linux-kernel - [PATCH 1/2] clk: ti: divider: try to fix ti_clk_register

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Date:   Wed, 19 Apr 2017 19:44:55 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Tero Kristo <t-kristo@...com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>
Cc:     Arnd Bergmann <arnd@...db.de>, Tony Lindgren <tony@...mide.com>,
        Keerthy <j-keerthy@...com>, linux-omap@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] clk: ti: divider: try to fix ti_clk_register_divider

The newly introduced function is entirely bogus as I found when looking
at this warning:

drivers/clk/ti/divider.c: In function 'ti_clk_register_divider':
drivers/clk/ti/divider.c:460:8: error: 'reg' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Treating a 'u32' variable as a structure leads to a stack overflow here,
and the register address we pass down is never initialized.

As the code in its original form makes no sense, I can only guess what
the intention was, and change it to take the address from div->reg.ptr
instead.

Fixes: d96f774b2538 ("clk: ti: divider: add support for legacy divider init")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/clk/ti/divider.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/ti/divider.c b/drivers/clk/ti/divider.c
index d6dcb283b72b..a6d3bbfbbd31 100644
--- a/drivers/clk/ti/divider.c
+++ b/drivers/clk/ti/divider.c
@@ -428,22 +428,17 @@ struct clk_hw *ti_clk_build_component_div(struct ti_clk_divider *setup)
 
 struct clk *ti_clk_register_divider(struct ti_clk *setup)
 {
-	struct ti_clk_divider *div;
-	struct clk_omap_reg *reg_setup;
-	u32 reg;
+	struct ti_clk_divider *div = setup->data;
+	struct clk_omap_reg reg_setup = {
+		.index = div->module,
+		.offset = div->reg,
+	};
 	u8 width;
 	u32 flags = 0;
 	u8 div_flags = 0;
 	const struct clk_div_table *table;
 	struct clk *clk;
 
-	div = setup->data;
-
-	reg_setup = (struct clk_omap_reg *)&reg;
-
-	reg_setup->index = div->module;
-	reg_setup->offset = div->reg;
-
 	if (div->flags & CLKF_INDEX_STARTS_AT_ONE)
 		div_flags |= CLK_DIVIDER_ONE_BASED;
 
@@ -458,7 +453,7 @@ struct clk *ti_clk_register_divider(struct ti_clk *setup)
 		return (struct clk *)table;
 
 	clk = _register_divider(NULL, setup->name, div->parent,
-				flags, (void __iomem *)reg, div->bit_shift,
+				flags, &reg_setup, div->bit_shift,
 				width, div_flags, table);
 
 	if (IS_ERR(clk))
-- 
2.9.0