Hi Sergei, On Thu, 21 Sep 2006 21:01:14 +0400 Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx> wrote: > Hello. > > Yoichi Yuasa wrote: > > >>>Some mtc0_tlbw_hazard() were broken by "[MIPS] Cleanup hazard handling" patch. > >>>Please apply this patch. > > >>>tlb-r4k.o disassemble: > > >>>8009018c <local_flush_tlb_all>: > >>>8009018c: 40066000 mfc0 a2,$12 > >>>80090190: 34c1001f ori at,a2,0x1f > >>>80090194: 3821001f xori at,at,0x1f > >>>80090198: 40816000 mtc0 at,$12 > >>>8009019c: 00000040 ssnop > >>>800901a0: 00000040 ssnop > >>>800901a4: 00000040 ssnop > > >> Hm, why there are ssnop's here... > > > ssnop is a part of dvpe(). > > Yep, this is irq_disable_hazard, looking sane. > > >>>800901a8: 40075000 mfc0 a3,$10 > >>>800901ac: 40801000 mtc0 zero,$2 > >>>800901b0: 40801800 mtc0 zero,$3 > >>>800901b4: 40043000 mfc0 a0,$6 > >>>800901b8: 3c028035 lui v0,0x8035 > >>>800901bc: 8c457ac0 lw a1,31424(v0) > >>>800901c0: 0085182a slt v1,a0,a1 > >>>800901c4: 1060000b beqz v1,800901f4 <local_flush_tlb_all+0x68> > >>>800901c8: 00044340 sll t0,a0,0xd > >>>800901cc: 3c098000 lui t1,0x8000 > >>>800901d0: 01091821 addu v1,t0,t1 > >>>800901d4: 40835000 mtc0 v1,$10 > >>>800901d8: 10000002 b 800901e4 <local_flush_tlb_all+0x58> <-- mtc0_tlbw_hazard() > >>>800901dc: 40840000 mtc0 a0,$0 > >>>800901e0: 42000002 tlbwi > > >>>Yoichi > > >>>Signed-off-by: Yoichi Yuasa <yoichi_yuasa@xxxxxxxxxxxxxx> > >>> > >>>diff -pruN -X mips/Documentation/dontdiff mips-orig/include/asm-mips/hazards.h mips/include/asm-mips/hazards.h > >>>--- mips-orig/include/asm-mips/hazards.h 2006-09-21 18:21:11.793973750 +0900 > >>>+++ mips/include/asm-mips/hazards.h 2006-09-21 18:55:07.569201750 +0900 > >>>@@ -138,7 +138,7 @@ ASMMACRO(back_to_back_c0_hazard, > > This is under #elif defined(CONFIG_CPU_SB1), right? right. > >>> * Mostly like R4000 for historic reasons > >>> */ > >>> ASMMACRO(mtc0_tlbw_hazard, > >>>- b . + 8 > >>>+ nop; nop; nop; nop; nop; nop > > >> ... and nop's there? This looks inconsistent. > > > previous mtc0_tlbw_hazard() for C used nop. > > "b . + 8" is trick for R4000/R4400, see comment in old hazard.h . > > I fail to see what was changed WRT SB1 CPUs by the suspected patch. Though > wait... the previous version was inconsistent, using the different barrier > definitions for C and assembly (nops in the former, and branch in the latter). > But since the assembly version was not really used, it couldn't break > anything... :-/ > > Anyway, shouldn't ssnop's be used for SB1 instead? CPU has quad-issue > pipeline, hasn't it? I don't know SB1 hazard requirement. This patch has kept previous mtc0_tlbw_hazard(). You can optimize it for SB1. Yoichi
