target/arm/tcg/translate-m-nocp.c

   1 /*
   2  *  ARM translation: M-profile NOCP special-case instructions
   3  *
   4  *  Copyright (c) 2020 Linaro, Ltd.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "translate.h"
  22 #include "translate-a32.h"
  23
  24 #include "decode-m-nocp.c.inc"
  25
  26 /*
  27  * Decode VLLDM and VLSTM are nonstandard because:
  28  *  * if there is no FPU then these insns must NOP in
  29  *    Secure state and UNDEF in Nonsecure state
  30  *  * if there is an FPU then these insns do not have
  31  *    the usual behaviour that vfp_access_check() provides of
  32  *    being controlled by CPACR/NSACR enable bits or the
  33  *    lazy-stacking logic.
  34  */
  35 static bool trans_VLLDM_VLSTM(DisasContext *s, arg_VLLDM_VLSTM *a)
  36 {
  37     TCGv_i32 fptr;
  38
  39     if (!arm_dc_feature(s, ARM_FEATURE_M) ||
  40         !arm_dc_feature(s, ARM_FEATURE_V8)) {
  41         return false;
  42     }
  43
  44     if (a->op) {
  45         /*
  46          * T2 encoding ({D0-D31} reglist): v8.1M and up. We choose not
  47          * to take the IMPDEF option to make memory accesses to the stack
  48          * slots that correspond to the D16-D31 registers (discarding
  49          * read data and writing UNKNOWN values), so for us the T2
  50          * encoding behaves identically to the T1 encoding.
  51          */
  52         if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
  53             return false;
  54         }
  55     } else {
  56         /*
  57          * T1 encoding ({D0-D15} reglist); undef if we have 32 Dregs.
  58          * This is currently architecturally impossible, but we add the
  59          * check to stay in line with the pseudocode. Note that we must
  60          * emit code for the UNDEF so it takes precedence over the NOCP.
  61          */
  62         if (dc_isar_feature(aa32_simd_r32, s)) {
  63             unallocated_encoding(s);
  64             return true;
  65         }
  66     }
  67
  68     /*
  69      * If not secure, UNDEF. We must emit code for this
  70      * rather than returning false so that this takes
  71      * precedence over the m-nocp.decode NOCP fallback.
  72      */
  73     if (!s->v8m_secure) {
  74         unallocated_encoding(s);
  75         return true;
  76     }
  77
  78     s->eci_handled = true;
  79
  80     /* If no fpu, NOP. */
  81     if (!dc_isar_feature(aa32_vfp, s)) {
  82         clear_eci_state(s);
  83         return true;
  84     }
  85
  86     fptr = load_reg(s, a->rn);
  87     if (a->l) {
  88         gen_helper_v7m_vlldm(tcg_env, fptr);
  89     } else {
  90         gen_helper_v7m_vlstm(tcg_env, fptr);
  91     }
  92
  93     clear_eci_state(s);
  94
  95     /*
  96      * End the TB, because we have updated FP control bits,
  97      * and possibly VPR or LTPSIZE.
  98      */
  99     s->base.is_jmp = DISAS_UPDATE_EXIT;
 100     return true;
 101 }
 102
 103 static bool trans_VSCCLRM(DisasContext *s, arg_VSCCLRM *a)
 104 {
 105     int btmreg, topreg;
 106     TCGv_i64 zero;
 107     TCGv_i32 aspen, sfpa;
 108
 109     if (!dc_isar_feature(aa32_m_sec_state, s)) {
 110         /* Before v8.1M, fall through in decode to NOCP check */
 111         return false;
 112     }
 113
 114     /* Explicitly UNDEF because this takes precedence over NOCP */
 115     if (!arm_dc_feature(s, ARM_FEATURE_M_MAIN) || !s->v8m_secure) {
 116         unallocated_encoding(s);
 117         return true;
 118     }
 119
 120     s->eci_handled = true;
 121
 122     if (!dc_isar_feature(aa32_vfp_simd, s)) {
 123         /* NOP if we have neither FP nor MVE */
 124         clear_eci_state(s);
 125         return true;
 126     }
 127
 128     /*
 129      * If FPCCR.ASPEN != 0 && CONTROL_S.SFPA == 0 then there is no
 130      * active floating point context so we must NOP (without doing
 131      * any lazy state preservation or the NOCP check).
 132      */
 133     aspen = load_cpu_field(v7m.fpccr[M_REG_S]);
 134     sfpa = load_cpu_field(v7m.control[M_REG_S]);
 135     tcg_gen_andi_i32(aspen, aspen, R_V7M_FPCCR_ASPEN_MASK);
 136     tcg_gen_xori_i32(aspen, aspen, R_V7M_FPCCR_ASPEN_MASK);
 137     tcg_gen_andi_i32(sfpa, sfpa, R_V7M_CONTROL_SFPA_MASK);
 138     tcg_gen_or_i32(sfpa, sfpa, aspen);
 139     arm_gen_condlabel(s);
 140     tcg_gen_brcondi_i32(TCG_COND_EQ, sfpa, 0, s->condlabel.label);
 141
 142     if (s->fp_excp_el != 0) {
 143         gen_exception_insn_el(s, 0, EXCP_NOCP,
 144                               syn_uncategorized(), s->fp_excp_el);
 145         return true;
 146     }
 147
 148     topreg = a->vd + a->imm - 1;
 149     btmreg = a->vd;
 150
 151     /* Convert to Sreg numbers if the insn specified in Dregs */
 152     if (a->size == 3) {
 153         topreg = topreg * 2 + 1;
 154         btmreg *= 2;
 155     }
 156
 157     if (topreg > 63 || (topreg > 31 && !(topreg & 1))) {
 158         /* UNPREDICTABLE: we choose to undef */
 159         unallocated_encoding(s);
 160         return true;
 161     }
 162
 163     /* Silently ignore requests to clear D16-D31 if they don't exist */
 164     if (topreg > 31 && !dc_isar_feature(aa32_simd_r32, s)) {
 165         topreg = 31;
 166     }
 167
 168     if (!vfp_access_check(s)) {
 169         return true;
 170     }
 171
 172     /* Zero the Sregs from btmreg to topreg inclusive. */
 173     zero = tcg_constant_i64(0);
 174     if (btmreg & 1) {
 175         write_neon_element64(zero, btmreg >> 1, 1, MO_32);
 176         btmreg++;
 177     }
 178     for (; btmreg + 1 <= topreg; btmreg += 2) {
 179         write_neon_element64(zero, btmreg >> 1, 0, MO_64);
 180     }
 181     if (btmreg == topreg) {
 182         write_neon_element64(zero, btmreg >> 1, 0, MO_32);
 183         btmreg++;
 184     }
 185     assert(btmreg == topreg + 1);
 186     if (dc_isar_feature(aa32_mve, s)) {
 187         store_cpu_field(tcg_constant_i32(0), v7m.vpr);
 188     }
 189
 190     clear_eci_state(s);
 191     return true;
 192 }
 193
 194 /*
 195  * M-profile provides two different sets of instructions that can
 196  * access floating point system registers: VMSR/VMRS (which move
 197  * to/from a general purpose register) and VLDR/VSTR sysreg (which
 198  * move directly to/from memory). In some cases there are also side
 199  * effects which must happen after any write to memory (which could
 200  * cause an exception). So we implement the common logic for the
 201  * sysreg access in gen_M_fp_sysreg_write() and gen_M_fp_sysreg_read(),
 202  * which take pointers to callback functions which will perform the
 203  * actual "read/write general purpose register" and "read/write
 204  * memory" operations.
 205  */
 206
 207 /*
 208  * Emit code to store the sysreg to its final destination; frees the
 209  * TCG temp 'value' it is passed. do_access is true to do the store,
 210  * and false to skip it and only perform side-effects like base
 211  * register writeback.
 212  */
 213 typedef void fp_sysreg_storefn(DisasContext *s, void *opaque, TCGv_i32 value,
 214                                bool do_access);
 215 /*
 216  * Emit code to load the value to be copied to the sysreg; returns
 217  * a new TCG temporary. do_access is true to do the store,
 218  * and false to skip it and only perform side-effects like base
 219  * register writeback.
 220  */
 221 typedef TCGv_i32 fp_sysreg_loadfn(DisasContext *s, void *opaque,
 222                                   bool do_access);
 223
 224 /* Common decode/access checks for fp sysreg read/write */
 225 typedef enum FPSysRegCheckResult {
 226     FPSysRegCheckFailed, /* caller should return false */
 227     FPSysRegCheckDone, /* caller should return true */
 228     FPSysRegCheckContinue, /* caller should continue generating code */
 229 } FPSysRegCheckResult;
 230
 231 static FPSysRegCheckResult fp_sysreg_checks(DisasContext *s, int regno)
 232 {
 233     if (!dc_isar_feature(aa32_fpsp_v2, s) && !dc_isar_feature(aa32_mve, s)) {
 234         return FPSysRegCheckFailed;
 235     }
 236
 237     switch (regno) {
 238     case ARM_VFP_FPSCR:
 239     case QEMU_VFP_FPSCR_NZCV:
 240         break;
 241     case ARM_VFP_FPSCR_NZCVQC:
 242         if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
 243             return FPSysRegCheckFailed;
 244         }
 245         break;
 246     case ARM_VFP_FPCXT_S:
 247     case ARM_VFP_FPCXT_NS:
 248         if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
 249             return FPSysRegCheckFailed;
 250         }
 251         if (!s->v8m_secure) {
 252             return FPSysRegCheckFailed;
 253         }
 254         break;
 255     case ARM_VFP_VPR:
 256     case ARM_VFP_P0:
 257         if (!dc_isar_feature(aa32_mve, s)) {
 258             return FPSysRegCheckFailed;
 259         }
 260         break;
 261     default:
 262         return FPSysRegCheckFailed;
 263     }
 264
 265     /*
 266      * FPCXT_NS is a special case: it has specific handling for
 267      * "current FP state is inactive", and must do the PreserveFPState()
 268      * but not the usual full set of actions done by ExecuteFPCheck().
 269      * So we don't call vfp_access_check() and the callers must handle this.
 270      */
 271     if (regno != ARM_VFP_FPCXT_NS && !vfp_access_check(s)) {
 272         return FPSysRegCheckDone;
 273     }
 274     return FPSysRegCheckContinue;
 275 }
 276
 277 static void gen_branch_fpInactive(DisasContext *s, TCGCond cond,
 278                                   TCGLabel *label)
 279 {
 280     /*
 281      * FPCXT_NS is a special case: it has specific handling for
 282      * "current FP state is inactive", and must do the PreserveFPState()
 283      * but not the usual full set of actions done by ExecuteFPCheck().
 284      * We don't have a TB flag that matches the fpInactive check, so we
 285      * do it at runtime as we don't expect FPCXT_NS accesses to be frequent.
 286      *
 287      * Emit code that checks fpInactive and does a conditional
 288      * branch to label based on it:
 289      *  if cond is TCG_COND_NE then branch if fpInactive != 0 (ie if inactive)
 290      *  if cond is TCG_COND_EQ then branch if fpInactive == 0 (ie if active)
 291      */
 292     assert(cond == TCG_COND_EQ || cond == TCG_COND_NE);
 293
 294     /* fpInactive = FPCCR_NS.ASPEN == 1 && CONTROL.FPCA == 0 */
 295     TCGv_i32 aspen, fpca;
 296     aspen = load_cpu_field(v7m.fpccr[M_REG_NS]);
 297     fpca = load_cpu_field(v7m.control[M_REG_S]);
 298     tcg_gen_andi_i32(aspen, aspen, R_V7M_FPCCR_ASPEN_MASK);
 299     tcg_gen_xori_i32(aspen, aspen, R_V7M_FPCCR_ASPEN_MASK);
 300     tcg_gen_andi_i32(fpca, fpca, R_V7M_CONTROL_FPCA_MASK);
 301     tcg_gen_or_i32(fpca, fpca, aspen);
 302     tcg_gen_brcondi_i32(tcg_invert_cond(cond), fpca, 0, label);
 303 }
 304
 305 static bool gen_M_fp_sysreg_write(DisasContext *s, int regno,
 306                                   fp_sysreg_loadfn *loadfn,
 307                                   void *opaque)
 308 {
 309     /* Do a write to an M-profile floating point system register */
 310     TCGv_i32 tmp;
 311     TCGLabel *lab_end = NULL;
 312
 313     switch (fp_sysreg_checks(s, regno)) {
 314     case FPSysRegCheckFailed:
 315         return false;
 316     case FPSysRegCheckDone:
 317         return true;
 318     case FPSysRegCheckContinue:
 319         break;
 320     }
 321
 322     switch (regno) {
 323     case ARM_VFP_FPSCR:
 324         tmp = loadfn(s, opaque, true);
 325         gen_helper_vfp_set_fpscr(tcg_env, tmp);
 326         gen_lookup_tb(s);
 327         break;
 328     case ARM_VFP_FPSCR_NZCVQC:
 329     {
 330         TCGv_i32 fpscr;
 331         tmp = loadfn(s, opaque, true);
 332         if (dc_isar_feature(aa32_mve, s)) {
 333             /* QC is only present for MVE; otherwise RES0 */
 334             TCGv_i32 qc = tcg_temp_new_i32();
 335             tcg_gen_andi_i32(qc, tmp, FPSR_QC);
 336             /*
 337              * The 4 vfp.qc[] fields need only be "zero" vs "non-zero";
 338              * here writing the same value into all elements is simplest.
 339              */
 340             tcg_gen_gvec_dup_i32(MO_32, offsetof(CPUARMState, vfp.qc),
 341                                  16, 16, qc);
 342         }
 343         tcg_gen_andi_i32(tmp, tmp, FPSR_NZCV_MASK);
 344         fpscr = load_cpu_field_low32(vfp.fpsr);
 345         tcg_gen_andi_i32(fpscr, fpscr, ~FPSR_NZCV_MASK);
 346         tcg_gen_or_i32(fpscr, fpscr, tmp);
 347         store_cpu_field_low32(fpscr, vfp.fpsr);
 348         break;
 349     }
 350     case ARM_VFP_FPCXT_NS:
 351     {
 352         TCGLabel *lab_active = gen_new_label();
 353
 354         lab_end = gen_new_label();
 355         gen_branch_fpInactive(s, TCG_COND_EQ, lab_active);
 356         /*
 357          * fpInactive case: write is a NOP, so only do side effects
 358          * like register writeback before we branch to end
 359          */
 360         loadfn(s, opaque, false);
 361         tcg_gen_br(lab_end);
 362
 363         gen_set_label(lab_active);
 364         /*
 365          * !fpInactive: if FPU disabled, take NOCP exception;
 366          * otherwise PreserveFPState(), and then FPCXT_NS writes
 367          * behave the same as FPCXT_S writes.
 368          */
 369         if (!vfp_access_check_m(s, true)) {
 370             /*
 371              * This was only a conditional exception, so override
 372              * gen_exception_insn_el()'s default to DISAS_NORETURN
 373              */
 374             s->base.is_jmp = DISAS_NEXT;
 375             break;
 376         }
 377     }
 378     /* fall through */
 379     case ARM_VFP_FPCXT_S:
 380     {
 381         TCGv_i32 sfpa, control;
 382         /*
 383          * Set FPSCR and CONTROL.SFPA from value; the new FPSCR takes
 384          * bits [27:0] from value and zeroes bits [31:28].
 385          */
 386         tmp = loadfn(s, opaque, true);
 387         sfpa = tcg_temp_new_i32();
 388         tcg_gen_shri_i32(sfpa, tmp, 31);
 389         control = load_cpu_field(v7m.control[M_REG_S]);
 390         tcg_gen_deposit_i32(control, control, sfpa,
 391                             R_V7M_CONTROL_SFPA_SHIFT, 1);
 392         store_cpu_field(control, v7m.control[M_REG_S]);
 393         tcg_gen_andi_i32(tmp, tmp, ~FPSR_NZCV_MASK);
 394         gen_helper_vfp_set_fpscr(tcg_env, tmp);
 395         s->base.is_jmp = DISAS_UPDATE_NOCHAIN;
 396         break;
 397     }
 398     case ARM_VFP_VPR:
 399         /* Behaves as NOP if not privileged */
 400         if (IS_USER(s)) {
 401             loadfn(s, opaque, false);
 402             break;
 403         }
 404         tmp = loadfn(s, opaque, true);
 405         store_cpu_field(tmp, v7m.vpr);
 406         s->base.is_jmp = DISAS_UPDATE_NOCHAIN;
 407         break;
 408     case ARM_VFP_P0:
 409     {
 410         TCGv_i32 vpr;
 411         tmp = loadfn(s, opaque, true);
 412         vpr = load_cpu_field(v7m.vpr);
 413         tcg_gen_deposit_i32(vpr, vpr, tmp,
 414                             R_V7M_VPR_P0_SHIFT, R_V7M_VPR_P0_LENGTH);
 415         store_cpu_field(vpr, v7m.vpr);
 416         s->base.is_jmp = DISAS_UPDATE_NOCHAIN;
 417         break;
 418     }
 419     default:
 420         g_assert_not_reached();
 421     }
 422     if (lab_end) {
 423         gen_set_label(lab_end);
 424     }
 425     return true;
 426 }
 427
 428 static bool gen_M_fp_sysreg_read(DisasContext *s, int regno,
 429                                  fp_sysreg_storefn *storefn,
 430                                  void *opaque)
 431 {
 432     /* Do a read from an M-profile floating point system register */
 433     TCGv_i32 tmp;
 434     TCGLabel *lab_end = NULL;
 435     bool lookup_tb = false;
 436
 437     switch (fp_sysreg_checks(s, regno)) {
 438     case FPSysRegCheckFailed:
 439         return false;
 440     case FPSysRegCheckDone:
 441         return true;
 442     case FPSysRegCheckContinue:
 443         break;
 444     }
 445
 446     if (regno == ARM_VFP_FPSCR_NZCVQC && !dc_isar_feature(aa32_mve, s)) {
 447         /* QC is RES0 without MVE, so NZCVQC simplifies to NZCV */
 448         regno = QEMU_VFP_FPSCR_NZCV;
 449     }
 450
 451     switch (regno) {
 452     case ARM_VFP_FPSCR:
 453         tmp = tcg_temp_new_i32();
 454         gen_helper_vfp_get_fpscr(tmp, tcg_env);
 455         storefn(s, opaque, tmp, true);
 456         break;
 457     case ARM_VFP_FPSCR_NZCVQC:
 458         tmp = tcg_temp_new_i32();
 459         gen_helper_vfp_get_fpscr(tmp, tcg_env);
 460         tcg_gen_andi_i32(tmp, tmp, FPSR_NZCVQC_MASK);
 461         storefn(s, opaque, tmp, true);
 462         break;
 463     case QEMU_VFP_FPSCR_NZCV:
 464         /*
 465          * Read just NZCV; this is a special case to avoid the
 466          * helper call for the "VMRS to CPSR.NZCV" insn.
 467          */
 468         tmp = load_cpu_field_low32(vfp.fpsr);
 469         tcg_gen_andi_i32(tmp, tmp, FPSR_NZCV_MASK);
 470         storefn(s, opaque, tmp, true);
 471         break;
 472     case ARM_VFP_FPCXT_S:
 473     {
 474         TCGv_i32 control, sfpa, fpscr;
 475         /* Bits [27:0] from FPSCR, bit [31] from CONTROL.SFPA */
 476         tmp = tcg_temp_new_i32();
 477         sfpa = tcg_temp_new_i32();
 478         gen_helper_vfp_get_fpscr(tmp, tcg_env);
 479         tcg_gen_andi_i32(tmp, tmp, ~FPSR_NZCV_MASK);
 480         control = load_cpu_field(v7m.control[M_REG_S]);
 481         tcg_gen_andi_i32(sfpa, control, R_V7M_CONTROL_SFPA_MASK);
 482         tcg_gen_shli_i32(sfpa, sfpa, 31 - R_V7M_CONTROL_SFPA_SHIFT);
 483         tcg_gen_or_i32(tmp, tmp, sfpa);
 484         /*
 485          * Store result before updating FPSCR etc, in case
 486          * it is a memory write which causes an exception.
 487          */
 488         storefn(s, opaque, tmp, true);
 489         /*
 490          * Now we must reset FPSCR from FPDSCR_NS, and clear
 491          * CONTROL.SFPA; so we'll end the TB here.
 492          */
 493         tcg_gen_andi_i32(control, control, ~R_V7M_CONTROL_SFPA_MASK);
 494         store_cpu_field(control, v7m.control[M_REG_S]);
 495         fpscr = load_cpu_field(v7m.fpdscr[M_REG_NS]);
 496         gen_helper_vfp_set_fpscr(tcg_env, fpscr);
 497         lookup_tb = true;
 498         break;
 499     }
 500     case ARM_VFP_FPCXT_NS:
 501     {
 502         TCGv_i32 control, sfpa, fpscr, fpdscr;
 503         TCGLabel *lab_active = gen_new_label();
 504
 505         lookup_tb = true;
 506
 507         gen_branch_fpInactive(s, TCG_COND_EQ, lab_active);
 508         /* fpInactive case: reads as FPDSCR_NS */
 509         tmp = load_cpu_field(v7m.fpdscr[M_REG_NS]);
 510         storefn(s, opaque, tmp, true);
 511         lab_end = gen_new_label();
 512         tcg_gen_br(lab_end);
 513
 514         gen_set_label(lab_active);
 515         /*
 516          * !fpInactive: if FPU disabled, take NOCP exception;
 517          * otherwise PreserveFPState(), and then FPCXT_NS
 518          * reads the same as FPCXT_S.
 519          */
 520         if (!vfp_access_check_m(s, true)) {
 521             /*
 522              * This was only a conditional exception, so override
 523              * gen_exception_insn_el()'s default to DISAS_NORETURN
 524              */
 525             s->base.is_jmp = DISAS_NEXT;
 526             break;
 527         }
 528         tmp = tcg_temp_new_i32();
 529         sfpa = tcg_temp_new_i32();
 530         fpscr = tcg_temp_new_i32();
 531         gen_helper_vfp_get_fpscr(fpscr, tcg_env);
 532         tcg_gen_andi_i32(tmp, fpscr, ~FPSR_NZCV_MASK);
 533         control = load_cpu_field(v7m.control[M_REG_S]);
 534         tcg_gen_andi_i32(sfpa, control, R_V7M_CONTROL_SFPA_MASK);
 535         tcg_gen_shli_i32(sfpa, sfpa, 31 - R_V7M_CONTROL_SFPA_SHIFT);
 536         tcg_gen_or_i32(tmp, tmp, sfpa);
 537         /* Store result before updating FPSCR, in case it faults */
 538         storefn(s, opaque, tmp, true);
 539         /* If SFPA is zero then set FPSCR from FPDSCR_NS */
 540         fpdscr = load_cpu_field(v7m.fpdscr[M_REG_NS]);
 541         tcg_gen_movcond_i32(TCG_COND_EQ, fpscr, sfpa, tcg_constant_i32(0),
 542                             fpdscr, fpscr);
 543         gen_helper_vfp_set_fpscr(tcg_env, fpscr);
 544         break;
 545     }
 546     case ARM_VFP_VPR:
 547         /* Behaves as NOP if not privileged */
 548         if (IS_USER(s)) {
 549             storefn(s, opaque, NULL, false);
 550             break;
 551         }
 552         tmp = load_cpu_field(v7m.vpr);
 553         storefn(s, opaque, tmp, true);
 554         break;
 555     case ARM_VFP_P0:
 556         tmp = load_cpu_field(v7m.vpr);
 557         tcg_gen_extract_i32(tmp, tmp, R_V7M_VPR_P0_SHIFT, R_V7M_VPR_P0_LENGTH);
 558         storefn(s, opaque, tmp, true);
 559         break;
 560     default:
 561         g_assert_not_reached();
 562     }
 563
 564     if (lab_end) {
 565         gen_set_label(lab_end);
 566     }
 567     if (lookup_tb) {
 568         gen_lookup_tb(s);
 569     }
 570     return true;
 571 }
 572
 573 static void fp_sysreg_to_gpr(DisasContext *s, void *opaque, TCGv_i32 value,
 574                              bool do_access)
 575 {
 576     arg_VMSR_VMRS *a = opaque;
 577
 578     if (!do_access) {
 579         return;
 580     }
 581
 582     if (a->rt == 15) {
 583         /* Set the 4 flag bits in the CPSR */
 584         gen_set_nzcv(value);
 585     } else {
 586         store_reg(s, a->rt, value);
 587     }
 588 }
 589
 590 static TCGv_i32 gpr_to_fp_sysreg(DisasContext *s, void *opaque, bool do_access)
 591 {
 592     arg_VMSR_VMRS *a = opaque;
 593
 594     if (!do_access) {
 595         return NULL;
 596     }
 597     return load_reg(s, a->rt);
 598 }
 599
 600 static bool trans_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a)
 601 {
 602     /*
 603      * Accesses to R15 are UNPREDICTABLE; we choose to undef.
 604      * FPSCR -> r15 is a special case which writes to the PSR flags;
 605      * set a->reg to a special value to tell gen_M_fp_sysreg_read()
 606      * we only care about the top 4 bits of FPSCR there.
 607      */
 608     if (a->rt == 15) {
 609         if (a->l && a->reg == ARM_VFP_FPSCR) {
 610             a->reg = QEMU_VFP_FPSCR_NZCV;
 611         } else {
 612             return false;
 613         }
 614     }
 615
 616     if (a->l) {
 617         /* VMRS, move FP system register to gp register */
 618         return gen_M_fp_sysreg_read(s, a->reg, fp_sysreg_to_gpr, a);
 619     } else {
 620         /* VMSR, move gp register to FP system register */
 621         return gen_M_fp_sysreg_write(s, a->reg, gpr_to_fp_sysreg, a);
 622     }
 623 }
 624
 625 static void fp_sysreg_to_memory(DisasContext *s, void *opaque, TCGv_i32 value,
 626                                 bool do_access)
 627 {
 628     arg_vldr_sysreg *a = opaque;
 629     uint32_t offset = a->imm;
 630     TCGv_i32 addr;
 631
 632     if (!a->a) {
 633         offset = -offset;
 634     }
 635
 636     if (!do_access && !a->w) {
 637         return;
 638     }
 639
 640     addr = load_reg(s, a->rn);
 641     if (a->p) {
 642         tcg_gen_addi_i32(addr, addr, offset);
 643     }
 644
 645     if (s->v8m_stackcheck && a->rn == 13 && a->w) {
 646         gen_helper_v8m_stackcheck(tcg_env, addr);
 647     }
 648
 649     if (do_access) {
 650         gen_aa32_st_i32(s, value, addr, get_mem_index(s),
 651                         MO_UL | MO_ALIGN | s->be_data);
 652     }
 653
 654     if (a->w) {
 655         /* writeback */
 656         if (!a->p) {
 657             tcg_gen_addi_i32(addr, addr, offset);
 658         }
 659         store_reg(s, a->rn, addr);
 660     }
 661 }
 662
 663 static TCGv_i32 memory_to_fp_sysreg(DisasContext *s, void *opaque,
 664                                     bool do_access)
 665 {
 666     arg_vldr_sysreg *a = opaque;
 667     uint32_t offset = a->imm;
 668     TCGv_i32 addr;
 669     TCGv_i32 value = NULL;
 670
 671     if (!a->a) {
 672         offset = -offset;
 673     }
 674
 675     if (!do_access && !a->w) {
 676         return NULL;
 677     }
 678
 679     addr = load_reg(s, a->rn);
 680     if (a->p) {
 681         tcg_gen_addi_i32(addr, addr, offset);
 682     }
 683
 684     if (s->v8m_stackcheck && a->rn == 13 && a->w) {
 685         gen_helper_v8m_stackcheck(tcg_env, addr);
 686     }
 687
 688     if (do_access) {
 689         value = tcg_temp_new_i32();
 690         gen_aa32_ld_i32(s, value, addr, get_mem_index(s),
 691                         MO_UL | MO_ALIGN | s->be_data);
 692     }
 693
 694     if (a->w) {
 695         /* writeback */
 696         if (!a->p) {
 697             tcg_gen_addi_i32(addr, addr, offset);
 698         }
 699         store_reg(s, a->rn, addr);
 700     }
 701     return value;
 702 }
 703
 704 static bool trans_VLDR_sysreg(DisasContext *s, arg_vldr_sysreg *a)
 705 {
 706     if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
 707         return false;
 708     }
 709     if (a->rn == 15) {
 710         return false;
 711     }
 712     return gen_M_fp_sysreg_write(s, a->reg, memory_to_fp_sysreg, a);
 713 }
 714
 715 static bool trans_VSTR_sysreg(DisasContext *s, arg_vldr_sysreg *a)
 716 {
 717     if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
 718         return false;
 719     }
 720     if (a->rn == 15) {
 721         return false;
 722     }
 723     return gen_M_fp_sysreg_read(s, a->reg, fp_sysreg_to_memory, a);
 724 }
 725
 726 static bool trans_NOCP(DisasContext *s, arg_nocp *a)
 727 {
 728     /*
 729      * Handle M-profile early check for disabled coprocessor:
 730      * all we need to do here is emit the NOCP exception if
 731      * the coprocessor is disabled. Otherwise we return false
 732      * and the real VFP/etc decode will handle the insn.
 733      */
 734     assert(arm_dc_feature(s, ARM_FEATURE_M));
 735
 736     if (a->cp == 11) {
 737         a->cp = 10;
 738     }
 739     if (arm_dc_feature(s, ARM_FEATURE_V8_1M) &&
 740         (a->cp == 8 || a->cp == 9 || a->cp == 14 || a->cp == 15)) {
 741         /* in v8.1M cp 8, 9, 14, 15 also are governed by the cp10 enable */
 742         a->cp = 10;
 743     }
 744
 745     if (a->cp != 10) {
 746         gen_exception_insn(s, 0, EXCP_NOCP, syn_uncategorized());
 747         return true;
 748     }
 749
 750     if (s->fp_excp_el != 0) {
 751         gen_exception_insn_el(s, 0, EXCP_NOCP,
 752                               syn_uncategorized(), s->fp_excp_el);
 753         return true;
 754     }
 755
 756     return false;
 757 }
 758
 759 static bool trans_NOCP_8_1(DisasContext *s, arg_nocp *a)
 760 {
 761     /* This range needs a coprocessor check for v8.1M and later only */
 762     if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
 763         return false;
 764     }
 765     return trans_NOCP(s, a);
 766 }