From 4dcb3aa4a5ad6f9f89a8ad34df8dc39c77e87c1e Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 22 Apr 2021 12:02:29 +0300 Subject: [PATCH] firmware: arm_scpi: Prevent the ternary sign expansion bug [ Upstream commit d9cd78edb2e6b7e26747c0ec312be31e7ef196fe ] How the 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. Link: https://lore.kernel.org/r/YIE7pdqV/h10tEAK@mwanda Fixes: 8cb7cf56c9fe ("firmware: add support for ARM System Control and Power Interface(SCPI) protocol") Reviewed-by: Cristian Marussi Signed-off-by: Dan Carpenter [sudeep.holla: changed to return 0 as clock rate on error] Signed-off-by: Sudeep Holla Signed-off-by: Sasha Levin --- 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..4ceba5ef7895 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 0; - return ret ? ret : le32_to_cpu(rate); + return le32_to_cpu(rate); } static int scpi_clk_set_val(u16 clk_id, unsigned long rate) -- 2.34.1