[xen staging] x86/time: split CMOS read and probe logic into function

[patchbot@xxxxxxx]

commit 413c25e03e4c6d140b65cd01e8c36c28af6dbed6
Author:     Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Mon Sep 9 13:42:17 2024 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Sep 9 13:42:17 2024 +0200

    x86/time: split CMOS read and probe logic into function
    
    The current logic to probe for the CMOS RTC is open-coded in 
get_cmos_time(),
    move it to a separate function that both serves the purpose of testing for 
the
    CMOS RTC existence and returning its value.
    
    The goal is to be able to split the probing and the reading logic into 
separate
    helpers, and putting the current logic in a separate function helps 
simplifying
    further changes.
    
    A transient *rtc_p variable is introduced as a parameter to the function, 
that
    will be removed by further changes.  Also note that due to the code 
movement,
    now cmos_rtc_probe will only get cleared on a second call to 
get_cmos_time(),
    as the newly introduced cmos_probe() function doesn't modify the variable
    anymore.
    
    No functional change intended.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/time.c | 59 +++++++++++++++++++++++++++++++----------------------
 1 file changed, 35 insertions(+), 24 deletions(-)

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index e55e76bd63..f37300946e 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -1291,45 +1291,32 @@ static bool __get_cmos_time(struct rtc_time *rtc)
     return t1 <= SECONDS(1) && t2 < MILLISECS(3);
 }
 
-static unsigned long get_cmos_time(void)
+static bool cmos_probe(struct rtc_time *rtc_p, bool cmos_rtc_probe)
 {
-    unsigned long res;
-    struct rtc_time rtc;
     unsigned int seconds = 60;
-    static bool __read_mostly cmos_rtc_probe;
-    boolean_param("cmos-rtc-probe", cmos_rtc_probe);
-
-    if ( efi_enabled(EFI_RS) )
-    {
-        res = efi_get_time();
-        if ( res )
-            return res;
-    }
-
-    if ( likely(!(acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC)) )
-        cmos_rtc_probe = false;
-    else if ( system_state < SYS_STATE_smp_boot && !cmos_rtc_probe )
-        panic("System with no CMOS RTC advertised must be booted from EFI"
-              " (or with command line option \"cmos-rtc-probe\")\n");
 
     for ( ; ; )
     {
-        bool success = __get_cmos_time(&rtc);
+        bool success = __get_cmos_time(rtc_p);
+        struct rtc_time rtc = *rtc_p;
 
-        if ( likely(!cmos_rtc_probe) || !success ||
+        if ( likely(!cmos_rtc_probe) )
+            return true;
+
+        if ( !success ||
              rtc.sec >= 60 || rtc.min >= 60 || rtc.hour >= 24 ||
              !rtc.day || rtc.day > 31 ||
              !rtc.mon || rtc.mon > 12 )
-            break;
+            return false;
 
         if ( seconds < 60 )
         {
             if ( rtc.sec != seconds )
             {
-                cmos_rtc_probe = false;
                 acpi_gbl_FADT.boot_flags &= ~ACPI_FADT_NO_CMOS_RTC;
+                return true;
             }
-            break;
+            return false;
         }
 
         process_pending_softirqs();
@@ -1337,7 +1324,31 @@ static unsigned long get_cmos_time(void)
         seconds = rtc.sec;
     }
 
-    if ( unlikely(cmos_rtc_probe) )
+    ASSERT_UNREACHABLE();
+    return false;
+}
+
+static unsigned long get_cmos_time(void)
+{
+    unsigned long res;
+    struct rtc_time rtc;
+    static bool __read_mostly cmos_rtc_probe;
+    boolean_param("cmos-rtc-probe", cmos_rtc_probe);
+
+    if ( efi_enabled(EFI_RS) )
+    {
+        res = efi_get_time();
+        if ( res )
+            return res;
+    }
+
+    if ( likely(!(acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC)) )
+        cmos_rtc_probe = false;
+    else if ( system_state < SYS_STATE_smp_boot && !cmos_rtc_probe )
+        panic("System with no CMOS RTC advertised must be booted from EFI"
+              " (or with command line option \"cmos-rtc-probe\")\n");
+
+    if ( !cmos_probe(&rtc, cmos_rtc_probe) )
         panic("No CMOS RTC found - system must be booted from EFI\n");
 
     return mktime(rtc.year, rtc.mon, rtc.day, rtc.hour, rtc.min, rtc.sec);
--
generated by git-patchbot for /home/xen/git/xen.git#staging