2019-06-07 12:45:23

by Stefan Mavrodiev

Subject: [PATCH v3 1/2] mfd: rk808: Check pm_power_off pointer

The function pointer pm_power_off may point to function from other
module (PSCI for example). If rk808 is removed, pm_power_off is
overwritten to NULL and the system cannot be powered off.

This patch checks if pm_power_off points to a module function.

Signed-off-by: Stefan Mavrodiev <[email protected]>
---
Changes is v3:
- Add explanation comments
Changes in v2:
- Initial release actually

drivers/mfd/rk808.c | 17 +++++++++++------
include/linux/mfd/rk808.h | 1 +
2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/mfd/rk808.c b/drivers/mfd/rk808.c
index 94377782d208..46d26e141cc4 100644
--- a/drivers/mfd/rk808.c
+++ b/drivers/mfd/rk808.c
@@ -438,7 +438,6 @@ static int rk808_probe(struct i2c_client *client,
struct rk808 *rk808;
const struct rk808_reg_data *pre_init_reg;
const struct mfd_cell *cells;
- void (*pm_pwroff_fn)(void);
int nr_pre_init_regs;
int nr_cells;
int pm_off = 0, msb, lsb;
@@ -475,7 +474,7 @@ static int rk808_probe(struct i2c_client *client,
nr_pre_init_regs = ARRAY_SIZE(rk805_pre_init_reg);
cells = rk805s;
nr_cells = ARRAY_SIZE(rk805s);
- pm_pwroff_fn = rk805_device_shutdown;
+ rk808->pm_pwroff_fn = rk805_device_shutdown;
break;
case RK808_ID:
rk808->regmap_cfg = &rk808_regmap_config;
@@ -484,7 +483,7 @@ static int rk808_probe(struct i2c_client *client,
nr_pre_init_regs = ARRAY_SIZE(rk808_pre_init_reg);
cells = rk808s;
nr_cells = ARRAY_SIZE(rk808s);
- pm_pwroff_fn = rk808_device_shutdown;
+ rk808->pm_pwroff_fn = rk808_device_shutdown;
break;
case RK818_ID:
rk808->regmap_cfg = &rk818_regmap_config;
@@ -493,7 +492,7 @@ static int rk808_probe(struct i2c_client *client,
nr_pre_init_regs = ARRAY_SIZE(rk818_pre_init_reg);
cells = rk818s;
nr_cells = ARRAY_SIZE(rk818s);
- pm_pwroff_fn = rk818_device_shutdown;
+ rk808->pm_pwroff_fn = rk818_device_shutdown;
break;
default:
dev_err(&client->dev, "Unsupported RK8XX ID %lu\n",
@@ -548,7 +547,7 @@ static int rk808_probe(struct i2c_client *client,
"rockchip,system-power-controller");
if (pm_off && !pm_power_off) {
rk808_i2c_client = client;
- pm_power_off = pm_pwroff_fn;
+ pm_power_off = rk808->pm_pwroff_fn;
}

return 0;
@@ -563,7 +562,13 @@ static int rk808_remove(struct i2c_client *client)
struct rk808 *rk808 = i2c_get_clientdata(client);

regmap_del_irq_chip(client->irq, rk808->irq_data);
- pm_power_off = NULL;
+
+ /**
+ * pm_power_off may points to a function from another module.
+ * Check if the pointer is set by us and only then overwrite it.
+ */
+ if (rk808->pm_pwroff_fn && pm_power_off == rk808->pm_pwroff_fn)
+ pm_power_off = NULL;

return 0;
}
diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h
index d3156594674c..8b5d68a7bb9c 100644
--- a/include/linux/mfd/rk808.h
+++ b/include/linux/mfd/rk808.h
@@ -453,5 +453,6 @@ struct rk808 {
long variant;
const struct regmap_config *regmap_cfg;
const struct regmap_irq_chip *regmap_irq_chip;
+ void (*pm_pwroff_fn)(void);
};
#endif /* __LINUX_REGULATOR_RK808_H */
--
2.17.1

2019-06-12 09:43:07

by Lee Jones

Subject: Re: [PATCH v3 1/2] mfd: rk808: Check pm_power_off pointer

On Fri, 07 Jun 2019, Stefan Mavrodiev wrote:

> The function pointer pm_power_off may point to function from other
> module (PSCI for example). If rk808 is removed, pm_power_off is
> overwritten to NULL and the system cannot be powered off.
>
> This patch checks if pm_power_off points to a module function.
>
> Signed-off-by: Stefan Mavrodiev <[email protected]>
> ---
> Changes is v3:
> - Add explanation comments
> Changes in v2:
> - Initial release actually
>
> drivers/mfd/rk808.c | 17 +++++++++++------
> include/linux/mfd/rk808.h | 1 +
> 2 files changed, 12 insertions(+), 6 deletions(-)

Applied, thanks.

--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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