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kernel/arch/powerpc/kvm/tm.S
Paul Mackerras 7854f7545b KVM: PPC: Book3S: Rework TM save/restore code and make it C-callable 
This adds a parameter to __kvmppc_save_tm and __kvmppc_restore_tm
which allows the caller to indicate whether it wants the nonvolatile
register state to be preserved across the call, as required by the C
calling conventions.  This parameter being non-zero also causes the
MSR bits that enable TM, FP, VMX and VSX to be preserved.  The
condition register and DSCR are now always preserved.

With this, kvmppc_save_tm_hv and kvmppc_restore_tm_hv can be called
from C code provided the 3rd parameter is non-zero.  So that these
functions can be called from modules, they now include code to set
the TOC pointer (r2) on entry, as they can call other built-in C
functions which will assume the TOC to have been set.

Also, the fake suspend code in kvmppc_save_tm_hv is modified here to
assume that treclaim in fake-suspend state does not modify any registers,
which is the case on POWER9.  This enables the code to be simplified
quite a bit.

_kvmppc_save_tm_pr and _kvmppc_restore_tm_pr become much simpler with
this change, since they now only need to save and restore TAR and pass
1 for the 3rd argument to __kvmppc_{save,restore}_tm.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-10-09 16:04:27 +11:00

406 lines
9.3 KiB
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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Derived from book3s_hv_rmhandlers.S, which is:
*
* Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
*/
#include <asm/reg.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/export.h>
#include <asm/tm.h>
#include <asm/cputable.h>
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
#define VCPU_GPRS_TM(reg) (((reg) * ULONG_SIZE) + VCPU_GPR_TM)
/*
* Save transactional state and TM-related registers.
* Called with:
* - r3 pointing to the vcpu struct
* - r4 containing the MSR with current TS bits:
* (For HV KVM, it is VCPU_MSR ; For PR KVM, it is host MSR).
* - r5 containing a flag indicating that non-volatile registers
* must be preserved.
* If r5 == 0, this can modify all checkpointed registers, but
* restores r1, r2 before exit. If r5 != 0, this restores the
* MSR TM/FP/VEC/VSX bits to their state on entry.
*/
_GLOBAL(__kvmppc_save_tm)
mflr r0
std r0, PPC_LR_STKOFF(r1)
stdu r1, -SWITCH_FRAME_SIZE(r1)
mr r9, r3
cmpdi cr7, r5, 0
/* Turn on TM. */
mfmsr r8
mr r10, r8
li r0, 1
rldimi r8, r0, MSR_TM_LG, 63-MSR_TM_LG
ori r8, r8, MSR_FP
oris r8, r8, (MSR_VEC | MSR_VSX)@h
mtmsrd r8
rldicl. r4, r4, 64 - MSR_TS_S_LG, 62
beq 1f /* TM not active in guest. */
std r1, HSTATE_SCRATCH2(r13)
std r3, HSTATE_SCRATCH1(r13)
/* Save CR on the stack - even if r5 == 0 we need to get cr7 back. */
mfcr r6
SAVE_GPR(6, r1)
/* Save DSCR so we can restore it to avoid running with user value */
mfspr r7, SPRN_DSCR
SAVE_GPR(7, r1)
/*
* We are going to do treclaim., which will modify all checkpointed
* registers. Save the non-volatile registers on the stack if
* preservation of non-volatile state has been requested.
*/
beq cr7, 3f
SAVE_NVGPRS(r1)
/* MSR[TS] will be 0 (non-transactional) once we do treclaim. */
li r0, 0
rldimi r10, r0, MSR_TS_S_LG, 63 - MSR_TS_T_LG
SAVE_GPR(10, r1) /* final MSR value */
3:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
BEGIN_FTR_SECTION
/* Emulation of the treclaim instruction needs TEXASR before treclaim */
mfspr r6, SPRN_TEXASR
std r6, VCPU_ORIG_TEXASR(r3)
END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
#endif
/* Clear the MSR RI since r1, r13 are all going to be foobar. */
li r5, 0
mtmsrd r5, 1
li r3, TM_CAUSE_KVM_RESCHED
/* All GPRs are volatile at this point. */
TRECLAIM(R3)
/* Temporarily store r13 and r9 so we have some regs to play with */
SET_SCRATCH0(r13)
GET_PACA(r13)
std r9, PACATMSCRATCH(r13)
ld r9, HSTATE_SCRATCH1(r13)
/* Save away PPR soon so we don't run with user value. */
std r0, VCPU_GPRS_TM(0)(r9)
mfspr r0, SPRN_PPR
HMT_MEDIUM
/* Reload stack pointer. */
std r1, VCPU_GPRS_TM(1)(r9)
ld r1, HSTATE_SCRATCH2(r13)
/* Set MSR RI now we have r1 and r13 back. */
std r2, VCPU_GPRS_TM(2)(r9)
li r2, MSR_RI
mtmsrd r2, 1
/* Reload TOC pointer. */
ld r2, PACATOC(r13)
/* Save all but r0-r2, r9 & r13 */
reg = 3
.rept 29
.if (reg != 9) && (reg != 13)
std reg, VCPU_GPRS_TM(reg)(r9)
.endif
reg = reg + 1
.endr
/* ... now save r13 */
GET_SCRATCH0(r4)
std r4, VCPU_GPRS_TM(13)(r9)
/* ... and save r9 */
ld r4, PACATMSCRATCH(r13)
std r4, VCPU_GPRS_TM(9)(r9)
/* Restore host DSCR and CR values, after saving guest values */
mfcr r6
mfspr r7, SPRN_DSCR
stw r6, VCPU_CR_TM(r9)
std r7, VCPU_DSCR_TM(r9)
REST_GPR(6, r1)
REST_GPR(7, r1)
mtcr r6
mtspr SPRN_DSCR, r7
/* Save away checkpointed SPRs. */
std r0, VCPU_PPR_TM(r9)
mflr r5
mfctr r7
mfspr r8, SPRN_AMR
mfspr r10, SPRN_TAR
mfxer r11
std r5, VCPU_LR_TM(r9)
std r7, VCPU_CTR_TM(r9)
std r8, VCPU_AMR_TM(r9)
std r10, VCPU_TAR_TM(r9)
std r11, VCPU_XER_TM(r9)
/* Save FP/VSX. */
addi r3, r9, VCPU_FPRS_TM
bl store_fp_state
addi r3, r9, VCPU_VRS_TM
bl store_vr_state
mfspr r6, SPRN_VRSAVE
stw r6, VCPU_VRSAVE_TM(r9)
/* Restore non-volatile registers if requested to */
beq cr7, 1f
REST_NVGPRS(r1)
REST_GPR(10, r1)
1:
/*
* We need to save these SPRs after the treclaim so that the software
* error code is recorded correctly in the TEXASR. Also the user may
* change these outside of a transaction, so they must always be
* context switched.
*/
mfspr r7, SPRN_TEXASR
std r7, VCPU_TEXASR(r9)
mfspr r5, SPRN_TFHAR
mfspr r6, SPRN_TFIAR
std r5, VCPU_TFHAR(r9)
std r6, VCPU_TFIAR(r9)
/* Restore MSR state if requested */
beq cr7, 2f
mtmsrd r10, 0
2:
addi r1, r1, SWITCH_FRAME_SIZE
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
blr
/*
* _kvmppc_save_tm_pr() is a wrapper around __kvmppc_save_tm(), so that it can
* be invoked from C function by PR KVM only.
*/
_GLOBAL(_kvmppc_save_tm_pr)
mflr r0
std r0, PPC_LR_STKOFF(r1)
stdu r1, -PPC_MIN_STKFRM(r1)
mfspr r8, SPRN_TAR
std r8, PPC_MIN_STKFRM-8(r1)
li r5, 1 /* preserve non-volatile registers */
bl __kvmppc_save_tm
ld r8, PPC_MIN_STKFRM-8(r1)
mtspr SPRN_TAR, r8
addi r1, r1, PPC_MIN_STKFRM
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
blr
EXPORT_SYMBOL_GPL(_kvmppc_save_tm_pr);
/*
* Restore transactional state and TM-related registers.
* Called with:
* - r3 pointing to the vcpu struct.
* - r4 is the guest MSR with desired TS bits:
* For HV KVM, it is VCPU_MSR
* For PR KVM, it is provided by caller
* - r5 containing a flag indicating that non-volatile registers
* must be preserved.
* If r5 == 0, this potentially modifies all checkpointed registers, but
* restores r1, r2 from the PACA before exit.
* If r5 != 0, this restores the MSR TM/FP/VEC/VSX bits to their state on entry.
*/
_GLOBAL(__kvmppc_restore_tm)
mflr r0
std r0, PPC_LR_STKOFF(r1)
cmpdi cr7, r5, 0
/* Turn on TM/FP/VSX/VMX so we can restore them. */
mfmsr r5
mr r10, r5
li r6, MSR_TM >> 32
sldi r6, r6, 32
or r5, r5, r6
ori r5, r5, MSR_FP
oris r5, r5, (MSR_VEC | MSR_VSX)@h
mtmsrd r5
/*
* The user may change these outside of a transaction, so they must
* always be context switched.
*/
ld r5, VCPU_TFHAR(r3)
ld r6, VCPU_TFIAR(r3)
ld r7, VCPU_TEXASR(r3)
mtspr SPRN_TFHAR, r5
mtspr SPRN_TFIAR, r6
mtspr SPRN_TEXASR, r7
mr r5, r4
rldicl. r5, r5, 64 - MSR_TS_S_LG, 62
beq 9f /* TM not active in guest */
/* Make sure the failure summary is set, otherwise we'll program check
* when we trechkpt. It's possible that this might have been not set
* on a kvmppc_set_one_reg() call but we shouldn't let this crash the
* host.
*/
oris r7, r7, (TEXASR_FS)@h
mtspr SPRN_TEXASR, r7
/*
* Make a stack frame and save non-volatile registers if requested.
*/
stdu r1, -SWITCH_FRAME_SIZE(r1)
std r1, HSTATE_SCRATCH2(r13)
mfcr r6
mfspr r7, SPRN_DSCR
SAVE_GPR(2, r1)
SAVE_GPR(6, r1)
SAVE_GPR(7, r1)
beq cr7, 4f
SAVE_NVGPRS(r1)
/* MSR[TS] will be 1 (suspended) once we do trechkpt */
li r0, 1
rldimi r10, r0, MSR_TS_S_LG, 63 - MSR_TS_T_LG
SAVE_GPR(10, r1) /* final MSR value */
4:
/*
* We need to load up the checkpointed state for the guest.
* We need to do this early as it will blow away any GPRs, VSRs and
* some SPRs.
*/
mr r31, r3
addi r3, r31, VCPU_FPRS_TM
bl load_fp_state
addi r3, r31, VCPU_VRS_TM
bl load_vr_state
mr r3, r31
lwz r7, VCPU_VRSAVE_TM(r3)
mtspr SPRN_VRSAVE, r7
ld r5, VCPU_LR_TM(r3)
lwz r6, VCPU_CR_TM(r3)
ld r7, VCPU_CTR_TM(r3)
ld r8, VCPU_AMR_TM(r3)
ld r9, VCPU_TAR_TM(r3)
ld r10, VCPU_XER_TM(r3)
mtlr r5
mtcr r6
mtctr r7
mtspr SPRN_AMR, r8
mtspr SPRN_TAR, r9
mtxer r10
/*
* Load up PPR and DSCR values but don't put them in the actual SPRs
* till the last moment to avoid running with userspace PPR and DSCR for
* too long.
*/
ld r29, VCPU_DSCR_TM(r3)
ld r30, VCPU_PPR_TM(r3)
/* Clear the MSR RI since r1, r13 are all going to be foobar. */
li r5, 0
mtmsrd r5, 1
/* Load GPRs r0-r28 */
reg = 0
.rept 29
ld reg, VCPU_GPRS_TM(reg)(r31)
reg = reg + 1
.endr
mtspr SPRN_DSCR, r29
mtspr SPRN_PPR, r30
/* Load final GPRs */
ld 29, VCPU_GPRS_TM(29)(r31)
ld 30, VCPU_GPRS_TM(30)(r31)
ld 31, VCPU_GPRS_TM(31)(r31)
/* TM checkpointed state is now setup. All GPRs are now volatile. */
TRECHKPT
/* Now let's get back the state we need. */
HMT_MEDIUM
GET_PACA(r13)
ld r1, HSTATE_SCRATCH2(r13)
REST_GPR(7, r1)
mtspr SPRN_DSCR, r7
/* Set the MSR RI since we have our registers back. */
li r5, MSR_RI
mtmsrd r5, 1
/* Restore TOC pointer and CR */
REST_GPR(2, r1)
REST_GPR(6, r1)
mtcr r6
/* Restore non-volatile registers if requested to. */
beq cr7, 5f
REST_GPR(10, r1)
REST_NVGPRS(r1)
5: addi r1, r1, SWITCH_FRAME_SIZE
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
9: /* Restore MSR bits if requested */
beqlr cr7
mtmsrd r10, 0
blr
/*
* _kvmppc_restore_tm_pr() is a wrapper around __kvmppc_restore_tm(), so that it
* can be invoked from C function by PR KVM only.
*/
_GLOBAL(_kvmppc_restore_tm_pr)
mflr r0
std r0, PPC_LR_STKOFF(r1)
stdu r1, -PPC_MIN_STKFRM(r1)
/* save TAR so that it can be recovered later */
mfspr r8, SPRN_TAR
std r8, PPC_MIN_STKFRM-8(r1)
li r5, 1
bl __kvmppc_restore_tm
ld r8, PPC_MIN_STKFRM-8(r1)
mtspr SPRN_TAR, r8
addi r1, r1, PPC_MIN_STKFRM
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
blr
EXPORT_SYMBOL_GPL(_kvmppc_restore_tm_pr);
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
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