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powerpc/64s: relocation, register save fixes for system reset interrupt

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This patch does a couple of things. First of all, powernv immediately
explodes when running a relocated kernel, because the system reset
exception for handling sleeps does not do correct relocated branches.

Secondly, the sleep handling code trashes the condition and cfar
registers, which we would like to preserve for debugging purposes (for
non-sleep case exception).

This patch changes the exception to use the standard format that saves
registers before any tests or branches are made. It adds the test for
idle-wakeup as an "extra" to break out of the normal exception path.
Then it branches to a relocated idle handler that calls the various
idle handling functions.

After this patch, POWER8 CPU simulator now boots powernv kernel that is
running at non-zero.

Fixes: 948cf67c47 ("powerpc: Add NAP mode support on Power7 in HV mode")
Cc: stable@vger.kernel.org # v3.0+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2016-10-13 13:17:14 +11:00 committed by Michael Ellerman
parent bd77c44986
commit fb479e44a9
2 changed files with 45 additions and 21 deletions
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16
arch/powerpc/include/asm/exception-64s.h
View file

@ -93,6 +93,10 @@
ld reg,PACAKBASE(r13); /* get high part of &label */ \
ori reg,reg,(FIXED_SYMBOL_ABS_ADDR(label))@l;
#define __LOAD_HANDLER(reg, label) \
ld reg,PACAKBASE(r13); \
ori reg,reg,(ABS_ADDR(label))@l;
/* Exception register prefixes */
#define EXC_HV H
#define EXC_STD
@ -208,6 +212,18 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
#define kvmppc_interrupt kvmppc_interrupt_pr
#endif
#ifdef CONFIG_RELOCATABLE
#define BRANCH_TO_COMMON(reg, label) \
__LOAD_HANDLER(reg, label); \
mtctr reg; \
bctr
#else
#define BRANCH_TO_COMMON(reg, label) \
b label
#endif
#define __KVM_HANDLER_PROLOG(area, n) \
BEGIN_FTR_SECTION_NESTED(947) \
ld r10,area+EX_CFAR(r13); \

50
arch/powerpc/kernel/exceptions-64s.S
View file

@ -95,19 +95,35 @@ __start_interrupts:
/* No virt vectors corresponding with 0x0..0x100 */
EXC_VIRT_NONE(0x4000, 0x4100)
#ifdef CONFIG_PPC_P7_NAP
/*
* If running native on arch 2.06 or later, check if we are waking up
* from nap/sleep/winkle, and branch to idle handler.
*/
#define IDLETEST(n) \
BEGIN_FTR_SECTION ; \
mfspr r10,SPRN_SRR1 ; \
rlwinm. r10,r10,47-31,30,31 ; \
beq- 1f ; \
cmpwi cr3,r10,2 ; \
BRANCH_TO_COMMON(r10, system_reset_idle_common) ; \
1: \
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
#else
#define IDLETEST NOTEST
#endif
EXC_REAL_BEGIN(system_reset, 0x100, 0x200)
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/sleep/winkle.
*/
mfspr r13,SPRN_SRR1
rlwinm. r13,r13,47-31,30,31
beq 9f
EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common, EXC_STD,
IDLETEST, 0x100)
cmpwi cr3,r13,2
GET_PACA(r13)
EXC_REAL_END(system_reset, 0x100, 0x200)
EXC_VIRT_NONE(0x4100, 0x4200)
#ifdef CONFIG_PPC_P7_NAP
EXC_COMMON_BEGIN(system_reset_idle_common)
bl pnv_restore_hyp_resource
li r0,PNV_THREAD_RUNNING
@ -130,14 +146,8 @@ BEGIN_FTR_SECTION
blt cr3,2f
b pnv_wakeup_loss
2: b pnv_wakeup_noloss
#endif
9:
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
#endif /* CONFIG_PPC_P7_NAP */
EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common, EXC_STD,
NOTEST, 0x100)
EXC_REAL_END(system_reset, 0x100, 0x200)
EXC_VIRT_NONE(0x4100, 0x4200)
EXC_COMMON(system_reset_common, 0x100, system_reset_exception)
#ifdef CONFIG_PPC_PSERIES
@ -817,10 +827,8 @@ EXC_VIRT(trap_0b, 0x4b00, 0x4c00, 0xb00)
TRAMP_KVM(PACA_EXGEN, 0xb00)
EXC_COMMON(trap_0b_common, 0xb00, unknown_exception)
#define LOAD_SYSCALL_HANDLER(reg) \
ld reg,PACAKBASE(r13); \
ori reg,reg,(ABS_ADDR(system_call_common))@l;
#define LOAD_SYSCALL_HANDLER(reg) \
__LOAD_HANDLER(reg, system_call_common)
/* Syscall routine is used twice, in reloc-off and reloc-on paths */
#define SYSCALL_PSERIES_1 \