path: root/arch/powerpc/kernel/tm.S

/*
 * Transactional memory support routines to reclaim and recheckpoint
 * transactional process state.
 *
 * Copyright 2012 Matt Evans & Michael Neuling, IBM Corporation.
 */

#include <asm/asm-offsets.h>
#include <asm/ppc_asm.h>
#include <asm/ppc-opcode.h>
#include <asm/ptrace.h>
#include <asm/reg.h>
#include <asm/bug.h>

#ifdef CONFIG_VSX
/* See fpu.S, this is borrowed from there */
#define __SAVE_32FPRS_VSRS(n,c,base)		\
BEGIN_FTR_SECTION				\
	b	2f;				\
END_FTR_SECTION_IFSET(CPU_FTR_VSX);		\
	SAVE_32FPRS(n,base);			\
	b	3f;				\
2:	SAVE_32VSRS(n,c,base);			\
3:
#define __REST_32FPRS_VSRS(n,c,base)		\
BEGIN_FTR_SECTION				\
	b	2f;				\
END_FTR_SECTION_IFSET(CPU_FTR_VSX);		\
	REST_32FPRS(n,base);			\
	b	3f;				\
2:	REST_32VSRS(n,c,base);			\
3:
#else
#define __SAVE_32FPRS_VSRS(n,c,base)	SAVE_32FPRS(n, base)
#define __REST_32FPRS_VSRS(n,c,base)	REST_32FPRS(n, base)
#endif
#define SAVE_32FPRS_VSRS(n,c,base) \
	__SAVE_32FPRS_VSRS(n,__REG_##c,__REG_##base)
#define REST_32FPRS_VSRS(n,c,base) \
	__REST_32FPRS_VSRS(n,__REG_##c,__REG_##base)

/* Stack frame offsets for local variables. */
#define TM_FRAME_L0	TM_FRAME_SIZE-16
#define TM_FRAME_L1	TM_FRAME_SIZE-8


/* In order to access the TM SPRs, TM must be enabled.  So, do so: */
_GLOBAL(tm_enable)
	mfmsr	r4
	li	r3, MSR_TM >> 32
	sldi	r3, r3, 32
	and.	r0, r4, r3
	bne	1f
	or	r4, r4, r3
	mtmsrd	r4
1:	blr

_GLOBAL(tm_save_sprs)
	mfspr	r0, SPRN_TFHAR
	std	r0, THREAD_TM_TFHAR(r3)
	mfspr	r0, SPRN_TEXASR
	std	r0, THREAD_TM_TEXASR(r3)
	mfspr	r0, SPRN_TFIAR
	std	r0, THREAD_TM_TFIAR(r3)
	blr

_GLOBAL(tm_restore_sprs)
	ld	r0, THREAD_TM_TFHAR(r3)
	mtspr	SPRN_TFHAR, r0
	ld	r0, THREAD_TM_TEXASR(r3)
	mtspr	SPRN_TEXASR, r0
	ld	r0, THREAD_TM_TFIAR(r3)
	mtspr	SPRN_TFIAR, r0
	blr

	/* Passed an 8-bit failure cause as first argument. */
_GLOBAL(tm_abort)
	TABORT(R3)
	blr

/* void tm_reclaim(struct thread_struct *thread,
 *                 unsigned long orig_msr,
 *		   uint8_t cause)
 *
 *	- Performs a full reclaim.  This destroys outstanding
 *	  transactions and updates thread->regs.tm_ckpt_* with the
 *	  original checkpointed state.  Note that thread->regs is
 *	  unchanged.
 *	- FP regs are written back to thread->transact_fpr before
 *	  reclaiming.  These are the transactional (current) versions.
 *
 * Purpose is to both abort transactions of, and preserve the state of,
 * a transactions at a context switch. We preserve/restore both sets of process
 * state to restore them when the thread's scheduled again.  We continue in
 * userland as though nothing happened, but when the transaction is resumed
 * they will abort back to the checkpointed state we save out here.
 *
 * Call with IRQs off, stacks get all out of sync for some periods in here!
 */
_GLOBAL(tm_reclaim)
	mfcr	r6
	mflr	r0
	stw	r6, 8(r1)
	std	r0, 16(r1)
	std	r2, STK_GOT(r1)
	stdu	r1, -TM_FRAME_SIZE(r1)

	/* We've a struct pt_regs at [r1+STACK_FRAME_OVERHEAD]. */

	std	r3, STK_PARAM(R3)(r1)
	std	r4, STK_PARAM(R4)(r1)
	SAVE_NVGPRS(r1)

	/* We need to setup MSR for VSX register save instructions. */
	mfmsr	r14
	mr	r15, r14
	ori	r15, r15, MSR_FP
	li	r16, 0
	ori	r16, r16, MSR_EE /* IRQs hard off */
	andc	r15, r15, r16
	oris	r15, r15, MSR_VEC@h
#ifdef CONFIG_VSX
	BEGIN_FTR_SECTION
	oris	r15,r15, MSR_VSX@h
	END_FTR_SECTION_IFSET(CPU_FTR_VSX)
#endif
	mtmsrd	r15
	std	r14, TM_FRAME_L0(r1)

	/* Do sanity check on MSR to make sure we are suspended */
	li	r7, (MSR_TS_S)@higher
	srdi	r6, r14, 32
	and	r6, r6, r7
1:	tdeqi   r6, 0
	EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0

	/* Stash the stack pointer away for use after reclaim */
	std	r1, PACAR1(r13)

	/* Clear MSR RI since we are about to change r1, EE is already off. */
	li	r4, 0
	mtmsrd	r4, 1

	/*
	 * BE CAREFUL HERE:
	 * At this point we can't take an SLB miss since we have MSR_RI
	 * off. Load only to/from the stack/paca which are in SLB bolted regions
	 * until we turn MSR RI back on.
	 *
	 * The moment we treclaim, ALL of our GPRs will switch
	 * to user register state.  (FPRs, CCR etc. also!)
	 * Use an sprg and a tm_scratch in the PACA to shuffle.
	 */
	TRECLAIM(R5)				/* Cause in r5 */

	/* ******************** GPRs ******************** */
	/* Stash the checkpointed r13 away in the scratch SPR and get the real
	 *  paca
	 */
	SET_SCRATCH0(r13)
	GET_PACA(r13)

	/* Stash the checkpointed r1 away in paca tm_scratch and get the real
	 * stack pointer back
	 */
	std	r1, PACATMSCRATCH(r13)
	ld	r1, PACAR1(r13)

	/* Store the PPR in r11 and reset to decent value */
	std	r11, GPR11(r1)			/* Temporary stash */

	/* Reset MSR RI so we can take SLB faults again */
	li	r11, MSR_RI
	mtmsrd	r11, 1

	mfspr	r11, SPRN_PPR
	HMT_MEDIUM

	/* Now get some more GPRS free */
	std	r7, GPR7(r1)			/* Temporary stash */
	std	r12, GPR12(r1)			/* ''   ''    ''   */
	ld	r12, STK_PARAM(R3)(r1)		/* Param 0, thread_struct * */

	std	r11, THREAD_TM_PPR(r12)		/* Store PPR and free r11 */

	addi	r7, r12, PT_CKPT_REGS		/* Thread's ckpt_regs */

	/* Make r7 look like an exception frame so that we
	 * can use the neat GPRx(n) macros.  r7 is NOT a pt_regs ptr!
	 */
	subi	r7, r7, STACK_FRAME_OVERHEAD

	/* Sync the userland GPRs 2-12, 14-31 to thread->regs: */
	SAVE_GPR(0, r7)				/* user r0 */
	SAVE_GPR(2, r7)			/* user r2 */
	SAVE_4GPRS(3, r7)			/* user r3-r6 */
	SAVE_GPR(8, r7)				/* user r8 */
	SAVE_GPR(9, r7)				/* user r9 */
	SAVE_GPR(10, r7)			/* user r10 */
	ld	r3, PACATMSCRATCH(r13)		/* user r1 */
	ld	r4, GPR7(r1)			/* user r7 */
	ld	r5, GPR11(r1)			/* user r11 */
	ld	r6, GPR12(r1)			/* user r12 */
	GET_SCRATCH0(8)				/* user r13 */
	std	r3, GPR1(r7)
	std	r4, GPR7(r7)
	std	r5, GPR11(r7)
	std	r6, GPR12(r7)
	std	r8, GPR13(r7)

	SAVE_NVGPRS(r7)				/* user r14-r31 */

	/* ******************** NIP ******************** */
	mfspr	r3, SPRN_TFHAR
	std	r3, _NIP(r7)			/* Returns to failhandler */
	/* The checkpointed NIP is ignored when rescheduling/rechkpting,
	 * but is used in sig