linux-kernel - Re: [PATCH 1/3] firmware/psci: Fix cpu_resume entry points with THUMB2

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Message-ID: <b21ea7e5-9ca7-f76e-1bbf-9d29374553f8@gmail.com>
Date:   Fri, 28 Sep 2018 10:50:31 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Mark Rutland <mark.rutland@....com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        Russell King <linux@...linux.org.uk>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Brian Norris <computersforpeace@...il.com>,
        Gregory Fong <gregory.0xf0@...il.com>,
        "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <bcm-kernel-feedback-list@...adcom.com>,
        Rob Herring <robh@...nel.org>, Doug Berger <opendmb@...il.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] firmware/psci: Fix cpu_resume entry points with
 THUMB2_KERNEL

On 09/28/2018 06:47 AM, Mark Rutland wrote:
> On Thu, Sep 27, 2018 at 12:27:09PM -0700, Florian Fainelli wrote:
>> When THUMB2_KERNEL is enabled, we would be failing to resume from an
>> idle or system suspend call where the reentry point is set to
>> cpu_resume() because that function is in Thumb2. Utilize
>> cpu_resume_arm() for ARM 32-bit kernels which takes care of the mode
>> switching for us.
> 
> Looking at the PSCI spec, if bit[0] of the entry point address is set,
> the CPU should be placed into thumb state.
> 
> So either there's a FW bug here, or perhaps we're stripping bit[0] when
> we do the __pa_symbol() dance.
> 
> Which firmware have you seen this with?

This is a custom implementation use with ARCH_BRCMSTB, the same way I
managed to miss it during code review, I missed it again here, sorry
about that and thanks for pointing me in the right direction.
-- 
Florian