Turning on PRINTK_TIME causes us to die in early boot when sched_clock()
tries to access per-cpu data which isn't set up yet.
We can avoid this by doing a speculative load on the per-cpu data and
just returning zero if we fail. This matches the way sched_clock()
appears to behave on most other arches if it gets called before we
know the cpu frequency.
Signed-off-by: Jason Uhlenkott <[EMAIL PROTECTED]>
Index: linux/arch/ia64/kernel/head.S
===================================================================
--- linux.orig/arch/ia64/kernel/head.S 2005-08-15 15:54:56.130313231 -0700
+++ linux/arch/ia64/kernel/head.S 2005-08-16 12:49:23.843747550 -0700
@@ -983,9 +983,10 @@
addl r8=THIS_CPU(cpu_info) + IA64_CPUINFO_NSEC_PER_CYC_OFFSET,r0
mov.m r9=ar.itc // fetch cycle-counter
(35 cyc)
;;
- ldf8 f8=[r8]
+ ldf8.s f8=[r8]
;;
setf.sig f9=r9 // certain to stall, so issue it _after_ ldf8...
+ chk.s r8, .recover
;;
xmpy.lu f10=f9,f8 // calculate low 64 bits of 128-bit product
(4 cyc)
xmpy.hu f11=f9,f8 // calculate high 64 bits of 128-bit product
@@ -995,6 +996,10 @@
;;
shrp r8=r9,r8,IA64_NSEC_PER_CYC_SHIFT
br.ret.sptk.many rp
+.recover: // per-cpu data isn't set up yet,
+ // so just return 0.
+ mov r8=r0
+ br.ret.sptk.many rp
END(sched_clock)
GLOBAL_ENTRY(start_kernel_thread)
-
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