On 14 January 2012 14:48, Aurelien Jarno <aurel...@aurel32.net> wrote: > On Thu, Jan 12, 2012 at 02:00:38PM +0000, Peter Maydell wrote: >> When doing TCG code translation, the target-foo translate.c >> code is allowed to bake assumptions into the generated code from >> the current values of various fields in the CPUState. This then >> imposes the requirement that if the field is changed then tb_flush >> must be called to throw away the now-incorrect generated code. >> >> However, cpu_reset() changes (unsurprisingly) lots of fields in >> the CPUState, but it doesn't call tb_flush()... >> >> So should cpu_reset() implementations be changed to call tb_flush() >> as well as tlb_flush(), or is this supposed to work in some other >> way? > > We use the hflags to determine in which conditions the cached code has > been generated, so that we only used the cache code if the CPU is in the > same mode. I therefore don't think there is a real need to flush the > cached code.
This only applies for things which are encoded in tb->flags. Look at handling of eg env->cp15.c1_coproc or env->teecr for env changes that do need a flush. Perhaps this just indicates that CPUs using this approach for some env fields should be calling tb_flush() but not those that do not. It looks as if that's just ARM at the moment. Hmm. -- PMM
