diff --git a/target/arm/a32.decode b/target/arm/a32.decode index 182f2b6725..52a66dd1d5 100644 --- a/target/arm/a32.decode +++ b/target/arm/a32.decode @@ -211,3 +211,5 @@ BXJ .... 0001 0010 1111 1111 1111 0010 .... @rm BLX_r .... 0001 0010 1111 1111 1111 0011 .... @rm CLZ .... 0001 0110 1111 .... 1111 0001 .... @rdm + +ERET ---- 0001 0110 0000 0000 0000 0110 1110 diff --git a/target/arm/t32.decode b/target/arm/t32.decode index 67724efe4b..6236d28b99 100644 --- a/target/arm/t32.decode +++ b/target/arm/t32.decode @@ -218,4 +218,12 @@ CLZ 1111 1010 1011 ---- 1111 .... 1000 .... @rdm MSR_v7m 1111 0011 100 0 rn:4 1000 mask:2 00 sysm:8 } BXJ 1111 0011 1100 rm:4 1000 1111 0000 0000 &r + { + # At v6T2, this is the T5 encoding of SUBS PC, LR, #IMM, and works as for + # every other encoding of SUBS. With v7VE, IMM=0 is redefined as ERET. + # The distinction between the two only matters for Hyp mode. + ERET 1111 0011 1101 1110 1000 1111 0000 0000 + SUB_rri 1111 0011 1101 1110 1000 1111 imm:8 \ + &s_rri_rot rot=0 s=1 rd=15 rn=14 + } } diff --git a/target/arm/translate.c b/target/arm/translate.c index 7de6949db3..9589e9bbb9 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -8503,6 +8503,27 @@ static bool trans_CLZ(DisasContext *s, arg_CLZ *a) return true; } +static bool trans_ERET(DisasContext *s, arg_ERET *a) +{ + TCGv_i32 tmp; + + if (!arm_dc_feature(s, ARM_FEATURE_V7VE)) { + return false; + } + if (IS_USER(s)) { + unallocated_encoding(s); + return true; + } + if (s->current_el == 2) { + /* ERET from Hyp uses ELR_Hyp, not LR */ + tmp = load_cpu_field(elr_el[2]); + } else { + tmp = load_reg(s, 14); + } + gen_exception_return(s, tmp); + return true; +} + /* * Legacy decoder. */ @@ -8797,29 +8818,10 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn) case 0x4: /* crc32 */ /* All done in decodetree. Illegal ops reach here. */ goto illegal_op; - case 0x5: - /* Saturating addition and subtraction. */ + case 0x5: /* Saturating addition and subtraction. */ + case 0x6: /* ERET */ /* All done in decodetree. Reach here for illegal ops. */ goto illegal_op; - case 0x6: /* ERET */ - if (op1 != 3) { - goto illegal_op; - } - if (!arm_dc_feature(s, ARM_FEATURE_V7VE)) { - goto illegal_op; - } - if ((insn & 0x000fff0f) != 0x0000000e) { - /* UNPREDICTABLE; we choose to UNDEF */ - goto illegal_op; - } - - if (s->current_el == 2) { - tmp = load_cpu_field(elr_el[2]); - } else { - tmp = load_reg(s, 14); - } - gen_exception_return(s, tmp); - break; case 7: { int imm16 = extract32(insn, 0, 4) | (extract32(insn, 8, 12) << 4); @@ -10628,24 +10630,6 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn) case 4: /* bxj, in decodetree */ goto illegal_op; case 5: /* Exception return. */ - if (IS_USER(s)) { - goto illegal_op; - } - if (rn != 14 || rd != 15) { - goto illegal_op; - } - if (s->current_el == 2) { - /* ERET from Hyp uses ELR_Hyp, not LR */ - if (insn & 0xff) { - goto illegal_op; - } - tmp = load_cpu_field(elr_el[2]); - } else { - tmp = load_reg(s, rn); - tcg_gen_subi_i32(tmp, tmp, insn & 0xff); - } - gen_exception_return(s, tmp); - break; case 6: /* MRS, in decodetree */ case 7: /* MSR, in decodetree */ goto illegal_op;