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firmware: arm_scpi: Prevent the ternary sign expansion bug

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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: 8cb7cf56c9 ("firmware: add support for ARM System Control and Power Interface(SCPI) protocol")
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
[sudeep.holla: changed to return 0 as clock rate on error]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Dan Carpenter 2021-04-22 12:02:29 +03:00 committed by Sudeep Holla
parent d4f9dddd21
commit d9cd78edb2
1 changed files with 3 additions and 1 deletions
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4
drivers/firmware/arm_scpi.c
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@ -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)