Commit cba313da authored Dec 05, 2011 by Paul Mackerras Committed by Benjamin Herrenschmidt Dec 08, 2011

powerpc/powernv: Fix problems in onlining CPUs

At present, on the powernv platform, if you off-line a CPU that was
online, and then try to on-line it again, the kernel generates a
warning message "OPAL Error -1 starting CPU n". Furthermore, if the
CPU is a secondary thread that was used by KVM while it was off-line,
the CPU fails to come online.

The first problem is fixed by only calling OPAL to start the CPU the
first time it is on-lined, as indicated by the cpu_start field of its
PACA being zero. The second problem is fixed by restoring the
cpu_start field to 1 instead of 0 when using the CPU within KVM.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

parent 33392640

arch/powerpc/kernel/exceptions-64s.S

+1 −1

Original line number	Diff line number	Diff line
		@@ -65,7 +65,7 @@ BEGIN_FTR_SECTION
		lbz r0,PACAPROCSTART(r13)
		cmpwi r0,0x80
		bne 1f
		li r0,0
		li r0,1
		stb r0,PACAPROCSTART(r13)
		b kvm_start_guest
		1:

arch/powerpc/platforms/powernv/smp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -75,7 +75,7 @@ int __devinit pnv_smp_kick_cpu(int nr)
		/* On OPAL v2 the CPU are still spinning inside OPAL itself,
		* get them back now
		*/
		if (firmware_has_feature(FW_FEATURE_OPALv2)) {
		if (!paca[nr].cpu_start && firmware_has_feature(FW_FEATURE_OPALv2)) {
		pr_devel("OPAL: Starting CPU %d (HW 0x%x)...\n", nr, pcpu);
		rc = opal_start_cpu(pcpu, start_here);
		if (rc != OPAL_SUCCESS)