Hi Sergey, On Fri, Dec 30, 2022 at 4:53 PM Sergey Matyukevich <geomatsi@xxxxxxxxx> wrote: > > Hi Prabhakar, > > > Hi Sergey, > > > > On Sat, Dec 24, 2022 at 11:48 AM Sergey Matyukevich <geomatsi@xxxxxxxxx> wrote: > > > > > > Hi Prabhakar, > > > > > > > > > > > > > > > > Current implementation of update_mmu_cache function performs local TLB > > > > > > > > > > > > > flush. It does not take into account ASID information. Besides, it does > > > > > > > > > > > > > not take into account other harts currently running the same mm context > > > > > > > > > > > > > or possible migration of the running context to other harts. Meanwhile > > > > > > > > > > > > > TLB flush is not performed for every context switch if ASID support > > > > > > > > > > > > > is enabled. > > > > > > > > > > > > > > > > > > > > > > > > > > Patch [1] proposed to add ASID support to update_mmu_cache to avoid > > > > > > > > > > > > > flushing local TLB entirely. This patch takes into account other > > > > > > > > > > > > > harts currently running the same mm context as well as possible > > > > > > > > > > > > > migration of this context to other harts. > > > > > > > > > > > > > > > > > > > > > > > > > > For this purpose the approach from flush_icache_mm is reused. Remote > > > > > > > > > > > > > harts currently running the same mm context are informed via SBI calls > > > > > > > > > > > > > that they need to flush their local TLBs. All the other harts are marked > > > > > > > > > > > > > as needing a deferred TLB flush when this mm context runs on them. > > > > > > > > > > > > > > > > > > > > > > > > > > [1] https://lore.kernel.org/linux-riscv/20220821013926.8968-1-tjytimi@xxxxxxx/ > > > > > > > > > > > > > > > > > > > > > > > > > > Signed-off-by: Sergey Matyukevich <sergey.matyukevich@xxxxxxxxxxxxx> > > > > > > > > > > > > > --- > > > > > > > > > > > > > arch/riscv/include/asm/mmu.h | 2 ++ > > > > > > > > > > > > > arch/riscv/include/asm/pgtable.h | 2 +- > > > > > > > > > > > > > arch/riscv/include/asm/tlbflush.h | 18 ++++++++++++++++++ > > > > > > > > > > > > > arch/riscv/mm/context.c | 10 ++++++++++ > > > > > > > > > > > > > arch/riscv/mm/tlbflush.c | 28 +++++++++++----------------- > > > > > > > > > > > > > 5 files changed, 42 insertions(+), 18 deletions(-) > > > > > > > > > > > > > > > > > > > > > > > <snip> > > > > > > > > > > > > [ 133.008752] Hardware name: Renesas SMARC EVK based on r9a07g043f01 (DT) > > > > > > > > > > > > [ 133.015338] Call Trace: > > > > > > > > > > > > [ 133.017778] [<ffffffff800055cc>] dump_backtrace+0x1c/0x24 > > > > > > > > > > > > [ 133.023174] [<ffffffff80776836>] show_stack+0x2c/0x38 > > > > > > > > > > > > [ 133.028214] [<ffffffff80780244>] dump_stack_lvl+0x3c/0x54 > > > > > > > > > > > > [ 133.033597] [<ffffffff80780270>] dump_stack+0x14/0x1c > > > > > > > > > > > > [ 133.038633] [<ffffffff80776c00>] panic+0x102/0x29a > > > > > > > > > > > > [ 133.043409] [<ffffffff800137ba>] do_exit+0x704/0x70a > > > > > > > > > > > > [ 133.048362] [<ffffffff8001390e>] do_group_exit+0x24/0x70 > > > > > > > > > > > > [ 133.053659] [<ffffffff8001de54>] get_signal+0x68a/0x6dc > > > > > > > > > > > > [ 133.058874] [<ffffffff8000494e>] do_work_pending+0xd6/0x44e > > > > > > > > > > > > [ 133.064427] [<ffffffff800036c2>] resume_userspace_slow+0x8/0xa > > > > > > > > > > > > [ 133.070249] ---[ end Kernel panic - not syncing: Attempted to kill > > > > > > > > > > > > init! exitcode=0x0000000b ]--- > > > > > > > > > > > > > > > > > > > > > > > > If I revert this patch [0] bonnie++ works as expected. > > > > > > > > > > > > > > > > > > > > > > > > Any pointers on what could be the issue here? > > > > > > > > > > > > > > > > > > > > > > > > [0] https://git.kernel.org/pub/scm/linux/kernel/git/palmer/linux.git/commit/?h=for-next&id=4bd1d80efb5af640f99157f39b50fb11326ce641 > > > > > > > > > > > > > > > > > > > > > > > > Cheers, > > > > > > > > > > > > Prabhakar > > > > > > > > > > > > > > > > > > > > > > Good catch. Thanks for reporting ! Discussion around the issue and > > > > > > > > > > > possible ways to fix it can be found in the following email thread: > > > > > > > > > > > > > > > > > > > > > > https://lore.kernel.org/linux-riscv/20221111075902.798571-1-guoren@xxxxxxxxxx/ > > > > > > > > > > > > > > > > > > > > > > Could you please apply the patch from Guo Ren instead of [0] and check > > > > > > > > > > > if you have any issues with your test ? Besides, could you please share > > > > > > > > > > > your kernel configuration and the actual bonnie++ params from emmc_t_002.sh script ? > > > > > > > > > > > > > > > > > > > > > Thanks for the pointer, I'll undo my changes and test Guo's patch. > > > > > > > > > > > > > > > > > > > > I have pasted the script here [0] and attached config. > > > > > > > > > > > > > > > > > > > > [0] https://paste.debian.net/hidden/a7a769b5/ > > > > > > > > > > > > > > > > > > Thanks for the script and config. Could you please also share the > > > > > > > > > following information: > > > > > > > > > - how many cores your system has > > > > > > > > The Renesas RZ/Five SoC has a single Andes AX45MP core. > > > > > > > > > > > > > > > > > - does your system support ASID > > > > > > > > > > > > > > > > > With a quick look at [0] It does support ASID, unless there is a way > > > > > > > > to disable it. > > > > > > > > > > > > > > > > [0] http://www.andestech.com/wp-content/uploads/AX45MP-1C-Rev.-5.0.0-Datasheet.pdf > > > > > > > > > > > > > > So you have a single-core system, but your kernel configuration enables > > > > > > > CONFIG_SMP. Additional 'deferred TLB flush' logic is dropped at build > > > > > > > time if CONFIG_SMP is disabled. On the other hand, system should not > > > > > > > fail that way even if SMP is enabled. > > > > > > > > > > > > > I enabled CONFIG_SMP while doing some testing of PMA code and indeed > > > > > > enabling this config should not introduce a failure. > > > > > > > > > > > > > Let me double-check if anything can go wrong if cpumasks may have only > > > > > > > a single cpu. Another suspect is a change in update_mmu_cache: probably > > > > > > > making it asid-specific (and thus more granular) was a bad idea. > > > > > > > > > > > > > Thanks. > > > > > > > > > > > > BTW I tested the patch [0] which you pointed out and that fixes the > > > > > > issues seen earlier. > > > > > > > > > > > > [0] https://patchwork.kernel.org/project/linux-riscv/patch/20221111075902.798571-1-guoren@xxxxxxxxxx/ > > > > > > > > > > All looks good with cpumasks in the single-core case. So deferred TLB > > > > > flush logic is not even executed in your case. So the root cause > > > > > should be in update_mmu_cache change. > > > > > > > > > > May I ask you to repeat the original emmc test on your platform from > > > > > for-next (i.e. with [0] and without [1]) with the following partial revert: > > > > > > > > > > : diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > > > > > : index ec6fb83349ce..92ec2d9d7273 100644 > > > > > : --- a/arch/riscv/include/asm/pgtable.h > > > > > : +++ b/arch/riscv/include/asm/pgtable.h > > > > > : @@ -415,7 +415,7 @@ static inline void update_mmu_cache(struct vm_area_struct *vma, > > > > > : * Relying on flush_tlb_fix_spurious_fault would suffice, but > > > > > : * the extra traps reduce performance. So, eagerly SFENCE.VMA. > > > > > : */ > > > > > : - flush_tlb_page(vma, address); > > > > > : + local_flush_tlb_page(address); > > > > > : } > > > > > : > > > > > : static inline void update_mmu_cache_pmd(struct vm_area_struct *vma, > > > > > > > > > I tested your above proposed changes and I am no longer seeing an > > > > issue on my platform. > > > > > > Great. I will send a fixup after I double-check on several other > > > hardware platforms. Thanks for testing ! > > > > > Actuall, I did hit an issue now with your proposed changes with bonnie++ again! > > > > [ 1873.355279] EXT4-fs (sda1): mounted filesystem > > 050ad3b9-b571-4b4c-9500-db56feed01ab with ordered data mode. Quota > > mode: disabled. > > Using uid:0, gid:0. > > Writing with putc()...done > > Writing intelligently...done > > Rewriting...done > > Reading with getc()...[ 2682.180114] sd-resolve[126]: unhandled signal > > 11 code 0x1 at 0x0000000000000000 in libc-2.28.so[3fbe503000+ff000] > > [ 2682.190552] CPU: 0 PID: 126 Comm: sd-resolve Not tainted > > 6.2.0-rc1-00111-g7bcd7d932cf6 #189 > > [ 2682.198917] Hardware name: Renesas SMARC EVK based on r9a07g043f01 (DT) > > [ 2682.205536] epc : 0000003fbe568004 ra : 0000003fbe569440 sp : > > 0000003fbe417b10 > > [ 2682.212770] gp : 0000002ab8d18b88 tp : 0000003fbe41e810 t0 : > > 0000000000000022 > > [ 2682.219987] t1 : 0000003fbdbf1e4c t2 : 0000003fbe417290 s0 : > > 00000000000000e0 > > [ 2682.227219] s1 : 0000000000000000 a0 : 0000000000000000 a1 : > > 8080808080808080 > > [ 2682.234433] a2 : 0000003fb80019f0 a3 : 0000003fbe41e8f0 a4 : > > 0000000000000008 > > [ 2682.241648] a5 : 0000000000000000 a6 : fefefefefefefeff a7 : > > 0000000000000039 > > [ 2682.248863] s2 : 0000003fbe417b37 s3 : 0000003fbe417e48 s4 : > > 0000000000000001 > > [ 2682.256082] s5 : 0000003fbe417eb0 s6 : 00000000000000e0 s7 : > > 0000003fbdbf2f2a > > [ 2682.263297] s8 : ffffffffffffffff s9 : fffffffffffffffd s10: > > ffffffffffffffff > > [ 2682.270511] s11: fffffffffffffffe t3 : 0000000000000000 t4 : > > 000000077ce2ea37 > > [ 2682.277733] t5 : 000000000000003f t6 : 0000000000000000 > > [ 2682.283046] status: 0000000200004020 badaddr: 0000000000000000 > > cause: 000000000000000d > > [ 2682.441183] audit: type=1701 audit(1671222620.403:17): > > auid=4294967295 uid=995 gid=994 ses=4294967295 pid=124 > > comm="sd-resolve" exe="/lib/systemd/systemd-timesyncd" sig=11 res=1 > > done > > Reading intelligently...done > > > > Let me know if you want me to share my branch. > > Hmmm... I assume you hit the issue after you applied suggested partial > revert for the update_mmu_cache function. If so, then your issue is not > related to the the remaining part (deferred local_flush_tlb_all_asid) > of the commit 4bd1d80efb5a. This is because that flush is not executed > on a single-core system, even if CONFIG_SMP is enabled. > > Could you please run your tests for a while on your branch with reverted > commit 4bd1d80efb5a ("riscv: mm: notify remote harts about mmu cache > updates"). It looks like the change in the function update_mmu_cache > from the commit 4bd1d80efb5a increases the probability of crash, but > there is also something else in the new kernel that bites your system. > > Yes, could you please share your branch. I will take a look and run > some tests on different boards that I have at hand. > Do you have any further updates on this? Cheers, Prabhakar
