From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: build scripts for the WIP xenomai porting to kernel 5.4 References: <20201014132459.GB24671@linux.intel.com> <8e59bc35-84ae-78be-8296-4f2367e8e844@siemens.com> <20201016033638.GB5581@linux.intel.com> <0ba45dfa-4755-c627-e1fd-9f2c32ea8b8a@siemens.com> <9153481d-6df6-314f-c2c0-f413a34fb815@siemens.com> <20201021114329.GA4344@linux.intel.com> <88232cd0-0713-4e45-bad2-e22acdeb7632@siemens.com> <3a85c6c8-6792-40d1-5ef2-6ee634fc3c91@siemens.com> <20201022114938.GA8098@linux.intel.com> From: Jan Kiszka Message-ID: <39ccbc86-3f64-0941-241b-30e2431468cf@siemens.com> Date: Thu, 22 Oct 2020 14:15:23 +0200 MIME-Version: 1.0 In-Reply-To: <20201022114938.GA8098@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fino Meng Cc: xenomai@xenomai.org On 22.10.20 13:49, Fino Meng wrote: > On 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? >> > > I cannot reproduce it, > > I use this config with IPIPE_DEBUG > https://github.com/intel/linux-stable-xenomai/blob/review/5.4.59/stable/ipipe-x86/config_xenomai.xeno_debug > > test on a real WHL-U board (UP Xtreme), kernel boot OK and swtichtest > runs continously without error. > > another config also have no error: > https://github.com/intel/linux-stable-xenomai/blob/review/5.4.59/stable/ipipe-x86/config_xenomai.kernel_debug > > am I missing something? need to test the image inside QEMU/KVM? and this issue happens > during boot or after launch the switchtest? This comes once during boot (in QEMU/KVM, but that should not matter - famous last words). I have this set here: CONFIG_IPIPE_DEBUG=y CONFIG_IPIPE_DEBUG_CONTEXT=y CONFIG_IPIPE_DEBUG_INTERNAL=y CONFIG_HAVE_IPIPE_TRACER_SUPPORT=y CONFIG_IPIPE_TRACE=y # CONFIG_IPIPE_TRACE_ENABLE is not set CONFIG_IPIPE_TRACE_MCOUNT=y # CONFIG_IPIPE_TRACE_IRQSOFF is not set CONFIG_IPIPE_TRACE_SHIFT=14 CONFIG_IPIPE_TRACE_VMALLOC=y CONFIG_IPIPE_TRACE_PANIC=y If you look at the source of the warning, you can see that CONFIG_IPIPE_DEBUG_INTERNAL=y makes the difference. Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux