diff options
Diffstat (limited to 'target/arm/translate.c')
| -rw-r--r-- | target/arm/translate.c | 181 |
1 files changed, 122 insertions, 59 deletions
diff --git a/target/arm/translate.c b/target/arm/translate.c index e32e38cadd..0b5a0bca06 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -296,6 +296,30 @@ static void gen_step_complete_exception(DisasContext *s) s->is_jmp = DISAS_EXC; } +static void gen_singlestep_exception(DisasContext *s) +{ + /* Generate the right kind of exception for singlestep, which is + * either the architectural singlestep or EXCP_DEBUG for QEMU's + * gdb singlestepping. + */ + if (s->ss_active) { + gen_step_complete_exception(s); + } else { + gen_exception_internal(EXCP_DEBUG); + } +} + +static inline bool is_singlestepping(DisasContext *s) +{ + /* Return true if we are singlestepping either because of + * architectural singlestep or QEMU gdbstub singlestep. This does + * not include the command line '-singlestep' mode which is rather + * misnamed as it only means "one instruction per TB" and doesn't + * affect the code we generate. + */ + return s->singlestep_enabled || s->ss_active; +} + static void gen_smul_dual(TCGv_i32 a, TCGv_i32 b) { TCGv_i32 tmp1 = tcg_temp_new_i32(); @@ -880,6 +904,21 @@ static const uint8_t table_logic_cc[16] = { 1, /* mvn */ }; +static inline void gen_set_condexec(DisasContext *s) +{ + if (s->condexec_mask) { + uint32_t val = (s->condexec_cond << 4) | (s->condexec_mask >> 1); + TCGv_i32 tmp = tcg_temp_new_i32(); + tcg_gen_movi_i32(tmp, val); + store_cpu_field(tmp, condexec_bits); + } +} + +static inline void gen_set_pc_im(DisasContext *s, target_ulong val) +{ + tcg_gen_movi_i32(cpu_R[15], val); +} + /* Set PC and Thumb state from an immediate address. */ static inline void gen_bx_im(DisasContext *s, uint32_t addr) { @@ -904,6 +943,51 @@ static inline void gen_bx(DisasContext *s, TCGv_i32 var) store_cpu_field(var, thumb); } +/* Set PC and Thumb state from var. var is marked as dead. + * For M-profile CPUs, include logic to detect exception-return + * branches and handle them. This is needed for Thumb POP/LDM to PC, LDR to PC, + * and BX reg, and no others, and happens only for code in Handler mode. + */ +static inline void gen_bx_excret(DisasContext *s, TCGv_i32 var) +{ + /* Generate the same code here as for a simple bx, but flag via + * s->is_jmp that we need to do the rest of the work later. + */ + gen_bx(s, var); + if (s->v7m_handler_mode && arm_dc_feature(s, ARM_FEATURE_M)) { + s->is_jmp = DISAS_BX_EXCRET; + } +} + +static inline void gen_bx_excret_final_code(DisasContext *s) +{ + /* Generate the code to finish possible exception return and end the TB */ + TCGLabel *excret_label = gen_new_label(); + + /* Is the new PC value in the magic range indicating exception return? */ + tcg_gen_brcondi_i32(TCG_COND_GEU, cpu_R[15], 0xff000000, excret_label); + /* No: end the TB as we would for a DISAS_JMP */ + if (is_singlestepping(s)) { + gen_singlestep_exception(s); + } else { + tcg_gen_exit_tb(0); + } + gen_set_label(excret_label); + /* Yes: this is an exception return. + * At this point in runtime env->regs[15] and env->thumb will hold + * the exception-return magic number, which do_v7m_exception_exit() + * will read. Nothing else will be able to see those values because + * the cpu-exec main loop guarantees that we will always go straight + * from raising the exception to the exception-handling code. + * + * gen_ss_advance(s) does nothing on M profile currently but + * calling it is conceptually the right thing as we have executed + * this instruction (compare SWI, HVC, SMC handling). + */ + gen_ss_advance(s); + gen_exception_internal(EXCP_EXCEPTION_EXIT); +} + /* Variant of store_reg which uses branch&exchange logic when storing to r15 in ARM architecture v7 and above. The source must be a temporary and will be marked as dead. */ @@ -923,7 +1007,7 @@ static inline void store_reg_bx(DisasContext *s, int reg, TCGv_i32 var) static inline void store_reg_from_load(DisasContext *s, int reg, TCGv_i32 var) { if (reg == 15 && ENABLE_ARCH_5) { - gen_bx(s, var); + gen_bx_excret(s, var); } else { store_reg(s, reg, var); } @@ -1056,11 +1140,6 @@ DO_GEN_ST(8, MO_UB) DO_GEN_ST(16, MO_UW) DO_GEN_ST(32, MO_UL) -static inline void gen_set_pc_im(DisasContext *s, target_ulong val) -{ - tcg_gen_movi_i32(cpu_R[15], val); -} - static inline void gen_hvc(DisasContext *s, int imm16) { /* The pre HVC helper handles cases when HVC gets trapped @@ -1094,17 +1173,6 @@ static inline void gen_smc(DisasContext *s) s->is_jmp = DISAS_SMC; } -static inline void -gen_set_condexec (DisasContext *s) -{ - if (s->condexec_mask) { - uint32_t val = (s->condexec_cond << 4) | (s->condexec_mask >> 1); - TCGv_i32 tmp = tcg_temp_new_i32(); - tcg_gen_movi_i32(tmp, val); - store_cpu_field(tmp, condexec_bits); - } -} - static void gen_exception_internal_insn(DisasContext *s, int offset, int excp) { gen_set_condexec(s); @@ -4092,7 +4160,7 @@ static inline void gen_goto_tb(DisasContext *s, int n, target_ulong dest) static inline void gen_jmp (DisasContext *s, uint32_t dest) { - if (unlikely(s->singlestep_enabled || s->ss_active)) { + if (unlikely(is_singlestepping(s))) { /* An indirect jump so that we still trigger the debug exception. */ if (s->thumb) dest |= 1; @@ -9858,7 +9926,7 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw tmp = tcg_temp_new_i32(); gen_aa32_ld32u(s, tmp, addr, get_mem_index(s)); if (i == 15) { - gen_bx(s, tmp); + gen_bx_excret(s, tmp); } else if (i == rn) { loaded_var = tmp; loaded_base = 1; @@ -9959,7 +10027,7 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw gen_arm_shift_reg(tmp, op, tmp2, logic_cc); if (logic_cc) gen_logic_CC(tmp); - store_reg_bx(s, rd, tmp); + store_reg(s, rd, tmp); break; case 1: /* Sign/zero extend. */ op = (insn >> 20) & 7; @@ -10485,7 +10553,12 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw } break; case 4: /* bxj */ - /* Trivial implementation equivalent to bx. */ + /* Trivial implementation equivalent to bx. + * This instruction doesn't exist at all for M-profile. + */ + if (arm_dc_feature(s, ARM_FEATURE_M)) { + goto illegal_op; + } tmp = load_reg(s, rn); gen_bx(s, tmp); break; @@ -10885,7 +10958,7 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw goto illegal_op; } if (rs == 15) { - gen_bx(s, tmp); + gen_bx_excret(s, tmp); } else { store_reg(s, rs, tmp); } @@ -11075,9 +11148,11 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s) tmp2 = tcg_temp_new_i32(); tcg_gen_movi_i32(tmp2, val); store_reg(s, 14, tmp2); + gen_bx(s, tmp); + } else { + /* Only BX works as exception-return, not BLX */ + gen_bx_excret(s, tmp); } - /* already thumb, no need to check */ - gen_bx(s, tmp); break; } break; @@ -11752,6 +11827,7 @@ void gen_intermediate_code(CPUARMState *env, TranslationBlock *tb) dc->vec_len = ARM_TBFLAG_VECLEN(tb->flags); dc->vec_stride = ARM_TBFLAG_VECSTRIDE(tb->flags); dc->c15_cpar = ARM_TBFLAG_XSCALE_CPAR(tb->flags); + dc->v7m_handler_mode = ARM_TBFLAG_HANDLER(tb->flags); dc->cp_regs = cpu->cp_regs; dc->features = env->features; @@ -11851,14 +11927,6 @@ void gen_intermediate_code(CPUARMState *env, TranslationBlock *tb) dc->is_jmp = DISAS_EXC; break; } -#else - if (arm_dc_feature(dc, ARM_FEATURE_M)) { - /* Branches to the magic exception-return addresses should - * already have been caught via the arm_v7m_unassigned_access hook, - * and never get here. - */ - assert(dc->pc < 0xfffffff0); - } #endif if (unlikely(!QTAILQ_EMPTY(&cs->breakpoints))) { @@ -11953,9 +12021,8 @@ void gen_intermediate_code(CPUARMState *env, TranslationBlock *tb) ((dc->pc >= next_page_start - 3) && insn_crosses_page(env, dc)); } while (!dc->is_jmp && !tcg_op_buf_full() && - !cs->singlestep_enabled && + !is_singlestepping(dc) && !singlestep && - !dc->ss_active && !end_of_page && num_insns < max_insns); @@ -11971,9 +12038,16 @@ void gen_intermediate_code(CPUARMState *env, TranslationBlock *tb) /* At this stage dc->condjmp will only be set when the skipped instruction was a conditional branch or trap, and the PC has already been written. */ - if (unlikely(cs->singlestep_enabled || dc->ss_active)) { + gen_set_condexec(dc); + if (dc->is_jmp == DISAS_BX_EXCRET) { + /* Exception return branches need some special case code at the + * end of the TB, which is complex enough that it has to + * handle the single-step vs not and the condition-failed + * insn codepath itself. + */ + gen_bx_excret_final_code(dc); + } else if (unlikely(is_singlestepping(dc))) { /* Unconditional and "condition passed" instruction codepath. */ - gen_set_condexec(dc); switch (dc->is_jmp) { case DISAS_SWI: gen_ss_advance(dc); @@ -11993,24 +12067,8 @@ void gen_intermediate_code(CPUARMState *env, TranslationBlock *tb) gen_set_pc_im(dc, dc->pc); /* fall through */ default: - if (dc->ss_active) { - gen_step_complete_exception(dc); - } else { - /* FIXME: Single stepping a WFI insn will not halt - the CPU. */ - gen_exception_internal(EXCP_DEBUG); - } - } - if (dc->condjmp) { - /* "Condition failed" instruction codepath. */ - gen_set_label(dc->condlabel); - gen_set_condexec(dc); - gen_set_pc_im(dc, dc->pc); - if (dc->ss_active) { - gen_step_complete_exception(dc); - } else { - gen_exception_internal(EXCP_DEBUG); - } + /* FIXME: Single stepping a WFI insn will not halt the CPU. */ + gen_singlestep_exception(dc); } } else { /* While branches must always occur at the end of an IT block, @@ -12021,7 +12079,6 @@ void gen_intermediate_code(CPUARMState *env, TranslationBlock *tb) - Hardware watchpoints. Hardware breakpoints have already been handled and skip this code. */ - gen_set_condexec(dc); switch(dc->is_jmp) { case DISAS_NEXT: gen_goto_tb(dc, 1, dc->pc); @@ -12061,11 +12118,17 @@ void gen_intermediate_code(CPUARMState *env, TranslationBlock *tb) gen_exception(EXCP_SMC, syn_aa32_smc(), 3); break; } - if (dc->condjmp) { - gen_set_label(dc->condlabel); - gen_set_condexec(dc); + } + + if (dc->condjmp) { + /* "Condition failed" instruction codepath for the branch/trap insn */ + gen_set_label(dc->condlabel); + gen_set_condexec(dc); + if (unlikely(is_singlestepping(dc))) { + gen_set_pc_im(dc, dc->pc); + gen_singlestep_exception(dc); + } else { gen_goto_tb(dc, 1, dc->pc); - dc->condjmp = 0; } } |