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[Xen-devel] [PATCH 1/2] xen: event channel arrays are xen_ulong_t and not unsigned long



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@xxxxxxxxxx>
Cc: Jan Beulich <JBeulich@xxxxxxxx>
Cc: Keir (Xen.org) <keir@xxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 arch/arm/include/asm/xen/events.h |   22 +++++++++++
 arch/x86/include/asm/xen/events.h |    2 +
 drivers/xen/events.c              |   75 ++++++++++++++++++++----------------
 include/xen/interface/xen.h       |    8 ++--
 4 files changed, 70 insertions(+), 37 deletions(-)

diff --git a/arch/arm/include/asm/xen/events.h 
b/arch/arm/include/asm/xen/events.h
index 94b4e90..92dbb89 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 xen_read_evtchn_pending_sel(struct vcpu_info 
*vcpu_info)
+{
+       xen_ulong_t val;
+       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" (val), "=&r" (tmp)
+                       : "r" (0), "r" (&vcpu_info->evtchn_pending_sel)
+                       : "memory", "cc");
+       return val;
+}
+
 #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..55edd58 100644
--- a/arch/x86/include/asm/xen/events.h
+++ b/arch/x86/include/asm/xen/events.h
@@ -16,4 +16,6 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)
        return raw_irqs_disabled_flags(regs->flags);
 }
 
+#define xen_read_evtchn_pending_sel(v) xchg(&(v)->evtchn_pending_sel, 0)
+
 #endif /* _ASM_X86_XEN_EVENTS_H */
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 0be4df3..e90a440 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. */
@@ -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);
@@ -1214,25 +1222,27 @@ 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   " : " ");
 
@@ -1247,16 +1257,16 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 
        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");
                }
        }
@@ -1304,9 +1314,8 @@ static void __xen_evtchn_do_upcall(void)
 
 #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 = xen_read_evtchn_pending_sel(vcpu_info);
 
                start_word_idx = __this_cpu_read(current_word_idx);
                start_bit_idx = __this_cpu_read(current_bit_idx);
@@ -1355,7 +1364,7 @@ static void __xen_evtchn_do_upcall(void)
                                bit_idx = __ffs(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 +1373,12 @@ 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 +1386,7 @@ 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 +1496,8 @@ 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 +1545,8 @@ 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 886a5d8..53ec416 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
-- 
1.7.2.5


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