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powerpc: Add NAP mode support on Power7 in HV mode

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Wakeup comes from the system reset handler with a potential loss of
the non-hypervisor CPU state. We save the non-volatile state on the
stack and a pointer to it in the PACA, which the system reset handler
uses to restore things

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt
2011-01-24 18:42:41 +11:00
parent 9d07bc841c
commit 948cf67c47
7 changed files with 139 additions and 2 deletions
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30
arch/powerpc/kernel/exceptions-64s.S
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@@ -37,7 +37,35 @@
.globl __start_interrupts
__start_interrupts:
STD_EXCEPTION_PSERIES(0x100, 0x100, system_reset)
.globl system_reset_pSeries;
system_reset_pSeries:
HMT_MEDIUM;
DO_KVM 0x100;
SET_SCRATCH0(r13)
#ifdef CONFIG_PPC_P7_NAP
BEGIN_FTR_SECTION
/* Running native on arch 2.06 or later, check if we are
* waking up from nap. We only handle no state loss and
* supervisor state loss. We do -not- handle hypervisor
* state loss at this time.
*/
mfspr r13,SPRN_SRR1
rlwinm r13,r13,47-31,30,31
cmpwi cr0,r13,1
bne 1f
b .power7_wakeup_noloss
1: cmpwi cr0,r13,2
bne 1f
b .power7_wakeup_loss
/* Total loss of HV state is fatal, we could try to use the
* PIR to locate a PACA, then use an emergency stack etc...
* but for now, let's just stay stuck here
*/
1: cmpwi cr0,r13,3
beq .
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE_206)
#endif /* CONFIG_PPC_P7_NAP */
EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common, EXC_STD)
. = 0x200
_machine_check_pSeries: