Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 14 Nov 2022 14:54:28 +0000
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Will Deacon <will@kernel.org>
Cc:     Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        Amit Pundir <amit.pundir@linaro.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Bjorn Andersson <andersson@kernel.org>,
        Sibi Sankar <quic_sibis@quicinc.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Subject: Re: [GIT PULL] arm64 updates for 6.1-rc1
Message-ID: <Y3JWpCV1LoScdJn1@arm.com>
References: <20221005144116.2256580-1-catalin.marinas@arm.com>
 <CAMi1Hd38YB2m_r=m0wuDz+wErii37fUq1BJnvN9=y6opDzo_Fw@mail.gmail.com>
 <Y0aq8y5mEZi14lJ/@arm.com>
 <CAMi1Hd3Y9AibeVnh9_KYJ2EXar7bBSypKm4Tixj47htM7ZOURw@mail.gmail.com>
 <CAMi1Hd1VBCFhf7+EXWHQWcGy4k=tcyLa7RGiFdprtRnegSG0Mw@mail.gmail.com>
 <Y24uvyDJU3CL1jOi@arm.com>
 <20221111173952.GB5393@thinkpad>
 <20221111191820.GC5393@thinkpad>
 <20221114140903.GF30263@willie-the-truck>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20221114140903.GF30263@willie-the-truck>
Precedence: bulk

On Mon, Nov 14, 2022 at 02:09:04PM +0000, Will Deacon wrote:
> On Sat, Nov 12, 2022 at 12:48:20AM +0530, Manivannan Sadhasivam wrote:
> > I digged a little further and found that the crash was due to the secure
> > processor (XPU) violation. It happens because, CPU tried acccessing the memory
> > after sharing it with the modem for firmware metadata validation.
[...]
> > Sibi tried fixing this problem earlier by using a hack in the remoteproc driver
> > [1], but I guess that got negated due to c44094eee32f?
> 
> Performing a clean rather than a clean+invalidate when the buffer is
> allocated (which is what is achieved by c44094eee32f) shouldn't affect
> this afaict.

I agree. The DMA_ATTR_NO_KERNEL_MAPPING used in the qcom_q6v5_mss fix
only ensures that there is no non-cacheable DMA mapping but we still
have the kernel linear map in place that may be accessed speculatively
by the CPU at any point. I can't tell why the clean+inval makes any
difference but I suspect it's a matter of time before you'd hit similar
conditions again (maybe not at boot).

-- 
Catalin