We have confused the number of instructions that have been
executed in the TB with the number of instructions needed
to repeat the I/O instruction.
We have used cpu_restore_state_from_tb, which means that
the guest pc is pointing to the I/O instruction. The only
time the answer to the later question is not 1 is when
MIPS or SH4 need to re-execute the branch for the delay
slot as well.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
accel/tcg/translate-all.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 67795cd78c..d4190602d1 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1736,37 +1736,32 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
cpu_abort(cpu, "cpu_io_recompile: could not find TB for pc=%p",
(void *)retaddr);
}
- n = cpu->icount_decr.u16.low + tb->icount;
cpu_restore_state_from_tb(cpu, tb, retaddr);
- /* Calculate how many instructions had been executed before the fault
- occurred. */
- n = n - cpu->icount_decr.u16.low;
- /* Generate a new TB ending on the I/O insn. */
- n++;
+
/* On MIPS and SH, delay slot instructions can only be restarted if
they were already the first instruction in the TB. If this is not
the first instruction in a TB then re-execute the preceding
branch. */
+ n = 1;
#if defined(TARGET_MIPS)
- if ((env->hflags & MIPS_HFLAG_BMASK) != 0 && n > 1) {
+ if ((env->hflags & MIPS_HFLAG_BMASK) != 0
+ && env->active_tc.PC != tb->pc) {
env->active_tc.PC -= (env->hflags & MIPS_HFLAG_B16 ? 2 : 4);
cpu->icount_decr.u16.low++;
env->hflags &= ~MIPS_HFLAG_BMASK;
+ n = 2;
}
#elif defined(TARGET_SH4)
if ((env->flags & ((DELAY_SLOT | DELAY_SLOT_CONDITIONAL))) != 0
- && n > 1) {
+ && env->pc != tb->pc) {
env->pc -= 2;
cpu->icount_decr.u16.low++;
env->flags &= ~(DELAY_SLOT | DELAY_SLOT_CONDITIONAL);
+ n = 2;
}
#endif
- /* This should never happen. */
- if (n > CF_COUNT_MASK) {
- cpu_abort(cpu, "TB too big during recompile");
- }
- /* Adjust the execution state of the next TB. */
+ /* Generate a new TB executing the I/O insn. */
cpu->cflags_next_tb = curr_cflags() | CF_LAST_IO | n;
if (tb->cflags & CF_NOCACHE) {
--
2.14.3
