Re: [Xen-devel] [PATCH v3 08/11] xen: arm: rewrite start of day page table and cpu bring up

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2013-09-27 at 15:10 +0100, Ian Campbell wrote:
> On Fri, 2013-09-27 at 14:30 +0100, Julien Grall wrote:
> 
> > > @@ -581,6 +589,12 @@ static void __init init_cpus_maps(void)
> > >              }
> > >          }
> > >  
> > > +        if ( (rc = arch_cpu_init(hwid, cpu)) < 0 )
> > 
> > As I understand your patch #6, arch_cpu_init take a logical cpu id (on
> > ARM64 it's used as an index in an array).
> 
> Yes, I thought I wanted to pass the hwid here, but it looks like I've
> got my wires crossed.
> 
> > So you should used j here.
> 
> You mean cpuidx I think, after having moved the call after the cpuidx++
> 
> I wanted to handle the case where the function failed by having
> possible_map not contain failed cpus. I think I'll handle this by making
> tmp_map[i] == INVALID_MIDR in that case and checking that in the loop
> which sets bits in cpu_possible_map.

Incrementally this looks like:

diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 5923cfc..b836be4 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -165,12 +165,6 @@ void __init smp_init_cpus(void)
             }
         }
 
-        if ( (rc = arch_cpu_init(hwid, cpu)) < 0 )
-        {
-            printk("cpu init failed (hwid %x): %d\n", hwid, rc);
-            continue;
-        }
-
         /*
          * Build a stashed array of MPIDR values. Numbering scheme requires
          * that if detected the boot CPU must be assigned logical id 0. Other
@@ -196,7 +190,13 @@ void __init smp_init_cpus(void)
             break;
         }
 
-        tmp_map[i] = hwid;
+        if ( (rc = arch_cpu_init(i, cpu)) < 0 )
+        {
+            printk("cpu%d init failed (hwid %x): %d\n", i, hwid, rc);
+            tmp_map[i] = MPIDR_INVALID;
+        }
+        else
+            tmp_map[i] = hwid;
     }
 
     if ( !bootcpu_valid )
@@ -208,6 +208,8 @@ void __init smp_init_cpus(void)
 
     for ( i = 0; i < cpuidx; i++ )
     {
+        if ( tmp_map[i] == MPIDR_INVALID )
+            continue;
         cpumask_set_cpu(i, &cpu_possible_map);
         cpu_logical_map(i) = tmp_map[i];
     }



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