powerpc: Add NAP mode support on Power7 in HV mode
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>
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