1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* 3 * Copyright 2018, IBM Corporation. 4 * 5 * This file contains general idle entry/exit functions to save 6 * and restore stack and NVGPRs which allows C code to call idle 7 * states that lose GPRs, and it will return transparently with 8 * SRR1 wakeup reason return value. 9 * 10 * The platform / CPU caller must ensure SPRs and any other non-GPR 11 * state is saved and restored correctly, handle KVM, interrupts, etc. 12 */ 13 14#include <asm/ppc_asm.h> 15#include <asm/asm-offsets.h> 16#include <asm/ppc-opcode.h> 17#include <asm/cpuidle.h> 18#include <asm/thread_info.h> /* TLF_NAPPING */ 19 20#ifdef CONFIG_PPC_P7_NAP 21/* 22 * Desired PSSCR in r3 23 * 24 * No state will be lost regardless of wakeup mechanism (interrupt or NIA). 25 * 26 * An EC=0 type wakeup will return with a value of 0. SRESET wakeup (which can 27 * happen with xscom SRESET and possibly MCE) may clobber volatiles except LR, 28 * and must blr, to return to caller with r3 set according to caller's expected 29 * return code (for Book3S/64 that is SRR1). 30 */ 31_GLOBAL(isa300_idle_stop_noloss) 32 mtspr SPRN_PSSCR,r3 33 PPC_STOP 34 li r3,0 35 blr 36 37/* 38 * Desired PSSCR in r3 39 * 40 * GPRs may be lost, so they are saved here. Wakeup is by interrupt only. 41 * The SRESET wakeup returns to this function's caller by calling 42 * idle_return_gpr_loss with r3 set to desired return value. 43 * 44 * A wakeup without GPR loss may alteratively be handled as in 45 * isa300_idle_stop_noloss and blr directly, as an optimisation. 46 * 47 * The caller is responsible for saving/restoring SPRs, MSR, timebase, 48 * etc. 49 */ 50_GLOBAL(isa300_idle_stop_mayloss) 51 mtspr SPRN_PSSCR,r3 52 std r1,PACAR1(r13) 53 mflr r4 54 mfcr r5 55 /* use stack red zone rather than a new frame for saving regs */ 56 std r2,-8*0(r1) 57 std r14,-8*1(r1) 58 std r15,-8*2(r1) 59 std r16,-8*3(r1) 60 std r17,-8*4(r1) 61 std r18,-8*5(r1) 62 std r19,-8*6(r1) 63 std r20,-8*7(r1) 64 std r21,-8*8(r1) 65 std r22,-8*9(r1) 66 std r23,-8*10(r1) 67 std r24,-8*11(r1) 68 std r25,-8*12(r1) 69 std r26,-8*13(r1) 70 std r27,-8*14(r1) 71 std r28,-8*15(r1) 72 std r29,-8*16(r1) 73 std r30,-8*17(r1) 74 std r31,-8*18(r1) 75 std r4,-8*19(r1) 76 std r5,-8*20(r1) 77 /* 168 bytes */ 78 PPC_STOP 79 b . /* catch bugs */ 80 81/* 82 * Desired return value in r3 83 * 84 * The idle wakeup SRESET interrupt can call this after calling 85 * to return to the idle sleep function caller with r3 as the return code. 86 * 87 * This must not be used if idle was entered via a _noloss function (use 88 * a simple blr instead). 89 */ 90_GLOBAL(idle_return_gpr_loss) 91 ld r1,PACAR1(r13) 92 ld r4,-8*19(r1) 93 ld r5,-8*20(r1) 94 mtlr r4 95 mtcr r5 96 /* 97 * KVM nap requires r2 to be saved, rather than just restoring it 98 * from PACATOC. This could be avoided for that less common case 99 * if KVM saved its r2. 100 */ 101 ld r2,-8*0(r1) 102 ld r14,-8*1(r1) 103 ld r15,-8*2(r1) 104 ld r16,-8*3(r1) 105 ld r17,-8*4(r1) 106 ld r18,-8*5(r1) 107 ld r19,-8*6(r1) 108 ld r20,-8*7(r1) 109 ld r21,-8*8(r1) 110 ld r22,-8*9(r1) 111 ld r23,-8*10(r1) 112 ld r24,-8*11(r1) 113 ld r25,-8*12(r1) 114 ld r26,-8*13(r1) 115 ld r27,-8*14(r1) 116 ld r28,-8*15(r1) 117 ld r29,-8*16(r1) 118 ld r30,-8*17(r1) 119 ld r31,-8*18(r1) 120 blr 121 122/* 123 * This is the sequence required to execute idle instructions, as 124 * specified in ISA v2.07 (and earlier). MSR[IR] and MSR[DR] must be 0. 125 * 126 * The 0(r1) slot is used to save r2 in isa206, so use that here. 127 */ 128#define IDLE_STATE_ENTER_SEQ_NORET(IDLE_INST) \ 129 /* Magic NAP/SLEEP/WINKLE mode enter sequence */ \ 130 std r2,0(r1); \ 131 ptesync; \ 132 ld r2,0(r1); \ 133236: cmpd cr0,r2,r2; \ 134 bne 236b; \ 135 IDLE_INST; \ 136 b . /* catch bugs */ 137 138/* 139 * Desired instruction type in r3 140 * 141 * GPRs may be lost, so they are saved here. Wakeup is by interrupt only. 142 * The SRESET wakeup returns to this function's caller by calling 143 * idle_return_gpr_loss with r3 set to desired return value. 144 * 145 * A wakeup without GPR loss may alteratively be handled as in 146 * isa300_idle_stop_noloss and blr directly, as an optimisation. 147 * 148 * The caller is responsible for saving/restoring SPRs, MSR, timebase, 149 * etc. 150 * 151 * This must be called in real-mode (MSR_IDLE). 152 */ 153_GLOBAL(isa206_idle_insn_mayloss) 154 std r1,PACAR1(r13) 155 mflr r4 156 mfcr r5 157 /* use stack red zone rather than a new frame for saving regs */ 158 std r2,-8*0(r1) 159 std r14,-8*1(r1) 160 std r15,-8*2(r1) 161 std r16,-8*3(r1) 162 std r17,-8*4(r1) 163 std r18,-8*5(r1) 164 std r19,-8*6(r1) 165 std r20,-8*7(r1) 166 std r21,-8*8(r1) 167 std r22,-8*9(r1) 168 std r23,-8*10(r1) 169 std r24,-8*11(r1) 170 std r25,-8*12(r1) 171 std r26,-8*13(r1) 172 std r27,-8*14(r1) 173 std r28,-8*15(r1) 174 std r29,-8*16(r1) 175 std r30,-8*17(r1) 176 std r31,-8*18(r1) 177 std r4,-8*19(r1) 178 std r5,-8*20(r1) 179 cmpwi r3,PNV_THREAD_NAP 180 bne 1f 181 IDLE_STATE_ENTER_SEQ_NORET(PPC_NAP) 1821: cmpwi r3,PNV_THREAD_SLEEP 183 bne 2f 184 IDLE_STATE_ENTER_SEQ_NORET(PPC_SLEEP) 1852: IDLE_STATE_ENTER_SEQ_NORET(PPC_WINKLE) 186#endif 187 188#ifdef CONFIG_PPC_970_NAP 189_GLOBAL(power4_idle_nap) 190 LOAD_REG_IMMEDIATE(r7, MSR_KERNEL|MSR_EE|MSR_POW) 191 ld r9,PACA_THREAD_INFO(r13) 192 ld r8,TI_LOCAL_FLAGS(r9) 193 ori r8,r8,_TLF_NAPPING 194 std r8,TI_LOCAL_FLAGS(r9) 195 /* 196 * NAPPING bit is set, from this point onward power4_fixup_nap 197 * will cause exceptions to return to power4_idle_nap_return. 198 */ 1991: sync 200 isync 201 mtmsrd r7 202 isync 203 b 1b 204#endif 205