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-rw-r--r--arch/powerpc/kernel/tm.S554
1 files changed, 554 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S
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+++ b/arch/powerpc/kernel/tm.S
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Transactional memory support routines to reclaim and recheckpoint
+ * transactional process state.
+ *
+ * Copyright 2012 Matt Evans & Michael Neuling, IBM Corporation.
+ */
+
+#include <linux/export.h>
+#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>
+#include <asm/feature-fixups.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
+EXPORT_SYMBOL_GPL(tm_enable);
+
+_GLOBAL(tm_disable)
+ mfmsr r4
+ li r3, MSR_TM >> 32
+ sldi r3, r3, 32
+ andc r4, r4, r3
+ mtmsrd r4
+ blr
+EXPORT_SYMBOL_GPL(tm_disable);
+
+_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
+EXPORT_SYMBOL_GPL(tm_abort);
+
+/*
+ * void tm_reclaim(struct thread_struct *thread,
+ * uint8_t cause)
+ *
+ * - Performs a full reclaim. This destroys outstanding
+ * transactions and updates thread.ckpt_regs, thread.ckfp_state and
+ * thread.ckvr_state with the original checkpointed state. Note that
+ * thread->regs is unchanged.
+ *
+ * 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 r5
+ mflr r0
+ stw r5, 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_INT_FRAME_REGS]. */
+
+ std r3, STK_PARAM(R3)(r1)
+ SAVE_NVGPRS(r1)
+
+ /*
+ * Save kernel live AMR since it will be clobbered by treclaim
+ * but can be used elsewhere later in kernel space.
+ */
+ mfspr r3, SPRN_AMR
+ std r3, TM_FRAME_L1(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 use SCRATCH0, 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.
+ *
+ * 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(R4) /* Cause in r4 */
+
+ /*
+ * ******************** GPRs ********************
+ * Stash the checkpointed r13 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 into r1.
+ */
+ std r1, PACATMSCRATCH(r13)
+ ld r1, PACAR1(r13)
+
+ std r11, GPR11(r1) /* Temporary stash */
+
+ /*
+ * Move the saved user r1 to the kernel stack in case PACATMSCRATCH is
+ * clobbered by an exception once we turn on MSR_RI below.
+ */
+ ld r11, PACATMSCRATCH(r13)
+ std r11, GPR1(r1)
+
+ /*
+ * Store r13 away so we can free up the scratch SPR for the SLB fault
+ * handler (needed once we start accessing the thread_struct).
+ */
+ GET_SCRATCH0(r11)
+ std r11, GPR13(r1)
+
+ /* Reset MSR RI so we can take SLB faults again */
+ li r11, MSR_RI
+ mtmsrd r11, 1
+
+ /* Store the PPR in r11 and reset to decent value */
+ 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_INT_FRAME_REGS
+
+ /* Sync the userland GPRs 2-12, 14-31 to thread->regs: */
+ SAVE_GPR(0, r7) /* user r0 */
+ SAVE_GPRS(2, 6, r7) /* user r2-r6 */
+ SAVE_GPRS(8, 10, r7) /* user r8-r10 */
+ ld r3, GPR1(r1) /* user r1 */
+ ld r4, GPR7(r1) /* user r7 */
+ ld r5, GPR11(r1) /* user r11 */
+ ld r6, GPR12(r1) /* user r12 */
+ ld r8, GPR13(r1) /* 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 signal return to 'wind back' to the abort handler.
+ */
+
+ /* ***************** CTR, LR, CR, XER ********** */
+ mfctr r3
+ mflr r4
+ mfcr r5
+ mfxer r6
+
+ std r3, _CTR(r7)
+ std r4, _LINK(r7)
+ std r5, _CCR(r7)
+ std r6, _XER(r7)
+
+ /* ******************** TAR, DSCR ********** */
+ mfspr r3, SPRN_TAR
+ mfspr r4, SPRN_DSCR
+
+ std r3, THREAD_TM_TAR(r12)
+ std r4, THREAD_TM_DSCR(r12)
+
+ /* ******************** AMR **************** */
+ mfspr r3, SPRN_AMR
+ std r3, THREAD_TM_AMR(r12)
+
+ /*
+ * MSR and flags: We don't change CRs, and we don't need to alter MSR.
+ */
+
+
+ /*
+ * ******************** FPR/VR/VSRs ************
+ * After reclaiming, capture the checkpointed FPRs/VRs.
+ *
+ * We enabled VEC/FP/VSX in the msr above, so we can execute these
+ * instructions!
+ */
+ mr r3, r12
+
+ /* Altivec (VEC/VMX/VR)*/
+ addi r7, r3, THREAD_CKVRSTATE
+ SAVE_32VRS(0, r6, r7) /* r6 scratch, r7 ckvr_state */
+ mfvscr v0
+ li r6, VRSTATE_VSCR
+ stvx v0, r7, r6
+
+ /* VRSAVE */
+ mfspr r0, SPRN_VRSAVE
+ std r0, THREAD_CKVRSAVE(r3)
+
+ /* Floating Point (FP) */
+ addi r7, r3, THREAD_CKFPSTATE
+ SAVE_32FPRS_VSRS(0, R6, R7) /* r6 scratch, r7 ckfp_state */
+ mffs fr0
+ stfd fr0,FPSTATE_FPSCR(r7)
+
+
+ /*
+ * TM regs, incl TEXASR -- these live in thread_struct. Note they've
+ * been updated by the treclaim, to explain to userland the failure
+ * cause (aborted).
+ */
+ mfspr r0, SPRN_TEXASR
+ mfspr r3, SPRN_TFHAR
+ mfspr r4, SPRN_TFIAR
+ std r0, THREAD_TM_TEXASR(r12)
+ std r3, THREAD_TM_TFHAR(r12)
+ std r4, THREAD_TM_TFIAR(r12)
+
+ /* Restore kernel live AMR */
+ ld r8, TM_FRAME_L1(r1)
+ mtspr SPRN_AMR, r8
+
+ /* Restore original MSR/IRQ state & clear TM mode */
+ ld r14, TM_FRAME_L0(r1) /* Orig MSR */
+
+ li r15, 0
+ rldimi r14, r15, MSR_TS_LG, (63-MSR_TS_LG)-1
+ mtmsrd r14
+
+ 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
+
+
+ /*
+ * void __tm_recheckpoint(struct thread_struct *thread)
+ * - Restore the checkpointed register state saved by tm_reclaim
+ * when we switch_to a process.
+ *
+ * Call with IRQs off, stacks get all out of sync for
+ * some periods in here!
+ */
+_GLOBAL(__tm_recheckpoint)
+ mfcr r5
+ mflr r0
+ stw r5, 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_INT_FRAME_REGS].
+ * This is used for backing up the NVGPRs:
+ */
+ SAVE_NVGPRS(r1)
+
+ /*
+ * Save kernel live AMR since it will be clobbered for trechkpt
+ * but can be used elsewhere later in kernel space.
+ */
+ mfspr r8, SPRN_AMR
+ std r8, TM_FRAME_L0(r1)
+
+ /* Load complete register state from ts_ckpt* registers */
+
+ addi r7, r3, 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 now NOT a pt_regs ptr!
+ */
+ subi r7, r7, STACK_INT_FRAME_REGS
+
+ /* We need to setup MSR for FP/VMX/VSX register save instructions. */
+ mfmsr r6
+ mr r5, r6
+ ori r5, r5, MSR_FP
+#ifdef CONFIG_ALTIVEC
+ oris r5, r5, MSR_VEC@h
+#endif
+#ifdef CONFIG_VSX
+ BEGIN_FTR_SECTION
+ oris r5,r5, MSR_VSX@h
+ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
+#endif
+ mtmsrd r5
+
+#ifdef CONFIG_ALTIVEC
+ /*
+ * FP and VEC registers: These are recheckpointed from
+ * thread.ckfp_state and thread.ckvr_state respectively. The
+ * thread.fp_state[] version holds the 'live' (transactional)
+ * and will be loaded subsequently by any FPUnavailable trap.
+ */
+ addi r8, r3, THREAD_CKVRSTATE
+ li r5, VRSTATE_VSCR
+ lvx v0, r8, r5
+ mtvscr v0
+ REST_32VRS(0, r5, r8) /* r5 scratch, r8 ptr */
+ ld r5, THREAD_CKVRSAVE(r3)
+ mtspr SPRN_VRSAVE, r5
+#endif
+
+ addi r8, r3, THREAD_CKFPSTATE
+ lfd fr0, FPSTATE_FPSCR(r8)
+ MTFSF_L(fr0)
+ REST_32FPRS_VSRS(0, R4, R8)
+
+ mtmsr r6 /* FP/Vec off again! */
+
+restore_gprs:
+
+ /* ****************** CTR, LR, XER ************* */
+ ld r4, _CTR(r7)
+ ld r5, _LINK(r7)
+ ld r8, _XER(r7)
+
+ mtctr r4
+ mtlr r5
+ mtxer r8
+
+ /* ******************** TAR ******************** */
+ ld r4, THREAD_TM_TAR(r3)
+ mtspr SPRN_TAR, r4
+
+ /* ******************** AMR ******************** */
+ ld r4, THREAD_TM_AMR(r3)
+ mtspr SPRN_AMR, r4
+
+ /* Load up the PPR and DSCR in GPRs only at this stage */
+ ld r5, THREAD_TM_DSCR(r3)
+ ld r6, THREAD_TM_PPR(r3)
+
+ REST_GPR(0, r7) /* GPR0 */
+ REST_GPRS(2, 4, r7) /* GPR2-4 */
+ REST_GPRS(8, 12, r7) /* GPR8-12 */
+ REST_GPRS(14, 31, r7) /* GPR14-31 */
+
+ /* 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 user r1 and r5 and r13 on the stack (in the unused save
+ * areas / compiler reserved areas), so that we can access them after
+ * we clear MSR RI.
+ */
+
+ REST_GPR(5, r7)
+ std r5, -8(r1)
+ ld r5, GPR13(r7)
+ std r5, -16(r1)
+ ld r5, GPR1(r7)
+ std r5, -24(r1)
+
+ REST_GPR(7, r7)
+
+ /* Stash the stack pointer away for use after recheckpoint */
+ std r1, PACAR1(r13)
+
+ /* Clear MSR RI since we are about to clobber r13. 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.
+ */
+
+ ld r5, -8(r1)
+ ld r13, -16(r1)
+ ld r1, -24(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)
+ ld r1, PACAR1(r13)
+
+ /* R13, R1 is restored, so we are recoverable again. EE is still off */
+ li r4, MSR_RI
+ mtmsrd r4, 1
+
+ /* Restore kernel live AMR */
+ ld r8, TM_FRAME_L0(r1)
+ mtspr SPRN_AMR, r8
+
+ 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
+
+ /* ****************************************************************** */