diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2021-11-03 00:03:50 -0400 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2021-12-15 10:35:26 +0000 |
| commit | 7055fe4baf4d8b331863e51a15e93d3bdea29e36 (patch) | |
| tree | dffae3f23b9b544e17ff2edc57b50d7d6b527376 | |
| parent | ee03027a2cef00f977a3d28242c0a250b8552495 (diff) | |
target/arm: Assert thumb pc is aligned
Misaligned thumb PC is architecturally impossible.
Assert is better than proceeding, in case we've missed
something somewhere.
Expand a comment about aligning the pc in gdbstub.
Fail an incoming migrate if a thumb pc is misaligned.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| -rw-r--r-- | target/arm/gdbstub.c | 9 | ||||
| -rw-r--r-- | target/arm/machine.c | 10 | ||||
| -rw-r--r-- | target/arm/translate.c | 3 |
3 files changed, 20 insertions, 2 deletions
diff --git a/target/arm/gdbstub.c b/target/arm/gdbstub.c index 134da0d0ae..ca1de47511 100644 --- a/target/arm/gdbstub.c +++ b/target/arm/gdbstub.c @@ -77,8 +77,13 @@ int arm_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n) tmp = ldl_p(mem_buf); - /* Mask out low bit of PC to workaround gdb bugs. This will probably - cause problems if we ever implement the Jazelle DBX extensions. */ + /* + * Mask out low bits of PC to workaround gdb bugs. + * This avoids an assert in thumb_tr_translate_insn, because it is + * architecturally impossible to misalign the pc. + * This will probably cause problems if we ever implement the + * Jazelle DBX extensions. + */ if (n == 15) { tmp &= ~1; } diff --git a/target/arm/machine.c b/target/arm/machine.c index c74d8c3f4b..135d2420b5 100644 --- a/target/arm/machine.c +++ b/target/arm/machine.c @@ -794,6 +794,16 @@ static int cpu_post_load(void *opaque, int version_id) return -1; } } + + /* + * Misaligned thumb pc is architecturally impossible. + * We have an assert in thumb_tr_translate_insn to verify this. + * Fail an incoming migrate to avoid this assert. + */ + if (!is_a64(env) && env->thumb && (env->regs[15] & 1)) { + return -1; + } + if (!kvm_enabled()) { pmu_op_finish(&cpu->env); } diff --git a/target/arm/translate.c b/target/arm/translate.c index 45917c3a6d..0a3840d227 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -9646,6 +9646,9 @@ static void thumb_tr_translate_insn(DisasContextBase *dcbase, CPUState *cpu) uint32_t insn; bool is_16bit; + /* Misaligned thumb PC is architecturally impossible. */ + assert((dc->base.pc_next & 1) == 0); + if (arm_check_ss_active(dc) || arm_check_kernelpage(dc)) { dc->base.pc_next = pc + 2; return; |