diff mbox

[LINUX] xen: event channel arrays are xen_ulong_t and not unsigned long

Message ID 1361285357-26696-1-git-send-email-ian.campbell@citrix.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ian Campbell Feb. 19, 2013, 2:49 p.m. UTC
On ARM we want these to be the same size on 32- and 64-bit.

This is an ABI change on ARM. X86 does not change.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Keir (Xen.org) <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: xen-devel@lists.xen.org
---
Changes since V1
  use find_first_set not __ffs
  fix some more unsigned long -> xen_ulong_t
  use more generic xchg_xen_ulong instead of ...read_evtchn...
---
 arch/arm/include/asm/xen/events.h |   22 ++++++++
 arch/x86/include/asm/xen/events.h |    3 +
 drivers/xen/events.c              |  103 ++++++++++++++++++++-----------------
 include/xen/interface/xen.h       |    8 ++--
 4 files changed, 84 insertions(+), 52 deletions(-)

Comments

Stefano Stabellini Feb. 19, 2013, 5:11 p.m. UTC | #1
On Tue, 19 Feb 2013, Ian Campbell wrote:
> On ARM we want these to be the same size on 32- and 64-bit.
> 
> This is an ABI change on ARM. X86 does not change.
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: Jan Beulich <JBeulich@suse.com>
> Cc: Keir (Xen.org) <keir@xen.org>
> Cc: Tim Deegan <tim@xen.org>
> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: xen-devel@lists.xen.org
> ---
> Changes since V1
>   use find_first_set not __ffs
>   fix some more unsigned long -> xen_ulong_t
>   use more generic xchg_xen_ulong instead of ...read_evtchn...
> ---
>  arch/arm/include/asm/xen/events.h |   22 ++++++++
>  arch/x86/include/asm/xen/events.h |    3 +
>  drivers/xen/events.c              |  103 ++++++++++++++++++++-----------------
>  include/xen/interface/xen.h       |    8 ++--
>  4 files changed, 84 insertions(+), 52 deletions(-)

You might have to rebase this patch: it doesn't apply on Linux 3.8.


> diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h
> index 94b4e90..9bb5f50 100644
> --- a/arch/arm/include/asm/xen/events.h
> +++ b/arch/arm/include/asm/xen/events.h
> @@ -15,4 +15,26 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)
>         return raw_irqs_disabled_flags(regs->ARM_cpsr);
>  }
> 
> +/*
> + * We cannot use xchg because it does not support 8-byte
> + * values. However it is safe to use {ldr,dtd}exd directly because all
> + * platforms which Xen can run on support those instructions.
> + */
> +static inline xen_ulong_t xchg_xen_ulong(xen_ulong_t *ptr, xen_ulong_t val)
> +{
> +       xen_ulong_t oldval;
> +       unsigned int tmp;
> +
> +       wmb();
> +       asm volatile("@ read_evtchn_pending_sel\n"
                           ^ do we need this?


> +               "1:     ldrexd  %0, %H0, [%3]\n"
> +               "       strexd  %1, %2, %H2, [%3]\n"
> +               "       teq     %1, #0\n"
> +               "       bne     1b"
> +               : "=&r" (oldval), "=&r" (tmp)
> +               : "r" (val), "r" (ptr)
> +               : "memory", "cc");
> +       return oldval;
> +}
> +
>  #endif /* _ASM_ARM_XEN_EVENTS_H */

[...]

> @@ -1295,18 +1306,14 @@ static void __xen_evtchn_do_upcall(void)
>         unsigned count;
> 
>         do {
> -               unsigned long pending_words;
> +               xen_ulong_t pending_words;
> 
>                 vcpu_info->evtchn_upcall_pending = 0;
> 
>                 if (__this_cpu_inc_return(xed_nesting_count) - 1)
>                         goto out;
> 
> -#ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
> -               /* Clear master flag /before/ clearing selector flag. */
> -               wmb();
> -#endif

Even though I understand that moving wmb() into xchg_xen_ulong gets rid
of an ugly ifndef, I am not sure whether it is a good thing from the
code readability point of view. I'll let Konrad decide on this one.


> -               pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
> +               pending_words = xchg_xen_ulong(&vcpu_info->evtchn_pending_sel, 0);
> 
>                 start_word_idx = __this_cpu_read(current_word_idx);
>                 start_bit_idx = __this_cpu_read(current_bit_idx);
> @@ -1314,8 +1321,8 @@ static void __xen_evtchn_do_upcall(void)
>                 word_idx = start_word_idx;
> 
>                 for (i = 0; pending_words != 0; i++) {
> -                       unsigned long pending_bits;
> -                       unsigned long words;
> +                       xen_ulong_t pending_bits;
> +                       xen_ulong_t words;
> 
>                         words = MASK_LSBS(pending_words, word_idx);
> 
> @@ -1327,7 +1334,7 @@ static void __xen_evtchn_do_upcall(void)
>                                 bit_idx = 0;
>                                 continue;
>                         }
> -                       word_idx = __ffs(words);
> +                       word_idx = find_first_bit(BM(&words), sizeof(words));
> 
>                         pending_bits = active_evtchns(cpu, s, word_idx);
>                         bit_idx = 0; /* usually scan entire word from start */

is that because find_first_bit can actually cope with a bit number >=
32 and __ffs can't?
In that case it is worth adding a comment somewhere in this file,
reminding people to only use bit operations that can handle size >
unsigned long
Ian Campbell Feb. 19, 2013, 5:17 p.m. UTC | #2
On Tue, 2013-02-19 at 17:11 +0000, Stefano Stabellini wrote:
> On Tue, 19 Feb 2013, Ian Campbell wrote:
> > On ARM we want these to be the same size on 32- and 64-bit.
> > 
> > This is an ABI change on ARM. X86 does not change.
> > 
> > Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> > Cc: Jan Beulich <JBeulich@suse.com>
> > Cc: Keir (Xen.org) <keir@xen.org>
> > Cc: Tim Deegan <tim@xen.org>
> > Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > Cc: linux-arm-kernel@lists.infradead.org
> > Cc: xen-devel@lists.xen.org
> > ---
> > Changes since V1
> >   use find_first_set not __ffs
> >   fix some more unsigned long -> xen_ulong_t
> >   use more generic xchg_xen_ulong instead of ...read_evtchn...
> > ---
> >  arch/arm/include/asm/xen/events.h |   22 ++++++++
> >  arch/x86/include/asm/xen/events.h |    3 +
> >  drivers/xen/events.c              |  103 ++++++++++++++++++++-----------------
> >  include/xen/interface/xen.h       |    8 ++--
> >  4 files changed, 84 insertions(+), 52 deletions(-)
> 
> You might have to rebase this patch: it doesn't apply on Linux 3.8.

Will do.

> 
> 
> > diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h
> > index 94b4e90..9bb5f50 100644
> > --- a/arch/arm/include/asm/xen/events.h
> > +++ b/arch/arm/include/asm/xen/events.h
> > @@ -15,4 +15,26 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)
> >         return raw_irqs_disabled_flags(regs->ARM_cpsr);
> >  }
> > 
> > +/*
> > + * We cannot use xchg because it does not support 8-byte
> > + * values. However it is safe to use {ldr,dtd}exd directly because all
> > + * platforms which Xen can run on support those instructions.
> > + */
> > +static inline xen_ulong_t xchg_xen_ulong(xen_ulong_t *ptr, xen_ulong_t val)
> > +{
> > +       xen_ulong_t oldval;
> > +       unsigned int tmp;
> > +
> > +       wmb();
> > +       asm volatile("@ read_evtchn_pending_sel\n"
>                            ^ do we need this?

It means that the .s files (if you create them) and such are a bit more
readable, it's not that uncommon in the ARM inline assembly.

> > +               "1:     ldrexd  %0, %H0, [%3]\n"
> > +               "       strexd  %1, %2, %H2, [%3]\n"
> > +               "       teq     %1, #0\n"
> > +               "       bne     1b"
> > +               : "=&r" (oldval), "=&r" (tmp)
> > +               : "r" (val), "r" (ptr)
> > +               : "memory", "cc");
> > +       return oldval;
> > +}
> > +
> >  #endif /* _ASM_ARM_XEN_EVENTS_H */
> 
> [...]
> 
> > @@ -1295,18 +1306,14 @@ static void __xen_evtchn_do_upcall(void)
> >         unsigned count;
> > 
> >         do {
> > -               unsigned long pending_words;
> > +               xen_ulong_t pending_words;
> > 
> >                 vcpu_info->evtchn_upcall_pending = 0;
> > 
> >                 if (__this_cpu_inc_return(xed_nesting_count) - 1)
> >                         goto out;
> > 
> > -#ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
> > -               /* Clear master flag /before/ clearing selector flag. */
> > -               wmb();
> > -#endif
> 
> Even though I understand that moving wmb() into xchg_xen_ulong gets rid
> of an ugly ifndef, I am not sure whether it is a good thing from the
> code readability point of view. I'll let Konrad decide on this one.

I actually see this the other way -- this barrier is logically part of
the exchange operation, implicitly on x86 and explicitly on ARM. I will
add a comment here though, which I think is best of both.

> 
> 
> > -               pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
> > +               pending_words = xchg_xen_ulong(&vcpu_info->evtchn_pending_sel, 0);
> > 
> >                 start_word_idx = __this_cpu_read(current_word_idx);
> >                 start_bit_idx = __this_cpu_read(current_bit_idx);
> > @@ -1314,8 +1321,8 @@ static void __xen_evtchn_do_upcall(void)
> >                 word_idx = start_word_idx;
> > 
> >                 for (i = 0; pending_words != 0; i++) {
> > -                       unsigned long pending_bits;
> > -                       unsigned long words;
> > +                       xen_ulong_t pending_bits;
> > +                       xen_ulong_t words;
> > 
> >                         words = MASK_LSBS(pending_words, word_idx);
> > 
> > @@ -1327,7 +1334,7 @@ static void __xen_evtchn_do_upcall(void)
> >                                 bit_idx = 0;
> >                                 continue;
> >                         }
> > -                       word_idx = __ffs(words);
> > +                       word_idx = find_first_bit(BM(&words), sizeof(words));
> > 
> >                         pending_bits = active_evtchns(cpu, s, word_idx);
> >                         bit_idx = 0; /* usually scan entire word from start */
> 
> is that because find_first_bit can actually cope with a bit number >=
> 32 and __ffs can't?

Yes.

> In that case it is worth adding a comment somewhere in this file,
> reminding people to only use bit operations that can handle size >
> unsigned long

Will do.
Tim Deegan Feb. 19, 2013, 5:26 p.m. UTC | #3
At 17:17 +0000 on 19 Feb (1361294248), Ian Campbell wrote:
> On Tue, 2013-02-19 at 17:11 +0000, Stefano Stabellini wrote:
> > On Tue, 19 Feb 2013, Ian Campbell wrote:
> > > +/*
> > > + * We cannot use xchg because it does not support 8-byte
> > > + * values. However it is safe to use {ldr,dtd}exd directly because all
> > > + * platforms which Xen can run on support those instructions.
> > > + */
> > > +static inline xen_ulong_t xchg_xen_ulong(xen_ulong_t *ptr, xen_ulong_t val)
> > > +{
> > > +       xen_ulong_t oldval;
> > > +       unsigned int tmp;
> > > +
> > > +       wmb();
> > > +       asm volatile("@ read_evtchn_pending_sel\n"
> >                            ^ do we need this?
> 
> It means that the .s files (if you create them) and such are a bit more
> readable, it's not that uncommon in the ARM inline assembly.

+1.  s/read_evtchn_pending_sel/xchg_xen_ulong/ though.

Tim.
Ian Campbell Feb. 19, 2013, 5:28 p.m. UTC | #4
On Tue, 2013-02-19 at 17:26 +0000, Tim Deegan wrote:
> At 17:17 +0000 on 19 Feb (1361294248), Ian Campbell wrote:
> > On Tue, 2013-02-19 at 17:11 +0000, Stefano Stabellini wrote:
> > > On Tue, 19 Feb 2013, Ian Campbell wrote:
> > > > +/*
> > > > + * We cannot use xchg because it does not support 8-byte
> > > > + * values. However it is safe to use {ldr,dtd}exd directly because all
> > > > + * platforms which Xen can run on support those instructions.
> > > > + */
> > > > +static inline xen_ulong_t xchg_xen_ulong(xen_ulong_t *ptr, xen_ulong_t val)
> > > > +{
> > > > +       xen_ulong_t oldval;
> > > > +       unsigned int tmp;
> > > > +
> > > > +       wmb();
> > > > +       asm volatile("@ read_evtchn_pending_sel\n"
> > >                            ^ do we need this?
> > 
> > It means that the .s files (if you create them) and such are a bit more
> > readable, it's not that uncommon in the ARM inline assembly.
> 
> +1.  s/read_evtchn_pending_sel/xchg_xen_ulong/ though.

Damn, yes. I just sent v3 too :-(

Ian.
diff mbox

Patch

diff --git a/arch/arm/include/asm/xen/events.h b/arch/arm/include/asm/xen/events.h
index 94b4e90..9bb5f50 100644
--- a/arch/arm/include/asm/xen/events.h
+++ b/arch/arm/include/asm/xen/events.h
@@ -15,4 +15,26 @@  static inline int xen_irqs_disabled(struct pt_regs *regs)
 	return raw_irqs_disabled_flags(regs->ARM_cpsr);
 }
 
+/*
+ * We cannot use xchg because it does not support 8-byte
+ * values. However it is safe to use {ldr,dtd}exd directly because all
+ * platforms which Xen can run on support those instructions.
+ */
+static inline xen_ulong_t xchg_xen_ulong(xen_ulong_t *ptr, xen_ulong_t val)
+{
+	xen_ulong_t oldval;
+	unsigned int tmp;
+
+	wmb();
+	asm volatile("@ read_evtchn_pending_sel\n"
+		"1:     ldrexd  %0, %H0, [%3]\n"
+		"       strexd  %1, %2, %H2, [%3]\n"
+		"       teq     %1, #0\n"
+		"       bne     1b"
+		: "=&r" (oldval), "=&r" (tmp)
+		: "r" (val), "r" (ptr)
+		: "memory", "cc");
+	return oldval;
+}
+
 #endif /* _ASM_ARM_XEN_EVENTS_H */
diff --git a/arch/x86/include/asm/xen/events.h b/arch/x86/include/asm/xen/events.h
index cc146d5..ca842f2 100644
--- a/arch/x86/include/asm/xen/events.h
+++ b/arch/x86/include/asm/xen/events.h
@@ -16,4 +16,7 @@  static inline int xen_irqs_disabled(struct pt_regs *regs)
 	return raw_irqs_disabled_flags(regs->flags);
 }
 
+/* No need for a barrier -- XCHG is a barrier on x86. */
+#define xchg_xen_ulong(ptr, val) xchg((ptr), (val))
+
 #endif /* _ASM_X86_XEN_EVENTS_H */
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 0be4df3..5618ca0 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -80,6 +80,12 @@  enum xen_irq_type {
 };
 
 /*
+ * Make a bitmask (i.e. unsigned long *) of a xen_ulong_t
+ * array. Primarily to avoid long lines (hence the terse name).
+ */
+#define BM(x) (unsigned long *)(x)
+
+/*
  * Packed IRQ information:
  * type - enum xen_irq_type
  * event channel - irq->event channel mapping
@@ -120,7 +126,9 @@  static unsigned long *pirq_eoi_map;
 #endif
 static bool (*pirq_needs_eoi)(unsigned irq);
 
-static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
+#define BITS_PER_EVTCHN_WORD (sizeof(xen_ulong_t)*8)
+
+static DEFINE_PER_CPU(xen_ulong_t [NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD],
 		      cpu_evtchn_mask);
 
 /* Xen will never allocate port zero for any purpose. */
@@ -294,9 +302,9 @@  static bool pirq_needs_eoi_flag(unsigned irq)
 	return info->u.pirq.flags & PIRQ_NEEDS_EOI;
 }
 
-static inline unsigned long active_evtchns(unsigned int cpu,
-					   struct shared_info *sh,
-					   unsigned int idx)
+static inline xen_ulong_t active_evtchns(unsigned int cpu,
+					 struct shared_info *sh,
+					 unsigned int idx)
 {
 	return sh->evtchn_pending[idx] &
 		per_cpu(cpu_evtchn_mask, cpu)[idx] &
@@ -312,8 +320,8 @@  static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 	cpumask_copy(irq_to_desc(irq)->irq_data.affinity, cpumask_of(cpu));
 #endif
 
-	clear_bit(chn, per_cpu(cpu_evtchn_mask, cpu_from_irq(irq)));
-	set_bit(chn, per_cpu(cpu_evtchn_mask, cpu));
+	clear_bit(chn, BM(per_cpu(cpu_evtchn_mask, cpu_from_irq(irq))));
+	set_bit(chn, BM(per_cpu(cpu_evtchn_mask, cpu)));
 
 	info_for_irq(irq)->cpu = cpu;
 }
@@ -339,19 +347,19 @@  static void init_evtchn_cpu_bindings(void)
 static inline void clear_evtchn(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
-	sync_clear_bit(port, &s->evtchn_pending[0]);
+	sync_clear_bit(port, BM(&s->evtchn_pending[0]));
 }
 
 static inline void set_evtchn(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
-	sync_set_bit(port, &s->evtchn_pending[0]);
+	sync_set_bit(port, BM(&s->evtchn_pending[0]));
 }
 
 static inline int test_evtchn(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
-	return sync_test_bit(port, &s->evtchn_pending[0]);
+	return sync_test_bit(port, BM(&s->evtchn_pending[0]));
 }
 
 
@@ -375,7 +383,7 @@  EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 static void mask_evtchn(int port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
-	sync_set_bit(port, &s->evtchn_mask[0]);
+	sync_set_bit(port, BM(&s->evtchn_mask[0]));
 }
 
 static void unmask_evtchn(int port)
@@ -389,7 +397,7 @@  static void unmask_evtchn(int port)
 	if (unlikely((cpu != cpu_from_evtchn(port))))
 		do_hypercall = 1;
 	else
-		evtchn_pending = sync_test_bit(port, &s->evtchn_pending[0]);
+		evtchn_pending = sync_test_bit(port, BM(&s->evtchn_pending[0]));
 
 	if (unlikely(evtchn_pending && xen_hvm_domain()))
 		do_hypercall = 1;
@@ -403,7 +411,7 @@  static void unmask_evtchn(int port)
 	} else {
 		struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
 
-		sync_clear_bit(port, &s->evtchn_mask[0]);
+		sync_clear_bit(port, BM(&s->evtchn_mask[0]));
 
 		/*
 		 * The following is basically the equivalent of
@@ -411,8 +419,8 @@  static void unmask_evtchn(int port)
 		 * the interrupt edge' if the channel is masked.
 		 */
 		if (evtchn_pending &&
-		    !sync_test_and_set_bit(port / BITS_PER_LONG,
-					   &vcpu_info->evtchn_pending_sel))
+		    !sync_test_and_set_bit(port / BITS_PER_EVTCHN_WORD,
+					   BM(&vcpu_info->evtchn_pending_sel)))
 			vcpu_info->evtchn_upcall_pending = 1;
 	}
 
@@ -1189,7 +1197,7 @@  irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 {
 	struct shared_info *sh = HYPERVISOR_shared_info;
 	int cpu = smp_processor_id();
-	unsigned long *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
+	xen_ulong_t *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
 	int i;
 	unsigned long flags;
 	static DEFINE_SPINLOCK(debug_lock);
@@ -1205,7 +1213,7 @@  irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 		pending = (get_irq_regs() && i == cpu)
 			? xen_irqs_disabled(get_irq_regs())
 			: v->evtchn_upcall_mask;
-		printk("%d: masked=%d pending=%d event_sel %0*lx\n  ", i,
+		printk("%d: masked=%d pending=%d event_sel %0*"PRI_xen_ulong"\n  ", i,
 		       pending, v->evtchn_upcall_pending,
 		       (int)(sizeof(v->evtchn_pending_sel)*2),
 		       v->evtchn_pending_sel);
@@ -1214,49 +1222,52 @@  irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 
 	printk("\npending:\n   ");
 	for (i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
-		printk("%0*lx%s", (int)sizeof(sh->evtchn_pending[0])*2,
+		printk("%0*"PRI_xen_ulong"%s",
+		       (int)sizeof(sh->evtchn_pending[0])*2,
 		       sh->evtchn_pending[i],
 		       i % 8 == 0 ? "\n   " : " ");
 	printk("\nglobal mask:\n   ");
 	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
-		printk("%0*lx%s",
+		printk("%0*"PRI_xen_ulong"%s",
 		       (int)(sizeof(sh->evtchn_mask[0])*2),
 		       sh->evtchn_mask[i],
 		       i % 8 == 0 ? "\n   " : " ");
 
 	printk("\nglobally unmasked:\n   ");
 	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
-		printk("%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
+		printk("%0*"PRI_xen_ulong"%s",
+		       (int)(sizeof(sh->evtchn_mask[0])*2),
 		       sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 		       i % 8 == 0 ? "\n   " : " ");
 
 	printk("\nlocal cpu%d mask:\n   ", cpu);
-	for (i = (NR_EVENT_CHANNELS/BITS_PER_LONG)-1; i >= 0; i--)
-		printk("%0*lx%s", (int)(sizeof(cpu_evtchn[0])*2),
+	for (i = (NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD)-1; i >= 0; i--)
+		printk("%0*"PRI_xen_ulong"%s", (int)(sizeof(cpu_evtchn[0])*2),
 		       cpu_evtchn[i],
 		       i % 8 == 0 ? "\n   " : " ");
 
 	printk("\nlocally unmasked:\n   ");
 	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) {
-		unsigned long pending = sh->evtchn_pending[i]
+		xen_ulong_t pending = sh->evtchn_pending[i]
 			& ~sh->evtchn_mask[i]
 			& cpu_evtchn[i];
-		printk("%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
+		printk("%0*"PRI_xen_ulong"%s",
+		       (int)(sizeof(sh->evtchn_mask[0])*2),
 		       pending, i % 8 == 0 ? "\n   " : " ");
 	}
 
 	printk("\npending list:\n");
 	for (i = 0; i < NR_EVENT_CHANNELS; i++) {
-		if (sync_test_bit(i, sh->evtchn_pending)) {
-			int word_idx = i / BITS_PER_LONG;
+		if (sync_test_bit(i, BM(sh->evtchn_pending))) {
+			int word_idx = i / BITS_PER_EVTCHN_WORD;
 			printk("  %d: event %d -> irq %d%s%s%s\n",
 			       cpu_from_evtchn(i), i,
 			       evtchn_to_irq[i],
-			       sync_test_bit(word_idx, &v->evtchn_pending_sel)
+			       sync_test_bit(word_idx, BM(&v->evtchn_pending_sel))
 					     ? "" : " l2-clear",
-			       !sync_test_bit(i, sh->evtchn_mask)
+			       !sync_test_bit(i, BM(sh->evtchn_mask))
 					     ? "" : " globally-masked",
-			       sync_test_bit(i, cpu_evtchn)
+			       sync_test_bit(i, BM(cpu_evtchn))
 					     ? "" : " locally-masked");
 		}
 	}
@@ -1273,7 +1284,7 @@  static DEFINE_PER_CPU(unsigned int, current_bit_idx);
 /*
  * Mask out the i least significant bits of w
  */
-#define MASK_LSBS(w, i) (w & ((~0UL) << i))
+#define MASK_LSBS(w, i) (w & ((~((xen_ulong_t)0UL)) << i))
 
 /*
  * Search the CPUs pending events bitmasks.  For each one found, map
@@ -1295,18 +1306,14 @@  static void __xen_evtchn_do_upcall(void)
 	unsigned count;
 
 	do {
-		unsigned long pending_words;
+		xen_ulong_t pending_words;
 
 		vcpu_info->evtchn_upcall_pending = 0;
 
 		if (__this_cpu_inc_return(xed_nesting_count) - 1)
 			goto out;
 
-#ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
-		/* Clear master flag /before/ clearing selector flag. */
-		wmb();
-#endif
-		pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
+		pending_words = xchg_xen_ulong(&vcpu_info->evtchn_pending_sel, 0);
 
 		start_word_idx = __this_cpu_read(current_word_idx);
 		start_bit_idx = __this_cpu_read(current_bit_idx);
@@ -1314,8 +1321,8 @@  static void __xen_evtchn_do_upcall(void)
 		word_idx = start_word_idx;
 
 		for (i = 0; pending_words != 0; i++) {
-			unsigned long pending_bits;
-			unsigned long words;
+			xen_ulong_t pending_bits;
+			xen_ulong_t words;
 
 			words = MASK_LSBS(pending_words, word_idx);
 
@@ -1327,7 +1334,7 @@  static void __xen_evtchn_do_upcall(void)
 				bit_idx = 0;
 				continue;
 			}
-			word_idx = __ffs(words);
+			word_idx = find_first_bit(BM(&words), sizeof(words));
 
 			pending_bits = active_evtchns(cpu, s, word_idx);
 			bit_idx = 0; /* usually scan entire word from start */
@@ -1342,7 +1349,7 @@  static void __xen_evtchn_do_upcall(void)
 			}
 
 			do {
-				unsigned long bits;
+				xen_ulong_t bits;
 				int port, irq;
 				struct irq_desc *desc;
 
@@ -1352,10 +1359,10 @@  static void __xen_evtchn_do_upcall(void)
 				if (bits == 0)
 					break;
 
-				bit_idx = __ffs(bits);
+				bit_idx = find_first_bit(BM(&bits), sizeof(bits));
 
 				/* Process port. */
-				port = (word_idx * BITS_PER_LONG) + bit_idx;
+				port = (word_idx * BITS_PER_EVTCHN_WORD) + bit_idx;
 				irq = evtchn_to_irq[port];
 
 				if (irq != -1) {
@@ -1364,12 +1371,12 @@  static void __xen_evtchn_do_upcall(void)
 						generic_handle_irq_desc(irq, desc);
 				}
 
-				bit_idx = (bit_idx + 1) % BITS_PER_LONG;
+				bit_idx = (bit_idx + 1) % BITS_PER_EVTCHN_WORD;
 
 				/* Next caller starts at last processed + 1 */
 				__this_cpu_write(current_word_idx,
 						 bit_idx ? word_idx :
-						 (word_idx+1) % BITS_PER_LONG);
+						 (word_idx+1) % BITS_PER_EVTCHN_WORD);
 				__this_cpu_write(current_bit_idx, bit_idx);
 			} while (bit_idx != 0);
 
@@ -1377,7 +1384,7 @@  static void __xen_evtchn_do_upcall(void)
 			if ((word_idx != start_word_idx) || (i != 0))
 				pending_words &= ~(1UL << word_idx);
 
-			word_idx = (word_idx + 1) % BITS_PER_LONG;
+			word_idx = (word_idx + 1) % BITS_PER_EVTCHN_WORD;
 		}
 
 		BUG_ON(!irqs_disabled());
@@ -1487,8 +1494,8 @@  int resend_irq_on_evtchn(unsigned int irq)
 	if (!VALID_EVTCHN(evtchn))
 		return 1;
 
-	masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
-	sync_set_bit(evtchn, s->evtchn_pending);
+	masked = sync_test_and_set_bit(evtchn, BM(s->evtchn_mask));
+	sync_set_bit(evtchn, BM(s->evtchn_pending));
 	if (!masked)
 		unmask_evtchn(evtchn);
 
@@ -1536,8 +1543,8 @@  static int retrigger_dynirq(struct irq_data *data)
 	if (VALID_EVTCHN(evtchn)) {
 		int masked;
 
-		masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
-		sync_set_bit(evtchn, sh->evtchn_pending);
+		masked = sync_test_and_set_bit(evtchn, BM(sh->evtchn_mask));
+		sync_set_bit(evtchn, BM(sh->evtchn_pending));
 		if (!masked)
 			unmask_evtchn(evtchn);
 		ret = 1;
diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index 5d6c272..a9075df 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -285,7 +285,7 @@  DEFINE_GUEST_HANDLE_STRUCT(multicall_entry);
  * Event channel endpoints per domain:
  *  1024 if a long is 32 bits; 4096 if a long is 64 bits.
  */
-#define NR_EVENT_CHANNELS (sizeof(unsigned long) * sizeof(unsigned long) * 64)
+#define NR_EVENT_CHANNELS (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64)
 
 struct vcpu_time_info {
 	/*
@@ -341,7 +341,7 @@  struct vcpu_info {
 	 */
 	uint8_t evtchn_upcall_pending;
 	uint8_t evtchn_upcall_mask;
-	unsigned long evtchn_pending_sel;
+	xen_ulong_t evtchn_pending_sel;
 	struct arch_vcpu_info arch;
 	struct pvclock_vcpu_time_info time;
 }; /* 64 bytes (x86) */
@@ -384,8 +384,8 @@  struct shared_info {
 	 * per-vcpu selector word to be set. Each bit in the selector covers a
 	 * 'C long' in the PENDING bitfield array.
 	 */
-	unsigned long evtchn_pending[sizeof(unsigned long) * 8];
-	unsigned long evtchn_mask[sizeof(unsigned long) * 8];
+	xen_ulong_t evtchn_pending[sizeof(xen_ulong_t) * 8];
+	xen_ulong_t evtchn_mask[sizeof(xen_ulong_t) * 8];
 
 	/*
 	 * Wallclock time: updated only by control software. Guests should base