[PATCH] firmware: arm_scpi: prevent ternary sign expansion bug
Dan Carpenter
dan.carpenter at oracle.com
Thu Apr 22 10:02:29 BST 2021
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 at 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
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