linux-kernel - Re: [PATCH v3 1/2] soc: qcom: smp2p: Add irqchip state support

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <aXv/W2CDvixANtIx@hu-clew-lv.qualcomm.com>
Date: Thu, 29 Jan 2026 16:46:19 -0800
From: Chris Lew <christopher.lew@....qualcomm.com>
To: Deepak Kumar Singh <deepak.singh@....qualcomm.com>
Cc: Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        Chris Lew <chris.lew@....qualcomm.com>
Subject: Re: [PATCH v3 1/2] soc: qcom: smp2p: Add irqchip state support

On Thu, Jan 29, 2026 at 04:26:38PM +0530, Deepak Kumar Singh wrote:
> 
> On 1/27/2026 6:25 PM, Konrad Dybcio wrote:
> > On 1/27/26 11:38 AM, Deepak Kumar Singh wrote:
> > > From: Chris Lew <chris.lew@....qualcomm.com>
> > > 
> > > A remoteproc booted during earlier boot stages such as UEFI or the
> > > bootloader, may need to be attached to without restarting the remoteproc
> > > hardware. To do this the remoteproc will need to check the ready and
> > > handover states in smp2p without an interrupt notification. Create
> > > qcom_smp2p_start_in() to initialize the shadow state without notifying
> > > clients because these early events happened in the past.
> > > 
> > > Add support for the .irq_get_irqchip_state callback so remoteproc can
> > > read the current state of the fatal, ready and handover bits.
> > > 
> > > Signed-off-by: Chris Lew <chris.lew@....qualcomm.com>
> > > Signed-off-by: Deepak Kumar Singh <deepak.singh@....qualcomm.com>
> > > ---
> > >   drivers/soc/qcom/smp2p.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++
> > >   1 file changed, 55 insertions(+)
> > > 
> > > diff --git a/drivers/soc/qcom/smp2p.c b/drivers/soc/qcom/smp2p.c
> > > index cb515c2340c1..c27ffb44b825 100644
> > > --- a/drivers/soc/qcom/smp2p.c
> > > +++ b/drivers/soc/qcom/smp2p.c
> > > @@ -222,6 +222,39 @@ static void qcom_smp2p_negotiate(struct qcom_smp2p *smp2p)
> > >   	}
> > >   }
> > > +static void qcom_smp2p_start_in(struct qcom_smp2p *smp2p)
> > > +{
> > > +	unsigned int smem_id = smp2p->smem_items[SMP2P_INBOUND];
> > > +	unsigned int pid = smp2p->remote_pid;
> > > +	char buf[SMP2P_MAX_ENTRY_NAME];
> > > +	struct smp2p_smem_item *in;
> > > +	struct smp2p_entry *entry;
> > > +	size_t size;
> > > +	int i;
> > > +
> > > +	in = qcom_smem_get(pid, smem_id, &size);
> > > +	if (IS_ERR(in))
> > > +		return;
> > > +
> > > +	smp2p->in = in;
> > > +
> > > +	/* Check if version is initialized by the remote. */
> > > +	if (in->version == 0)
> > > +		return;
> > > +
> > > +	for (i = smp2p->valid_entries; i < in->valid_entries; i++) {
> > > +		list_for_each_entry(entry, &smp2p->inbound, node) {
> > > +			memcpy(buf, in->entries[i].name, sizeof(buf));
> > Is there a reason for this copy at all?
> I don't see a compelling reason. This code snippet is same as present in
> qcom_smp2p_notify_in().

My understanding was that we do this copy because we don't want to do a
strcmp on memory that the remote could change at any time. Maybe it's
overkill but I thought it was considered good practice and as Deepak
mentioned, it is similarly present in qcom_smp2p_notify_in().

> > [...]
> > 
> > > +	/* Check inbound entries in the case of early boot processor */
> > "in case a remote processor has already been started"?
> This i can update in case new patch set is required.
> > Konrad
> >