From dc1adde622e5de70b647ed49fedb64fd9749be39 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Thu, 4 Apr 2019 11:16:20 -0700 Subject: 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 Reported-by: John Garry Cc: John Garry Acked-by: John Garry Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin --- drivers/hwmon/pc87427.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'drivers/hwmon') 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); -- cgit v1.2.3