O Thu, Oct 22, 2020 at 09:26:59AM +0200, Jan Kiszka wrote: > On 22.10.20 08:27, Jan Kiszka via Xenomai wrote: > > On 21.10.20 13:43, Fino Meng wrote: > >> On Wed, Oct 21, 2020 at 08:36:04AM +0200, Jan Kiszka wrote: > >>> On 18.10.20 23:41, Jan Kiszka via Xenomai wrote: > >>>> On 16.10.20 05:36, Fino Meng wrote: > >>>>> On Thu, Oct 15, 2020 at 04:20:11PM +0200, Jan Kiszka wrote: > >>>>>> On 14.10.20 15:25, Fino Meng wrote: > >>>>>>> hi team, > >>>>>>> > >>>>>>> I just updated the scripts to build the WIP version xenomai porting to > >>>>>>> kernel 5.4, just follow the steps: > >>>>>>> > >>>>>>> git clone https://github.com/finomeng/xenomai-mirror.git > >>>>>>> /tmp/xenomai-mirror.next-5.4 > >>>>>>> cd /tmp/xenomai-mirror.next-5.4 > >>>>>>> git checkout -t origin/wip/next-5.4-porting > >>>>>>> > >>>>>>> git clone https://github.com/intel/linux-stable-xenomai /tmp/kernel > >>>>>>> cd /tmp/kernel > >>>>>>> git checkout -t review/5.4.59/stable/ipipe-x86 > >>>>>>> > >>>>>>> ./patching-xenomai2kernel.sh > >>>>>>> > >>>>>>> cp config_xenomai.kernel_debug .config > >>>>>>> make olddefconfig > >>>>>>> ./build-debpkg.sh > >>>>>>> > >>>>>>> > >>>>>>> I didn't put it togethter with ISAR/Debian yet. I test it with a PC > >>>>>>> with Debian 10 installed. > >>>>>>> > >>>>>>> if no error, linux-image-*.deb and linux-headers-*.deb should > >>>>>>> generated outside kernel folder, > >>>>>>> copy them to your target test device with already installed a > >>>>>>> Debian/Ubuntu, > >>>>>>> install the deb with "dpkg -i", update-grub should be called during > >>>>>>> install linux-image-*.deb > >>>>>>> reboot and select to boot the new kernel in grub's menu > >>>>>>> > >>>>>>> the build steps also written in patching-xenomai2kernel.sh and > >>>>>>> build-debpkg.sh > >>>>>>> > >>>>>>> switchtest will fail in current version, for example: "./switchtest > >>>>>>> rtk_fp_ufpp0" > >>>>>>> will print: > >>>>>>> > >>>>>>> r0: 2147483648 != 1000 > >>>>>>> r1: 2147483648 != 1000 > >>>>>>> r2: 2147483648 != 1000 > >>>>>>> r3: 2147483648 != 1000 > >>>>>>> r4: 2147483648 != 1000 > >>>>>>> r5: 2147483648 != 1000 > >>>>>>> r6: 2147483648 != 1000 > >>>>>>> r7: 2147483648 != 1000 > >>>>>>> ymm0: 2676586395008836901/0 != 1000/1000 > >>>>>>> ymm1: 71776119061217280/0 != 1000/1000 > >>>>>>> ymm2: 0/0 != 1000/1000 > >>>>>>> ymm3: 1000/0 != 1000/1000 > >>>>>>> ymm4: 1000/0 != 1000/1000 > >>>>>>> ymm5: 1000/0 != 1000/1000 > >>>>>>> ymm6: 1000/0 != 1000/1000 > >>>>>>> ymm7: 1000/0 != 1000/1000 > >>>>>>> Error after context switch from task 1(rtk_fp_ufpp0-1) to task > >>>>>>> 0(sleeper_ufps0-0), > >>>>>>> FPU registers were set to 0 (maybe task sleeper_ufps0-0) > >>>>>>> > >>>>>>> if meet more questions just write to me, thanks! > >>>>>>> > >>>>>>> BR fino > >>>>>>> > >>>>>> > >>>>>> I can reproduce in KVM and poked around a bit, though without finding > >>>>>> the needle yet. Likely, there are multiple aspects. The change in > >>>>>> upstream to FPU switching on user-return is a hot lead, but it takes a > >>>>>> bit to fully grasp that and map it on our scenarios with Xenomai. > >>>>>> > >>>>>> Jan > >>>>> > >>>>> it seems that, switch_fpu_prepare() and switch_fpu_finish() are > >>>>> for kernel thread context switch (in __switch_to() )and > >>>>> switch_fpu_return() is needed > >>>>> before return to userspace( in prepare_exit_to_usermode()). > >>>>> > >>>> > >>>> Yes, we need explicit switch_fpu_return() (likely open-coded, to skip > >>>> the PF_KTHREAD check) at the end of xnarch_switch_to, at least as long > >>>> as we do not add that to all fast (primary-mode) return-to-user paths. > >>>> > >>>> But it's more complex. The removal of fpu_initialized changed the > >>>> condition under which __switch_to() does FPU saving and restoring: All > >>>> kernel threads, also ours, are excluded. That needs to be compensated. > >>>> > >>>> But I'm still facing corruptions - continuing to debug. > >>>> > >>> > >>> Quick update: > >>> > >>> I made some progress with changes like below, but I'm still facing > >>> issues, not with weird AVX register corruptions. They confuse me because > >>> classic FPU registers are updated and saved/restored the same way, but > >>> they are currently unaffected. > >>> > >>> Jan > >> > >> in my current understand, > >> a userspace Xenomai/Cobalt process's context switch always need FPU > >> state save/restore; but how about the other case? > >> > >> in vanilla kernel, I see if a pure kernel thread want to use FPU, need > >> manually call kernel_fpu_begin() and kernel_fpu_end(), like a critical > >> area. > > > > Xenomai kernel threads can use the FPU, and that without > > kernel_fpu_begin/end. That this works is also tested by switchtest, and > > there were several issues, possibly there are still more. > > > > One step further: My weird avx register corruption is understand. It was > > the local instrumentation. xnftrace_printf likely uses xmm regs > > internally, and I had such an output after setting up the test pattern. > > Fixing that, I still have a corruption, but not a "normal one" again, > > ie. of the legacy FPU regs. > > > > Jan > > > > Got it working: > > diff --git a/kernel/cobalt/arch/x86/thread.c b/kernel/cobalt/arch/x86/thread.c > index aa7b5d19d8..9a014818ef 100644 > --- a/kernel/cobalt/arch/x86/thread.c > +++ b/kernel/cobalt/arch/x86/thread.c > @@ -215,6 +215,15 @@ void xnarch_switch_to(struct xnthread *out, struct > xnthread *in) > */ > clts(); > #endif /* ! IPIPE_X86_FPU_EAGER */ > + if (!xnthread_test_state(out, XNROOT | XNUSER) && > + !test_thread_flag(TIF_NEED_FPU_LOAD)) { > + struct fpu *prev_fpu = &prev->thread.fpu; > + > + if (!copy_fpregs_to_fpstate(prev_fpu)) > + prev_fpu->last_cpu = -1; > + else > + prev_fpu->last_cpu = smp_processor_id(); > + } > > next = in_tcb->core.host_task; > #ifndef IPIPE_X86_FPU_EAGER > @@ -260,6 +269,19 @@ void xnarch_switch_to(struct xnthread *out, struct > xnthread *in) > #ifndef IPIPE_X86_FPU_EAGER > stts(); > #endif /* ! IPIPE_X86_FPU_EAGER */ > + if (xnthread_current() && > + !xnthread_test_state(xnthread_current(), XNROOT) && > + test_thread_flag(TIF_NEED_FPU_LOAD)) { > + struct fpu *fpu = ¤t->thread.fpu; > + int cpu = smp_processor_id(); > + > + if (!fpregs_state_valid(fpu, cpu)) { > + copy_kernel_to_fpregs(&fpu->state); > + fpregs_activate(fpu); > + fpu->last_cpu = cpu; > + } > + clear_thread_flag(TIF_NEED_FPU_LOAD); > + } > } > > #ifndef IPIPE_X86_FPU_EAGER > @@ -488,6 +510,7 @@ void xnarch_switch_fpu(struct xnthread *from, struct > xnthread *to) > return; > > copy_kernel_to_fpregs(&to_tcb->kfpu->state); > + __cpu_invalidate_fpregs_state(); > kernel_fpu_disable(); > } > #endif /* ! IPIPE_X86_FPU_EAGER */ > @@ -541,7 +564,8 @@ void xnarch_init_shadow_tcb(struct xnthread *thread) > #if LINUX_VERSION_CODE < KERNEL_VERSION(4,14,0) > fpu__activate_fpstate_read(&p->thread.fpu); > #else > - fpu__clear(&p->thread.fpu); > + set_thread_flag(TIF_NEED_FPU_LOAD); > + fpstate_init(&p->thread.fpu.state); > #endif > #endif /* ! IPIPE_X86_FPU_EAGER */ > } > > > This still requires proper wrapping for the different kernel versions > and some comments. But maybe you can continue testing from there. > > > BTW, there are more to-dos: > > [ 0.182466] Freeing SMP alternatives memory: 44K > [ 0.182656] ------------[ cut here ]------------ > [ 0.183038] WARNING: CPU: 0 PID: 0 at ../kernel/ipipe/core.c:1968 > __ipipe_spin_unlock_debug+0x14/0x20 > [ 0.183600] Modules linked in: > [ 0.183600] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.59-xenomai+ #64 > [ 0.183600] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS > rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 > [ 0.183600] I-pipe domain: Linux > [ 0.183600] RIP: 0010:__ipipe_spin_unlock_debug+0x14/0x20 > [ 0.183600] Code: 8b 07 5b e9 0e d5 c7 00 5b c3 66 66 2e 0f 1f 84 00 00 00 > 00 00 90 e8 bb de a7 00 f7 c7 00 02 00 00 74 09 9c 58 f6 c4 02 75 02 <0f> 0b > c3 66 0f 1f 84 00 00 00 00 00 e8 9b de a7 00 41 54 55 53 9c > [ 0.183600] RSP: 0000:ffffffff82403d68 EFLAGS: 00010046 > [ 0.183600] RAX: 0000000000000006 RBX: b74e512d1320154d RCX: > ffff88803e6f2cc0 > [ 0.183600] RDX: 0000000000000001 RSI: ffffffff810c1c9e RDI: > 0000000000000200 > [ 0.183600] RBP: ffff88803ea3afe4 R08: 0000000000000000 R09: > ffff88803dd0e540 > [ 0.183600] R10: 0000000000000002 R11: 0000000000000001 R12: > 0000000000000200 > [ 0.183600] R13: ffff88803dd0da00 R14: ffffffff82403eb0 R15: > 0000000000000000 > [ 0.183600] FS: 0000000000000000(0000) GS:ffff88803ea00000(0000) > knlGS:0000000000000000 > [ 0.183600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.183600] CR2: ffff888003201000 CR3: 000000000240a001 CR4: > 0000000000360ef0 > [ 0.183600] DR0: 0000000000000000 DR1: 0000000000000000 DR2: > 0000000000000000 > [ 0.183600] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: > 0000000000000400 > [ 0.183600] Call Trace: > [ 0.183600] get_random_u64+0x68/0x80 > [ 0.183600] copy_process+0x37e/0x1ae0 > [ 0.183600] _do_fork+0x92/0x340 > [ 0.183600] ? acpi_hw_register_read+0x93/0x123 > [ 0.183600] kernel_thread+0x55/0x70 > [ 0.183600] ? rest_init+0xc0/0xc0 > [ 0.183600] rest_init+0x1e/0xc0 > [ 0.183600] start_kernel+0x4d4/0x4f9 > [ 0.183600] secondary_startup_64+0xa4/0xb0 > [ 0.183600] ---[ end trace 9d5e39ac2de18173 ]--- > > This is with I-pipe debugging enabled. Could you have a look? > > Jan
great! thanks~ sure I will test it, try to reproduce it first. BR Fino > > -- > Siemens AG, T RDA IOT > Corporate Competence Center Embedded Linux
