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author | Guenter Roeck <linux@roeck-us.net> | 2019-04-04 21:16:20 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 16:46:22 +0300 |
commit | 8cfe000d0a69e9d21e809c81d5ee690b8af0860e (patch) | |
tree | 4607ec75fd3a026b34250c222e0f45e55006d53a /drivers | |
parent | 48b31e8a025f544e6a8342c2812ceeb07391d802 (diff) | |
download | linux-8cfe000d0a69e9d21e809c81d5ee690b8af0860e.tar.xz |
hwmon: (pc87427) Use request_muxed_region for Super-IO accesses
[ Upstream commit 755a9b0f8aaa5639ba5671ca50080852babb89ce ]
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: ba224e2c4f0a7 ("hwmon: New PC87427 hardware monitoring driver")
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')
-rw-r--r-- | drivers/hwmon/pc87427.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/hwmon/pc87427.c b/drivers/hwmon/pc87427.c index dc5a9d5ada51..81a05cd1a512 100644 --- a/drivers/hwmon/pc87427.c +++ b/drivers/hwmon/pc87427.c @@ -106,6 +106,13 @@ static const char *logdev_str[2] = { DRVNAME " FMC", DRVNAME " HMC" }; #define LD_IN 1 #define LD_TEMP 1 +static inline int superio_enter(int sioaddr) +{ + if (!request_muxed_region(sioaddr, 2, DRVNAME)) + return -EBUSY; + return 0; +} + static inline void superio_outb(int sioaddr, int reg, int val) { outb(reg, sioaddr); @@ -122,6 +129,7 @@ static inline void superio_exit(int sioaddr) { outb(0x02, sioaddr); outb(0x02, sioaddr + 1); + release_region(sioaddr, 2); } /* @@ -1220,7 +1228,11 @@ static int __init pc87427_find(int sioaddr, struct pc87427_sio_data *sio_data) { u16 val; u8 cfg, cfg_b; - int i, err = 0; + int i, err; + + err = superio_enter(sioaddr); + if (err) + return err; /* Identify device */ val = force_id ? force_id : superio_inb(sioaddr, SIOREG_DEVID); |