diff options
Diffstat (limited to 'target-arm/translate-a64.c')
| -rw-r--r-- | target-arm/translate-a64.c | 98 |
1 files changed, 90 insertions, 8 deletions
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c index f04ca49631..8e66b6c972 100644 --- a/target-arm/translate-a64.c +++ b/target-arm/translate-a64.c @@ -205,10 +205,39 @@ static void gen_exception_insn(DisasContext *s, int offset, int excp, s->is_jmp = DISAS_EXC; } +static void gen_ss_advance(DisasContext *s) +{ + /* If the singlestep state is Active-not-pending, advance to + * Active-pending. + */ + if (s->ss_active) { + s->pstate_ss = 0; + gen_helper_clear_pstate_ss(cpu_env); + } +} + +static void gen_step_complete_exception(DisasContext *s) +{ + /* We just completed step of an insn. Move from Active-not-pending + * to Active-pending, and then also take the swstep exception. + * This corresponds to making the (IMPDEF) choice to prioritize + * swstep exceptions over asynchronous exceptions taken to an exception + * level where debug is disabled. This choice has the advantage that + * we do not need to maintain internal state corresponding to the + * ISV/EX syndrome bits between completion of the step and generation + * of the exception, and our syndrome information is always correct. + */ + gen_ss_advance(s); + gen_exception(EXCP_UDEF, syn_swstep(s->ss_same_el, 1, s->is_ldex)); + s->is_jmp = DISAS_EXC; +} + static inline bool use_goto_tb(DisasContext *s, int n, uint64_t dest) { - /* No direct tb linking with singlestep or deterministic io */ - if (s->singlestep_enabled || (s->tb->cflags & CF_LAST_IO)) { + /* No direct tb linking with singlestep (either QEMU's or the ARM + * debug architecture kind) or deterministic io + */ + if (s->singlestep_enabled || s->ss_active || (s->tb->cflags & CF_LAST_IO)) { return false; } @@ -232,11 +261,14 @@ static inline void gen_goto_tb(DisasContext *s, int n, uint64_t dest) s->is_jmp = DISAS_TB_JUMP; } else { gen_a64_set_pc_im(dest); - if (s->singlestep_enabled) { + if (s->ss_active) { + gen_step_complete_exception(s); + } else if (s->singlestep_enabled) { gen_exception_internal(EXCP_DEBUG); + } else { + tcg_gen_exit_tb(0); + s->is_jmp = DISAS_TB_JUMP; } - tcg_gen_exit_tb(0); - s->is_jmp = DISAS_JUMP; } } @@ -1448,6 +1480,12 @@ static void disas_exc(DisasContext *s, uint32_t insn) unallocated_encoding(s); break; } + /* For SVC, HVC and SMC we advance the single-step state + * machine before taking the exception. This is architecturally + * mandated, to ensure that single-stepping a system call + * instruction works properly. + */ + gen_ss_advance(s); gen_exception_insn(s, 0, EXCP_SWI, syn_aa64_svc(imm16)); break; case 1: @@ -1456,7 +1494,7 @@ static void disas_exc(DisasContext *s, uint32_t insn) break; } /* BRK */ - gen_exception_insn(s, 0, EXCP_BKPT, syn_aa64_bkpt(imm16)); + gen_exception_insn(s, 4, EXCP_BKPT, syn_aa64_bkpt(imm16)); break; case 2: if (op2_ll != 0) { @@ -1728,6 +1766,7 @@ static void disas_ldst_excl(DisasContext *s, uint32_t insn) if (is_excl) { if (!is_store) { + s->is_ldex = true; gen_load_exclusive(s, rt, rt2, tcg_addr, size, is_pair); } else { gen_store_exclusive(s, rs, rt, rt2, tcg_addr, size, is_pair); @@ -10868,6 +10907,26 @@ void gen_intermediate_code_internal_a64(ARMCPU *cpu, dc->current_pl = arm_current_pl(env); dc->features = env->features; + /* Single step state. The code-generation logic here is: + * SS_ACTIVE == 0: + * generate code with no special handling for single-stepping (except + * that anything that can make us go to SS_ACTIVE == 1 must end the TB; + * this happens anyway because those changes are all system register or + * PSTATE writes). + * SS_ACTIVE == 1, PSTATE.SS == 1: (active-not-pending) + * emit code for one insn + * emit code to clear PSTATE.SS + * emit code to generate software step exception for completed step + * end TB (as usual for having generated an exception) + * SS_ACTIVE == 1, PSTATE.SS == 0: (active-pending) + * emit code to generate a software step exception + * end the TB + */ + dc->ss_active = ARM_TBFLAG_AA64_SS_ACTIVE(tb->flags); + dc->pstate_ss = ARM_TBFLAG_AA64_PSTATE_SS(tb->flags); + dc->is_ldex = false; + dc->ss_same_el = (arm_debug_target_el(env) == dc->current_pl); + init_tmp_a64_array(dc); next_page_start = (pc_start & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE; @@ -10916,6 +10975,23 @@ void gen_intermediate_code_internal_a64(ARMCPU *cpu, tcg_gen_debug_insn_start(dc->pc); } + if (dc->ss_active && !dc->pstate_ss) { + /* Singlestep state is Active-pending. + * If we're in this state at the start of a TB then either + * a) we just took an exception to an EL which is being debugged + * and this is the first insn in the exception handler + * b) debug exceptions were masked and we just unmasked them + * without changing EL (eg by clearing PSTATE.D) + * In either case we're going to take a swstep exception in the + * "did not step an insn" case, and so the syndrome ISV and EX + * bits should be zero. + */ + assert(num_insns == 0); + gen_exception(EXCP_UDEF, syn_swstep(dc->ss_same_el, 0, 0)); + dc->is_jmp = DISAS_EXC; + break; + } + disas_a64_insn(env, dc); if (tcg_check_temp_count()) { @@ -10932,6 +11008,7 @@ void gen_intermediate_code_internal_a64(ARMCPU *cpu, } while (!dc->is_jmp && tcg_ctx.gen_opc_ptr < gen_opc_end && !cs->singlestep_enabled && !singlestep && + !dc->ss_active && dc->pc < next_page_start && num_insns < max_insns); @@ -10939,7 +11016,8 @@ void gen_intermediate_code_internal_a64(ARMCPU *cpu, gen_io_end(); } - if (unlikely(cs->singlestep_enabled) && dc->is_jmp != DISAS_EXC) { + if (unlikely(cs->singlestep_enabled || dc->ss_active) + && dc->is_jmp != DISAS_EXC) { /* Note that this means single stepping WFI doesn't halt the CPU. * For conditional branch insns this is harmless unreachable code as * gen_goto_tb() has already handled emitting the debug exception @@ -10949,7 +11027,11 @@ void gen_intermediate_code_internal_a64(ARMCPU *cpu, if (dc->is_jmp != DISAS_JUMP) { gen_a64_set_pc_im(dc->pc); } - gen_exception_internal(EXCP_DEBUG); + if (cs->singlestep_enabled) { + gen_exception_internal(EXCP_DEBUG); + } else { + gen_step_complete_exception(dc); + } } else { switch (dc->is_jmp) { case DISAS_NEXT: |