linux-kernel - [PATCH 5.10 071/122] octeontx2-af: Add additional register check to rvu_poll

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 for Android: free password hash cracker in your pocket

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

Message-Id: <20210920163918.102007137@linuxfoundation.org>
Date:   Mon, 20 Sep 2021 18:44:03 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Smadar Fuks <smadarf@...vell.com>,
        Sunil Goutham <sgoutham@...vell.com>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 071/122] octeontx2-af: Add additional register check to rvu_poll_reg()

From: Smadar Fuks <smadarf@...vell.com>

[ Upstream commit 21274aa1781941884599a97ab59be7f8f36af98c ]

Check one more time before exiting the API with an error.
Fix API to poll at least twice, in case there are other high priority
tasks and this API doesn't get CPU cycles for multiple jiffies update.

In addition, increase timeout from usecs_to_jiffies(10000) to
usecs_to_jiffies(20000), to prevent the case that for CONFIG_100HZ
timeout will be a single jiffies.
A single jiffies results actual timeout that can be any time between
1usec and 10msec. To solve this, a value of usecs_to_jiffies(20000)
ensures that timeout is 2 jiffies.

Signed-off-by: Smadar Fuks <smadarf@...vell.com>
Signed-off-by: Sunil Goutham <sgoutham@...vell.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
index 644d28b0692b..c26652436c53 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
@@ -84,7 +84,8 @@ static void rvu_setup_hw_capabilities(struct rvu *rvu)
  */
 int rvu_poll_reg(struct rvu *rvu, u64 block, u64 offset, u64 mask, bool zero)
 {
-	unsigned long timeout = jiffies + usecs_to_jiffies(10000);
+	unsigned long timeout = jiffies + usecs_to_jiffies(20000);
+	bool twice = false;
 	void __iomem *reg;
 	u64 reg_val;
 
@@ -99,6 +100,15 @@ again:
 		usleep_range(1, 5);
 		goto again;
 	}
+	/* In scenarios where CPU is scheduled out before checking
+	 * 'time_before' (above) and gets scheduled in such that
+	 * jiffies are beyond timeout value, then check again if HW is
+	 * done with the operation in the meantime.
+	 */
+	if (!twice) {
+		twice = true;
+		goto again;
+	}
 	return -EBUSY;
 }
 
-- 
2.30.2