From 3960c336ad96c2183549c8bf32bbff93ecda7ea4 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 29 May 2015 11:29:00 +0100 Subject: target-arm: Avoid buffer overrun on UNPREDICTABLE ldrd/strd A LDRD or STRD where rd is not an even number is UNPREDICTABLE. We were letting this fall through, which is OK unless rd is 15, in which case we would attempt to do a load_reg or store_reg to a nonexistent r16 for the second half of the double-word. Catch the odd-numbered-rd cases and UNDEF them instead. To do this we rearrange the structure of the code a little so we can put the UNDEF catches at the top before we've allocated TCG temporaries. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell Message-id: 1431348973-21315-1-git-send-email-peter.maydell@linaro.org --- target-arm/translate.c | 56 ++++++++++++++++++++++++++++---------------------- 1 file changed, 32 insertions(+), 24 deletions(-) diff --git a/target-arm/translate.c b/target-arm/translate.c index 6493b9a523..39692d7a8e 100644 --- a/target-arm/translate.c +++ b/target-arm/translate.c @@ -8430,34 +8430,30 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn) } } else { int address_offset; - int load; + bool load = insn & (1 << 20); + bool doubleword = false; /* Misc load/store */ rn = (insn >> 16) & 0xf; rd = (insn >> 12) & 0xf; + + if (!load && (sh & 2)) { + /* doubleword */ + ARCH(5TE); + if (rd & 1) { + /* UNPREDICTABLE; we choose to UNDEF */ + goto illegal_op; + } + load = (sh & 1) == 0; + doubleword = true; + } + addr = load_reg(s, rn); if (insn & (1 << 24)) gen_add_datah_offset(s, insn, 0, addr); address_offset = 0; - if (insn & (1 << 20)) { - /* load */ - tmp = tcg_temp_new_i32(); - switch(sh) { - case 1: - gen_aa32_ld16u(tmp, addr, get_mem_index(s)); - break; - case 2: - gen_aa32_ld8s(tmp, addr, get_mem_index(s)); - break; - default: - case 3: - gen_aa32_ld16s(tmp, addr, get_mem_index(s)); - break; - } - load = 1; - } else if (sh & 2) { - ARCH(5TE); - /* doubleword */ - if (sh & 1) { + + if (doubleword) { + if (!load) { /* store */ tmp = load_reg(s, rd); gen_aa32_st32(tmp, addr, get_mem_index(s)); @@ -8466,7 +8462,6 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn) tmp = load_reg(s, rd + 1); gen_aa32_st32(tmp, addr, get_mem_index(s)); tcg_temp_free_i32(tmp); - load = 0; } else { /* load */ tmp = tcg_temp_new_i32(); @@ -8476,15 +8471,28 @@ static void disas_arm_insn(DisasContext *s, unsigned int insn) tmp = tcg_temp_new_i32(); gen_aa32_ld32u(tmp, addr, get_mem_index(s)); rd++; - load = 1; } address_offset = -4; + } else if (load) { + /* load */ + tmp = tcg_temp_new_i32(); + switch (sh) { + case 1: + gen_aa32_ld16u(tmp, addr, get_mem_index(s)); + break; + case 2: + gen_aa32_ld8s(tmp, addr, get_mem_index(s)); + break; + default: + case 3: + gen_aa32_ld16s(tmp, addr, get_mem_index(s)); + break; + } } else { /* store */ tmp = load_reg(s, rd); gen_aa32_st16(tmp, addr, get_mem_index(s)); tcg_temp_free_i32(tmp); - load = 0; } /* Perform base writeback before the loaded value to ensure correct behavior with overlapping index registers. -- cgit v1.2.3