linux-kernel - Re: [PATCH v5 1/9] arm64: dts: exynos: Add dts files for 64-bit Exynos5433 SoC

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-id: <54F9140B.3060109@samsung.com>
Date:	Fri, 06 Mar 2015 11:42:19 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	Mark Rutland <mark.rutland@....com>
Cc:	Chanwoo Choi <cwchoi00@...il.com>,
	"kgene@...nel.org" <kgene@...nel.org>,
	Marc Zyngier <Marc.Zyngier@....com>,
	"arnd@...db.de" <arnd@...db.de>, "olof@...om.net" <olof@...om.net>,
	Catalin Marinas <Catalin.Marinas@....com>,
	Will Deacon <Will.Deacon@....com>,
	"inki.dae@...sung.com" <inki.dae@...sung.com>,
	"chanho61.park@...sung.com" <chanho61.park@...sung.com>,
	"sw0312.kim@...sung.com" <sw0312.kim@...sung.com>,
	"jh80.chung@...sung.com" <jh80.chung@...sung.com>,
	"ideal.song@...sung.com" <ideal.song@...sung.com>,
	"a.kesavan@...sung.com" <a.kesavan@...sung.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 1/9] arm64: dts: exynos: Add dts files for 64-bit
 Exynos5433 SoC

Hi,

On 03/06/2015 03:54 AM, Mark Rutland wrote:
> Hi,
> 
>>>>>> +       psci {
>>>>>> +               compatible = "arm,psci";
>>>>>> +               method = "smc";
>>>>>> +               cpu_off = <0x84000002>;
>>>>>> +               cpu_on = <0xC4000003>;
>>>>>> +       };
>>>>>
>>>>> Back at v2 you mentioned that CPU_OFF wasn't working [1].
>>>>>
>>>>> Do both CPU_ON and CPU_OFF work for all CPUs, including the boot CPU?
>>>>
>>>> The CPU1 ~ CPU7 are well woking about CPU_ON/OFF.
>>>> CPU0 (boot CPU) is only well working for CPU_OFF.
>>>> But when I try to turn on the CPU0 after CPU_OFF, I failed it.
>>>
>>> That's rather worrying. Can you look into what's going on here? I'd
>>> rather not have dts describing things which are known to be broken.
>>
>> The board dts don't include any node for CPU_ON/OFF.
> 
> I don't understand. The CPU_ON and CPU_OFF IDs are in the psci node
> quoted above, and all the CPUs had enable-method = "psci".

I mean that there are not additional dt node except for 'cpu' and 'psci' node.

> 
>> When I try to turn on the CPU0 (boot CPU), fail to turn on and lockup happen.
>> After lockup happen, I cannot use the console.
> 
> That sounds like a pretty major bug.
> 
> Are you able to investigate with a hardware debugger?

I can't do because there are not any jtag connector.

> 
> Do other CPUs eventually log errors regarding the lockup? Or is the
> machine completely dead from this point on?

I tested CPU0 on/off. When I turn on the CPU0, I fail it. But, kernel just show the error log without lockup.
I gave you wrong infromation about CPU0 off.

[test result of CPU0 on/off on Linux 4.0-rc2]
root@...alhost:~# echo 0 > /sys/devices/system/cpu/cpu0/online 
[  420.965435] IRQ1 no longer affine to CPU0
[  420.965439] IRQ2 no longer affine to CPU0
[ 4631.194227] CPU0: shutdown
root@...alhost:~# echo 1 > /sys/devices/system/cpu/cpu0/online
[ 1164.601644] CPU0: failed to come online
-bash: echo: write error: Input/output error

As I experienced, Exynos SoC could not turn off the CPU0 (boot cpu).
I think that we may need the hidden information of Exynos5433 from Exynos5433 architector.

> 
>>>>> I take it CPUs boot at EL2?
>>>
>>> Do the CPUs boot at EL1 or EL2?
>>
>> Unfortunately, I cannot check the secure firmware for Exynos5433 SoC.
>> I think that a few SoC provider probably would know it.
> 
> I guess I asked the wrong question.
> 
> Do CPUs enter the kernel at EL2 or at EL1?

Could you give me a tip how to check the kernel at EL2 or EL1?

Thanks,
Chanwoo Choi


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/