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| author | Yibo Cai <yibo.cai@csr.com> | 2015-08-04 14:45:28 +0000 |
|---|---|---|
| committer | Michael Turquette <mturquette@baylibre.com> | 2015-08-24 16:49:06 -0700 |
| commit | 6132e89aef51df044246b5aef822144217794ae1 (patch) | |
| tree | a4fe32bdd7218f86792eb8b5d26daa2de417200b /drivers/clk/sirf | |
| parent | b1062298fea59dca23cdbcafaa5bed79c273d88f (diff) | |
| download | linux-6132e89aef51df044246b5aef822144217794ae1.tar.gz linux-6132e89aef51df044246b5aef822144217794ae1.tar.xz | |
clk: atlas7: fix integer overflow in dto rate calculation
I cannot believe that I spend quite a lot time in finding this bug.
It seems a pitfall people tend to fall in.
In "int64 = int32 * int32", conversion from 32-bits to 64-bits comes
after the multiplication. So this statement may not work as expected.
Signed-off-by: Yibo Cai <yibo.cai@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Diffstat (limited to 'drivers/clk/sirf')
| -rw-r--r-- | drivers/clk/sirf/clk-atlas7.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/clk/sirf/clk-atlas7.c b/drivers/clk/sirf/clk-atlas7.c index 07b970ff50f1..ed77fd51692c 100644 --- a/drivers/clk/sirf/clk-atlas7.c +++ b/drivers/clk/sirf/clk-atlas7.c @@ -519,7 +519,7 @@ static unsigned long dto_clk_recalc_rate(struct clk_hw *hw, static long dto_clk_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *parent_rate) { - u64 dividend = rate * (1 << 29); + u64 dividend = (u64)rate * (1 << 29); do_div(dividend, *parent_rate); dividend *= *parent_rate; @@ -531,7 +531,7 @@ static long dto_clk_round_rate(struct clk_hw *hw, unsigned long rate, static int dto_clk_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { - u64 dividend = rate * (1 << 29); + u64 dividend = (u64)rate * (1 << 29); struct clk_dto *clk = to_dtoclk(hw); do_div(dividend, parent_rate); |