The patch titled
wdt: fix locking
has been added to the -mm tree. Its filename is
wdt-fix-locking.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: wdt: fix locking
From: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
The audit of _p usage shows various drivers assume inb_p is somehow atomic.
Of course it isn't and the delay can be split from the I/O cycle causing a
timing violation on chips that matter (eg this one)
With the proposed use of udelay() for some _p delays this will cease to be
a mostly theoretical bug (as the delay stall is unsplittable) and wants
fixing.
Lots of other drivers need fixing this way too.
Signed-off-by: Alan Cox <alan@xxxxxxxxxx>
Cc: Wim Van Sebroeck <wim@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/watchdog/wdt.c | 30 +++++++++++++++++++++++++++---
1 file changed, 27 insertions(+), 3 deletions(-)
diff -puN drivers/watchdog/wdt.c~wdt-fix-locking drivers/watchdog/wdt.c
--- a/drivers/watchdog/wdt.c~wdt-fix-locking
+++ a/drivers/watchdog/wdt.c
@@ -70,6 +70,8 @@ MODULE_PARM_DESC(nowayout, "Watchdog can
static int io=0x240;
static int irq=11;
+static DEFINE_SPINLOCK(wdt_lock);
+
module_param(io, int, 0);
MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
module_param(irq, int, 0);
@@ -109,6 +111,8 @@ static void wdt_ctr_load(int ctr, int va
static int wdt_start(void)
{
+ unsigned long flags;
+ spin_lock_irqsave(&wdt_lock, flags);
inb_p(WDT_DC); /* Disable watchdog */
wdt_ctr_mode(0,3); /* Program CTR0 for Mode 3: Square Wave Generator */
wdt_ctr_mode(1,2); /* Program CTR1 for Mode 2: Rate Generator */
@@ -117,6 +121,7 @@ static int wdt_start(void)
wdt_ctr_load(1,wd_heartbeat); /* Heartbeat */
wdt_ctr_load(2,65535); /* Length of reset pulse */
outb_p(0, WDT_DC); /* Enable watchdog */
+ spin_unlock_irqrestore(&wdt_lock, flags);
return 0;
}
@@ -128,9 +133,12 @@ static int wdt_start(void)
static int wdt_stop (void)
{
+ unsigned long flags;
+ spin_lock_irqsave(&wdt_lock, flags);
/* Turn the card off */
inb_p(WDT_DC); /* Disable watchdog */
wdt_ctr_load(2,0); /* 0 length reset pulses now */
+ spin_unlock_irqrestore(&wdt_lock, flags);
return 0;
}
@@ -143,11 +151,14 @@ static int wdt_stop (void)
static int wdt_ping(void)
{
+ unsigned long flags;
+ spin_lock_irqsave(&wdt_lock, flags);
/* Write a watchdog value */
inb_p(WDT_DC); /* Disable watchdog */
wdt_ctr_mode(1,2); /* Re-Program CTR1 for Mode 2: Rate Generator */
wdt_ctr_load(1,wd_heartbeat); /* Heartbeat */
outb_p(0, WDT_DC); /* Enable watchdog */
+ spin_unlock_irqrestore(&wdt_lock, flags);
return 0;
}
@@ -182,7 +193,12 @@ static int wdt_set_heartbeat(int t)
static int wdt_get_status(int *status)
{
- unsigned char new_status=inb_p(WDT_SR);
+ unsigned char new_status;
+ unsigned long flags;
+
+ spin_lock_irqsave(&wdt_lock, flags);
+ new_status = inb_p(WDT_SR);
+ spin_unlock_irqrestore(&wdt_lock, flags);
*status=0;
if (new_status & WDC_SR_ISOI0)
@@ -214,8 +230,12 @@ static int wdt_get_status(int *status)
static int wdt_get_temperature(int *temperature)
{
- unsigned short c=inb_p(WDT_RT);
+ unsigned short c;
+ unsigned long flags;
+ spin_lock_irqsave(&wdt_lock, flags);
+ c=inb_p(WDT_RT);
+ spin_unlock_irqrestore(&wdt_lock, flags);
*temperature = (c * 11 / 15) + 7;
return 0;
}
@@ -237,7 +257,10 @@ static irqreturn_t wdt_interrupt(int irq
* Read the status register see what is up and
* then printk it.
*/
- unsigned char status=inb_p(WDT_SR);
+ unsigned char status;
+
+ spin_lock(&wdt_lock);
+ status = inb_p(WDT_SR);
printk(KERN_CRIT "WDT status %d\n", status);
@@ -265,6 +288,7 @@ static irqreturn_t wdt_interrupt(int irq
printk(KERN_CRIT "Reset in 5ms.\n");
#endif
}
+ spin_unlock(&wdt_lock);
return IRQ_HANDLED;
}
_
Patches currently in -mm which might be from alan@xxxxxxxxxxxxxxxxxxx are
pl2303-fix-mode-switching-regression.patch
pl2303-fix-mode-switching-regression-fix.patch
git-arm.patch
git-libata-all.patch
git-libata-all-fix-pata_winbond-borkage.patch
git-libata-all-wtf.patch
libata-fix-early-use-of-port-printk-checkpatch-fixes.patch
pata_pdc202xx_old-further-fixups.patch
git-netdev-all.patch
bluetooth-rfcomm-tty_close-before-destruct.patch
pcmcia-convert-some-internal-only-ioaddr_t-to-unsigned-int.patch
pcmcia-replace-kio_addr_t-with-unsigned-int-everywhere.patch
serial-keep-the-dtr-setting-for-serial-console.patch
8250c-support-specifying-dw-apb-uarts-in-device-platform_data.patch
avoid-waking-up-closed-serial-ports-on-resume.patch
serial-avoid-stalling-suspend-if-serial-port-wont-drain.patch
wdt-fix-locking.patch
libata-sff-pci-irq-handling-fix.patch
libata-correct-handling-of-tss-dvd.patch
geode-lists-are-subscriber-only.patch
get-rid-of-nr_open-and-introduce-a-sysctl_nr_open.patch
get-rid-of-nr_open-and-introduce-a-sysctl_nr_open-fix.patch
sc26xx-new-serial-driver-for-sc2681-uarts.patch
sc26xx-new-serial-driver-for-sc2681-uarts-update.patch
documentation-about-unaligned-memory-access.patch
tty-enable-the-echoing-of-c-in-the-n_tty-discipline.patch
tty-enable-the-echoing-of-c-in-the-n_tty-discipline-checkpatch-fixes.patch
fix-ixany-and-restart-after-signal-eg-ctrl-c-in-n_tty-line-discipline.patch
tty-kill-tty_flipbuf_size.patch
drivers-edac-turnon-edac-device-error-logging.patch
drivers-edac-use-round_jiffies_relative.patch
drivers-edac-add-cell-xdr-memory-types.patch
drivers-edac-add-cell-mc-driver.patch
drivers-edac-i3000-code-tidying.patch
drivers-edac-i3000-replace-macros-with-functions.patch
drivers-edac-add-freescale-mpc85xx-driver.patch
drivers-edac-add-marvell-mv64x60-driver.patch
drivers-edac-add-marvell-mv64x60-driver-fix.patch
dz-clean-up-and-improve-the-setup-of-termios-settings.patch
char-rocket-switch-long-delay-to-sleep.patch
char-rocket-printk-cleanup.patch
char-char-serial-remove-serial_type_normal-redefines.patch
char-mxser_new-ioaddresses-are-ulong.patch
char-stallion-fix-compiler-warnings.patch
char-riscom8-change-rc_init_drivers-prototype.patch
mxser-mxser_new-first-pass-over-termios-reporting-for-the.patch
tty-let-architectures-override-the-user-kernel-macros.patch
tty-s390-support-for-termios2.patch
moxa-first-pass-at-termios-reporting.patch
n_tty-clean-up-old-code-to-follow-coding-style-and-mostly-checkpatch.patch
rocket-first-pass-at-termios-reporting.patch
rocket-dont-let-random-users-reset-the-controller.patch
tty_audit-fix-checkpatch-complaint.patch
tty_io-drag-screaming-into-coding-style-compliance.patch
tty_ioctl-drag-screaming-into-compliance-with-the-coding.patch
8250_early-coding-style.patch
8250_gsc-coding-style.patch
8250_hp300-coding-style.patch
8250_hub6-codding-style.patch
8250_pci-coding-style.patch
serial8250-coding-style.patch
8250-enable-rate-reporting-via-termios.patch
serial_core-bring-mostly-into-line-with-coding-style.patch
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