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Subject: Re: [PATCH v3 08/16] irqchip/gic: Configure SGIs as standard
 interrupts
To:     Marc Zyngier <maz@kernel.org>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Will Deacon <will@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Russell King <linux@arm.linux.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>,
        Sumit Garg <sumit.garg@linaro.org>,
        Valentin Schneider <Valentin.Schneider@arm.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Gregory Clement <gregory.clement@bootlin.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Saravana Kannan <saravanak@google.com>,
        kernel-team@android.com,
        'Linux Samsung SOC' <linux-samsung-soc@vger.kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
From:   Marek Szyprowski <m.szyprowski@samsung.com>
Message-ID: <ce90375a-6752-1fa9-6927-991a99168b33@samsung.com>
Date:   Tue, 15 Sep 2020 10:35:27 +0200
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References: <20200901144324.1071694-1-maz@kernel.org>
        <20200901144324.1071694-9-maz@kernel.org>
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        <65565f85-d932-37f3-a8cd-dbd13d7dbfad@samsung.com>
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Hi Marc,

On 15.09.2020 10:07, Marc Zyngier wrote:
> On 2020-09-15 07:48, Marek Szyprowski wrote:
>>>> Both Exynos 4210 and 4412 use non-zero cpu-offset in GIC node in
>>>> device-tree: arch/arm/boot/dts/exynos{4210,4412}.dtsi, so I assume 
>>>> that
>>>> the GIC registers are not banked.
>>>
>>> Annoyingly, it seems to work correctly in QEMU:
>
> [...]
>
>>> Do you happen to know whether the QEMU emulation is trustworthy?
>>
>> I didn't play much with Exynos emulation on QEMU. All I know is that
>> this patch simply doesn't work on the real hw.
>
> I don't doubt it. The question was more whether we could trust QEMU
> to be reliable, in which case the issue would be around a kernel
> configuration problem. Could you stash your kernel config somewhere?

I just use the vanilla exynos_defconfig for my tests.

>> If there is anything to check or test, let me know. I will try to help
>> as much as possible.
>
> It would be interesting to see whether the CPUs are getting any IPI.
> Can you try the following patch, and send the results back?

Starting kernel ...

[    0.000000] Booting Linux on physical CPU 0x900
[    0.000000] Linux version 5.9.0-rc4-00008-gac063232d4b0-dirty 
(mszyprow@AMDC2765) (arm-linux-gnueabi-gcc (Linaro GCC 4.9-2017.01) 
4.9.4, GNU ld (Linaro_Binutils-2017.01) 2.24.0.20141017 Linaro 
2014_11-3-git) #9174 SMP PREEMPT Tue Sep 15 10:30:46 CEST 2020
[    0.000000] CPU: ARMv7 Processor [412fc091] revision 1 (ARMv7), 
cr=10c5387d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing 
instruction cache
[    0.000000] OF: fdt: Machine model: Samsung Trats based on Exynos4210
[    0.000000] earlycon: exynos4210 at MMIO 0x13820000 (options '115200n8')
[    0.000000] printk: bootconsole [exynos4210] enabled
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] cma: Reserved 96 MiB at 0x7a000000
[    0.000000] Samsung CPU ID: 0x43210211
[    0.000000] Zone ranges:
[    0.000000]   Normal   [mem 0x0000000040000000-0x000000006fffffff]
[    0.000000]   HighMem  [mem 0x0000000070000000-0x000000007fffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000040000000-0x000000007fffffff]
[    0.000000] Initmem setup node 0 [mem 
0x0000000040000000-0x000000007fffffff]
[    0.000000] percpu: Embedded 20 pages/cpu s51904 r8192 d21824 u81920
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 260608
[    0.000000] Kernel command line: root=PARTLABEL=data rootwait 
console=tty1 console=ttySAC2,115200n8 earlycon
[    0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 
bytes, linear)
[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 
bytes, linear)
[    0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[    0.000000] Memory: 917072K/1048576K available (10240K kernel code, 
958K rwdata, 4000K rodata, 1024K init, 6487K bss, 33200K reserved, 
98304K cma-reserved, 163840K highmem)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
[    0.000000] Running RCU self tests
[    0.000000] rcu: Preemptible hierarchical RCU implementation.
[    0.000000] rcu:     RCU event tracing is enabled.
[    0.000000] rcu:     RCU lockdep checking is enabled.
[    0.000000] rcu:     RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=2.
[    0.000000]  Trampoline variant of Tasks RCU enabled.
[    0.000000] rcu: RCU calculated value of scheduler-enlistment delay 
is 10 jiffies.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=2
[    0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[    0.000000] CPU0 IPI0 base = f0800000
[    0.000000] CPU0 IPI1 base = f0800000
[    0.000000] CPU0 IPI2 base = f0800000
[    0.000000] CPU0 IPI3 base = f0800000
[    0.000000] CPU0 IPI4 base = f0800000
[    0.000000] CPU0 IPI5 base = f0800000
[    0.000000] CPU0 IPI6 base = f0800000
[    0.000000] CPU0 IPI7 base = f0800000
[    0.000000] L2C: platform modifies aux control register: 0x02070000 
-> 0x3e470000
[    0.000000] L2C: DT/platform modifies aux control register: 
0x02070000 -> 0x3e470000
[    0.000000] L2C-310 enabling early BRESP for Cortex-A9
[    0.000000] L2C-310 full line of zeros enabled for Cortex-A9
[    0.000000] L2C-310 dynamic clock gating enabled, standby mode enabled
[    0.000000] L2C-310 cache controller enabled, 16 ways, 1024 kB
[    0.000000] L2C-310: CACHE_ID 0x4100c4c5, AUX_CTRL 0x4e470001
[    0.000000] random: get_random_bytes called from 
start_kernel+0x4c0/0x67c with crng_init=0
[    0.000000] Exynos4210 clocks: sclk_apll = 800000000, sclk_mpll = 
800000000
[    0.000000]  sclk_epll = 96000000, sclk_vpll = 108000000, arm_clk = 
800000000
[    0.000000] Switching to timer-based delay loop, resolution 41ns
[    0.000000] clocksource: mct-frc: mask: 0xffffffff max_cycles: 
0xffffffff, max_idle_ns: 79635851949 ns
[    0.000007] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps 
every 89478484971ns
[    0.008850] Console: colour dummy device 80x30
[    0.017306] printk: console [tty1] enabled
[    0.019992] Lock dependency validator: Copyright (c) 2006 Red Hat, 
Inc., Ingo Molnar
[    0.027791] ... MAX_LOCKDEP_SUBCLASSES:  8
[    0.031793] ... MAX_LOCK_DEPTH:          48
[    0.035959] ... MAX_LOCKDEP_KEYS:        8192
[    0.040327] ... CLASSHASH_SIZE:          4096
[    0.044643] ... MAX_LOCKDEP_ENTRIES:     32768
[    0.049096] ... MAX_LOCKDEP_CHAINS:      65536
[    0.053497] ... CHAINHASH_SIZE:          32768
[    0.057948]  memory used by lock dependency info: 4029 kB
[    0.063318]  memory used for stack traces: 2112 kB
[    0.068110]  per task-struct memory footprint: 1536 bytes
[    0.073536] Calibrating delay loop (skipped), value calculated using 
timer frequency.. 48.00 BogoMIPS (lpj=240000)
[    0.083901] pid_max: default: 32768 minimum: 301
[    0.088789] Mount-cache hash table entries: 2048 (order: 1, 8192 
bytes, linear)
[    0.095733] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 
bytes, linear)
[    0.106706] CPU: Testing write buffer coherency: ok
[    0.110276] CPU0: Spectre v2: using BPIALL workaround
[    0.116474] CPU0: thread -1, cpu 0, socket 9, mpidr 80000900
[    0.124225] Setting up static identity map for 0x40100000 - 0x40100060
[    0.130539] rcu: Hierarchical SRCU implementation.
[    0.137562] soc soc0: Exynos: CPU[EXYNOS4210] PRO_ID[0x43210211] 
REV[0x11] Detected
[    0.145493] smp: Bringing up secondary CPUs ...
[    0.152740] CPU0 send IPI0 base = f0800000
[    0.152786] CPU1: Booted secondary processor
[    0.155582] CPU0 send IPI0 base = f0800000
[    0.163945] CPU1 IPI0 base = f0808000
[    0.163956] CPU1 IPI1 base = f0808000
[    0.163966] CPU1 IPI2 base = f0808000
[    0.163976] CPU1 IPI3 base = f0808000
[    0.163986] CPU1 IPI4 base = f0808000
[    0.163995] CPU1 IPI5 base = f0808000
[    0.164004] CPU1 IPI6 base = f0808000
[    0.164014] CPU1 IPI7 base = f0808000
[    0.164025] CPU1: thread -1, cpu 1, socket 9, mpidr 80000901
[    0.164035] CPU1: Spectre v2: using BPIALL workaround
[    0.203803] CPU1 send IPI2 base = f0808000
[    0.207834] CPU1 IPI0 received
[    0.207839] CPU0 IPI2 received
[    0.214052] CPU0 send IPI2 base = f0800000
[    0.217990] CPU1 IPI2 received
[    0.222188] CPU1 send IPI2 base = f0808000
[    2.754062] random: fast init done

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland