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> <39ccbc86-3f64-0941-241b-30e2431468cf@siemens.com> <20201022132522.GA9776@linux.intel.com> From: Jan Kiszka Message-ID: Date: Thu, 22 Oct 2020 17:22:35 +0200 MIME-Version: 1.0 In-Reply-To: <20201022132522.GA9776@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 15:25, Fino Meng wrote: > On Thu, Oct 22, 2020 at 02:15:23PM +0200, Jan Kiszka wrote: >> 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 > > well I still boot OK with IPIPE_DEBUG_INTERNAL. Will check source code > tomorrow. > Found, not yet fixed though: fpregs_unlock does not use the flags that fpregs_lock saves. That can kill kittens. We likely need to change the signature of that functions AND patch all callers. Examining... Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux