[PATCH] ARM: socfpga: put back v7_invalidate_l1 in socfpga_secondary_startup

[dinguyen@opensource.altera.com (Dinh Nguyen)]

On 07/08/2015 11:51 AM, Russell King - ARM Linux wrote:
> On Wed, Jul 08, 2015 at 10:51:51AM -0500, dinguyen at opensource.altera.com wrote:
>> From: Dinh Nguyen <dinguyen@opensource.altera.com>
>>
>> The commit "02b4e2756e01 ARM: v7 setup function should invalidate L1 cache"
>> caused the SoCFPGA to not boot reliably. About 20% of the time or roughly
>> (1 in 5), booting the platform would cause this kernel panic:
>>
>> CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
>> Internal error: Oops - undefined instruction: 0 [#1] SMP ARM
>> Modules linked in:
>> CPU: 1 PID: 0 Comm: swapper/1 Not tainted
>> 4.1.0-rc8-next-20150617-00002-gdd1f624 #1
>> Hardware name: Altera SOCFPGA
>> task: eecaeac0 ti: eecce000 task.ti: eecce000
>> PC is at vfp_notifier+0x58/0x12c
>> LR is at notifier_call_chain+0x44/0x84
>> pc : [<c000a6bc>]    lr : [<c003d134>]    psr: 80000193
>> sp : eeccff48  ip : c06563c8  fp : eeccffd4
>> r10: eecaef80  r9 : ef1f1300  r8 : 00000002
>> r7 : eecd0000  r6 : c0656bc0  r5 : 00000000  r4 : eecd0000
>> r3 : c000a664  r2 : eecd0000  r1 : 00000002  r0 : c06563c8
>> Flags: Nzcv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
>> Control: 10c5387d  Table: 0000404a  DAC: 00000015
>> Process swapper/1 (pid: 0, stack limit = 0xeecce218)
>> Stack: (0xeeccff48 to 0xeecd0000)
>> ff40:                   c000a664 ffffffff 00000000 c003d134 eecd0018 eecaeac0
>> ff60: c06648e0 0b52d2f9 c048cfa8 c003d18c 00000000 f0002100 00000001 c003d1ac
>> ff80: 00000000 eecaeac0 c064f300 c001369c c064b304 c0013140 00000000 ef1ed328
>> ffa0: eeccffe8 c001e760 c0486ec4 2eba2000 c06957c0 c06524dc 00000015 c06957c0
>> ffc0: c048c778 c064b304 c06957c0 00000000 eeccffdc c0486ec4 eeccffe4 c0487138
>> ffe0: 00000001 c00544e8 c0009494 c0697bc0 00000000 000094ac 7ef5bffd 3f39b3f8
>> [<c000a6bc>] (vfp_notifier) from [<c003d134>] (notifier_call_chain+0x44/0x84)
>> [<c003d134>] (notifier_call_chain) from [<c003d18c>]
>> (__atomic_notifier_call_chain+0x18/0x20)
>> [<c003d18c>] (__atomic_notifier_call_chain) from [<c003d1ac>]
>> (atomic_notifier_call_chain+0x18/0x20)
>> [<c003d1ac>] (atomic_notifier_call_chain) from [<c001369c>]
>> (__switch_to+0x34/0x58)
>> Code: e3a03002 e5843208 e3a00000 e8bd8038 (eef85a10)
>> ---[ end trace 9eaea9661b3b550a ]---
>> Kernel panic - not syncing: Attempted to kill the idle task!
>> SMP: failed to stop secondary CPUs
>> ---[ end Kernel panic - not syncing: Attempted to kill the idle task!
>>
>> So this patch puts back the call to v7_invalidate_l1 in the secondary_startup
>> path, and the platform is now able to boot up reliably.
>>
>> Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
> 
> Can you print the value of CPACR in the oops and reproduce please?
> I suspect, somehow, the CPACR is not allowing CPU1 access to the VFP,
> but this is not controlled by data as such (it can only go wrong if
> the hotplug notifier call chain misses calling into the VFP code.)
> 

The value of CPACR is 0x00F00000. So cp11 and cp10 are privileged and
user mode access.

Dinh