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From:   Stephen Boyd <sboyd@kernel.org>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     David Collins <collinsd@codeaurora.org>,
        linux-kernel@vger.kernel.org, patches@lists.linux.dev,
        Fenglin Wu <quic_fenglinw@quicinc.com>
Subject: [PATCH 8/9] spmi: pmic-arb: block access for invalid PMIC arbiter v5 SPMI writes
Date:   Thu, 29 Sep 2022 17:50:17 -0700
Message-Id: <20220930005019.2663064-9-sboyd@kernel.org>
In-Reply-To: <20220930005019.2663064-1-sboyd@kernel.org>
References: <20220930005019.2663064-1-sboyd@kernel.org>
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From: David Collins <collinsd@codeaurora.org>

The system crashes due to an access permission violation when
writing to a PMIC peripheral which is not owned by the current
ee.  Add a check for PMIC arbiter version 5 for such invalid
write requests and return an error instead of crashing the
system.

Signed-off-by: David Collins <collinsd@codeaurora.org>
Signed-off-by: Fenglin Wu <quic_fenglinw@quicinc.com>
Link: https://lore.kernel.org/r/1655004286-11493-8-git-send-email-quic_fenglinw@quicinc.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
---
 drivers/spmi/spmi-pmic-arb.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/spmi/spmi-pmic-arb.c b/drivers/spmi/spmi-pmic-arb.c
index cf92abc51689..39f25bc26233 100644
--- a/drivers/spmi/spmi-pmic-arb.c
+++ b/drivers/spmi/spmi-pmic-arb.c
@@ -1133,6 +1133,11 @@ static int pmic_arb_offset_v5(struct spmi_pmic_arb *pmic_arb, u8 sid, u16 addr,
 		offset = 0x10000 * pmic_arb->ee + 0x80 * apid;
 		break;
 	case PMIC_ARB_CHANNEL_RW:
+		if (pmic_arb->apid_data[apid].write_ee != pmic_arb->ee) {
+			dev_err(&pmic_arb->spmic->dev, "disallowed SPMI write to sid=%u, addr=0x%04X\n",
+				sid, addr);
+			return -EPERM;
+		}
 		offset = 0x10000 * apid;
 		break;
 	}
-- 
https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git/
https://git.kernel.org/pub/scm/linux/kernel/git/sboyd/spmi.git