From 103d6f2b182d8079b80e7b346c53ac32bd052207 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Thu, 4 Apr 2019 10:52:43 -0700 Subject: [PATCH] hwmon: (f71805f) Use request_muxed_region for Super-IO accesses BugLink: https://bugs.launchpad.net/bugs/1838700 [ Upstream commit 73e6ff71a7ea924fb7121d576a2d41e3be3fc6b5 ] Super-IO accesses may fail on a system with no or unmapped LPC bus. Unable to handle kernel paging request at virtual address ffffffbffee0002e pgd = ffffffc1d68d4000 [ffffffbffee0002e] *pgd=0000000000000000, *pud=0000000000000000 Internal error: Oops: 94000046 [#1] PREEMPT SMP Modules linked in: f71805f(+) hwmon CPU: 3 PID: 1659 Comm: insmod Not tainted 4.5.0+ #88 Hardware name: linux,dummy-virt (DT) task: ffffffc1f6665400 ti: ffffffc1d6418000 task.ti: ffffffc1d6418000 PC is at f71805f_find+0x6c/0x358 [f71805f] 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: e53004e20a58e ("hwmon: New f71805f 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 Signed-off-by: Kamal Mostafa Signed-off-by: Khalid Elmously --- drivers/hwmon/f71805f.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/hwmon/f71805f.c b/drivers/hwmon/f71805f.c index 73c681162653..623736d2a7c1 100644 --- a/drivers/hwmon/f71805f.c +++ b/drivers/hwmon/f71805f.c @@ -96,17 +96,23 @@ superio_select(int base, int ld) outb(ld, base + 1); } -static inline void +static inline int superio_enter(int base) { + if (!request_muxed_region(base, 2, DRVNAME)) + return -EBUSY; + outb(0x87, base); outb(0x87, base); + + return 0; } static inline void superio_exit(int base) { outb(0xaa, base); + release_region(base, 2); } /* @@ -1561,7 +1567,7 @@ exit: static int __init f71805f_find(int sioaddr, unsigned short *address, struct f71805f_sio_data *sio_data) { - int err = -ENODEV; + int err; u16 devid; static const char * const names[] = { @@ -1569,8 +1575,11 @@ static int __init f71805f_find(int sioaddr, unsigned short *address, "F71872F/FG or F71806F/FG", }; - superio_enter(sioaddr); + err = superio_enter(sioaddr); + if (err) + return err; + err = -ENODEV; devid = superio_inw(sioaddr, SIO_REG_MANID); if (devid != SIO_FINTEK_ID) goto exit; -- 2.39.2