On Wed, Dec 2, 2020 at 5:53 PM Utkarsh Rai <utkarsh.ra...@gmail.com> wrote:
> Hello, > As discussed in this > <https://lists.rtems.org/pipermail/devel/2020-November/063341.html> thread, > I have compiled a list of the tests that deal with inter stack > communication and fail with the thread stack protection option. Most of > these tests pass when, as Sebastian suggested and had provided a > wonderful example, I disable memory protection at places where contents of > different thread stacks are accessed by the current thread. There are a few > tests that still fail due to inter-stack access in the application code > itself. > > The changes I have made are - > > diff --git a/bsps/arm/realview-pbx-a9/mmu/bsp-set-mmu-attr.c > b/bsps/arm/realview-pbx-a9/mmu/bsp-set-mmu-attr.c > index c176d4b8c5..a45b175395 100644 > --- a/bsps/arm/realview-pbx-a9/mmu/bsp-set-mmu-attr.c > +++ b/bsps/arm/realview-pbx-a9/mmu/bsp-set-mmu-attr.c > @@ -1,15 +1,49 @@ > #include <bsp/arm-cp15-start.h> > #include <rtems/score/memoryprotection.h> > +#include <rtems/score/threadimpl.h> > #include <libcpu/arm-cp15.h> > > +bool set_memory_flags(Thread_Control* thread, void* arg) > +{ > + uintptr_t begin; > + uintptr_t end; > + uint32_t flags; > + rtems_interrupt_level irq_level; > + Thread_Control *executing; > + > + executing = _Thread_Executing; > + > + if(thread != executing) { > This is not concurrency-safe. By time the check happens, or following code happens, the thread could become executing. > + > + flags = *( uint32_t *)( arg ); > + begin = thread->Start.Initial_stack.area; > + end = begin + thread->Start.Initial_stack.size; > + > + rtems_interrupt_disable(irq_level); > + arm_cp15_set_translation_table_entries(begin, end, flags); > + rtems_interrupt_enable(irq_level); > + } > + > + return false; > why -- what does the return value mean? > +} > + > +rtems_status_code _Memory_protection_Enable( void ) > +{ > + uint32_t access_flags; > + > + access_flags = translate_flags( RTEMS_NO_ACCESS ); > + > + _Thread_Iterate( set_memory_flags, &access_flags ); > + > + return RTEMS_SUCCESSFUL; // check the return values for iterating > function and current method. > +} > + > +rtems_status_code _Memory_protection_Disable( void ) > +{ > + uint32_t access_flags; > + > + access_flags = translate_flags( RTEMS_READ_WRITE ); > + > + _Thread_Iterate( set_memory_flags, &access_flags ); > + > + return RTEMS_SUCCESSFUL; > } > \ No newline at end of file > diff --git a/cpukit/include/rtems/score/coremsgimpl.h > b/cpukit/include/rtems/score/coremsgimpl.h > index e598dce96a..3719a3d3c8 100644 > --- a/cpukit/include/rtems/score/coremsgimpl.h > +++ b/cpukit/include/rtems/score/coremsgimpl.h > @@ -27,6 +27,10 @@ > #include <rtems/score/threaddispatch.h> > #include <rtems/score/threadqimpl.h> > > +#if defined RTEMS_THREAD_STACK_PROTECTION > + #include <rtems/score/memoryprotection.h> > +#endif > + > #include <limits.h> > #include <string.h> > > @@ -586,7 +590,9 @@ RTEMS_INLINE_ROUTINE Thread_Control > *_CORE_message_queue_Dequeue_receiver( > if ( the_thread == NULL ) { > return NULL; > } > - > +#if defined RTEMS_THREAD_STACK_PROTECTION > + _Memory_protection_Disable(); > I wonder if it is necessary to disable all protection, or can you just disable the protection applied to 'the_thread' (or maybe to 'executing')? > +#endif > *(size_t *) the_thread->Wait.return_argument = size; > the_thread->Wait.count = (uint32_t) submit_type; > > @@ -595,6 +601,9 @@ RTEMS_INLINE_ROUTINE Thread_Control > *_CORE_message_queue_Dequeue_receiver( > the_thread->Wait.return_argument_second.mutable_object, > size > ); > +#if defined RTEMS_THREAD_STACK_PROTECTION > + _Memory_protection_Enable(); > +#endif > > _Thread_queue_Extract_critical( > &the_message_queue->Wait_queue.Queue, > > diff --git a/cpukit/posix/src/psignalunblockthread.c > b/cpukit/posix/src/psignalunblockthread.c > index 80a0f33a09..e0f8468de6 100644 > --- a/cpukit/posix/src/psignalunblockthread.c > +++ b/cpukit/posix/src/psignalunblockthread.c > @@ -24,6 +24,9 @@ > #include <signal.h> > > #include <rtems/score/isr.h> > +#if defined RTEMS_THREAD_STACK_PROTECTION > +#include <rtems/score/memoryprotection.h> > +#endif > #include <rtems/score/threadimpl.h> > #include <rtems/score/threadqimpl.h> > #include <rtems/score/watchdogimpl.h> > @@ -205,6 +208,10 @@ bool _POSIX_signals_Unblock_thread( > > the_info = (siginfo_t *) the_thread->Wait.return_argument; > > +#if defined RTEMS_THREAD_STACK_PROTECTION > +_Memory_protection_Disable(); > +#endif > + > if ( !info ) { > the_info->si_signo = signo; > the_info->si_code = SI_USER; > @@ -212,6 +219,9 @@ bool _POSIX_signals_Unblock_thread( > } else { > *the_info = *info; > } > +#if defined RTEMS_THREAD_STACK_PROTECTION > +_Memory_protection_Enable(); > +#endif > > _Thread_queue_Extract_with_proxy( the_thread ); > return _POSIX_signals_Unblock_thread_done( the_thread, api, true ); > diff --git a/cpukit/rtems/src/eventsurrender.c > b/cpukit/rtems/src/eventsurrender.c > index 49f77d2663..5de62ec292 100644 > --- a/cpukit/rtems/src/eventsurrender.c > +++ b/cpukit/rtems/src/eventsurrender.c > @@ -23,6 +23,10 @@ > #include <rtems/score/threadimpl.h> > #include <rtems/score/watchdogimpl.h> > > +#if defined RTEMS_THREAD_STACK_PROTECTION > + #include <rtems/score/memoryprotection.h> > +#endif > + > static void _Event_Satisfy( > Thread_Control *the_thread, > Event_Control *event, > @@ -31,7 +35,13 @@ static void _Event_Satisfy( > ) > { > event->pending_events = _Event_sets_Clear( pending_events, > seized_events ); > +#if defined RTEMS_THREAD_STACK_PROTECTION > + _Memory_protection_Disable(); > +#endif > *(rtems_event_set *) the_thread->Wait.return_argument = seized_events; > +#if defined RTEMS_THREAD_STACK_PROTECTION > + _Memory_protection_Enable(); > +#endif > } > > static bool _Event_Is_blocking_on_event( > diff --git a/cpukit/rtems/src/regionprocessqueue.c > b/cpukit/rtems/src/regionprocessqueue.c > index 4adaf66674..29b078a38c 100644 > --- a/cpukit/rtems/src/regionprocessqueue.c > +++ b/cpukit/rtems/src/regionprocessqueue.c > @@ -22,6 +22,10 @@ > #include <rtems/score/status.h> > #include <rtems/score/threadqimpl.h> > > +#if defined RTEMS_THREAD_STACK_PROTECTION > + #include <rtems/score/memoryprotection.h> > +#endif > + > void _Region_Process_queue( > Region_Control *the_region > ) > @@ -63,8 +67,13 @@ void _Region_Process_queue( > > if ( the_segment == NULL ) > break; > - > +#if defined RTEMS_THREAD_STACK_PROTECTION > + _Memory_protection_Disable(); > +#endif > *(void **)the_thread->Wait.return_argument = the_segment; > +#if defined RTEMS_THREAD_STACK_PROTECTION > + _Memory_protection_Enable(); > +#endif > _Thread_queue_Extract( the_thread ); > the_thread->Wait.return_code = STATUS_SUCCESSFUL; > } > > _______________________________________________ > devel mailing list > devel@rtems.org > http://lists.rtems.org/mailman/listinfo/devel
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