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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>
This commit is contained in:
Paul Mackerras 2011-12-05 19:35:32 +00:00 committed by Benjamin Herrenschmidt
parent 3339264042
commit cba313da5c
2 changed files with 2 additions and 2 deletions
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2
arch/powerpc/kernel/exceptions-64s.S
View File

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

2
arch/powerpc/platforms/powernv/smp.c
View File

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