From cba313da5c8ddbe6bba74c9f2b8f6d9e0bc0e723 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Mon, 5 Dec 2011 19:35:32 +0000 Subject: [PATCH] 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 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/exceptions-64s.S | 2 +- arch/powerpc/platforms/powernv/smp.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index cf9c69b9189c..d4be7bb3dbdf 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -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: diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c index e87736685243..17210c526c52 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -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)