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leon, grcan: fixed race on interrupt mask register

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There was a potential read-modify-write race on the interrupt mask (imr)
register between the ISR and user functions.
This commit is contained in:
Martin Aberg
2017-01-26 11:01:10 +01:00
committed by Daniel Hellstrom
parent 5d367c56cf
commit 057496906f
1 changed files with 14 additions and 0 deletions
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14
c/src/lib/libbsp/sparc/shared/can/grcan.c
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@@ -1712,6 +1712,7 @@ int grcan_set_afilter(void *d, const struct grcan_filter *filter)
int grcan_set_sfilter(void *d, const struct grcan_filter *filter)
{
struct grcan_priv *pDev = d;
SPIN_IRQFLAGS(oldLevel);
FUNCDBG();
@@ -1721,13 +1722,17 @@ int grcan_set_sfilter(void *d, const struct grcan_filter *filter)
pDev->sfilter.mask = 0;
/* disable Sync interrupt */
SPIN_LOCK_IRQ(&pDev->devlock, oldLevel);
pDev->regs->imr = READ_REG(&pDev->regs->imr) & ~(GRCAN_RXSYNC_IRQ|GRCAN_TXSYNC_IRQ);
SPIN_UNLOCK_IRQ(&pDev->devlock, oldLevel);
}else{
/* Save filter */
pDev->sfilter = *filter;
/* Enable Sync interrupt */
SPIN_LOCK_IRQ(&pDev->devlock, oldLevel);
pDev->regs->imr = READ_REG(&pDev->regs->imr) | (GRCAN_RXSYNC_IRQ|GRCAN_TXSYNC_IRQ);
SPIN_UNLOCK_IRQ(&pDev->devlock, oldLevel);
}
/* Set Sync RX/TX filter */
grcan_hw_sync(pDev->regs,&pDev->sfilter);
@@ -1756,6 +1761,7 @@ static void grcan_interrupt(void *arg)
struct grcan_priv *pDev = arg;
unsigned int status = READ_REG(&pDev->regs->pimsr);
unsigned int canstat = READ_REG(&pDev->regs->stat);
SPIN_ISR_IRQFLAGS(irqflags);
/* Spurious IRQ call? */
if ( !status && !canstat )
@@ -1777,8 +1783,10 @@ static void grcan_interrupt(void *arg)
* that is blocked in read/write calls and stop futher calls
* to read/write until user has called ioctl(fd,START,0).
*/
SPIN_LOCK(&pDev->devlock, irqflags);
pDev->started = 0;
grcan_hw_stop(pDev); /* this mask all IRQ sources */
SPIN_UNLOCK(&pDev->devlock, irqflags);
status=0x1ffff; /* clear all interrupts */
goto out;
}
@@ -1803,13 +1811,17 @@ static void grcan_interrupt(void *arg)
if ( status & GRCAN_RXIRQ_IRQ ){
/* RX IRQ pointer interrupt */
/*printk("RxIrq 0x%x\n",status);*/
SPIN_LOCK(&pDev->devlock, irqflags);
pDev->regs->imr = READ_REG(&pDev->regs->imr) & ~GRCAN_RXIRQ_IRQ;
SPIN_UNLOCK(&pDev->devlock, irqflags);
rtems_semaphore_release(pDev->rx_sem);
}
if ( status & GRCAN_TXIRQ_IRQ ){
/* TX IRQ pointer interrupt */
SPIN_LOCK(&pDev->devlock, irqflags);
pDev->regs->imr = READ_REG(&pDev->regs->imr) & ~GRCAN_TXIRQ_IRQ;
SPIN_UNLOCK(&pDev->devlock, irqflags);
rtems_semaphore_release(pDev->tx_sem);
}
@@ -1824,7 +1836,9 @@ static void grcan_interrupt(void *arg)
}
if ( status & GRCAN_TXEMPTY_IRQ ){
SPIN_LOCK(&pDev->devlock, irqflags);
pDev->regs->imr = READ_REG(&pDev->regs->imr) & ~GRCAN_TXEMPTY_IRQ;
SPIN_UNLOCK(&pDev->devlock, irqflags);
rtems_semaphore_release(pDev->txempty_sem);
}