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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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powerpc: Add helper functions for transactional memory context switching
Here we add the helper functions to be used when context switching. These allow us to fully reclaim and recheckpoint a transaction. We introduce a new paca field called tm_scratch to help us store away register values when doing the low level tm reclaim register save. Signed-off-by: Matt Evans <matt@ozlabs.org> Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Neuling
Benjamin Herrenschmidt
parent
afc07701ce
commit
98ae22e15b
@ -797,7 +797,7 @@
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* HV mode in which case it is HSPRG0
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*
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* 64-bit server:
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* - SPRG0 unused (reserved for HV on Power4)
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* - SPRG0 scratch for TM recheckpoint/reclaim (reserved for HV on Power4)
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* - SPRG2 scratch for exception vectors
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* - SPRG3 CPU and NUMA node for VDSO getcpu (user visible)
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* - HSPRG0 stores PACA in HV mode
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20
arch/powerpc/include/asm/tm.h
Normal file
20
arch/powerpc/include/asm/tm.h
Normal file
@ -0,0 +1,20 @@
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/*
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* Transactional memory support routines to reclaim and recheckpoint
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* transactional process state.
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*
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* Copyright 2012 Matt Evans & Michael Neuling, IBM Corporation.
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*/
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#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
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extern void do_load_up_transact_fpu(struct thread_struct *thread);
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extern void do_load_up_transact_altivec(struct thread_struct *thread);
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#endif
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extern void tm_enable(void);
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extern void tm_reclaim(struct thread_struct *thread,
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unsigned long orig_msr, uint8_t cause);
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extern void tm_recheckpoint(struct thread_struct *thread,
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unsigned long orig_msr);
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extern void tm_abort(uint8_t cause);
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extern void tm_save_sprs(struct thread_struct *thread);
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extern void tm_restore_sprs(struct thread_struct *thread);
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@ -121,6 +121,8 @@ ifneq ($(CONFIG_PPC_INDIRECT_IO),y)
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obj-y += iomap.o
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endif
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obj64-$(CONFIG_PPC_TRANSACTIONAL_MEM) += tm.o
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obj-$(CONFIG_PPC64) += $(obj64-y)
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obj-$(CONFIG_PPC32) += $(obj32-y)
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388
arch/powerpc/kernel/tm.S
Normal file
388
arch/powerpc/kernel/tm.S
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@ -0,0 +1,388 @@
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/*
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* Transactional memory support routines to reclaim and recheckpoint
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* transactional process state.
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*
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* Copyright 2012 Matt Evans & Michael Neuling, IBM Corporation.
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*/
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#include <asm/asm-offsets.h>
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#include <asm/ppc_asm.h>
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#include <asm/ppc-opcode.h>
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#include <asm/ptrace.h>
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#include <asm/reg.h>
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#ifdef CONFIG_VSX
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/* See fpu.S, this is very similar but to save/restore checkpointed FPRs/VSRs */
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#define __SAVE_32FPRS_VSRS_TRANSACT(n,c,base) \
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BEGIN_FTR_SECTION \
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b 2f; \
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END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
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SAVE_32FPRS_TRANSACT(n,base); \
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b 3f; \
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2: SAVE_32VSRS_TRANSACT(n,c,base); \
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3:
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/* ...and this is just plain borrowed from there. */
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#define __REST_32FPRS_VSRS(n,c,base) \
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BEGIN_FTR_SECTION \
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b 2f; \
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END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
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REST_32FPRS(n,base); \
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b 3f; \
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2: REST_32VSRS(n,c,base); \
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3:
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#else
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#define __SAVE_32FPRS_VSRS_TRANSACT(n,c,base) SAVE_32FPRS_TRANSACT(n, base)
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#define __REST_32FPRS_VSRS(n,c,base) REST_32FPRS(n, base)
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#endif
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#define SAVE_32FPRS_VSRS_TRANSACT(n,c,base) \
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__SAVE_32FPRS_VSRS_TRANSACT(n,__REG_##c,__REG_##base)
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#define REST_32FPRS_VSRS(n,c,base) \
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__REST_32FPRS_VSRS(n,__REG_##c,__REG_##base)
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/* Stack frame offsets for local variables. */
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#define TM_FRAME_L0 TM_FRAME_SIZE-16
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#define TM_FRAME_L1 TM_FRAME_SIZE-8
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#define STACK_PARAM(x) (48+((x)*8))
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/* In order to access the TM SPRs, TM must be enabled. So, do so: */
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_GLOBAL(tm_enable)
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mfmsr r4
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li r3, MSR_TM >> 32
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sldi r3, r3, 32
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and. r0, r4, r3
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bne 1f
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or r4, r4, r3
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mtmsrd r4
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1: blr
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_GLOBAL(tm_save_sprs)
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mfspr r0, SPRN_TFHAR
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std r0, THREAD_TM_TFHAR(r3)
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mfspr r0, SPRN_TEXASR
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std r0, THREAD_TM_TEXASR(r3)
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mfspr r0, SPRN_TFIAR
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std r0, THREAD_TM_TFIAR(r3)
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blr
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_GLOBAL(tm_restore_sprs)
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ld r0, THREAD_TM_TFHAR(r3)
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mtspr SPRN_TFHAR, r0
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ld r0, THREAD_TM_TEXASR(r3)
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mtspr SPRN_TEXASR, r0
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ld r0, THREAD_TM_TFIAR(r3)
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mtspr SPRN_TFIAR, r0
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blr
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/* Passed an 8-bit failure cause as first argument. */
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_GLOBAL(tm_abort)
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TABORT(R3)
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blr
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/* void tm_reclaim(struct thread_struct *thread,
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* unsigned long orig_msr,
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* uint8_t cause)
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*
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* - Performs a full reclaim. This destroys outstanding
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* transactions and updates thread->regs.tm_ckpt_* with the
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* original checkpointed state. Note that thread->regs is
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* unchanged.
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* - FP regs are written back to thread->transact_fpr before
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* reclaiming. These are the transactional (current) versions.
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*
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* Purpose is to both abort transactions of, and preserve the state of,
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* a transactions at a context switch. We preserve/restore both sets of process
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* state to restore them when the thread's scheduled again. We continue in
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* userland as though nothing happened, but when the transaction is resumed
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* they will abort back to the checkpointed state we save out here.
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*
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* Call with IRQs off, stacks get all out of sync for some periods in here!
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*/
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_GLOBAL(tm_reclaim)
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mfcr r6
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mflr r0
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std r6, 8(r1)
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std r0, 16(r1)
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std r2, 40(r1)
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stdu r1, -TM_FRAME_SIZE(r1)
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/* We've a struct pt_regs at [r1+STACK_FRAME_OVERHEAD]. */
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std r3, STACK_PARAM(0)(r1)
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SAVE_NVGPRS(r1)
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mfmsr r14
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mr r15, r14
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ori r15, r15, MSR_FP
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oris r15, r15, MSR_VEC@h
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#ifdef CONFIG_VSX
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BEGIN_FTR_SECTION
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oris r15,r15, MSR_VSX@h
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END_FTR_SECTION_IFSET(CPU_FTR_VSX)
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#endif
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mtmsrd r15
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std r14, TM_FRAME_L0(r1)
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/* Stash the stack pointer away for use after reclaim */
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std r1, PACAR1(r13)
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/* ******************** FPR/VR/VSRs ************
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* Before reclaiming, capture the current/transactional FPR/VR
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* versions /if used/.
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*
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* (If VSX used, FP and VMX are implied. Or, we don't need to look
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* at MSR.VSX as copying FP regs if .FP, vector regs if .VMX covers it.)
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*
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* We're passed the thread's MSR as parameter 2.
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*
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* We enabled VEC/FP/VSX in the msr above, so we can execute these
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* instructions!
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*/
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andis. r0, r4, MSR_VEC@h
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beq dont_backup_vec
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SAVE_32VRS_TRANSACT(0, r6, r3) /* r6 scratch, r3 thread */
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mfvscr vr0
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li r6, THREAD_TRANSACT_VSCR
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stvx vr0, r3, r6
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mfspr r0, SPRN_VRSAVE
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std r0, THREAD_TRANSACT_VRSAVE(r3)
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dont_backup_vec:
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andi. r0, r4, MSR_FP
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beq dont_backup_fp
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SAVE_32FPRS_VSRS_TRANSACT(0, R6, R3) /* r6 scratch, r3 thread */
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mffs fr0
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stfd fr0,THREAD_TRANSACT_FPSCR(r3)
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dont_backup_fp:
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/* The moment we treclaim, ALL of our GPRs will switch
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* to user register state. (FPRs, CCR etc. also!)
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* Use an sprg and a tm_scratch in the PACA to shuffle.
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*/
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TRECLAIM(R5) /* Cause in r5 */
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/* ******************** GPRs ******************** */
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/* Stash the checkpointed r13 away in the scratch SPR and get the real
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* paca
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*/
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SET_SCRATCH0(r13)
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GET_PACA(r13)
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/* Stash the checkpointed r1 away in paca tm_scratch and get the real
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* stack pointer back
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*/
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std r1, PACATMSCRATCH(r13)
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ld r1, PACAR1(r13)
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/* Now get some more GPRS free */
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std r7, GPR7(r1) /* Temporary stash */
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std r12, GPR12(r1) /* '' '' '' */
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ld r12, STACK_PARAM(0)(r1) /* Param 0, thread_struct * */
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addi r7, r12, PT_CKPT_REGS /* Thread's ckpt_regs */
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/* Make r7 look like an exception frame so that we
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* can use the neat GPRx(n) macros. r7 is NOT a pt_regs ptr!
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*/
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subi r7, r7, STACK_FRAME_OVERHEAD
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/* Sync the userland GPRs 2-12, 14-31 to thread->regs: */
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SAVE_GPR(0, r7) /* user r0 */
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SAVE_GPR(2, r7) /* user r2 */
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SAVE_4GPRS(3, r7) /* user r3-r6 */
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SAVE_4GPRS(8, r7) /* user r8-r11 */
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ld r3, PACATMSCRATCH(r13) /* user r1 */
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ld r4, GPR7(r1) /* user r7 */
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ld r5, GPR12(r1) /* user r12 */
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GET_SCRATCH0(6) /* user r13 */
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std r3, GPR1(r7)
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std r4, GPR7(r7)
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std r5, GPR12(r7)
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std r6, GPR13(r7)
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SAVE_NVGPRS(r7) /* user r14-r31 */
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/* ******************** NIP ******************** */
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mfspr r3, SPRN_TFHAR
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std r3, _NIP(r7) /* Returns to failhandler */
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/* The checkpointed NIP is ignored when rescheduling/rechkpting,
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* but is used in signal return to 'wind back' to the abort handler.
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*/
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/* ******************** CR,LR,CCR,MSR ********** */
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mfctr r3
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mflr r4
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mfcr r5
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mfxer r6
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std r3, _CTR(r7)
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std r4, _LINK(r7)
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std r5, _CCR(r7)
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std r6, _XER(r7)
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/* MSR and flags: We don't change CRs, and we don't need to alter
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* MSR.
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*/
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/* TM regs, incl TEXASR -- these live in thread_struct. Note they've
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* been updated by the treclaim, to explain to userland the failure
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* cause (aborted).
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*/
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mfspr r0, SPRN_TEXASR
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mfspr r3, SPRN_TFHAR
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mfspr r4, SPRN_TFIAR
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std r0, THREAD_TM_TEXASR(r12)
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std r3, THREAD_TM_TFHAR(r12)
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std r4, THREAD_TM_TFIAR(r12)
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/* AMR and PPR are checkpointed too, but are unsupported by Linux. */
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/* Restore original MSR/IRQ state & clear TM mode */
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ld r14, TM_FRAME_L0(r1) /* Orig MSR */
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li r15, 0
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rldimi r14, r15, MSR_TS_LG, (63-MSR_TS_LG)-1
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mtmsrd r14
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REST_NVGPRS(r1)
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addi r1, r1, TM_FRAME_SIZE
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ld r4, 8(r1)
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ld r0, 16(r1)
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mtcr r4
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mtlr r0
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ld r2, 40(r1)
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blr
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/* void tm_recheckpoint(struct thread_struct *thread,
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* unsigned long orig_msr)
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* - Restore the checkpointed register state saved by tm_reclaim
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* when we switch_to a process.
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*
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* Call with IRQs off, stacks get all out of sync for
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* some periods in here!
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*/
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_GLOBAL(tm_recheckpoint)
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mfcr r5
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mflr r0
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std r5, 8(r1)
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std r0, 16(r1)
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std r2, 40(r1)
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stdu r1, -TM_FRAME_SIZE(r1)
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/* We've a struct pt_regs at [r1+STACK_FRAME_OVERHEAD].
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* This is used for backing up the NVGPRs:
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*/
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SAVE_NVGPRS(r1)
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std r1, PACAR1(r13)
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/* Load complete register state from ts_ckpt* registers */
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addi r7, r3, PT_CKPT_REGS /* Thread's ckpt_regs */
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/* Make r7 look like an exception frame so that we
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* can use the neat GPRx(n) macros. r7 is now NOT a pt_regs ptr!
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*/
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subi r7, r7, STACK_FRAME_OVERHEAD
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SET_SCRATCH0(r1)
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mfmsr r6
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/* R4 = original MSR to indicate whether thread used FP/Vector etc. */
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/* Enable FP/vec in MSR if necessary! */
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lis r5, MSR_VEC@h
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ori r5, r5, MSR_FP
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and. r5, r4, r5
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beq restore_gprs /* if neither, skip both */
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#ifdef CONFIG_VSX
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BEGIN_FTR_SECTION
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oris r5, r5, MSR_VSX@h
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END_FTR_SECTION_IFSET(CPU_FTR_VSX)
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#endif
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or r5, r6, r5 /* Set MSR.FP+.VSX/.VEC */
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mtmsr r5
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/* FP and VEC registers: These are recheckpointed from thread.fpr[]
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* and thread.vr[] respectively. The thread.transact_fpr[] version
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* is more modern, and will be loaded subsequently by any FPUnavailable
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* trap.
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*/
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andis. r0, r4, MSR_VEC@h
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beq dont_restore_vec
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li r5, THREAD_VSCR
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lvx vr0, r3, r5
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mtvscr vr0
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REST_32VRS(0, r5, r3) /* r5 scratch, r3 THREAD ptr */
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ld r5, THREAD_VRSAVE(r3)
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mtspr SPRN_VRSAVE, r5
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dont_restore_vec:
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andi. r0, r4, MSR_FP
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beq dont_restore_fp
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lfd fr0, THREAD_FPSCR(r3)
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MTFSF_L(fr0)
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REST_32FPRS_VSRS(0, R4, R3)
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dont_restore_fp:
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mtmsr r6 /* FP/Vec off again! */
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restore_gprs:
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/* ******************** CR,LR,CCR,MSR ********** */
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ld r3, _CTR(r7)
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ld r4, _LINK(r7)
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ld r5, _CCR(r7)
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ld r6, _XER(r7)
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mtctr r3
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mtlr r4
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mtcr r5
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mtxer r6
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/* MSR and flags: We don't change CRs, and we don't need to alter
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* MSR.
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*/
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REST_4GPRS(0, r7) /* GPR0-3 */
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REST_GPR(4, r7) /* GPR4-6 */
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REST_GPR(5, r7)
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REST_GPR(6, r7)
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REST_4GPRS(8, r7) /* GPR8-11 */
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REST_2GPRS(12, r7) /* GPR12-13 */
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REST_NVGPRS(r7) /* GPR14-31 */
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ld r7, GPR7(r7) /* GPR7 */
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/* Commit register state as checkpointed state: */
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TRECHKPT
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/* Our transactional state has now changed.
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*
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* Now just get out of here. Transactional (current) state will be
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* updated once restore is called on the return path in the _switch-ed
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* -to process.
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*/
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GET_PACA(r13)
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GET_SCRATCH0(r1)
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REST_NVGPRS(r1)
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addi r1, r1, TM_FRAME_SIZE
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ld r4, 8(r1)
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ld r0, 16(r1)
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mtcr r4
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mtlr r0
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ld r2, 40(r1)
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blr
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/* ****************************************************************** */
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