diff options
| author | Remi Pommarel <repk@triplefau.lt> | 2019-12-15 12:47:05 +0100 |
|---|---|---|
| committer | Jerome Brunet <jbrunet@baylibre.com> | 2019-12-16 10:58:57 +0100 |
| commit | d8488a41800d9f5c80bc0d17b9cc2c91b4841464 (patch) | |
| tree | 829a7fb5dc324d4843416272db45292f95d12c67 /drivers | |
| parent | b1b3f0622a9d52ac19a63619911823c89a4d85a4 (diff) | |
clk: meson: pll: Fix by 0 division in __pll_params_to_rate()
Some meson pll registers can be initialized with 0 as N value, introducing
the following division by 0 when computing rate :
UBSAN: Undefined behaviour in drivers/clk/meson/clk-pll.c:75:9
division by zero
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc3-608075-g86c9af8630e1-dirty #400
Call trace:
dump_backtrace+0x0/0x1c0
show_stack+0x14/0x20
dump_stack+0xc4/0x100
ubsan_epilogue+0x14/0x68
__ubsan_handle_divrem_overflow+0x98/0xb8
__pll_params_to_rate+0xdc/0x140
meson_clk_pll_recalc_rate+0x278/0x3a0
__clk_register+0x7c8/0xbb0
devm_clk_hw_register+0x54/0xc0
meson_eeclkc_probe+0xf4/0x1a0
platform_drv_probe+0x54/0xd8
really_probe+0x16c/0x438
driver_probe_device+0xb0/0xf0
device_driver_attach+0x94/0xa0
__driver_attach+0x70/0x108
bus_for_each_dev+0xd8/0x128
driver_attach+0x30/0x40
bus_add_driver+0x1b0/0x2d8
driver_register+0xbc/0x1d0
__platform_driver_register+0x78/0x88
axg_driver_init+0x18/0x20
do_one_initcall+0xc8/0x24c
kernel_init_freeable+0x2b0/0x344
kernel_init+0x10/0x128
ret_from_fork+0x10/0x18
This checks if N is null before doing the division.
Fixes: 7a29a869434e ("clk: meson: Add support for Meson clock controller")
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
[jbrunet@baylibre.com: update the comment in above the fix]
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/clk/meson/clk-pll.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c index ddb1e5634739..3a5853ca98c6 100644 --- a/drivers/clk/meson/clk-pll.c +++ b/drivers/clk/meson/clk-pll.c @@ -77,6 +77,15 @@ static unsigned long meson_clk_pll_recalc_rate(struct clk_hw *hw, unsigned int m, n, frac; n = meson_parm_read(clk->map, &pll->n); + + /* + * On some HW, N is set to zero on init. This value is invalid as + * it would result in a division by zero. The rate can't be + * calculated in this case + */ + if (n == 0) + return 0; + m = meson_parm_read(clk->map, &pll->m); frac = MESON_PARM_APPLICABLE(&pll->frac) ? |