diff options
Diffstat (limited to 'target-arm')
| -rw-r--r-- | target-arm/translate-a64.c | 82 |
1 files changed, 77 insertions, 5 deletions
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c index 3b15d2cf7f..16716a2c1f 100644 --- a/target-arm/translate-a64.c +++ b/target-arm/translate-a64.c @@ -41,6 +41,7 @@ static TCGv_i64 cpu_pc; /* Load/store exclusive handling */ static TCGv_i64 cpu_exclusive_high; +static TCGv_i64 cpu_reg(DisasContext *s, int reg); static const char *regnames[] = { "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7", @@ -176,6 +177,76 @@ void gen_a64_set_pc_im(uint64_t val) tcg_gen_movi_i64(cpu_pc, val); } +/* Load the PC from a generic TCG variable. + * + * If address tagging is enabled via the TCR TBI bits, then loading + * an address into the PC will clear out any tag in the it: + * + for EL2 and EL3 there is only one TBI bit, and if it is set + * then the address is zero-extended, clearing bits [63:56] + * + for EL0 and EL1, TBI0 controls addresses with bit 55 == 0 + * and TBI1 controls addressses with bit 55 == 1. + * If the appropriate TBI bit is set for the address then + * the address is sign-extended from bit 55 into bits [63:56] + * + * We can avoid doing this for relative-branches, because the + * PC + offset can never overflow into the tag bits (assuming + * that virtual addresses are less than 56 bits wide, as they + * are currently), but we must handle it for branch-to-register. + */ +static void gen_a64_set_pc(DisasContext *s, TCGv_i64 src) +{ + + if (s->current_el <= 1) { + /* Test if NEITHER or BOTH TBI values are set. If so, no need to + * examine bit 55 of address, can just generate code. + * If mixed, then test via generated code + */ + if (s->tbi0 && s->tbi1) { + TCGv_i64 tmp_reg = tcg_temp_new_i64(); + /* Both bits set, sign extension from bit 55 into [63:56] will + * cover both cases + */ + tcg_gen_shli_i64(tmp_reg, src, 8); + tcg_gen_sari_i64(cpu_pc, tmp_reg, 8); + tcg_temp_free_i64(tmp_reg); + } else if (!s->tbi0 && !s->tbi1) { + /* Neither bit set, just load it as-is */ + tcg_gen_mov_i64(cpu_pc, src); + } else { + TCGv_i64 tcg_tmpval = tcg_temp_new_i64(); + TCGv_i64 tcg_bit55 = tcg_temp_new_i64(); + TCGv_i64 tcg_zero = tcg_const_i64(0); + + tcg_gen_andi_i64(tcg_bit55, src, (1ull << 55)); + + if (s->tbi0) { + /* tbi0==1, tbi1==0, so 0-fill upper byte if bit 55 = 0 */ + tcg_gen_andi_i64(tcg_tmpval, src, + 0x00FFFFFFFFFFFFFFull); + tcg_gen_movcond_i64(TCG_COND_EQ, cpu_pc, tcg_bit55, tcg_zero, + tcg_tmpval, src); + } else { + /* tbi0==0, tbi1==1, so 1-fill upper byte if bit 55 = 1 */ + tcg_gen_ori_i64(tcg_tmpval, src, + 0xFF00000000000000ull); + tcg_gen_movcond_i64(TCG_COND_NE, cpu_pc, tcg_bit55, tcg_zero, + tcg_tmpval, src); + } + tcg_temp_free_i64(tcg_zero); + tcg_temp_free_i64(tcg_bit55); + tcg_temp_free_i64(tcg_tmpval); + } + } else { /* EL > 1 */ + if (s->tbi0) { + /* Force tag byte to all zero */ + tcg_gen_andi_i64(cpu_pc, src, 0x00FFFFFFFFFFFFFFull); + } else { + /* Load unmodified address */ + tcg_gen_mov_i64(cpu_pc, src); + } + } +} + typedef struct DisasCompare64 { TCGCond cond; TCGv_i64 value; @@ -1704,12 +1775,13 @@ static void disas_uncond_b_reg(DisasContext *s, uint32_t insn) switch (opc) { case 0: /* BR */ - case 2: /* RET */ - tcg_gen_mov_i64(cpu_pc, cpu_reg(s, rn)); - break; case 1: /* BLR */ - tcg_gen_mov_i64(cpu_pc, cpu_reg(s, rn)); - tcg_gen_movi_i64(cpu_reg(s, 30), s->pc); + case 2: /* RET */ + gen_a64_set_pc(s, cpu_reg(s, rn)); + /* BLR also needs to load return address */ + if (opc == 1) { + tcg_gen_movi_i64(cpu_reg(s, 30), s->pc); + } break; case 4: /* ERET */ if (s->current_el == 0) { |