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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Michael Chan <michael.chan@broadcom.com>,
        Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 5.16 0077/1017] net: bnxt_ptp: fix compilation error
Date:   Tue,  5 Apr 2022 09:16:30 +0200
Message-Id: <20220405070356.476374643@linuxfoundation.org>
In-Reply-To: <20220405070354.155796697@linuxfoundation.org>
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From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

commit dcf500065fabe27676dfe7b4ba521a4f1e0fc8ac upstream.

The Broadcom bnxt_ptp driver does not compile with GCC 11.2.2 when
CONFIG_WERROR is enabled. The following error is generated:

drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c: In function ‘bnxt_ptp_enable’:
drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c:400:43: error: array
subscript 255 is above array bounds of ‘struct pps_pin[4]’
[-Werror=array-bounds]
  400 |  ptp->pps_info.pins[pin_id].event = BNXT_PPS_EVENT_EXTERNAL;
      |  ~~~~~~~~~~~~~~~~~~^~~~~~~~
In file included from drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c:20:
drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h:75:24: note: while
referencing ‘pins’
   75 |         struct pps_pin pins[BNXT_MAX_TSIO_PINS];
      |                        ^~~~
cc1: all warnings being treated as errors

This is due to the function ptp_find_pin() returning a pin ID of -1 when
a valid pin is not found and this error never being checked.
Change the TSIO_PIN_VALID() function to also check that a pin ID is not
negative and use this macro in bnxt_ptp_enable() to check the result of
the calls to ptp_find_pin() to return an error early for invalid pins.
This fixes the compilation error.

Cc: <stable@vger.kernel.org>
Fixes: 9e518f25802c ("bnxt_en: 1PPS functions to configure TSIO pins")
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20220328062708.207079-1-damien.lemoal@opensource.wdc.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c |    6 +++++-
 drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h |    2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
@@ -329,7 +329,7 @@ static int bnxt_ptp_enable(struct ptp_cl
 	struct bnxt_ptp_cfg *ptp = container_of(ptp_info, struct bnxt_ptp_cfg,
 						ptp_info);
 	struct bnxt *bp = ptp->bp;
-	u8 pin_id;
+	int pin_id;
 	int rc;
 
 	switch (rq->type) {
@@ -337,6 +337,8 @@ static int bnxt_ptp_enable(struct ptp_cl
 		/* Configure an External PPS IN */
 		pin_id = ptp_find_pin(ptp->ptp_clock, PTP_PF_EXTTS,
 				      rq->extts.index);
+		if (!TSIO_PIN_VALID(pin_id))
+			return -EOPNOTSUPP;
 		if (!on)
 			break;
 		rc = bnxt_ptp_cfg_pin(bp, pin_id, BNXT_PPS_PIN_PPS_IN);
@@ -350,6 +352,8 @@ static int bnxt_ptp_enable(struct ptp_cl
 		/* Configure a Periodic PPS OUT */
 		pin_id = ptp_find_pin(ptp->ptp_clock, PTP_PF_PEROUT,
 				      rq->perout.index);
+		if (!TSIO_PIN_VALID(pin_id))
+			return -EOPNOTSUPP;
 		if (!on)
 			break;
 
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h
@@ -31,7 +31,7 @@ struct pps_pin {
 	u8 state;
 };
 
-#define TSIO_PIN_VALID(pin) ((pin) < (BNXT_MAX_TSIO_PINS))
+#define TSIO_PIN_VALID(pin) ((pin) >= 0 && (pin) < (BNXT_MAX_TSIO_PINS))
 
 #define EVENT_DATA2_PPS_EVENT_TYPE(data2)				\
 	((data2) & ASYNC_EVENT_CMPL_PPS_TIMESTAMP_EVENT_DATA2_EVENT_TYPE)