[xen staging] x86/HPET: avoid indirect call to event handler

[patchbot@xxxxxxx]

commit 93c8070e029dee61a83cb7408a155cf3ebe5c50c
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Jan 22 09:11:25 2026 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jan 22 09:11:25 2026 +0100

    x86/HPET: avoid indirect call to event handler
    
    It's only ever handle_hpet_broadcast() that's used. While we now don't
    enable IRQs right away, still play safe and convert the function pointer
    to a boolean, to make sure no calls occur too early.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/hpet.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/hpet.c b/xen/arch/x86/hpet.c
index a69abe2650..d94da24f42 100644
--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -40,7 +40,7 @@ struct hpet_event_channel
     s_time_t      next_event;
     cpumask_var_t cpumask;
     spinlock_t    lock;
-    void          (*event_handler)(struct hpet_event_channel *ch);
+    bool          event_handler;
 
     unsigned int idx;   /* physical channel idx */
     unsigned int cpu;   /* msi target */
@@ -194,7 +194,7 @@ static void evt_do_broadcast(cpumask_t *mask)
        cpumask_raise_softirq(mask, TIMER_SOFTIRQ);
 }
 
-static void cf_check handle_hpet_broadcast(struct hpet_event_channel *ch)
+static void handle_hpet_broadcast(struct hpet_event_channel *ch)
 {
     cpumask_t *scratch = this_cpu(hpet_scratch_cpumask);
     s_time_t now, next_event;
@@ -250,7 +250,7 @@ static void cf_check hpet_interrupt_handler(int irq, void 
*data)
         return;
     }
 
-    ch->event_handler(ch);
+    handle_hpet_broadcast(ch);
 }
 
 static void hpet_enable_channel(struct hpet_event_channel *ch)
@@ -657,7 +657,7 @@ void __init hpet_broadcast_init(void)
         hpet_events[i].next_event = STIME_MAX;
         spin_lock_init(&hpet_events[i].lock);
         smp_wmb();
-        hpet_events[i].event_handler = handle_hpet_broadcast;
+        hpet_events[i].event_handler = true;
 
         hpet_events[i].msi.msi_attrib.maskbit = 1;
         hpet_events[i].msi.msi_attrib.pos = MSI_TYPE_HPET;
@@ -814,7 +814,9 @@ int hpet_legacy_irq_tick(void)
          (hpet_events->flags & (HPET_EVT_DISABLE|HPET_EVT_LEGACY)) !=
          HPET_EVT_LEGACY )
         return 0;
-    hpet_events->event_handler(hpet_events);
+
+    handle_hpet_broadcast(hpet_events);
+
     return 1;
 }
 
--
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