[IA64] Fix CONFIG_PRINTK_TIME
There were two problems with enabling the PRINTK_TIME config
option:
1) The first calls to printk() occur before per-cpu data virtual
address is pinned into the TLB, so sched_clock() can fault.
2) sched_clock() is based on ar.itc, which may not be synchronized
across cpus.
Ken Chen started this patch, Tony Luck tinkered with it, and Jes
Sorensen perfected it.
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S
index fbc7ea3..f1778a8 100644
--- a/arch/ia64/kernel/head.S
+++ b/arch/ia64/kernel/head.S
@@ -352,6 +352,7 @@
mov ar.rsc=0 // place RSE in enforced lazy mode
;;
loadrs // clear the dirty partition
+ mov IA64_KR(PER_CPU_DATA)=r0 // clear physical per-CPU base
;;
mov ar.bspstore=r2 // establish the new RSE stack
;;
diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
index c076657..35f7835 100644
--- a/arch/ia64/kernel/setup.c
+++ b/arch/ia64/kernel/setup.c
@@ -71,6 +71,8 @@
EXPORT_SYMBOL(__per_cpu_offset);
#endif
+extern void ia64_setup_printk_clock(void);
+
DEFINE_PER_CPU(struct cpuinfo_ia64, cpu_info);
DEFINE_PER_CPU(unsigned long, local_per_cpu_offset);
DEFINE_PER_CPU(unsigned long, ia64_phys_stacked_size_p8);
@@ -445,6 +447,8 @@
/* process SAL system table: */
ia64_sal_init(efi.sal_systab);
+ ia64_setup_printk_clock();
+
#ifdef CONFIG_SMP
cpu_physical_id(0) = hard_smp_processor_id();
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 028a2b9..a094ec4 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -278,3 +278,30 @@
}
}
EXPORT_SYMBOL(udelay);
+
+static unsigned long long ia64_itc_printk_clock(void)
+{
+ if (ia64_get_kr(IA64_KR_PER_CPU_DATA))
+ return sched_clock();
+ return 0;
+}
+
+static unsigned long long ia64_default_printk_clock(void)
+{
+ return (unsigned long long)(jiffies_64 - INITIAL_JIFFIES) *
+ (1000000000/HZ);
+}
+
+unsigned long long (*ia64_printk_clock)(void) = &ia64_default_printk_clock;
+
+unsigned long long printk_clock(void)
+{
+ return ia64_printk_clock();
+}
+
+void __init
+ia64_setup_printk_clock(void)
+{
+ if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT))
+ ia64_printk_clock = ia64_itc_printk_clock;
+}