1/* 2 * Transactional memory support routines to reclaim and recheckpoint 3 * transactional process state. 4 * 5 * Copyright 2012 Matt Evans & Michael Neuling, IBM Corporation. 6 */ 7 8#include <asm/asm-offsets.h> 9#include <asm/ppc_asm.h> 10#include <asm/ppc-opcode.h> 11#include <asm/ptrace.h> 12#include <asm/reg.h> 13#include <asm/bug.h> 14 15#ifdef CONFIG_VSX 16/* See fpu.S, this is borrowed from there */ 17#define __SAVE_32FPRS_VSRS(n,c,base) \ 18BEGIN_FTR_SECTION \ 19 b 2f; \ 20END_FTR_SECTION_IFSET(CPU_FTR_VSX); \ 21 SAVE_32FPRS(n,base); \ 22 b 3f; \ 232: SAVE_32VSRS(n,c,base); \ 243: 25#define __REST_32FPRS_VSRS(n,c,base) \ 26BEGIN_FTR_SECTION \ 27 b 2f; \ 28END_FTR_SECTION_IFSET(CPU_FTR_VSX); \ 29 REST_32FPRS(n,base); \ 30 b 3f; \ 312: REST_32VSRS(n,c,base); \ 323: 33#else 34#define __SAVE_32FPRS_VSRS(n,c,base) SAVE_32FPRS(n, base) 35#define __REST_32FPRS_VSRS(n,c,base) REST_32FPRS(n, base) 36#endif 37#define SAVE_32FPRS_VSRS(n,c,base) \ 38 __SAVE_32FPRS_VSRS(n,__REG_##c,__REG_##base) 39#define REST_32FPRS_VSRS(n,c,base) \ 40 __REST_32FPRS_VSRS(n,__REG_##c,__REG_##base) 41 42/* Stack frame offsets for local variables. */ 43#define TM_FRAME_L0 TM_FRAME_SIZE-16 44#define TM_FRAME_L1 TM_FRAME_SIZE-8 45 46 47/* In order to access the TM SPRs, TM must be enabled. So, do so: */ 48_GLOBAL(tm_enable) 49 mfmsr r4 50 li r3, MSR_TM >> 32 51 sldi r3, r3, 32 52 and. r0, r4, r3 53 bne 1f 54 or r4, r4, r3 55 mtmsrd r4 561: blr 57 58_GLOBAL(tm_save_sprs) 59 mfspr r0, SPRN_TFHAR 60 std r0, THREAD_TM_TFHAR(r3) 61 mfspr r0, SPRN_TEXASR 62 std r0, THREAD_TM_TEXASR(r3) 63 mfspr r0, SPRN_TFIAR 64 std r0, THREAD_TM_TFIAR(r3) 65 blr 66 67_GLOBAL(tm_restore_sprs) 68 ld r0, THREAD_TM_TFHAR(r3) 69 mtspr SPRN_TFHAR, r0 70 ld r0, THREAD_TM_TEXASR(r3) 71 mtspr SPRN_TEXASR, r0 72 ld r0, THREAD_TM_TFIAR(r3) 73 mtspr SPRN_TFIAR, r0 74 blr 75 76 /* Passed an 8-bit failure cause as first argument. */ 77_GLOBAL(tm_abort) 78 TABORT(R3) 79 blr 80 81/* void tm_reclaim(struct thread_struct *thread, 82 * unsigned long orig_msr, 83 * uint8_t cause) 84 * 85 * - Performs a full reclaim. This destroys outstanding 86 * transactions and updates thread->regs.tm_ckpt_* with the 87 * original checkpointed state. Note that thread->regs is 88 * unchanged. 89 * - FP regs are written back to thread->transact_fpr before 90 * reclaiming. These are the transactional (current) versions. 91 * 92 * Purpose is to both abort transactions of, and preserve the state of, 93 * a transactions at a context switch. We preserve/restore both sets of process 94 * state to restore them when the thread's scheduled again. We continue in 95 * userland as though nothing happened, but when the transaction is resumed 96 * they will abort back to the checkpointed state we save out here. 97 * 98 * Call with IRQs off, stacks get all out of sync for some periods in here! 99 */ 100_GLOBAL(tm_reclaim) 101 mfcr r6 102 mflr r0 103 stw r6, 8(r1) 104 std r0, 16(r1) 105 std r2, STK_GOT(r1) 106 stdu r1, -TM_FRAME_SIZE(r1) 107 108 /* We've a struct pt_regs at [r1+STACK_FRAME_OVERHEAD]. */ 109 110 std r3, STK_PARAM(R3)(r1) 111 SAVE_NVGPRS(r1) 112 113 /* We need to setup MSR for VSX register save instructions. Here we 114 * also clear the MSR RI since when we do the treclaim, we won't have a 115 * valid kernel pointer for a while. We clear RI here as it avoids 116 * adding another mtmsr closer to the treclaim. This makes the region 117 * maked as non-recoverable wider than it needs to be but it saves on 118 * inserting another mtmsrd later. 119 */ 120 mfmsr r14 121 mr r15, r14 122 ori r15, r15, MSR_FP 123 li r16, MSR_RI 124 ori r16, r16, MSR_EE /* IRQs hard off */ 125 andc r15, r15, r16 126 oris r15, r15, MSR_VEC@h 127#ifdef CONFIG_VSX 128 BEGIN_FTR_SECTION 129 oris r15,r15, MSR_VSX@h 130 END_FTR_SECTION_IFSET(CPU_FTR_VSX) 131#endif 132 mtmsrd r15 133 std r14, TM_FRAME_L0(r1) 134 135 /* Stash the stack pointer away for use after reclaim */ 136 std r1, PACAR1(r13) 137 138 /* ******************** FPR/VR/VSRs ************ 139 * Before reclaiming, capture the current/transactional FPR/VR 140 * versions /if used/. 141 * 142 * (If VSX used, FP and VMX are implied. Or, we don't need to look 143 * at MSR.VSX as copying FP regs if .FP, vector regs if .VMX covers it.) 144 * 145 * We're passed the thread's MSR as parameter 2. 146 * 147 * We enabled VEC/FP/VSX in the msr above, so we can execute these 148 * instructions! 149 */ 150 andis. r0, r4, MSR_VEC@h 151 beq dont_backup_vec 152 153 addi r7, r3, THREAD_TRANSACT_VRSTATE 154 SAVE_32VRS(0, r6, r7) /* r6 scratch, r7 transact vr state */ 155 mfvscr vr0 156 li r6, VRSTATE_VSCR 157 stvx vr0, r7, r6 158dont_backup_vec: 159 mfspr r0, SPRN_VRSAVE 160 std r0, THREAD_TRANSACT_VRSAVE(r3) 161 162 andi. r0, r4, MSR_FP 163 beq dont_backup_fp 164 165 addi r7, r3, THREAD_TRANSACT_FPSTATE 166 SAVE_32FPRS_VSRS(0, R6, R7) /* r6 scratch, r7 transact fp state */ 167 168 mffs fr0 169 stfd fr0,FPSTATE_FPSCR(r7) 170 171dont_backup_fp: 172 /* Do sanity check on MSR to make sure we are suspended */ 173 li r7, (MSR_TS_S)@higher 174 srdi r6, r14, 32 175 and r6, r6, r7 1761: tdeqi r6, 0 177 EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0 178 179 /* The moment we treclaim, ALL of our GPRs will switch 180 * to user register state. (FPRs, CCR etc. also!) 181 * Use an sprg and a tm_scratch in the PACA to shuffle. 182 */ 183 TRECLAIM(R5) /* Cause in r5 */ 184 185 /* ******************** GPRs ******************** */ 186 /* Stash the checkpointed r13 away in the scratch SPR and get the real 187 * paca 188 */ 189 SET_SCRATCH0(r13) 190 GET_PACA(r13) 191 192 /* Stash the checkpointed r1 away in paca tm_scratch and get the real 193 * stack pointer back 194 */ 195 std r1, PACATMSCRATCH(r13) 196 ld r1, PACAR1(r13) 197 198 /* Store the PPR in r11 and reset to decent value */ 199 std r11, GPR11(r1) /* Temporary stash */ 200 mfspr r11, SPRN_PPR 201 HMT_MEDIUM 202 203 /* Now get some more GPRS free */ 204 std r7, GPR7(r1) /* Temporary stash */ 205 std r12, GPR12(r1) /* '' '' '' */ 206 ld r12, STK_PARAM(R3)(r1) /* Param 0, thread_struct * */ 207 208 std r11, THREAD_TM_PPR(r12) /* Store PPR and free r11 */ 209 210 addi r7, r12, PT_CKPT_REGS /* Thread's ckpt_regs */ 211 212 /* Make r7 look like an exception frame so that we 213 * can use the neat GPRx(n) macros. r7 is NOT a pt_regs ptr! 214 */ 215 subi r7, r7, STACK_FRAME_OVERHEAD 216 217 /* Sync the userland GPRs 2-12, 14-31 to thread->regs: */ 218 SAVE_GPR(0, r7) /* user r0 */ 219 SAVE_GPR(2, r7) /* user r2 */ 220 SAVE_4GPRS(3, r7) /* user r3-r6 */ 221 SAVE_GPR(8, r7) /* user r8 */ 222 SAVE_GPR(9, r7) /* user r9 */ 223 SAVE_GPR(10, r7) /* user r10 */ 224 ld r3, PACATMSCRATCH(r13) /* user r1 */ 225 ld r4, GPR7(r1) /* user r7 */ 226 ld r5, GPR11(r1) /* user r11 */ 227 ld r6, GPR12(r1) /* user r12 */ 228 GET_SCRATCH0(8) /* user r13 */ 229 std r3, GPR1(r7) 230 std r4, GPR7(r7) 231 std r5, GPR11(r7) 232 std r6, GPR12(r7) 233 std r8, GPR13(r7) 234 235 SAVE_NVGPRS(r7) /* user r14-r31 */ 236 237 /* ******************** NIP ******************** */ 238 mfspr r3, SPRN_TFHAR 239 std r3, _NIP(r7) /* Returns to failhandler */ 240 /* The checkpointed NIP is ignored when rescheduling/rechkpting, 241 * but is used in signal return to 'wind back' to the abort handler. 242 */ 243 244 /* ******************** CR,LR,CCR,MSR ********** */ 245 mfctr r3 246 mflr r4 247 mfcr r5 248 mfxer r6 249 250 std r3, _CTR(r7) 251 std r4, _LINK(r7) 252 std r5, _CCR(r7) 253 std r6, _XER(r7) 254 255 256 /* ******************** TAR, DSCR ********** */ 257 mfspr r3, SPRN_TAR 258 mfspr r4, SPRN_DSCR 259 260 std r3, THREAD_TM_TAR(r12) 261 std r4, THREAD_TM_DSCR(r12) 262 263 /* MSR and flags: We don't change CRs, and we don't need to alter 264 * MSR. 265 */ 266 267 /* TM regs, incl TEXASR -- these live in thread_struct. Note they've 268 * been updated by the treclaim, to explain to userland the failure 269 * cause (aborted). 270 */ 271 mfspr r0, SPRN_TEXASR 272 mfspr r3, SPRN_TFHAR 273 mfspr r4, SPRN_TFIAR 274 std r0, THREAD_TM_TEXASR(r12) 275 std r3, THREAD_TM_TFHAR(r12) 276 std r4, THREAD_TM_TFIAR(r12) 277 278 /* AMR is checkpointed too, but is unsupported by Linux. */ 279 280 /* Restore original MSR/IRQ state & clear TM mode */ 281 ld r14, TM_FRAME_L0(r1) /* Orig MSR */ 282 li r15, 0 283 rldimi r14, r15, MSR_TS_LG, (63-MSR_TS_LG)-1 284 mtmsrd r14 285 286 REST_NVGPRS(r1) 287 288 addi r1, r1, TM_FRAME_SIZE 289 lwz r4, 8(r1) 290 ld r0, 16(r1) 291 mtcr r4 292 mtlr r0 293 ld r2, STK_GOT(r1) 294 295 /* Load CPU's default DSCR */ 296 ld r0, PACA_DSCR(r13) 297 mtspr SPRN_DSCR, r0 298 299 blr 300 301 302 /* void tm_recheckpoint(struct thread_struct *thread, 303 * unsigned long orig_msr) 304 * - Restore the checkpointed register state saved by tm_reclaim 305 * when we switch_to a process. 306 * 307 * Call with IRQs off, stacks get all out of sync for 308 * some periods in here! 309 */ 310_GLOBAL(__tm_recheckpoint) 311 mfcr r5 312 mflr r0 313 stw r5, 8(r1) 314 std r0, 16(r1) 315 std r2, STK_GOT(r1) 316 stdu r1, -TM_FRAME_SIZE(r1) 317 318 /* We've a struct pt_regs at [r1+STACK_FRAME_OVERHEAD]. 319 * This is used for backing up the NVGPRs: 320 */ 321 SAVE_NVGPRS(r1) 322 323 /* Load complete register state from ts_ckpt* registers */ 324 325 addi r7, r3, PT_CKPT_REGS /* Thread's ckpt_regs */ 326 327 /* Make r7 look like an exception frame so that we 328 * can use the neat GPRx(n) macros. r7 is now NOT a pt_regs ptr! 329 */ 330 subi r7, r7, STACK_FRAME_OVERHEAD 331 332 SET_SCRATCH0(r1) 333 334 mfmsr r6 335 /* R4 = original MSR to indicate whether thread used FP/Vector etc. */ 336 337 /* Enable FP/vec in MSR if necessary! */ 338 lis r5, MSR_VEC@h 339 ori r5, r5, MSR_FP 340 and. r5, r4, r5 341 beq restore_gprs /* if neither, skip both */ 342 343#ifdef CONFIG_VSX 344 BEGIN_FTR_SECTION 345 oris r5, r5, MSR_VSX@h 346 END_FTR_SECTION_IFSET(CPU_FTR_VSX) 347#endif 348 or r5, r6, r5 /* Set MSR.FP+.VSX/.VEC */ 349 mtmsr r5 350 351#ifdef CONFIG_ALTIVEC 352 /* FP and VEC registers: These are recheckpointed from thread.fpr[] 353 * and thread.vr[] respectively. The thread.transact_fpr[] version 354 * is more modern, and will be loaded subsequently by any FPUnavailable 355 * trap. 356 */ 357 andis. r0, r4, MSR_VEC@h 358 beq dont_restore_vec 359 360 addi r8, r3, THREAD_VRSTATE 361 li r5, VRSTATE_VSCR 362 lvx vr0, r8, r5 363 mtvscr vr0 364 REST_32VRS(0, r5, r8) /* r5 scratch, r8 ptr */ 365dont_restore_vec: 366 ld r5, THREAD_VRSAVE(r3) 367 mtspr SPRN_VRSAVE, r5 368#endif 369 370 andi. r0, r4, MSR_FP 371 beq dont_restore_fp 372 373 addi r8, r3, THREAD_FPSTATE 374 lfd fr0, FPSTATE_FPSCR(r8) 375 MTFSF_L(fr0) 376 REST_32FPRS_VSRS(0, R4, R8) 377 378dont_restore_fp: 379 mtmsr r6 /* FP/Vec off again! */ 380 381restore_gprs: 382 383 /* ******************** CR,LR,CCR,MSR ********** */ 384 ld r4, _CTR(r7) 385 ld r5, _LINK(r7) 386 ld r8, _XER(r7) 387 388 mtctr r4 389 mtlr r5 390 mtxer r8 391 392 /* ******************** TAR ******************** */ 393 ld r4, THREAD_TM_TAR(r3) 394 mtspr SPRN_TAR, r4 395 396 /* Load up the PPR and DSCR in GPRs only at this stage */ 397 ld r5, THREAD_TM_DSCR(r3) 398 ld r6, THREAD_TM_PPR(r3) 399 400 /* Clear the MSR RI since we are about to change R1. EE is already off 401 */ 402 li r4, 0 403 mtmsrd r4, 1 404 405 REST_GPR(0, r7) /* GPR0 */ 406 REST_2GPRS(2, r7) /* GPR2-3 */ 407 REST_GPR(4, r7) /* GPR4 */ 408 REST_4GPRS(8, r7) /* GPR8-11 */ 409 REST_2GPRS(12, r7) /* GPR12-13 */ 410 411 REST_NVGPRS(r7) /* GPR14-31 */ 412 413 /* Load up PPR and DSCR here so we don't run with user values for long 414 */ 415 mtspr SPRN_DSCR, r5 416 mtspr SPRN_PPR, r6 417 418 /* Do final sanity check on TEXASR to make sure FS is set. Do this 419 * here before we load up the userspace r1 so any bugs we hit will get 420 * a call chain */ 421 mfspr r5, SPRN_TEXASR 422 srdi r5, r5, 16 423 li r6, (TEXASR_FS)@h 424 and r6, r6, r5 4251: tdeqi r6, 0 426 EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0 427 428 /* Do final sanity check on MSR to make sure we are not transactional 429 * or suspended 430 */ 431 mfmsr r6 432 li r5, (MSR_TS_MASK)@higher 433 srdi r6, r6, 32 434 and r6, r6, r5 4351: tdnei r6, 0 436 EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0 437 438 /* Restore CR */ 439 ld r6, _CCR(r7) 440 mtcr r6 441 442 REST_GPR(1, r7) /* GPR1 */ 443 REST_GPR(5, r7) /* GPR5-7 */ 444 REST_GPR(6, r7) 445 ld r7, GPR7(r7) 446 447 /* Commit register state as checkpointed state: */ 448 TRECHKPT 449 450 HMT_MEDIUM 451 452 /* Our transactional state has now changed. 453 * 454 * Now just get out of here. Transactional (current) state will be 455 * updated once restore is called on the return path in the _switch-ed 456 * -to process. 457 */ 458 459 GET_PACA(r13) 460 GET_SCRATCH0(r1) 461 462 /* R1 is restored, so we are recoverable again. EE is still off */ 463 li r4, MSR_RI 464 mtmsrd r4, 1 465 466 REST_NVGPRS(r1) 467 468 addi r1, r1, TM_FRAME_SIZE 469 lwz r4, 8(r1) 470 ld r0, 16(r1) 471 mtcr r4 472 mtlr r0 473 ld r2, STK_GOT(r1) 474 475 /* Load CPU's default DSCR */ 476 ld r0, PACA_DSCR(r13) 477 mtspr SPRN_DSCR, r0 478 479 blr 480 481 /* ****************************************************************** */ 482