Re: [PATCH v5 2/8] clk: Warn if clk_init_data is not zero initialized
From: Stephen Boyd <sboyd@kernel.org>
Date: 2019-09-17 20:38:56
Also in:
linux-arm-kernel, linux-clk, lkml
Quoting Manivannan Sadhasivam (2019-09-16 09:14:41)
quoted hunk ↗ jump to hunk
The new implementation for determining parent map uses multiple ways to pass parent info. The order in which it gets processed depends on the first available member. Hence, it is necessary to zero init the clk_init_data struct so that the expected member gets processed correctly. So, add a warning if multiple clk_init_data members are available during clk registration. Signed-off-by: Manivannan Sadhasivam <redacted> --- drivers/clk/clk.c | 8 ++++++++ 1 file changed, 8 insertions(+)diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index c0990703ce54..7d6d6984c979 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c@@ -3497,6 +3497,14 @@ static int clk_core_populate_parent_map(struct clk_core *core) if (!num_parents) return 0; + /* + * Check for non-zero initialized clk_init_data struct. This is + * required because, we only require one of the (parent_names/ + * parent_data/parent_hws) to be set at a time. Otherwise, the + * current code would use first available member. + */ + WARN_ON((parent_names && parent_data) || (parent_names && parent_hws)); +
This will warn for many drivers because they set clk_init_data on the stack and assign parent_names but let junk from the stack be assigned to parent_data. The code uses parent_names first and then looks for parent_data or parent_hws because of this fact of life that we've never required clk_init_data to be initialized to all zero.
/*
* Avoid unnecessary string look-ups of clk_core's possible parents by
* having a cache of names/clk_hw pointers to clk_core pointers.