| Message ID | 20170307155054.5833-8-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 03/08/2017 02:50 AM, Alex Bennée wrote: > The translation code uses cpu_ld*_code which can trigger a tlb_fill > which if it fails will erroneously attempts a fault resolution. This > never works during translation as the TB being generated hasn't been > added yet. The target should have checked retaddr before calling > cpu_restore_state but for those that have yet to be fixed we do it > here to avoid a recursive tb_lock() under MTTCG's new locking regime. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net> r~
diff --git a/translate-all.c b/translate-all.c index d42d003e67..34480aebba 100644 --- a/translate-all.c +++ b/translate-all.c @@ -333,6 +333,19 @@ bool cpu_restore_state(CPUState *cpu, uintptr_t retaddr) TranslationBlock *tb; bool r = false; + /* A retaddr of zero is invalid so we really shouldn't have ended + * up here. The target code has likely forgotten to check retaddr + * != 0 before attempting to restore state. We return early to + * avoid blowing up on a recursive tb_lock(). The target must have + * previously survived a failed cpu_restore_state because + * tb_find_pc(0) would have failed anyway. It still should be + * fixed though. + */ + + if (!retaddr) { + return r; + } + tb_lock(); tb = tb_find_pc(retaddr); if (tb) {
The translation code uses cpu_ld*_code which can trigger a tlb_fill which if it fails will erroneously attempts a fault resolution. This never works during translation as the TB being generated hasn't been added yet. The target should have checked retaddr before calling cpu_restore_state but for those that have yet to be fixed we do it here to avoid a recursive tb_lock() under MTTCG's new locking regime. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- v3 - check retaddr instead - reword commit/comments to be clearer --- translate-all.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)