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6bcb80143e
At the start of __tm_recheckpoint() we save the kernel stack pointer
(r1) in SPRG SCRATCH0 (SPRG2) so that we can restore it after the
trecheckpoint.
Unfortunately, the same SPRG is used in the SLB miss handler. If an
SLB miss is taken between the save and restore of r1 to the SPRG, the
SPRG is changed and hence r1 is also corrupted. We can end up with
the following crash when we start using r1 again after the restore
from the SPRG:
Oops: Bad kernel stack pointer, sig: 6 [#1]
SMP NR_CPUS=2048 NUMA pSeries
CPU: 658 PID: 143777 Comm: htm_demo Tainted: G EL X 4.4.13-0-default #1
task: c0000b56993a7810 ti: c00000000cfec000 task.ti: c0000b56993bc000
NIP: c00000000004f188 LR: 00000000100040b8 CTR: 0000000010002570
REGS: c00000000cfefd40 TRAP: 0300 Tainted: G EL X (4.4.13-0-default)
MSR: 8000000300001033 <SF,ME,IR,DR,RI,LE> CR: 02000424 XER: 20000000
CFAR: c000000000008468 DAR: 00003ffd84e66880 DSISR: 40000000 SOFTE: 0
PACATMSCRATCH: 00003ffbc865e680
GPR00: fffffffcfabc4268 00003ffd84e667a0 00000000100d8c38 000000030544bb80
GPR04: 0000000000000002 00000000100cf200 0000000000000449 00000000100cf100
GPR08: 000000000000c350 0000000000002569 0000000000002569 00000000100d6c30
GPR12: 00000000100d6c28 c00000000e6a6b00 00003ffd84660000 0000000000000000
GPR16: 0000000000000003 0000000000000449 0000000010002570 0000010009684f20
GPR20: 0000000000800000 00003ffd84e5f110 00003ffd84e5f7a0 00000000100d0f40
GPR24: 0000000000000000 0000000000000000 0000000000000000 00003ffff0673f50
GPR28: 00003ffd84e5e960 00000000003d0f00 00003ffd84e667a0 00003ffd84e5e680
NIP [c00000000004f188] restore_gprs+0x110/0x17c
LR [00000000100040b8] 0x100040b8
Call Trace:
Instruction dump:
f8a1fff0 e8e700a8 38a00000 7ca10164 e8a1fff8 e821fff0 7c0007dd 7c421378
7db142a6 7c3242a6 38800002 7c810164 <e9c100e0> e9e100e8 ea0100f0 ea2100f8
We hit this on large memory machines (> 2TB) but it can also be hit on
smaller machines when 1TB segments are disabled.
To hit this, you also need to be virtualised to ensure SLBs are
periodically removed by the hypervisor.
This patches moves the saving of r1 to the SPRG to the region where we
are guaranteed not to take any further SLB misses.
Fixes: 98ae22e15b ("powerpc: Add helper functions for transactional memory context switching")
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
508 lines
12 KiB
ArmAsm
508 lines
12 KiB
ArmAsm
/*
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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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#include <asm/bug.h>
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#ifdef CONFIG_VSX
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/* See fpu.S, this is borrowed from there */
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#define __SAVE_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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SAVE_32FPRS(n,base); \
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b 3f; \
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2: SAVE_32VSRS(n,c,base); \
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3:
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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(n,c,base) SAVE_32FPRS(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(n,c,base) \
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__SAVE_32FPRS_VSRS(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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/* 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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stw r6, 8(r1)
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std r0, 16(r1)
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std r2, STK_GOT(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, STK_PARAM(R3)(r1)
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SAVE_NVGPRS(r1)
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/* We need to setup MSR for VSX register save instructions. */
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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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li r16, 0
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ori r16, r16, MSR_EE /* IRQs hard off */
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andc r15, r15, r16
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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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addi r7, r3, THREAD_TRANSACT_VRSTATE
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SAVE_32VRS(0, r6, r7) /* r6 scratch, r7 transact vr state */
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mfvscr v0
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li r6, VRSTATE_VSCR
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stvx v0, r7, r6
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dont_backup_vec:
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mfspr r0, SPRN_VRSAVE
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std r0, THREAD_TRANSACT_VRSAVE(r3)
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andi. r0, r4, MSR_FP
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beq dont_backup_fp
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addi r7, r3, THREAD_TRANSACT_FPSTATE
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SAVE_32FPRS_VSRS(0, R6, R7) /* r6 scratch, r7 transact fp state */
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mffs fr0
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stfd fr0,FPSTATE_FPSCR(r7)
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dont_backup_fp:
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/* Do sanity check on MSR to make sure we are suspended */
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li r7, (MSR_TS_S)@higher
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srdi r6, r14, 32
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and r6, r6, r7
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1: tdeqi r6, 0
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EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0
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/* Clear MSR RI since we are about to change r1, EE is already off. */
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li r4, 0
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mtmsrd r4, 1
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/*
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* BE CAREFUL HERE:
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* At this point we can't take an SLB miss since we have MSR_RI
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* off. Load only to/from the stack/paca which are in SLB bolted regions
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* until we turn MSR RI back on.
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*
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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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/* Store the PPR in r11 and reset to decent value */
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std r11, GPR11(r1) /* Temporary stash */
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/* Reset MSR RI so we can take SLB faults again */
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li r11, MSR_RI
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mtmsrd r11, 1
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mfspr r11, SPRN_PPR
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HMT_MEDIUM
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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, STK_PARAM(R3)(r1) /* Param 0, thread_struct * */
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std r11, THREAD_TM_PPR(r12) /* Store PPR and free r11 */
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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_GPR(8, r7) /* user r8 */
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SAVE_GPR(9, r7) /* user r9 */
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SAVE_GPR(10, r7) /* user r10 */
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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, GPR11(r1) /* user r11 */
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ld r6, GPR12(r1) /* user r12 */
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GET_SCRATCH0(8) /* user r13 */
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std r3, GPR1(r7)
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std r4, GPR7(r7)
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std r5, GPR11(r7)
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std r6, GPR12(r7)
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std r8, 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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/* ******************** TAR, DSCR ********** */
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mfspr r3, SPRN_TAR
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mfspr r4, SPRN_DSCR
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std r3, THREAD_TM_TAR(r12)
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std r4, THREAD_TM_DSCR(r12)
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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 is checkpointed too, but is 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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lwz 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, STK_GOT(r1)
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/* Load CPU's default DSCR */
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ld r0, PACA_DSCR_DEFAULT(r13)
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mtspr SPRN_DSCR, r0
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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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stw r5, 8(r1)
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std r0, 16(r1)
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std r2, STK_GOT(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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/* 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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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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#ifdef CONFIG_ALTIVEC
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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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addi r8, r3, THREAD_VRSTATE
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li r5, VRSTATE_VSCR
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lvx v0, r8, r5
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mtvscr v0
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REST_32VRS(0, r5, r8) /* r5 scratch, r8 ptr */
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dont_restore_vec:
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ld r5, THREAD_VRSAVE(r3)
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mtspr SPRN_VRSAVE, r5
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#endif
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andi. r0, r4, MSR_FP
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beq dont_restore_fp
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addi r8, r3, THREAD_FPSTATE
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lfd fr0, FPSTATE_FPSCR(r8)
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MTFSF_L(fr0)
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REST_32FPRS_VSRS(0, R4, R8)
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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 r4, _CTR(r7)
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ld r5, _LINK(r7)
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ld r8, _XER(r7)
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mtctr r4
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mtlr r5
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mtxer r8
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/* ******************** TAR ******************** */
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ld r4, THREAD_TM_TAR(r3)
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mtspr SPRN_TAR, r4
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/* Load up the PPR and DSCR in GPRs only at this stage */
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ld r5, THREAD_TM_DSCR(r3)
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ld r6, THREAD_TM_PPR(r3)
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REST_GPR(0, r7) /* GPR0 */
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REST_2GPRS(2, r7) /* GPR2-3 */
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REST_GPR(4, r7) /* GPR4 */
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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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/* Load up PPR and DSCR here so we don't run with user values for long
|
|
*/
|
|
mtspr SPRN_DSCR, r5
|
|
mtspr SPRN_PPR, r6
|
|
|
|
/* Do final sanity check on TEXASR to make sure FS is set. Do this
|
|
* here before we load up the userspace r1 so any bugs we hit will get
|
|
* a call chain */
|
|
mfspr r5, SPRN_TEXASR
|
|
srdi r5, r5, 16
|
|
li r6, (TEXASR_FS)@h
|
|
and r6, r6, r5
|
|
1: tdeqi r6, 0
|
|
EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0
|
|
|
|
/* Do final sanity check on MSR to make sure we are not transactional
|
|
* or suspended
|
|
*/
|
|
mfmsr r6
|
|
li r5, (MSR_TS_MASK)@higher
|
|
srdi r6, r6, 32
|
|
and r6, r6, r5
|
|
1: tdnei r6, 0
|
|
EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0
|
|
|
|
/* Restore CR */
|
|
ld r6, _CCR(r7)
|
|
mtcr r6
|
|
|
|
REST_GPR(6, r7)
|
|
|
|
/*
|
|
* Store r1 and r5 on the stack so that we can access them
|
|
* after we clear MSR RI.
|
|
*/
|
|
|
|
REST_GPR(5, r7)
|
|
std r5, -8(r1)
|
|
ld r5, GPR1(r7)
|
|
std r5, -16(r1)
|
|
|
|
REST_GPR(7, r7)
|
|
|
|
/* Clear MSR RI since we are about to change r1. EE is already off */
|
|
li r5, 0
|
|
mtmsrd r5, 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.
|
|
*/
|
|
|
|
SET_SCRATCH0(r1)
|
|
ld r5, -8(r1)
|
|
ld r1, -16(r1)
|
|
|
|
/* Commit register state as checkpointed state: */
|
|
TRECHKPT
|
|
|
|
HMT_MEDIUM
|
|
|
|
/* Our transactional state has now changed.
|
|
*
|
|
* Now just get out of here. Transactional (current) state will be
|
|
* updated once restore is called on the return path in the _switch-ed
|
|
* -to process.
|
|
*/
|
|
|
|
GET_PACA(r13)
|
|
GET_SCRATCH0(r1)
|
|
|
|
/* R1 is restored, so we are recoverable again. EE is still off */
|
|
li r4, MSR_RI
|
|
mtmsrd r4, 1
|
|
|
|
REST_NVGPRS(r1)
|
|
|
|
addi r1, r1, TM_FRAME_SIZE
|
|
lwz r4, 8(r1)
|
|
ld r0, 16(r1)
|
|
mtcr r4
|
|
mtlr r0
|
|
ld r2, STK_GOT(r1)
|
|
|
|
/* Load CPU's default DSCR */
|
|
ld r0, PACA_DSCR_DEFAULT(r13)
|
|
mtspr SPRN_DSCR, r0
|
|
|
|
blr
|
|
|
|
/* ****************************************************************** */
|