* [tip:timers/urgent] Revert "clocksource/drivers/timer_sun5i: Replace code by clocksource_mmio_init"
2016-10-18 5:49 [PATCH] Revert "clocksource/drivers/timer_sun5i: Replace code by clocksource_mmio_init" Chen-Yu Tsai
@ 2016-10-20 20:03 ` tip-bot for Chen-Yu Tsai
2016-10-20 20:11 ` [PATCH] " Thomas Gleixner
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Chen-Yu Tsai @ 2016-10-20 20:03 UTC (permalink / raw)
To: linux-tip-commits
Cc: mingo, linux-kernel, wens, daniel.lezcano, maxime.ripard, hpa, tglx
Commit-ID: 593876838826914a7e4e05fbbcb728be6fbc4d89
Gitweb: http://git.kernel.org/tip/593876838826914a7e4e05fbbcb728be6fbc4d89
Author: Chen-Yu Tsai <wens@csie.org>
AuthorDate: Tue, 18 Oct 2016 13:49:18 +0800
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 20 Oct 2016 21:58:58 +0200
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>
---
drivers/clocksource/timer-sun5i.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/clocksource/timer-sun5i.c b/drivers/clocksource/timer-sun5i.c
index c184eb8..4f87f3e 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;
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] Revert "clocksource/drivers/timer_sun5i: Replace code by clocksource_mmio_init"
2016-10-18 5:49 [PATCH] Revert "clocksource/drivers/timer_sun5i: Replace code by clocksource_mmio_init" Chen-Yu Tsai
2016-10-20 20:03 ` [tip:timers/urgent] " tip-bot for Chen-Yu Tsai
@ 2016-10-20 20:11 ` Thomas Gleixner
1 sibling, 0 replies; 3+ messages in thread
From: Thomas Gleixner @ 2016-10-20 20:11 UTC (permalink / raw)
To: Chen-Yu Tsai; +Cc: Daniel Lezcano, linux-kernel, linux-arm-kernel, linux-sunxi
On Tue, 18 Oct 2016, Chen-Yu Tsai wrote:
> 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.
You can avoid the churn by making clocksurce_mmio_init() a wrapper around a
new function, which takes a pointer to a struct clocksource_mmio as
argument so you can hand in the structure you need: Something like the
patch below should do the trick.
Thanks,
tglx
8<--------------------------------
--- a/drivers/clocksource/mmio.c
+++ b/drivers/clocksource/mmio.c
@@ -10,11 +10,6 @@
#include <linux/init.h>
#include <linux/slab.h>
-struct clocksource_mmio {
- void __iomem *reg;
- struct clocksource clksrc;
-};
-
static inline struct clocksource_mmio *to_mmio_clksrc(struct clocksource *c)
{
return container_of(c, struct clocksource_mmio, clksrc);
@@ -41,6 +36,27 @@ cycle_t clocksource_mmio_readw_down(stru
}
/**
+ * FIXME: Add doc
+ */
+int __init clocksource_mmio_setup(struct clocksource_mmio *cs,
+ void __iomem *base , const char *name,
+ unsigned long hz , int rating, unsigned bits,
+ cycle_t (*read)(struct clocksource *))
+{
+ if (bits > 64 || bits < 16)
+ return -EINVAL;
+
+ cs->reg = base;
+ cs->clksrc.name = name;
+ cs->clksrc.rating = rating;
+ cs->clksrc.read = read;
+ cs->clksrc.mask = CLOCKSOURCE_MASK(bits);
+ cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+ return clocksource_register_hz(&cs->clksrc, hz);
+}
+
+/**
* clocksource_mmio_init - Initialize a simple mmio based clocksource
* @base: Virtual address of the clock readout register
* @name: Name of the clocksource
@@ -62,12 +78,5 @@ int __init clocksource_mmio_init(void __
if (!cs)
return -ENOMEM;
- cs->reg = base;
- cs->clksrc.name = name;
- cs->clksrc.rating = rating;
- cs->clksrc.read = read;
- cs->clksrc.mask = CLOCKSOURCE_MASK(bits);
- cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
-
- return clocksource_register_hz(&cs->clksrc, hz);
+ return clocksource_mmio_setup(cs, base, name, hz, rating, bits, read);
}
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -119,6 +119,14 @@ struct clocksource {
/* simplify initialization of mask field */
#define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
+/**
+ * FIXME: Add doc
+ */
+struct clocksource_mmio {
+ void __iomem *reg;
+ struct clocksource clksrc;
+};
+
static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from)
{
/* freq = cyc/from
@@ -241,6 +249,11 @@ extern cycle_t clocksource_mmio_readw_do
extern int clocksource_mmio_init(void __iomem *, const char *,
unsigned long, int, unsigned, cycle_t (*)(struct clocksource *));
+extern int clocksource_mmio_setup(struct clocksource_mmio *,
+ void __iomem *, const char *,
+ unsigned long, int, unsigned,
+ cycle_t (*)(struct clocksource *));
+
extern int clocksource_i8253_init(void);
#define CLOCKSOURCE_OF_DECLARE(name, compat, fn) \
^ permalink raw reply [flat|nested] 3+ messages in thread