[PATCH 13/15] powerpc: Add NAP mode support on Power7 in HV mode
Benjamin Herrenschmidt
benh at kernel.crashing.org
Tue Apr 5 16:14:09 EST 2011
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 at kernel.crashing.org>
---
arch/powerpc/include/asm/machdep.h | 1 +
arch/powerpc/include/asm/paca.h | 2 +-
arch/powerpc/include/asm/ppc-opcode.h | 6 ++
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/kernel/exceptions-64s.S | 30 ++++++++++-
arch/powerpc/kernel/idle_power7.S | 97 +++++++++++++++++++++++++++++++++
arch/powerpc/platforms/Kconfig | 4 ++
7 files changed, 139 insertions(+), 2 deletions(-)
create mode 100644 arch/powerpc/kernel/idle_power7.S
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index e4f0191..493dbb3 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -267,6 +267,7 @@ struct machdep_calls {
extern void e500_idle(void);
extern void power4_idle(void);
+extern void power7_idle(void);
extern void ppc6xx_idle(void);
extern void book3e_idle(void);
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index ec57540..f6da4f5 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -125,7 +125,7 @@ struct paca_struct {
struct task_struct *__current; /* Pointer to current */
u64 kstack; /* Saved Kernel stack addr */
u64 stab_rr; /* stab/slb round-robin counter */
- u64 saved_r1; /* r1 save for RTAS calls */
+ u64 saved_r1; /* r1 save for RTAS calls or PM */
u64 saved_msr; /* MSR saved here by enter_rtas */
u16 trap_save; /* Used when bad stack is encountered */
u8 soft_enabled; /* irq soft-enable flag */
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 1255569..384a96d 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -56,6 +56,9 @@
#define PPC_INST_TLBSRX_DOT 0x7c0006a5
#define PPC_INST_XXLOR 0xf0000510
+#define PPC_INST_NAP 0x4c000364
+#define PPC_INST_SLEEP 0x4c0003a4
+
/* macros to insert fields into opcodes */
#define __PPC_RA(a) (((a) & 0x1f) << 16)
#define __PPC_RB(b) (((b) & 0x1f) << 11)
@@ -126,4 +129,7 @@
#define XXLOR(t, a, b) stringify_in_c(.long PPC_INST_XXLOR | \
VSX_XX3((t), (a), (b)))
+#define PPC_NAP stringify_in_c(.long PPC_INST_NAP)
+#define PPC_SLEEP stringify_in_c(.long PPC_INST_SLEEP)
+
#endif /* _ASM_POWERPC_PPC_OPCODE_H */
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 7c6eb49..0fd6273 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_PPC_BOOK3E_64) += exceptions-64e.o idle_book3e.o
obj-$(CONFIG_PPC64) += vdso64/
obj-$(CONFIG_ALTIVEC) += vecemu.o
obj-$(CONFIG_PPC_970_NAP) += idle_power4.o
+obj-$(CONFIG_PPC_P7_NAP) += idle_power7.o
obj-$(CONFIG_PPC_OF) += of_platform.o prom_parse.o
obj-$(CONFIG_PPC_CLOCK) += clock.o
procfs-y := proc_powerpc.o
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 0c50a52..a6ead27 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -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:
diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S
new file mode 100644
index 0000000..f8f0bc7
--- /dev/null
+++ b/arch/powerpc/kernel/idle_power7.S
@@ -0,0 +1,97 @@
+/*
+ * This file contains the power_save function for 970-family CPUs.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/threads.h>
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <asm/cputable.h>
+#include <asm/thread_info.h>
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/ppc-opcode.h>
+
+#undef DEBUG
+
+ .text
+
+_GLOBAL(power7_idle)
+ /* Now check if user or arch enabled NAP mode */
+ LOAD_REG_ADDRBASE(r3,powersave_nap)
+ lwz r4,ADDROFF(powersave_nap)(r3)
+ cmpwi 0,r4,0
+ beqlr
+
+ /* NAP is a state loss, we create a regs frame on the
+ * stack, fill it up with the state we care about and
+ * stick a pointer to it in PACAR1. We really only
+ * need to save PC, some CR bits and the NV GPRs,
+ * but for now an interrupt frame will do.
+ */
+ mflr r0
+ std r0,16(r1)
+ stdu r1,-INT_FRAME_SIZE(r1)
+ std r0,_LINK(r1)
+ std r0,_NIP(r1)
+
+#ifndef CONFIG_SMP
+ /* Make sure FPU, VSX etc... are flushed as we may lose
+ * state when going to nap mode
+ */
+ bl .discard_lazy_cpu_state
+#endif /* CONFIG_SMP */
+
+ /* Hard disable interrupts */
+ mfmsr r9
+ rldicl r9,r9,48,1
+ rotldi r9,r9,16
+ mtmsrd r9,1 /* hard-disable interrupts */
+ li r0,0
+ stb r0,PACASOFTIRQEN(r13) /* we'll hard-enable shortly */
+ stb r0,PACAHARDIRQEN(r13)
+
+ /* Continue saving state */
+ SAVE_GPR(2, r1)
+ SAVE_NVGPRS(r1)
+ mfcr r3
+ std r3,_CCR(r1)
+ std r9,_MSR(r1)
+ std r1,PACAR1(r13)
+
+ /* Magic NAP mode enter sequence */
+ std r0,0(r1)
+ ptesync
+ ld r0,0(r1)
+1: cmp cr0,r0,r0
+ bne 1b
+ PPC_NAP
+ b .
+
+_GLOBAL(power7_wakeup_loss)
+ GET_PACA(r13)
+ ld r1,PACAR1(r13)
+ REST_NVGPRS(r1)
+ REST_GPR(2, r1)
+ ld r3,_CCR(r1)
+ ld r4,_MSR(r1)
+ ld r5,_NIP(r1)
+ addi r1,r1,INT_FRAME_SIZE
+ mtcr r3
+ mtspr SPRN_SRR1,r4
+ mtspr SPRN_SRR0,r5
+ rfid
+
+_GLOBAL(power7_wakeup_noloss)
+ GET_PACA(r13)
+ ld r1,PACAR1(r13)
+ ld r4,_MSR(r1)
+ ld r5,_NIP(r1)
+ addi r1,r1,INT_FRAME_SIZE
+ mtspr SPRN_SRR1,r4
+ mtspr SPRN_SRR0,r5
+ rfid
diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 2057682..59eeb77 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -147,6 +147,10 @@ config PPC_970_NAP
bool
default n
+config PPC_P7_NAP
+ bool
+ default n
+
config PPC_INDIRECT_IO
bool
select GENERIC_IOMAP
--
1.7.1
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