| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-id: <303243223348502.gep@pripojeni.net>
Date: Tue, 16 Oct 2007 13:50:01 -0400
From: Jiri Slaby <jirislaby@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/1] misc-phantom-improved-data-passing-fix
Andrew Morton wrote:
> On Mon, 15 Oct 2007 09:33:49 -0700
> Jiri Slaby <jirislaby@...il.com> wrote:
>
> > phantom, improved data passing
> >
> > this new version guarantees amb_bit switch in small enough intervals, so
> > that the device won't stop working in the middle of a movement anymore.
> > However it preserves old (openhaptics) functionality.
> >
> > ...
> >
> > +
> > + /* preserve amp bit (don't allow to change it when in NOT_OH) */
> > + if (r.reg == PHN_CONTROL && (dev->status & PHB_NOT_OH))
> > + dev->ctl_reg = r.value = (r.value & ~PHN_CTL_AMP) |
> > + (dev->ctl_reg & PHN_CTL_AMP);
>
> hm, is that coded as clearly and as simply as possible? Don't think so :(
Changed below.
> > static irqreturn_t phantom_isr(int irq, void *data)
> > {
> > struct phantom_device *dev = data;
> > + unsigned int i;
> > + u32 ctl;
> >
> > - if (!(ioread32(dev->iaddr + PHN_CONTROL) & PHN_CTL_IRQ))
> > + spin_lock(&dev->regs_lock);
> > + ctl = ioread32(dev->iaddr + PHN_CONTROL);
> > + if (!(ctl & PHN_CTL_IRQ)) {
> > + spin_unlock(&dev->regs_lock);
> > return IRQ_NONE;
> > + }
> >
> > iowrite32(0, dev->iaddr);
> > iowrite32(0xc0, dev->iaddr);
> > +
> > + if (dev->status & PHB_NOT_OH)
> > + for (i = 0; i < min(dev->oregs.count, 8U); i++)
>
> But this is the interrupt handler, and there's a pointer chase as well as
> the min() each time around the loop (I assume). I doubt if the world will
> end, but it seems a bit lazy?
Hmm, the compiler isn't as smart as I though. The fix follows, thanks.
--
misc-phantom-improved-data-passing-fix
Signed-off-by: Jiri Slaby <jirislaby@...il.com>
---
commit d1d9a974c008af6e7ad0347df7f9ca372da1bb4c
tree 9c9cda79e150a752f052831ea18f35f31c8f9a5f
parent 228d539e706cd42c2950aa26ac01590e413d8f51
author Jiri Slaby <jirislaby@...il.com> Tue, 16 Oct 2007 16:46:28 +0200
committer Jiri Slaby <jirislaby@...il.com> Tue, 16 Oct 2007 16:46:28 +0200
drivers/misc/phantom.c | 37 ++++++++++++++++++++++++-------------
1 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/drivers/misc/phantom.c b/drivers/misc/phantom.c
index 4a610cc..cd221fd 100644
--- a/drivers/misc/phantom.c
+++ b/drivers/misc/phantom.c
@@ -113,9 +113,11 @@ static long phantom_ioctl(struct file *file, unsigned int cmd,
pr_debug("phantom: writing %x to %u\n", r.value, r.reg);
/* preserve amp bit (don't allow to change it when in NOT_OH) */
- if (r.reg == PHN_CONTROL && (dev->status & PHB_NOT_OH))
- dev->ctl_reg = r.value = (r.value & ~PHN_CTL_AMP) |
- (dev->ctl_reg & PHN_CTL_AMP);
+ if (r.reg == PHN_CONTROL && (dev->status & PHB_NOT_OH)) {
+ r.value &= ~PHN_CTL_AMP;
+ r.value |= dev->ctl_reg & PHN_CTL_AMP;
+ dev->ctl_reg = r.value;
+ }
iowrite32(r.value, dev->iaddr + r.reg);
ioread32(dev->iaddr); /* PCI posting */
@@ -133,7 +135,8 @@ static long phantom_ioctl(struct file *file, unsigned int cmd,
if (dev->status & PHB_NOT_OH)
memcpy(&dev->oregs, &rs, sizeof(rs));
else {
- for (i = 0; i < min(rs.count, 8U); i++)
+ u32 m = min(rs.count, 8U);
+ for (i = 0; i < m; i++)
if (rs.mask & BIT(i))
iowrite32(rs.values[i], dev->oaddr + i);
ioread32(dev->iaddr); /* PCI posting */
@@ -152,13 +155,17 @@ static long phantom_ioctl(struct file *file, unsigned int cmd,
if (copy_to_user(argp, &r, sizeof(r)))
return -EFAULT;
break;
- case PHN_GET_REGS:
+ case PHN_GET_REGS: {
+ u32 m;
+
if (copy_from_user(&rs, argp, sizeof(rs)))
return -EFAULT;
+ m = min(rs.count, 8U);
+
pr_debug("phantom: GRS %u regs %x\n", rs.count, rs.mask);
spin_lock_irqsave(&dev->regs_lock, flags);
- for (i = 0; i < min(rs.count, 8U); i++)
+ for (i = 0; i < m; i++)
if (rs.mask & BIT(i))
rs.values[i] = ioread32(dev->iaddr + i);
spin_unlock_irqrestore(&dev->regs_lock, flags);
@@ -166,7 +173,7 @@ static long phantom_ioctl(struct file *file, unsigned int cmd,
if (copy_to_user(argp, &rs, sizeof(rs)))
return -EFAULT;
break;
- case PHN_NOT_OH:
+ } case PHN_NOT_OH:
spin_lock_irqsave(&dev->regs_lock, flags);
if (dev->status & PHB_RUNNING) {
printk(KERN_ERR "phantom: you need to set NOT_OH "
@@ -265,13 +272,17 @@ static irqreturn_t phantom_isr(int irq, void *data)
iowrite32(0, dev->iaddr);
iowrite32(0xc0, dev->iaddr);
- if (dev->status & PHB_NOT_OH)
- for (i = 0; i < min(dev->oregs.count, 8U); i++)
- if (dev->oregs.mask & BIT(i))
- iowrite32(dev->oregs.values[i], dev->oaddr + i);
+ if (dev->status & PHB_NOT_OH) {
+ struct phm_regs *r = &dev->oregs;
+ u32 m = min(r->count, 8U);
- dev->ctl_reg ^= PHN_CTL_AMP;
- iowrite32(dev->ctl_reg, dev->iaddr + PHN_CONTROL);
+ for (i = 0; i < m; i++)
+ if (r->mask & BIT(i))
+ iowrite32(r->values[i], dev->oaddr + i);
+
+ dev->ctl_reg ^= PHN_CTL_AMP;
+ iowrite32(dev->ctl_reg, dev->iaddr + PHN_CONTROL);
+ }
spin_unlock(&dev->regs_lock);
ioread32(dev->iaddr); /* PCI posting */
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists