linux-kernel - [PATCH] firmware: arm_scmi: Fix doorbell ring logic for !CONFIG

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]

Date:   Mon, 11 Nov 2019 16:36:17 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Sudeep Holla <sudeep.holla@....com>,
        linux-arm-kernel@...ts.infradead.org, hulkci@...wei.com,
        zhengyongjun3@...wei.com
Subject: [PATCH] firmware: arm_scmi: Fix doorbell ring logic for !CONFIG_64BIT

The logic to ring the scmi performance fastchannel ignores the
value read from the doorbell register in case of !CONFIG_64BIT.
This bug also shows up as warning with '-Wunused-but-set-variable' gcc
flag:

drivers/firmware/arm_scmi/perf.c: In function scmi_perf_fc_ring_db:
drivers/firmware/arm_scmi/perf.c:323:7: warning: variable val set but
			not used [-Wunused-but-set-variable]

Fix the same by aligning the logic with CONFIG_64BIT as used in the
macro SCMI_PERF_FC_RING_DB().

Fixes: 823839571d76 ("firmware: arm_scmi: Make use SCMI v2.0 fastchannel
	for performance protocol")
Reported-by: Hulk Robot <hulkci@...wei.com>
Reported-by: Zheng Yongjun <zhengyongjun3@...wei.com>
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/firmware/arm_scmi/perf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Hi Zheng,

Thanks for the bug report, but the fix is incorrect as discussed.
This is proper fix, let me know if this fixes the gcc warning you found.

Regards,
Sudeep

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 4a8012e3cb8c..601af4edad5e 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -323,7 +323,7 @@ static void scmi_perf_fc_ring_db(struct scmi_fc_db_info *db)

 		if (db->mask)
 			val = ioread64_hi_lo(db->addr) & db->mask;
-		iowrite64_hi_lo(db->set, db->addr);
+		iowrite64_hi_lo(db->set | val, db->addr);
 	}
 #endif
 }
--
2.17.1