Re: imx7d dual core boot

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello,

On 3/27/20 9:27 AM, Giorgio wrote:
> Hi,
> 
> maybe 'crash' was not the best word to describe the effect I see;
> 
> the bootloader just stops running, never returns from the call
> to __mmu_cache_on(), there's no debug messages or stack dumps;
> in this case the kernel image is not started.
> 
> I think on my arch / soc __mmu_cache_on() calls some asm coded function
> defined in arch/arm/cpu/cache-armv7.S (v7_mmu_cache_on) and one
> of the opcodes there crashes the cpu directly. Maybe I should try to
> dump the core state (registers, ...) on the console just before jumping
> to v7_mmu_cache_on.

AFAIU, non-secure barebox keeps reusing the secure monitor barebox till
it boots the kernel. The secure monitor already had translation tables
set up and active and non-secure barebox reuses those.

Given that this should've worked once, could you run a git-bisect and
see when it broke?

If you make bnet the default target, only board interaction you need
for bisecting should be the power cycle when you do a git bisect bad.

This is most likely the fastest way to find what broke it.

Cheers
Ahmad

> 
> giorgio
> 
> On 3/27/20 6:56 AM, Ahmad Fatoum wrote:
>> Hello,
>>
>> On 3/26/20 11:21 AM, Giorgio wrote:
>>> Hi,
>>>
>>> I'm having problems booting a linux kernel image on an imx7d.
>>>
>>> What I want is to boot in nonsecure mode and that the kernel enables the
>>> second core with the PSCI.
>>>
>>> What I see is that barebox crashes within the call to __mmu_cache_on()
>>> in the file arch/arm/cpu/sm.c:
>>
>> The kind of crash may be useful info. Can you copy the whole boot log?
>>
>>>
>>> int armv7_secure_monitor_install(void)
>>> {
>>> ...
>>> 	if (mmuon) {
>>> 		/*
>>> 		 * If the MMU was already turned on in secure mode, enable it in
>>> 		 * non-secure mode aswell
>>> 		 */
>>> 		__mmu_cache_on();
>>> 	}
>>> ...
>>>
>>>
>>> As a workaround, if I comment the call to __mmu_cache_on(), the system
>>> boots properly with 2 cores:
>>>
>>> Loading ARM Linux zImage '/mnt/boot/kernel.img'
>>> Loading devicetree from '/mnt/boot/devtree.dtb'
>>> commandline: console=ttymxc5,115200n8 ip=::::gdm:eth0:off root=PARTUUID=37199a57-ec72-41f9-ab27-445329d1bd77 rootwait
>>> Starting kernel in nonsecure mode
>>> [    0.000000] 000: Booting Linux on physical CPU 0x0
>>> [    0.000000] 000: Linux version 5.4.24-rt15-dirty (giorgio@BVblfs) (gcc version 9.2.1 20200110 (OSELAS.Toolchain 9.2.1)) #1 SMP PREEMPT_RT Fri Mar 13 17:25:51 CET 2020
>>> [    0.000000] 000: CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d
>>> [    0.000000] 000: CPU: div instructions available: patching division code
>>> [    0.000000] 000: CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
>>> t[    0.000000] 000: Memory policy: Data cache writealloc
>>> [    0.000000] 000: cma: Reserved 64 MiB at 0xfa000000
>>> [    0.000000] 000: psci: probing for conduit method from DT.
>>> [    0.000000] 000: psci: PSCIv1.0 detected in firmware.
>>> [    0.000000] 000: psci: Using standard PSCI v0.2 function IDs
>>> [    0.000000] 000: psci: MIGRATE_INFO_TYPE not supported.
>>> [    0.000000] 000: psci: SMC Calling Convention v1.0
>>> [    0.000000] 000: percpu: Embedded 9 pages/cpu s15008 r0 d21856 u36864
>>> [    0.000000] 000: Built 1 zonelists, mobility grouping on.  Total pages: 522751
>>> [    0.000000] 000: Kernel command line: console=ttymxc5,115200n8 ip=::::gdm:eth0:off root=PARTUUID=37199a57-ec72-41f9-ab27-445329d1bd77 rootwait
>>> [    0.000000] 000: Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes, linear)
>>> [    0.000000] 000: Inode-cache hash table entries: 65536 (order: 6, 262144 bytes, linear)
>>> [    0.000000] 000: mem auto-init: stack:off, heap alloc:off, heap free:off
>>> [    0.000000] 000: Memory: 1997464K/2097148K available (9216K kernel code, 430K rwdata, 3100K rodata, 1024K init, 733K bss, 34148K reserved, 65536K cma-reserved, 1244448K highmem)
>>> [    0.000000] 000: SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
>>> [    0.000000] 000: rcu: Preemptible hierarchical RCU implementation.
>>> [    0.000000] 000: rcu: 	RCU priority boosting: priority 1 delay 500 ms.
>>> [    0.000000] 000: rcu: 	RCU_SOFTIRQ processing moved to rcuc kthreads.
>>> [    0.000000] 000: 	No expedited grace period (rcu_normal_after_boot).
>>> [    0.000000] 000: 	Tasks RCU enabled.
>>> [    0.000000] 000: rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
>>> [    0.000000] 000: NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
>>> [    0.000000] 000: rcu: 	Offload RCU callbacks from CPUs: (none).
>>> [    0.000000] 000: arch_timer: cp15 timer(s) running at 8.00MHz (virt).
>>> [    0.000000] 000: clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x1d854df40, max_idle_ns: 440795202120 ns
>>> [    0.000001] 000: sched_clock: 56 bits at 8MHz, resolution 125ns, wraps every 2199023255500ns
>>> [    0.000013] 000: Switching to timer-based delay loop, resolution 125ns
>>> [    0.000426] 000: Switching to timer-based delay loop, resolution 41ns
>>> [    0.000438] 000: sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
>>> [    0.000450] 000: clocksource: mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
>>> [    0.001597] 000: Console: colour dummy device 80x30
>>> [    0.001642] 000: Calibrating delay loop (skipped), value calculated using timer frequency.. 48.00 BogoMIPS (lpj=240000)
>>> [    0.001650] 000: pid_max: default: 32768 minimum: 301
>>> [    0.001788] 000: Mount-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
>>> [    0.001807] 000: Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
>>> [    0.002631] 000: CPU: Testing write buffer coherency: ok
>>> [    0.059991] 000: Setting up static identity map for 0x80100000 - 0x80100060
>>> [    0.079972] 000: rcu: Hierarchical SRCU implementation.
>>> [    0.160105] 000: smp: Bringing up secondary CPUs ...
>>> [    0.280687] 000: smp: Brought up 1 node, 2 CPUs
>>> [    0.280697] 000: SMP: Total of 2 processors activated (96.00 BogoMIPS).
>>> [    0.280705] 000: CPU: All CPU(s) started in SVC mode.
>>> [    0.281170] 000: devtmpfs: initialized
>>> [    0.290961] 000: random: get_random_u32 called from bucket_table_alloc+0x58/0x14c with crng_init=0
>>>
>>>
>>> giorgio
>>>
>>> _______________________________________________
>>> barebox mailing list
>>> barebox@lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/barebox
>>>
>>
> 

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