On Thu, Mar 07, 2019 at 06:14:09PM +0000, Christophe Leroy wrote: > Hi, > > On 03/07/2019 02:11 PM, Guenter Roeck wrote: > >Hi, > > > >On Thu, Feb 21, 2019 at 10:37:55AM +0000, Christophe Leroy wrote: > >>Use SPRN_SPRG2 to store the current thread PGDIR and > >>avoid reading thread_struct.pgdir at every TLB miss. > >> > >This patch causes a number of silent (no crash) qemu boot stalls > >in -next. See > >https://kerneltests.org/builders/qemu-ppc-next/builds/1080/steps/qemubuildcommand/logs/stdio > >for an example. > > Oops. > Could you try the fix below ? >
Yes, that does the trick. With this patch applied on top of next-20190306, all my ppc qemu boot tests pass. Tested-by: Guenter Roeck <li...@roeck-us.net> Guenter > diff --git a/arch/powerpc/kernel/cpu_setup_6xx.S > b/arch/powerpc/kernel/cpu_setup_6xx.S > index 6f1c11e0691f..7534ecff5e92 100644 > --- a/arch/powerpc/kernel/cpu_setup_6xx.S > +++ b/arch/powerpc/kernel/cpu_setup_6xx.S > @@ -24,9 +24,6 @@ BEGIN_MMU_FTR_SECTION > li r10,0 > mtspr SPRN_SPRG_603_LRU,r10 /* init SW LRU tracking */ > END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU) > - lis r10, (swapper_pg_dir - PAGE_OFFSET)@h > - ori r10, r10, (swapper_pg_dir - PAGE_OFFSET)@l > - mtspr SPRN_SPRG_PGDIR, r10 > > BEGIN_FTR_SECTION > bl __init_fpu_registers > diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S > index ce6a972f2584..48051c8977c5 100644 > --- a/arch/powerpc/kernel/head_32.S > +++ b/arch/powerpc/kernel/head_32.S > @@ -855,6 +855,9 @@ __secondary_start: > li r3,0 > stw r3, RTAS_SP(r4) /* 0 => not in RTAS */ > #endif > + lis r4, (swapper_pg_dir - PAGE_OFFSET)@h > + ori r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l > + mtspr SPRN_SPRG_PGDIR, r4 > > /* enable MMU and jump to start_secondary */ > li r4,MSR_KERNEL > @@ -942,6 +945,9 @@ start_here: > li r3,0 > stw r3, RTAS_SP(r4) /* 0 => not in RTAS */ > #endif > + lis r4, (swapper_pg_dir - PAGE_OFFSET)@h > + ori r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l > + mtspr SPRN_SPRG_PGDIR, r4 > > /* stack */ > lis r1,init_thread_union@ha > diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S > index 1f13494efb2b..587e4550d83e 100644 > --- a/arch/powerpc/mm/hash_low_32.S > +++ b/arch/powerpc/mm/hash_low_32.S > @@ -70,12 +70,12 @@ _GLOBAL(hash_page) > lis r0,KERNELBASE@h /* check if kernel address */ > cmplw 0,r4,r0 > ori r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */ > - mfspr r5, SPRN_SPRG_PGDIR /* virt page-table root */ > + mfspr r5, SPRN_SPRG_PGDIR /* phys page-table root */ > blt+ 112f /* assume user more likely */ > - lis r5,swapper_pg_dir@ha /* if kernel address, use */ > - addi r5,r5,swapper_pg_dir@l /* kernel page table */ > + lis r5, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, > use */ > + addi r5 ,r5 , (swapper_pg_dir - PAGE_OFFSET)@l /* kernel page > table */ > rlwimi r3,r9,32-12,29,29 /* MSR_PR -> _PAGE_USER */ > -112: tophys(r5, r5) > +112: > #ifndef CONFIG_PTE_64BIT > rlwimi r5,r4,12,20,29 /* insert top 10 bits of address */ > lwz r8,0(r5) /* get pmd entry */ > > > Thanks > Christophe > > > > >Unfortunately, it is not possible to revert the patch due to subsequent > >patches, so I was unable to test a revert. > > > >Bisect log is attached. > > > >Guenter > > > >--- > ># bad: [cf08baa29613dd899954089e7cc7dba1d478b365] Add linux-next specific > >files for 20190306 > ># good: [1c163f4c7b3f621efff9b28a47abb36f7378d783] Linux 5.0 > >git bisect start 'HEAD' 'v5.0' > ># bad: [6cc8f3499ec8d31904ab9083980a91736512cb37] Merge remote-tracking > >branch 'vfs/for-next' > >git bisect bad 6cc8f3499ec8d31904ab9083980a91736512cb37 > ># good: [63bdf4284c38a48af21745ceb148a087b190cd21] Merge branch 'linus' of > >git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 > >git bisect good 63bdf4284c38a48af21745ceb148a087b190cd21 > ># good: [520b5fc601ab760fee7ea0c403b42d04e8ebfd93] Merge remote-tracking > >branch 'arm-soc/for-next' > >git bisect good 520b5fc601ab760fee7ea0c403b42d04e8ebfd93 > ># bad: [d7f54e4e0d4e90f5df78da8d6a830bafad3b535a] Merge remote-tracking > >branch 'xtensa/xtensa-for-next' > >git bisect bad d7f54e4e0d4e90f5df78da8d6a830bafad3b535a > ># good: [0c1a78523542fb3d2e6c5ac7955c8ca8f6482e6f] Merge remote-tracking > >branch 'clk/clk-next' > >git bisect good 0c1a78523542fb3d2e6c5ac7955c8ca8f6482e6f > ># bad: [fb0b0a73b223fc113e961b1d921322844e9c30d9] powerpc: Enable kcov > >git bisect bad fb0b0a73b223fc113e961b1d921322844e9c30d9 > ># good: [d0055df0c9c1471c389197a69f43e300185a75aa] Merge branch 'topic/dma' > >into next > >git bisect good d0055df0c9c1471c389197a69f43e300185a75aa > ># good: [0df977eafc792a5365a7f81d8d5920132e03afad] powerpc/6xx: Don't use > >SPRN_SPRG2 for storing stack pointer while in RTAS > >git bisect good 0df977eafc792a5365a7f81d8d5920132e03afad > ># bad: [665bed2386e5dc29844ad78c7ef1464664b103ec] powerpc/8xx: replace most > >#ifdef by IS_ENABLED() in 8xx_mmu.c > >git bisect bad 665bed2386e5dc29844ad78c7ef1464664b103ec > ># bad: [78ca1108b10927b3d068c8da91352b0f4cd01fc5] powerpc/book3s32: Reorder > >_PAGE_XXX flags to simplify TLB handling > >git bisect bad 78ca1108b10927b3d068c8da91352b0f4cd01fc5 > ># bad: [a8a121995b2e4f227fddc534c6bd5f1c02cbe2ee] powerpc/603: Don't handle > >kernel page TLB misses when not need > >git bisect bad a8a121995b2e4f227fddc534c6bd5f1c02cbe2ee > ># bad: [2c12393f577396a51b7e0537bd3eb29dcc26dc1b] powerpc/603: use physical > >address directly in TLB miss handlers. > >git bisect bad 2c12393f577396a51b7e0537bd3eb29dcc26dc1b > ># bad: [93c4a162b014d238a287f8264adb25c009c79e61] powerpc/6xx: Store PGDIR > >physical address in a SPRG > >git bisect bad 93c4a162b014d238a287f8264adb25c009c79e61 > ># first bad commit: [93c4a162b014d238a287f8264adb25c009c79e61] powerpc/6xx: > >Store PGDIR physical address in a SPRG > >
