diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2019-04-04 11:28:37 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 06:43:33 -0700 |
| commit | 02d5ae1cc84d9afde59ba1875c9f26e28f6a6276 (patch) | |
| tree | 1d45b875273ba98c6aaea20d6b20400a0a84c640 /drivers/hwmon | |
| parent | e2cab96556f2666758642daac95563258f4c3cc8 (diff) | |
| download | linux-stable-02d5ae1cc84d9afde59ba1875c9f26e28f6a6276.tar.gz linux-stable-02d5ae1cc84d9afde59ba1875c9f26e28f6a6276.tar.bz2 linux-stable-02d5ae1cc84d9afde59ba1875c9f26e28f6a6276.zip | |
hwmon: (smsc47m1) Use request_muxed_region for Super-IO accesses
[ Upstream commit d6410408ad2a798c4cc685252c1baa713be0ad69 ]
Super-IO accesses may fail on a system with no or unmapped LPC bus.
Also, other drivers may attempt to access the LPC bus at the same time,
resulting in undefined behavior.
Use request_muxed_region() to ensure that IO access on the requested
address space is supported, and to ensure that access by multiple drivers
is synchronized.
Fixes: 8d5d45fb1468 ("I2C: Move hwmon drivers (2/3)")
Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: John Garry <john.garry@huawei.com>
Cc: John Garry <john.garry@huawei.com>
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hwmon')
| -rw-r--r-- | drivers/hwmon/smsc47m1.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/drivers/hwmon/smsc47m1.c b/drivers/hwmon/smsc47m1.c index c7b6a425e2c0..5eeac9853d0a 100644 --- a/drivers/hwmon/smsc47m1.c +++ b/drivers/hwmon/smsc47m1.c @@ -73,16 +73,21 @@ superio_inb(int reg) /* logical device for fans is 0x0A */ #define superio_select() superio_outb(0x07, 0x0A) -static inline void +static inline int superio_enter(void) { + if (!request_muxed_region(REG, 2, DRVNAME)) + return -EBUSY; + outb(0x55, REG); + return 0; } static inline void superio_exit(void) { outb(0xAA, REG); + release_region(REG, 2); } #define SUPERIO_REG_ACT 0x30 @@ -531,8 +536,12 @@ static int __init smsc47m1_find(struct smsc47m1_sio_data *sio_data) { u8 val; unsigned short addr; + int err; + + err = superio_enter(); + if (err) + return err; - superio_enter(); val = force_id ? force_id : superio_inb(SUPERIO_REG_DEVID); /* @@ -608,13 +617,14 @@ static int __init smsc47m1_find(struct smsc47m1_sio_data *sio_data) static void smsc47m1_restore(const struct smsc47m1_sio_data *sio_data) { if ((sio_data->activate & 0x01) == 0) { - superio_enter(); - superio_select(); - - pr_info("Disabling device\n"); - superio_outb(SUPERIO_REG_ACT, sio_data->activate); - - superio_exit(); + if (!superio_enter()) { + superio_select(); + pr_info("Disabling device\n"); + superio_outb(SUPERIO_REG_ACT, sio_data->activate); + superio_exit(); + } else { + pr_warn("Failed to disable device\n"); + } } } |