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authorChen-Yu Tsai <wens@csie.org>2016-10-18 13:49:18 +0800
committerThomas Gleixner <tglx@linutronix.de>2016-10-20 21:58:58 +0200
commit593876838826914a7e4e05fbbcb728be6fbc4d89 (patch)
treed27db5cd1251ad7200c3965d0ab21a65a8a35337
parent9995f4f184613fb02ee73092b03545520a72b104 (diff)
downloadlinux-stericsson-593876838826914a7e4e05fbbcb728be6fbc4d89.tar.gz
Revert "clocksource/drivers/timer_sun5i: Replace code by clocksource_mmio_init"
struct clocksource is also used by the clk notifier callback, to unregister and re-register the clocksource with a different clock rate. clocksource_mmio_init does not pass back a pointer to the struct used, and the clk notifier callback assumes that the struct clocksource in struct sun5i_timer_clksrc is valid. This results in a kernel NULL pointer dereference when the hstimer clock is changed: Unable to handle kernel NULL pointer dereference at virtual address 00000004 [<c03a4678>] (clocksource_unbind) from [<c03a46d4>] (clocksource_unregister+0x2c/0x44) [<c03a46d4>] (clocksource_unregister) from [<c0a6f350>] (sun5i_rate_cb_clksrc+0x34/0x3c) [<c0a6f350>] (sun5i_rate_cb_clksrc) from [<c035ea50>] (notifier_call_chain+0x44/0x84) [<c035ea50>] (notifier_call_chain) from [<c035edc0>] (__srcu_notifier_call_chain+0x44/0x60) [<c035edc0>] (__srcu_notifier_call_chain) from [<c035edf4>] (srcu_notifier_call_chain+0x18/0x20) [<c035edf4>] (srcu_notifier_call_chain) from [<c0670174>] (__clk_notify+0x70/0x7c) [<c0670174>] (__clk_notify) from [<c06702c0>] (clk_propagate_rate_change+0xa4/0xc4) [<c06702c0>] (clk_propagate_rate_change) from [<c0670288>] (clk_propagate_rate_change+0x6c/0xc4) Revert the commit for now. clocksource_mmio_init can be made to pass back a pointer, but the code churn and usage of an inner struct might not be worth it. Fixes: 157dfadef832 ("clocksource/drivers/timer_sun5i: Replace code by clocksource_mmio_init") Reported-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Chen-Yu Tsai <wens@csie.org> Cc: linux-sunxi@googlegroups.com Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20161018054918.26855-1-wens@csie.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--drivers/clocksource/timer-sun5i.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/clocksource/timer-sun5i.c b/drivers/clocksource/timer-sun5i.c
index c184eb84101e..4f87f3e76d83 100644
--- a/drivers/clocksource/timer-sun5i.c
+++ b/drivers/clocksource/timer-sun5i.c
@@ -152,6 +152,13 @@ static irqreturn_t sun5i_timer_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static cycle_t sun5i_clksrc_read(struct clocksource *clksrc)
+{
+ struct sun5i_timer_clksrc *cs = to_sun5i_timer_clksrc(clksrc);
+
+ return ~readl(cs->timer.base + TIMER_CNTVAL_LO_REG(1));
+}
+
static int sun5i_rate_cb_clksrc(struct notifier_block *nb,
unsigned long event, void *data)
{
@@ -210,8 +217,13 @@ static int __init sun5i_setup_clocksource(struct device_node *node,
writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
base + TIMER_CTL_REG(1));
- ret = clocksource_mmio_init(base + TIMER_CNTVAL_LO_REG(1), node->name,
- rate, 340, 32, clocksource_mmio_readl_down);
+ cs->clksrc.name = node->name;
+ cs->clksrc.rating = 340;
+ cs->clksrc.read = sun5i_clksrc_read;
+ cs->clksrc.mask = CLOCKSOURCE_MASK(32);
+ cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+ ret = clocksource_register_hz(&cs->clksrc, rate);
if (ret) {
pr_err("Couldn't register clock source.\n");
goto err_remove_notifier;