Commit 755a9b0f authored by Guenter Roeck's avatar Guenter Roeck
Browse files

hwmon: (pc87427) Use request_muxed_region for Super-IO accesses 



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: ba224e2c ("hwmon: New PC87427 hardware monitoring driver")
Reported-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: default avatarJohn Garry <john.garry@huawei.com>
Cc: John Garry <john.garry@huawei.com>
Acked-by: default avatarJohn Garry <john.garry@huawei.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 73e6ff71

drivers/hwmon/pc87427.c

+13 −1
Original line number Diff line number Diff line
@@ -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);

}



/*
@@ -1195,7 +1203,11 @@ 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);