_CPU_HAS_MSA undefined, > handle_msa_fpe_int, do_msa_fpe, etc. are still generated with nonsensical > instructions: > > 80025128 <handle_msa_fpe_int>: > 80025128: 787e0859 lq s8,2137(v1) <<<----- > 8002512c: 00202821 move a1,at > 80025130: 0000040f sync.p > 80025134: 40086000 mfc0 t0,c0_sr > ... > > 80030f08 <do_msa_fpe>: > 80030f08: 27bdffd8 addiu sp,sp,-40 > 80030f0c: afb0001c sw s0,28(sp) > 80030f10: 00808021 move s0,a0 > ... > 80030f70: 02228824 and s1,s1,v0 > 80030f74: 02200821 move at,s1 > 80030f78: 783e0859 lq s8,2137(at) <<<----- > 80030f7c: 0000040f sync.p > 80030f80: 40016000 mfc0 at,c0_sr > ... > > I disabled both with the patch below (there seems to be more opportunities > for size reductions overall). Perhaps the MSA and the MSAFPE exception handlers could be improved somehow for configurations known not to support the MSA ASE, however your change as it stands will make the MSA exception handler default to `do_reserved', which in turn will cause MSA software to cause a kernel panic rather than sending SIGILL if run with CPU_HAS_MSA disabled on MSA hardware. This would be rather nasty IMO. Maciej
next prev parent reply other threads:[~2017-10-23 16:12 UTC|newest] Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-08-27 13:23 [PATCH] MIPS: Add basic R5900 support Fredrik Noring 2017-08-28 13:53 ` Ralf Baechle 2017-08-28 17:11 ` Maciej W. Rozycki 2017-08-29 17:33 ` Fredrik Noring 2017-08-29 17:24 ` Maciej W. Rozycki 2017-08-29 17:24 ` Maciej W. Rozycki 2017-08-30 13:23 ` Fredrik Noring 2017-08-31 15:11 ` Maciej W. Rozycki 2017-08-31 15:11 ` Maciej W. Rozycki 2017-09-02 10:28 ` Fredrik Noring 2017-09-09 10:13 ` Maciej W. Rozycki 2017-09-09 10:13 ` Maciej W. Rozycki 2017-09-11 5:21 ` Maciej W. Rozycki 2017-09-11 5:21 ` Maciej W. Rozycki 2017-09-12 17:59 ` Fredrik Noring 2017-09-15 11:12 ` Maciej W. Rozycki 2017-09-15 11:12 ` Maciej W. Rozycki 2017-09-15 13:19 ` Fredrik Noring 2017-09-15 18:28 ` Maciej W. Rozycki 2017-09-15 18:28 ` Maciej W. Rozycki 2017-09-02 14:10 ` [PATCH v2] " Fredrik Noring 2017-09-11 5:18 ` Maciej W. Rozycki 2017-09-11 5:18 ` Maciej W. Rozycki 2017-09-11 15:17 ` Fredrik Noring 2017-09-14 13:50 ` Maciej W. Rozycki 2017-09-14 13:50 ` Maciej W. Rozycki 2017-09-16 13:34 ` Fredrik Noring 2017-09-18 17:05 ` Maciej W. Rozycki 2017-09-18 17:05 ` Maciej W. Rozycki 2017-09-18 19:24 ` Fredrik Noring 2017-09-19 12:44 ` Maciej W. Rozycki 2017-09-19 12:44 ` Maciej W. Rozycki 2017-09-20 14:54 ` Fredrik Noring 2017-09-26 11:50 ` Maciej W. Rozycki 2017-09-26 11:50 ` Maciej W. Rozycki 2017-09-27 17:21 ` Fredrik Noring 2017-09-28 12:13 ` Maciej W. Rozycki 2017-09-28 12:13 ` Maciej W. Rozycki 2017-09-30 6:56 ` Fredrik Noring 2017-10-02 9:05 ` Maciej W. Rozycki 2017-10-02 9:05 ` Maciej W. Rozycki 2017-10-02 16:33 ` Fredrik Noring 2017-10-29 17:20 ` Fredrik Noring 2017-11-10 23:34 ` Maciej W. Rozycki 2017-11-10 23:34 ` Maciej W. Rozycki 2017-11-11 16:04 ` Fredrik Noring 2018-01-29 20:27 ` Fredrik Noring 2018-01-31 23:01 ` Maciej W. Rozycki 2018-02-11 7:29 ` [RFC] MIPS: R5900: Workaround for the short loop bug Fredrik Noring 2018-02-12 9:25 ` Maciej W. Rozycki 2018-02-12 15:22 ` Fredrik Noring 2018-02-11 7:46 ` [RFC] MIPS: R5900: Use SYNC.L for data cache and SYNC.P for instruction cache Fredrik Noring 2018-02-11 7:56 ` [RFC] MIPS: R5900: Workaround exception NOP execution bug (FLX05) Fredrik Noring 2018-02-12 9:28 ` Maciej W. Rozycki 2018-02-15 19:15 ` [RFC v2] " Fredrik Noring 2018-02-15 20:49 ` Maciej W. Rozycki 2018-02-17 11:16 ` Fredrik Noring 2018-02-17 11:57 ` Maciej W. Rozycki 2018-02-17 13:38 ` Fredrik Noring 2018-02-17 15:03 ` Maciej W. Rozycki 2018-02-17 20:04 ` Fredrik Noring 2018-02-20 14:09 ` Maciej W. Rozycki 2018-02-22 17:04 ` Fredrik Noring 2018-02-18 8:47 ` Fredrik Noring 2018-02-20 14:41 ` Maciej W. Rozycki 2018-02-22 17:27 ` Fredrik Noring 2018-02-11 8:01 ` [RFC] MIPS: R5900: Workaround for CACHE instruction near branch delay slot Fredrik Noring 2018-02-11 11:16 ` Aw: " "Jürgen Urban" 2018-02-11 8:09 ` [RFC] MIPS: R5900: The ERET instruction has issues with delay slot and CACHE Fredrik Noring 2018-02-11 11:07 ` Aw: " "Jürgen Urban" 2018-02-11 8:29 ` [RFC] MIPS: R5900: Use mandatory SYNC.L in exception handlers Fredrik Noring 2018-02-11 10:33 ` Aw: " "Jürgen Urban" 2018-02-12 9:22 ` Maciej W. Rozycki 2018-02-12 9:22 ` Maciej W. Rozycki 2018-02-18 10:30 ` Fredrik Noring 2018-02-17 14:43 ` [RFC] MIPS: R5900: Workaround for saving and restoring FPU registers Fredrik Noring 2018-02-17 15:18 ` Maciej W. Rozycki 2018-02-17 17:47 ` Fredrik Noring 2018-02-17 19:33 ` Maciej W. Rozycki 2018-02-18 9:26 ` [RFC] MIPS: R5900: Workaround where MSB must be 0 for the instruction cache Fredrik Noring 2018-02-18 11:08 ` [RFC] MIPS: R5900: Add mandatory SYNC.P to all M[FT]C0 instructions Fredrik Noring 2018-03-03 12:26 ` [RFC] MIPS: PS2: Interrupt request (IRQ) support Fredrik Noring 2018-03-03 13:09 ` Maciej W. Rozycki 2018-03-03 14:14 ` Fredrik Noring 2018-04-09 15:51 ` Fredrik Noring 2018-03-18 10:45 ` Fredrik Noring 2018-03-19 19:15 ` Thomas Gleixner 2018-06-18 18:52 ` [RFC v2] " Fredrik Noring 2017-10-30 17:55 ` [PATCH v2] MIPS: Add basic R5900 support Fredrik Noring 2017-11-24 10:26 ` Maciej W. Rozycki 2017-11-24 10:26 ` Maciej W. Rozycki 2017-11-24 10:39 ` Maciej W. Rozycki 2017-11-24 10:39 ` Maciej W. Rozycki 2017-09-20 14:07 ` Fredrik Noring 2017-09-21 21:07 ` Maciej W. Rozycki 2017-09-21 21:07 ` Maciej W. Rozycki 2017-09-22 16:37 ` Fredrik Noring 2017-09-22 16:37 ` Fredrik Noring 2017-09-29 23:55 ` Maciej W. Rozycki 2017-09-29 23:55 ` Maciej W. Rozycki 2017-09-30 18:26 ` Fredrik Noring 2017-10-02 9:11 ` Maciej W. Rozycki 2017-10-02 9:11 ` Maciej W. Rozycki 2017-10-03 19:49 ` Fredrik Noring 2017-10-05 19:04 ` Fredrik Noring 2017-10-06 20:28 ` Fredrik Noring 2017-10-15 16:39 ` Fredrik Noring 2017-10-17 12:23 ` Maciej W. Rozycki 2017-10-17 12:23 ` Maciej W. Rozycki 2017-10-21 18:00 ` Fredrik Noring 2017-10-23 16:10 ` Maciej W. Rozycki [this message] 2017-10-23 16:10 ` Maciej W. Rozycki 2017-09-21 18:11 ` Paul Burton 2017-09-21 18:11 ` Paul Burton 2017-09-21 19:48 ` Maciej W. Rozycki 2017-09-21 19:48 ` Maciej W. Rozycki 2017-10-29 18:42 ` Fredrik Noring
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