diff options
Diffstat (limited to 'arch/powerpc/kernel/tm.S')
| -rw-r--r-- | arch/powerpc/kernel/tm.S | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/tm.S b/arch/powerpc/kernel/tm.S new file mode 100644 index 000000000000..84dbace657ce --- /dev/null +++ b/arch/powerpc/kernel/tm.S @@ -0,0 +1,388 @@ +/* + * 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> + +#ifdef CONFIG_VSX +/* See fpu.S, this is very similar but to save/restore checkpointed FPRs/VSRs */ +#define __SAVE_32FPRS_VSRS_TRANSACT(n,c,base) \ +BEGIN_FTR_SECTION \ + b 2f; \ +END_FTR_SECTION_IFSET(CPU_FTR_VSX); \ + SAVE_32FPRS_TRANSACT(n,base); \ + b 3f; \ +2: SAVE_32VSRS_TRANSACT(n,c,base); \ +3: +/* ...and this is just plain borrowed from there. */ +#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_TRANSACT(n,c,base) SAVE_32FPRS_TRANSACT(n, base) +#define __REST_32FPRS_VSRS(n,c,base) REST_32FPRS(n, base) +#endif +#define SAVE_32FPRS_VSRS_TRANSACT(n,c,base) \ + __SAVE_32FPRS_VSRS_TRANSACT(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 +#define STACK_PARAM(x) (48+((x)*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 + std r6, 8(r1) + std r0, 16(r1) + std r2, 40(r1) + stdu r1, -TM_FRAME_SIZE(r1) + + /* We've a struct pt_regs at [r1+STACK_FRAME_OVERHEAD]. */ + + std r3, STACK_PARAM(0)(r1) + SAVE_NVGPRS(r1) + + mfmsr r14 + mr r15, r14 + ori r15, r15, MSR_FP + 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) + + /* Stash the stack pointer away for use after reclaim */ + std r1, PACAR1(r13) + + /* ******************** FPR/VR/VSRs ************ + * Before reclaiming, capture the current/transactional FPR/VR + * versions /if used/. + * + * (If VSX used, FP and VMX are implied. Or, we don't need to look + * at MSR.VSX as copying FP regs if .FP, vector regs if .VMX covers it.) + * + * We're passed the thread's MSR as parameter 2. + * + * We enabled VEC/FP/VSX in the msr above, so we can execute these + * instructions! + */ + andis. r0, r4, MSR_VEC@h + beq dont_backup_vec + + SAVE_32VRS_TRANSACT(0, r6, r3) /* r6 scratch, r3 thread */ + mfvscr vr0 + li r6, THREAD_TRANSACT_VSCR + stvx vr0, r3, r6 + mfspr r0, SPRN_VRSAVE + std r0, THREAD_TRANSACT_VRSAVE(r3) + +dont_backup_vec: + andi. r0, r4, MSR_FP + beq dont_backup_fp + + SAVE_32FPRS_VSRS_TRANSACT(0, R6, R3) /* r6 scratch, r3 thread */ + + mffs fr0 + stfd fr0,THREAD_TRANSACT_FPSCR(r3) + +dont_backup_fp: + /* 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) + + /* Now get some more GPRS free */ + std r7, GPR7(r1) /* Temporary stash */ + std r12, GPR12(r1) /* '' '' '' */ + ld r12, STACK_PARAM(0)(r1) /* Param 0, thread_struct * */ + + 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_4GPRS(8, r7) /* user r8-r11 */ + ld r3, PACATMSCRATCH(r13) /* user r1 */ + ld r4, GPR7(r1) /* user r7 */ + ld r5, GPR12(r1) /* user r12 */ + GET_SCRATCH0(6) /* user r13 */ + std r3, GPR1(r7) + std r4, GPR7(r7) + std r5, GPR12(r7) + std r6, 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. + */ + + /* ******************** CR,LR,CCR,MSR ********** */ + mfctr r3 + mflr r4 + mfcr r5 + mfxer r6 + + std r3, _CTR(r7) + std r4, _LINK(r7) + std r5, _CCR(r7) + std r6, _XER(r7) + + /* MSR and flags: We don't change CRs, and we don't need to alter + * MSR. + */ + + /* 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) + + /* AMR and PPR are checkpointed too, but are unsupported by Linux. */ + + /* 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 + ld r4, 8(r1) + ld r0, 16(r1) + mtcr r4 + mtlr r0 + ld r2, 40(r1) + blr + + + /* void tm_recheckpoint(struct thread_struct *thread, + * unsigned long orig_msr) + * - 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 + std r5, 8(r1) + std r0, 16(r1) + std r2, 40(r1) + stdu r1, -TM_FRAME_SIZE(r1) + + /* We've a struct pt_regs at [r1+STACK_FRAME_OVERHEAD]. + * This is used for backing up the NVGPRs: + */ + SAVE_NVGPRS(r1) + + std r1, PACAR1(r13) + + /* 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_FRAME_OVERHEAD + + SET_SCRATCH0(r1) + + mfmsr r6 + /* R4 = original MSR to indicate whether thread used FP/Vector etc. */ + + /* Enable FP/vec in MSR if necessary! */ + lis r5, MSR_VEC@h + ori r5, r5, MSR_FP + and. r5, r4, r5 + beq restore_gprs /* if neither, skip both */ + +#ifdef CONFIG_VSX + BEGIN_FTR_SECTION + oris r5, r5, MSR_VSX@h + END_FTR_SECTION_IFSET(CPU_FTR_VSX) +#endif + or r5, r6, r5 /* Set MSR.FP+.VSX/.VEC */ + mtmsr r5 + + /* FP and VEC registers: These are recheckpointed from thread.fpr[] + * and thread.vr[] respectively. The thread.transact_fpr[] version + * is more modern, and will be loaded subsequently by any FPUnavailable + * trap. + */ + andis. r0, r4, MSR_VEC@h + beq dont_restore_vec + + li r5, THREAD_VSCR + lvx vr0, r3, r5 + mtvscr vr0 + REST_32VRS(0, r5, r3) /* r5 scratch, r3 THREAD ptr */ + ld r5, THREAD_VRSAVE(r3) + mtspr SPRN_VRSAVE, r5 + +dont_restore_vec: + andi. r0, r4, MSR_FP + beq dont_restore_fp + + lfd fr0, THREAD_FPSCR(r3) + MTFSF_L(fr0) + REST_32FPRS_VSRS(0, R4, R3) + +dont_restore_fp: + mtmsr r6 /* FP/Vec off again! */ + +restore_gprs: + /* ******************** CR,LR,CCR,MSR ********** */ + ld r3, _CTR(r7) + ld r4, _LINK(r7) + ld r5, _CCR(r7) + ld r6, _XER(r7) + + mtctr r3 + mtlr r4 + mtcr r5 + mtxer r6 + + /* MSR and flags: We don't change CRs, and we don't need to alter + * MSR. + */ + + REST_4GPRS(0, r7) /* GPR0-3 */ + REST_GPR(4, r7) /* GPR4-6 */ + REST_GPR(5, r7) + REST_GPR(6, r7) + REST_4GPRS(8, r7) /* GPR8-11 */ + REST_2GPRS(12, r7) /* GPR12-13 */ + + REST_NVGPRS(r7) /* GPR14-31 */ + + ld r7, GPR7(r7) /* GPR7 */ + + /* Commit register state as checkpointed state: */ + TRECHKPT + + /* 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) + + REST_NVGPRS(r1) + + addi r1, r1, TM_FRAME_SIZE + ld r4, 8(r1) + ld r0, 16(r1) + mtcr r4 + mtlr r0 + ld r2, 40(r1) + blr + + /* ****************************************************************** */ |