powerpc/powernv: Rename idle_power7.S to idle_book3s.S

idle_power7.S handles idle entry/exit for POWER7, POWER8 and in next
patch for POWER9. Rename the file to a non-hardware specific
name.

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 527 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
new file mode 100644
index 000000000000..d5def062a544
--- /dev/null
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -0,0 +1,527 @@
+/*
+ *  This file contains the power_save function for Power7 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>
+#include <asm/hw_irq.h>
+#include <asm/kvm_book3s_asm.h>
+#include <asm/opal.h>
+#include <asm/cpuidle.h>
+#include <asm/book3s/64/mmu-hash.h>
+
+#undef DEBUG
+
+/*
+ * Use unused space in the interrupt stack to save and restore
+ * registers for winkle support.
+ */
+#define _SDR1	GPR3
+#define _RPR	GPR4
+#define _SPURR	GPR5
+#define _PURR	GPR6
+#define _TSCR	GPR7
+#define _DSCR	GPR8
+#define _AMOR	GPR9
+#define _WORT	GPR10
+#define _WORC	GPR11
+
+/* Idle state entry routines */
+
+#define	IDLE_STATE_ENTER_SEQ(IDLE_INST)				\
+	/* Magic NAP/SLEEP/WINKLE mode enter sequence */	\
+	std	r0,0(r1);					\
+	ptesync;						\
+	ld	r0,0(r1);					\
+1:	cmp	cr0,r0,r0;					\
+	bne	1b;						\
+	IDLE_INST;						\
+	b	.
+
+	.text
+
+/*
+ * Used by threads when the lock bit of core_idle_state is set.
+ * Threads will spin in HMT_LOW until the lock bit is cleared.
+ * r14 - pointer to core_idle_state
+ * r15 - used to load contents of core_idle_state
+ */
+
+core_idle_lock_held:
+	HMT_LOW
+3:	lwz	r15,0(r14)
+	andi.   r15,r15,PNV_CORE_IDLE_LOCK_BIT
+	bne	3b
+	HMT_MEDIUM
+	lwarx	r15,0,r14
+	blr
+
+/*
+ * Pass requested state in r3:
+ *	r3 - PNV_THREAD_NAP/SLEEP/WINKLE
+ *
+ * To check IRQ_HAPPENED in r4
+ * 	0 - don't check
+ * 	1 - check
+ */
+_GLOBAL(power7_powersave_common)
+	/* Use r3 to pass state nap/sleep/winkle */
+	/* 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)
+
+	/* Hard disable interrupts */
+	mfmsr	r9
+	rldicl	r9,r9,48,1
+	rotldi	r9,r9,16
+	mtmsrd	r9,1			/* hard-disable interrupts */
+
+	/* Check if something happened while soft-disabled */
+	lbz	r0,PACAIRQHAPPENED(r13)
+	andi.	r0,r0,~PACA_IRQ_HARD_DIS@l
+	beq	1f
+	cmpwi	cr0,r4,0
+	beq	1f
+	addi	r1,r1,INT_FRAME_SIZE
+	ld	r0,16(r1)
+	li	r3,0			/* Return 0 (no nap) */
+	mtlr	r0
+	blr
+
+1:	/* We mark irqs hard disabled as this is the state we'll
+	 * be in when returning and we need to tell arch_local_irq_restore()
+	 * about it
+	 */
+	li	r0,PACA_IRQ_HARD_DIS
+	stb	r0,PACAIRQHAPPENED(r13)
+
+	/* We haven't lost state ... yet */
+	li	r0,0
+	stb	r0,PACA_NAPSTATELOST(r13)
+
+	/* Continue saving state */
+	SAVE_GPR(2, r1)
+	SAVE_NVGPRS(r1)
+	mfcr	r4
+	std	r4,_CCR(r1)
+	std	r9,_MSR(r1)
+	std	r1,PACAR1(r13)
+
+	/*
+	 * Go to real mode to do the nap, as required by the architecture.
+	 * Also, we need to be in real mode before setting hwthread_state,
+	 * because as soon as we do that, another thread can switch
+	 * the MMU context to the guest.
+	 */
+	LOAD_REG_IMMEDIATE(r5, MSR_IDLE)
+	li	r6, MSR_RI
+	andc	r6, r9, r6
+	LOAD_REG_ADDR(r7, power7_enter_nap_mode)
+	mtmsrd	r6, 1		/* clear RI before setting SRR0/1 */
+	mtspr	SPRN_SRR0, r7
+	mtspr	SPRN_SRR1, r5
+	rfid
+
+	.globl	power7_enter_nap_mode
+power7_enter_nap_mode:
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+	/* Tell KVM we're napping */
+	li	r4,KVM_HWTHREAD_IN_NAP
+	stb	r4,HSTATE_HWTHREAD_STATE(r13)
+#endif
+	stb	r3,PACA_THREAD_IDLE_STATE(r13)
+	cmpwi	cr3,r3,PNV_THREAD_SLEEP
+	bge	cr3,2f
+	IDLE_STATE_ENTER_SEQ(PPC_NAP)
+	/* No return */
+2:
+	/* Sleep or winkle */
+	lbz	r7,PACA_THREAD_MASK(r13)
+	ld	r14,PACA_CORE_IDLE_STATE_PTR(r13)
+lwarx_loop1:
+	lwarx	r15,0,r14
+
+	andi.   r9,r15,PNV_CORE_IDLE_LOCK_BIT
+	bnel	core_idle_lock_held
+
+	andc	r15,r15,r7			/* Clear thread bit */
+
+	andi.	r15,r15,PNV_CORE_IDLE_THREAD_BITS
+
+/*
+ * If cr0 = 0, then current thread is the last thread of the core entering
+ * sleep. Last thread needs to execute the hardware bug workaround code if
+ * required by the platform.
+ * Make the workaround call unconditionally here. The below branch call is
+ * patched out when the idle states are discovered if the platform does not
+ * require it.
+ */
+.global pnv_fastsleep_workaround_at_entry
+pnv_fastsleep_workaround_at_entry:
+	beq	fastsleep_workaround_at_entry
+
+	stwcx.	r15,0,r14
+	bne-	lwarx_loop1
+	isync
+
+common_enter: /* common code for all the threads entering sleep or winkle */
+	bgt	cr3,enter_winkle
+	IDLE_STATE_ENTER_SEQ(PPC_SLEEP)
+
+fastsleep_workaround_at_entry:
+	ori	r15,r15,PNV_CORE_IDLE_LOCK_BIT
+	stwcx.	r15,0,r14
+	bne-	lwarx_loop1
+	isync
+
+	/* Fast sleep workaround */
+	li	r3,1
+	li	r4,1
+	li	r0,OPAL_CONFIG_CPU_IDLE_STATE
+	bl	opal_call_realmode
+
+	/* Clear Lock bit */
+	li	r0,0
+	lwsync
+	stw	r0,0(r14)
+	b	common_enter
+
+enter_winkle:
+	/*
+	 * Note all register i.e per-core, per-subcore or per-thread is saved
+	 * here since any thread in the core might wake up first
+	 */
+	mfspr	r3,SPRN_SDR1
+	std	r3,_SDR1(r1)
+	mfspr	r3,SPRN_RPR
+	std	r3,_RPR(r1)
+	mfspr	r3,SPRN_SPURR
+	std	r3,_SPURR(r1)
+	mfspr	r3,SPRN_PURR
+	std	r3,_PURR(r1)
+	mfspr	r3,SPRN_TSCR
+	std	r3,_TSCR(r1)
+	mfspr	r3,SPRN_DSCR
+	std	r3,_DSCR(r1)
+	mfspr	r3,SPRN_AMOR
+	std	r3,_AMOR(r1)
+	mfspr	r3,SPRN_WORT
+	std	r3,_WORT(r1)
+	mfspr	r3,SPRN_WORC
+	std	r3,_WORC(r1)
+	IDLE_STATE_ENTER_SEQ(PPC_WINKLE)
+
+_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
+	li	r3, 1
+	/* fall through */
+
+_GLOBAL(power7_nap)
+	mr	r4,r3
+	li	r3,PNV_THREAD_NAP
+	b	power7_powersave_common
+	/* No return */
+
+_GLOBAL(power7_sleep)
+	li	r3,PNV_THREAD_SLEEP
+	li	r4,1
+	b	power7_powersave_common
+	/* No return */
+
+_GLOBAL(power7_winkle)
+	li	r3,PNV_THREAD_WINKLE
+	li	r4,1
+	b	power7_powersave_common
+	/* No return */
+
+#define CHECK_HMI_INTERRUPT						\
+	mfspr	r0,SPRN_SRR1;						\
+BEGIN_FTR_SECTION_NESTED(66);						\
+	rlwinm	r0,r0,45-31,0xf;  /* extract wake reason field (P8) */	\
+FTR_SECTION_ELSE_NESTED(66);						\
+	rlwinm	r0,r0,45-31,0xe;  /* P7 wake reason field is 3 bits */	\
+ALT_FTR_SECTION_END_NESTED_IFSET(CPU_FTR_ARCH_207S, 66);		\
+	cmpwi	r0,0xa;			/* Hypervisor maintenance ? */	\
+	bne	20f;							\
+	/* Invoke opal call to handle hmi */				\
+	ld	r2,PACATOC(r13);					\
+	ld	r1,PACAR1(r13);						\
+	std	r3,ORIG_GPR3(r1);	/* Save original r3 */		\
+	li	r0,OPAL_HANDLE_HMI;	/* Pass opal token argument*/	\
+	bl	opal_call_realmode;					\
+	ld	r3,ORIG_GPR3(r1);	/* Restore original r3 */	\
+20:	nop;
+
+
+/*
+ * Called from reset vector. Check whether we have woken up with
+ * hypervisor state loss. If yes, restore hypervisor state and return
+ * back to reset vector.
+ *
+ * r13 - Contents of HSPRG0
+ * cr3 - set to gt if waking up with partial/complete hypervisor state loss
+ */
+_GLOBAL(power7_restore_hyp_resource)
+	/*
+	 * Check if last bit of HSPGR0 is set. This indicates whether we are
+	 * waking up from winkle.
+	 */
+	clrldi	r5,r13,63
+	clrrdi	r13,r13,1
+	cmpwi	cr4,r5,1
+	mtspr	SPRN_HSPRG0,r13
+
+	lbz	r0,PACA_THREAD_IDLE_STATE(r13)
+	cmpwi   cr2,r0,PNV_THREAD_NAP
+	bgt     cr2,power7_wakeup_tb_loss	/* Either sleep or Winkle */
+
+	/*
+	 * We fall through here if PACA_THREAD_IDLE_STATE shows we are waking
+	 * up from nap. At this stage CR3 shouldn't contains 'gt' since that
+	 * indicates we are waking with hypervisor state loss from nap.
+	 */
+	bgt	cr3,.
+
+	blr	/* Return back to System Reset vector from where
+		   power7_restore_hyp_resource was invoked */
+
+
+_GLOBAL(power7_wakeup_tb_loss)
+	ld	r2,PACATOC(r13);
+	ld	r1,PACAR1(r13)
+	/*
+	 * Before entering any idle state, the NVGPRs are saved in the stack
+	 * and they are restored before switching to the process context. Hence
+	 * until they are restored, they are free to be used.
+	 *
+	 * Save SRR1 and LR in NVGPRs as they might be clobbered in
+	 * opal_call_realmode (called in CHECK_HMI_INTERRUPT). SRR1 is required
+	 * to determine the wakeup reason if we branch to kvm_start_guest. LR
+	 * is required to return back to reset vector after hypervisor state
+	 * restore is complete.
+	 */
+	mflr	r17
+	mfspr	r16,SPRN_SRR1
+BEGIN_FTR_SECTION
+	CHECK_HMI_INTERRUPT
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
+
+	lbz	r7,PACA_THREAD_MASK(r13)
+	ld	r14,PACA_CORE_IDLE_STATE_PTR(r13)
+lwarx_loop2:
+	lwarx	r15,0,r14
+	andi.	r9,r15,PNV_CORE_IDLE_LOCK_BIT
+	/*
+	 * Lock bit is set in one of the 2 cases-
+	 * a. In the sleep/winkle enter path, the last thread is executing
+	 * fastsleep workaround code.
+	 * b. In the wake up path, another thread is executing fastsleep
+	 * workaround undo code or resyncing timebase or restoring context
+	 * In either case loop until the lock bit is cleared.
+	 */
+	bnel	core_idle_lock_held
+
+	cmpwi	cr2,r15,0
+	lbz	r4,PACA_SUBCORE_SIBLING_MASK(r13)
+	and	r4,r4,r15
+	cmpwi	cr1,r4,0	/* Check if first in subcore */
+
+	/*
+	 * At this stage
+	 * cr1 - 0b0100 if first thread to wakeup in subcore
+	 * cr2 - 0b0100 if first thread to wakeup in core
+	 * cr3-  0b0010 if waking up from sleep or winkle
+	 * cr4 - 0b0100 if waking up from winkle
+	 */
+
+	or	r15,r15,r7		/* Set thread bit */
+
+	beq	cr1,first_thread_in_subcore
+
+	/* Not first thread in subcore to wake up */
+	stwcx.	r15,0,r14
+	bne-	lwarx_loop2
+	isync
+	b	common_exit
+
+first_thread_in_subcore:
+	/* First thread in subcore to wakeup */
+	ori	r15,r15,PNV_CORE_IDLE_LOCK_BIT
+	stwcx.	r15,0,r14
+	bne-	lwarx_loop2
+	isync
+
+	/*
+	 * If waking up from sleep, subcore state is not lost. Hence
+	 * skip subcore state restore
+	 */
+	bne	cr4,subcore_state_restored
+
+	/* Restore per-subcore state */
+	ld      r4,_SDR1(r1)
+	mtspr   SPRN_SDR1,r4
+	ld      r4,_RPR(r1)
+	mtspr   SPRN_RPR,r4
+	ld	r4,_AMOR(r1)
+	mtspr	SPRN_AMOR,r4
+
+subcore_state_restored:
+	/*
+	 * Check if the thread is also the first thread in the core. If not,
+	 * skip to clear_lock.
+	 */
+	bne	cr2,clear_lock
+
+first_thread_in_core:
+
+	/*
+	 * First thread in the core waking up from fastsleep. It needs to
+	 * call the fastsleep workaround code if the platform requires it.
+	 * Call it unconditionally here. The below branch instruction will
+	 * be patched out when the idle states are discovered if platform
+	 * does not require workaround.
+	 */
+.global pnv_fastsleep_workaround_at_exit
+pnv_fastsleep_workaround_at_exit:
+	b	fastsleep_workaround_at_exit
+
+timebase_resync:
+	/* Do timebase resync if we are waking up from sleep. Use cr3 value
+	 * set in exceptions-64s.S */
+	ble	cr3,clear_lock
+	/* Time base re-sync */
+	li	r0,OPAL_RESYNC_TIMEBASE
+	bl	opal_call_realmode;
+	/* TODO: Check r3 for failure */
+
+	/*
+	 * If waking up from sleep, per core state is not lost, skip to
+	 * clear_lock.
+	 */
+	bne	cr4,clear_lock
+
+	/* Restore per core state */
+	ld	r4,_TSCR(r1)
+	mtspr	SPRN_TSCR,r4
+	ld	r4,_WORC(r1)
+	mtspr	SPRN_WORC,r4
+
+clear_lock:
+	andi.	r15,r15,PNV_CORE_IDLE_THREAD_BITS
+	lwsync
+	stw	r15,0(r14)
+
+common_exit:
+	/*
+	 * Common to all threads.
+	 *
+	 * If waking up from sleep, hypervisor state is not lost. Hence
+	 * skip hypervisor state restore.
+	 */
+	bne	cr4,hypervisor_state_restored
+
+	/* Waking up from winkle */
+
+	/* Restore per thread state */
+	bl	__restore_cpu_power8
+
+	/* Restore SLB  from PACA */
+	ld	r8,PACA_SLBSHADOWPTR(r13)
+
+	.rept	SLB_NUM_BOLTED
+	li	r3, SLBSHADOW_SAVEAREA
+	LDX_BE	r5, r8, r3
+	addi	r3, r3, 8
+	LDX_BE	r6, r8, r3
+	andis.	r7,r5,SLB_ESID_V@h
+	beq	1f
+	slbmte	r6,r5
+1:	addi	r8,r8,16
+	.endr
+
+	ld	r4,_SPURR(r1)
+	mtspr	SPRN_SPURR,r4
+	ld	r4,_PURR(r1)
+	mtspr	SPRN_PURR,r4
+	ld	r4,_DSCR(r1)
+	mtspr	SPRN_DSCR,r4
+	ld	r4,_WORT(r1)
+	mtspr	SPRN_WORT,r4
+
+hypervisor_state_restored:
+
+	mtspr	SPRN_SRR1,r16
+	mtlr	r17
+	blr	/* Return back to System Reset vector from where
+		   power7_restore_hyp_resource was invoked */
+
+fastsleep_workaround_at_exit:
+	li	r3,1
+	li	r4,0
+	li	r0,OPAL_CONFIG_CPU_IDLE_STATE
+	bl	opal_call_realmode
+	b	timebase_resync
+
+/*
+ * R3 here contains the value that will be returned to the caller
+ * of power7_nap.
+ */
+_GLOBAL(power7_wakeup_loss)
+	ld	r1,PACAR1(r13)
+BEGIN_FTR_SECTION
+	CHECK_HMI_INTERRUPT
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
+	REST_NVGPRS(r1)
+	REST_GPR(2, r1)
+	ld	r6,_CCR(r1)
+	ld	r4,_MSR(r1)
+	ld	r5,_NIP(r1)
+	addi	r1,r1,INT_FRAME_SIZE
+	mtcr	r6
+	mtspr	SPRN_SRR1,r4
+	mtspr	SPRN_SRR0,r5
+	rfid
+
+/*
+ * R3 here contains the value that will be returned to the caller
+ * of power7_nap.
+ */
+_GLOBAL(power7_wakeup_noloss)
+	lbz	r0,PACA_NAPSTATELOST(r13)
+	cmpwi	r0,0
+	bne	power7_wakeup_loss
+BEGIN_FTR_SECTION
+	CHECK_HMI_INTERRUPT
+END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
+	ld	r1,PACAR1(r13)
+	ld	r6,_CCR(r1)
+	ld	r4,_MSR(r1)
+	ld	r5,_NIP(r1)
+	addi	r1,r1,INT_FRAME_SIZE
+	mtcr	r6
+	mtspr	SPRN_SRR1,r4
+	mtspr	SPRN_SRR0,r5
+	rfid