When this code was written, indirect branches still weren't considered
much of a problem (besides being a little slower). Instead of a function
pointer, pass a boolean to _disable_pit_irq(), thus allowing to
eliminate two ENDBR (one of them in .text).

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -563,7 +563,7 @@ static void cf_check handle_rtc_once(uin
     }
 }
 
-void __init cf_check hpet_broadcast_init(void)
+void __init hpet_broadcast_init(void)
 {
     u64 hpet_rate = hpet_setup();
     u32 hpet_id, cfg;
@@ -634,7 +634,7 @@ void __init cf_check hpet_broadcast_init
         hpet_events->flags = HPET_EVT_LEGACY;
 }
 
-void cf_check hpet_broadcast_resume(void)
+void hpet_broadcast_resume(void)
 {
     u32 cfg;
     unsigned int i, n;
--- a/xen/arch/x86/include/asm/hpet.h
+++ b/xen/arch/x86/include/asm/hpet.h
@@ -89,8 +89,8 @@ void hpet_disable_legacy_replacement_mod
  * Temporarily use an HPET event counter for timer interrupt handling,
  * rather than using the LAPIC timer. Used for Cx state entry.
  */
-void cf_check hpet_broadcast_init(void);
-void cf_check hpet_broadcast_resume(void);
+void hpet_broadcast_init(void);
+void hpet_broadcast_resume(void);
 void cf_check hpet_broadcast_enter(void);
 void cf_check hpet_broadcast_exit(void);
 int hpet_broadcast_is_available(void);
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -2427,7 +2427,7 @@ void __init early_time_init(void)
 }
 
 /* keep pit enabled for pit_broadcast working while cpuidle enabled */
-static int _disable_pit_irq(void(*hpet_broadcast_setup)(void))
+static int _disable_pit_irq(bool init)
 {
     int ret = 1;
 
@@ -2442,13 +2442,13 @@ static int _disable_pit_irq(void(*hpet_b
      */
     if ( cpuidle_using_deep_cstate() && !boot_cpu_has(X86_FEATURE_ARAT) )
     {
-        hpet_broadcast_setup();
+        init ? hpet_broadcast_init() : hpet_broadcast_resume();
         if ( !hpet_broadcast_is_available() )
         {
             if ( xen_cpuidle > 0 )
             {
-                printk("%ps() failed, turning to PIT broadcast\n",
-                       hpet_broadcast_setup);
+                printk("hpet_broadcast_%s() failed, turning to PIT broadcast\n",
+                       init ? "init" : "resume");
                 return -1;
             }
             ret = 0;
@@ -2465,7 +2465,7 @@ static int _disable_pit_irq(void(*hpet_b
 
 static int __init cf_check disable_pit_irq(void)
 {
-    if ( !_disable_pit_irq(hpet_broadcast_init) )
+    if ( !_disable_pit_irq(true) )
     {
         xen_cpuidle = 0;
         printk("CPUIDLE: disabled due to no HPET. "
@@ -2526,7 +2526,7 @@ int time_resume(void)
 
     resume_platform_timer();
 
-    if ( !_disable_pit_irq(hpet_broadcast_resume) )
+    if ( !_disable_pit_irq(false) )
         BUG();
 
     init_percpu_time();

On 16/01/2024 4:56 pm, Jan Beulich wrote:
> When this code was written, indirect branches still weren't considered
> much of a problem (besides being a little slower). Instead of a function
> pointer, pass a boolean to _disable_pit_irq(), thus allowing to
> eliminate two ENDBR (one of them in .text).
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>