From: Dan Carpenter <dan.carpenter@oracle.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: Cristian Marussi <cristian.marussi@arm.com>,
"Jon Medhurst (Tixy)" <tixy@linaro.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] firmware: arm_scpi: prevent ternary sign expansion bug
Date: Thu, 22 Apr 2021 12:02:29 +0300 [thread overview]
Message-ID: <YIE7pdqV/h10tEAK@mwanda> (raw)
How type promotion works in ternary expressions is a bit tricky.
The problem is that scpi_clk_get_val() returns longs, "ret" is a int
which holds a negative error code, and le32_to_cpu() is an unsigned int.
We want the negative error code to be cast to a negative long. But
because le32_to_cpu() is an u32 then "ret" is type promoted to u32 and
becomes a high positive and then it is promoted to long and it is still
a high positive value.
Fix this by getting rid of the ternary.
Fixes: 8cb7cf56c9fe ("firmware: add support for ARM System Control and Power Interface(SCPI) protocol")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
drivers/firmware/arm_scpi.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
index d0dee37ad522..3bf61854121d 100644
--- a/drivers/firmware/arm_scpi.c
+++ b/drivers/firmware/arm_scpi.c
@@ -552,8 +552,10 @@ static unsigned long scpi_clk_get_val(u16 clk_id)
ret = scpi_send_message(CMD_GET_CLOCK_VALUE, &le_clk_id,
sizeof(le_clk_id), &rate, sizeof(rate));
+ if (ret)
+ return ret;
- return ret ? ret : le32_to_cpu(rate);
+ return le32_to_cpu(rate);
}
static int scpi_clk_set_val(u16 clk_id, unsigned long rate)
--
2.30.2
next reply other threads:[~2021-04-22 9:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 9:02 Dan Carpenter [this message]
2021-04-22 10:17 ` [PATCH] firmware: arm_scpi: prevent ternary sign expansion bug Cristian Marussi
2021-04-22 11:34 ` Cristian Marussi
2021-04-22 17:46 ` Sudeep Holla
2021-04-24 6:43 ` Dan Carpenter
2021-04-28 10:03 ` Sudeep Holla
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