>> Ok, the issue was introduced by the commit >> caca285e5ab4a7a19fede51688106ceed6fc45dd (powerpc/mm/radix: Use >> STD_MMU_64 to properly isolate hash related code) and 970mp dies on >> the following condition: > >> +BEGIN_MMU_FTR_SECTION >> bl slb_allocate_realmode >> - >> +END_MMU_FTR_SECTION_IFCLR(MMU_FTR_RADIX) > > Thanks. > > How did you work that out? > > That FTR section says to call slb_allocate_realmode() when MMU_FTR_RADIX is > clear (ie. zero). That should always be the case on your machine, unless > you've > plugged a Power9 into your G5 ;) > >> In my config I've enabled radix MMU lookup but in my understanding >> only recent IBM machines support this feature and we have to call SLB >> entry through slb_allocate_realmode on HPTE machine? > > That's right, and that's what the code should be doing. > > My G5 is booting OK: > > michael@cogito:~$ uname -a > Linux cogito 4.7.0-rc3-gdb06d75 #1 SMP Thu Jun 16 05:16:31 AEST 2016 ppc64 > GNU/Linux > > michael@cogito:~$ cat /proc/cpuinfo > processor : 0 > cpu : PPC970FX, altivec supported > clock : 1599.999000MHz > revision : 3.0 (pvr 003c 0300) > > timebase : 33333333 > platform : PowerMac > model : PowerMac8,1 > machine : PowerMac8,1 > motherboard : PowerMac8,1 MacRISC4 Power Macintosh > detected as : 338 (iMac G5) > pmac flags : 00000000 > L2 cache : 512K unified > pmac-generation : NewWorld > > michael@cogito:~$ zgrep RADIX /proc/config.gz > CONFIG_PPC_RADIX_MMU=y > > michael@cogito:~$ dmesg|grep _features > [ 0.000000] cpu_features = 0x0804806318100448 > [ 0.000000] cpu_user_features = 0xdc080000 0x00000000 > [ 0.000000] mmu_features = 0x0c000001 > [ 0.000000] firmware_features = 0x0000000000000000 > > In particular notice: > > #define MMU_FTR_RADIX ASM_CONST(0x80000000) > mmu_features = 0x0c000001 > > ie. MMU_FTR_RADIX is clear. > > Do you see a different value for mmu_features?
Oops, I messed things up, sorry :/ The reason is here: /* All done -- return from exception. */ ld r10,PACA_EXSLB+EX_LR(r13) @@ -1384,7 +1399,9 @@ slb_miss_realmode: lwz r9,PACA_EXSLB+EX_CCR(r13) /* get saved CR */ mtlr r10 - +BEGIN_MMU_FTR_SECTION + b 2f +END_MMU_FTR_SECTION_IFSET(MMU_FTR_RADIX) andi. r10,r12,MSR_RI /* check for unrecoverable exception */ beq- 2f So with the patch we got the direct jump to label 2 : c000000000006edc <slb_miss_realmode>: c000000000006edc: 7d 48 02 a6 mflr r10 c000000000006ee0: 91 2d 01 8c stw r9,396(r13) c000000000006ee4: f9 4d 01 98 std r10,408(r13) c000000000006ee8: 48 03 28 09 bl c0000000000396f0 <.slb_allocate_realmode> c000000000006eec: e9 4d 01 98 ld r10,408(r13) c000000000006ef0: e8 6d 01 90 ld r3,400(r13) c000000000006ef4: 81 2d 01 8c lwz r9,396(r13) c000000000006ef8: 7d 48 03 a6 mtlr r10 c000000000006efc: 48 00 00 38 b c000000000006f34 <slb_miss_realmode+0x58> c000000000006f00: 71 8a 00 02 andi. r10,r12,2 c000000000006f04: 41 82 00 30 beq c000000000006f34 <slb_miss_realmode+0x58> c000000000006f08: 7d 38 01 20 mtocrf 128,r9 c000000000006f0c: 7d 30 11 20 mtocrf 1,r9 c000000000006f10: e9 2d 01 a8 ld r9,424(r13) c000000000006f14: 7d 20 e3 a6 mtppr r9 c000000000006f18: e9 2d 01 50 ld r9,336(r13) c000000000006f1c: e9 4d 01 58 ld r10,344(r13) c000000000006f20: e9 6d 01 60 ld r11,352(r13) c000000000006f24: e9 8d 01 68 ld r12,360(r13) c000000000006f28: e9 ad 01 70 ld r13,368(r13) c000000000006f2c: 4c 00 00 24 rfid c000000000006f30: 48 00 00 00 b c000000000006f30 <slb_miss_realmode+0x54> c000000000006f34: 7d 7a 02 a6 mfsrr0 r11 c000000000006f38: e9 4d 00 18 ld r10,24(r13) c000000000006f3c: 61 4a 6f 54 ori r10,r10,28500 c000000000006f40: 7d 5a 03 a6 mtsrr0 r10 c000000000006f44: e9 4d 00 20 ld r10,32(r13) c000000000006f48: 7d 5b 03 a6 mtsrr1 r10 c000000000006f4c: 4c 00 00 24 rfid c000000000006f50: 48 00 00 00 b c000000000006f50 <slb_miss_realmode+0x74> Without the ftr conditional section everything looks fine: c000000000006edc <slb_miss_realmode>: c000000000006edc: 7d 48 02 a6 mflr r10 c000000000006ee0: 91 2d 01 8c stw r9,396(r13) c000000000006ee4: f9 4d 01 98 std r10,408(r13) c000000000006ee8: 48 03 28 09 bl c0000000000396f0 <.slb_allocate_realmode> c000000000006eec: e9 4d 01 98 ld r10,408(r13) c000000000006ef0: e8 6d 01 90 ld r3,400(r13) c000000000006ef4: 81 2d 01 8c lwz r9,396(r13) c000000000006ef8: 7d 48 03 a6 mtlr r10 c000000000006efc: 71 8a 00 02 andi. r10,r12,2 c000000000006f00: 41 82 00 30 beq c000000000006f30 <slb_miss_realmode+0x54> c000000000006f04: 7d 38 01 20 mtocrf 128,r9 c000000000006f08: 7d 30 11 20 mtocrf 1,r9 c000000000006f0c: e9 2d 01 a8 ld r9,424(r13) c000000000006f10: 7d 20 e3 a6 mtppr r9 c000000000006f14: e9 2d 01 50 ld r9,336(r13) c000000000006f18: e9 4d 01 58 ld r10,344(r13) c000000000006f1c: e9 6d 01 60 ld r11,352(r13) c000000000006f20: e9 8d 01 68 ld r12,360(r13) c000000000006f24: e9 ad 01 70 ld r13,368(r13) c000000000006f28: 4c 00 00 24 rfid c000000000006f2c: 48 00 00 00 b c000000000006f2c <slb_miss_realmode+0x50> c000000000006f30: 7d 7a 02 a6 mfsrr0 r11 c000000000006f34: e9 4d 00 18 ld r10,24(r13) c000000000006f38: 61 4a 6f 50 ori r10,r10,28496 c000000000006f3c: 7d 5a 03 a6 mtsrr0 r10 c000000000006f40: e9 4d 00 20 ld r10,32(r13) c000000000006f44: 7d 5b 03 a6 mtsrr1 r10 c000000000006f48: 4c 00 00 24 rfid c000000000006f4c: 48 00 00 00 b c000000000006f4c <slb_miss_realmode+0x70> > > cheers > >
ftr.config
Description: Binary data
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