o Introduce vm_sync_icache() for making the I-cache coherent with

    the memory or D-cache, depending on the semantics of the platform.
    vm_sync_icache() is basically a wrapper around pmap_sync_icache(),
    that translates the vm_map_t argumument to pmap_t.
o   Introduce pmap_sync_icache() to all PMAP implementation. For powerpc
    it replaces the pmap_page_executable() function, added to solve
    the I-cache problem in uiomove_fromphys().
o   In proc_rwmem() call vm_sync_icache() when writing to a page that
    has execute permissions. This assures that when breakpoints are
    written, the I-cache will be coherent and the process will actually
    hit the breakpoint.
o   This also fixes the Book-E PMAP implementation that was missing
    necessary locking while trying to deal with the I-cache coherency
    in pmap_enter() (read: mmu_booke_enter_locked).

The key property of this change is that the I-cache is made coherent
*after* writes have been done. Doing it in the PMAP layer when adding
or changing a mapping means that the I-cache is made coherent *before*
any writes happen. The difference is key when the I-cache prefetches.

3 files changed, 9 insertions, 0 deletions

diff --git a/sys/vm/pmap.h b/sys/vm/pmap.h
index 22d6118..02fda07 100644
--- a/sys/vm/pmap.h
+++ b/sys/vm/pmap.h
@@ -133,6 +133,7 @@ void		 pmap_remove(pmap_t, vm_offset_t, vm_offset_t);
 void		 pmap_remove_all(vm_page_t m);
 void		 pmap_remove_pages(pmap_t);
 void		 pmap_remove_write(vm_page_t m);
+void		 pmap_sync_icache(pmap_t, vm_offset_t, vm_size_t);
 void		 pmap_zero_page(vm_page_t);
 void		 pmap_zero_page_area(vm_page_t, int off, int size);
 void		 pmap_zero_page_idle(vm_page_t);
diff --git a/sys/vm/vm_extern.h b/sys/vm/vm_extern.h
index 65b6c8e..ff48983 100644
--- a/sys/vm/vm_extern.h
+++ b/sys/vm/vm_extern.h
@@ -63,6 +63,7 @@ int vm_forkproc(struct thread *, struct proc *, struct thread *, struct vmspace
 void vm_waitproc(struct proc *);
 int vm_mmap(vm_map_t, vm_offset_t *, vm_size_t, vm_prot_t, vm_prot_t, int, objtype_t, void *, vm_ooffset_t);
 void vm_set_page_size(void);
+void vm_sync_icache(vm_map_t, vm_offset_t, vm_size_t);
 struct vmspace *vmspace_alloc(vm_offset_t, vm_offset_t);
 struct vmspace *vmspace_fork(struct vmspace *, vm_ooffset_t *);
 int vmspace_exec(struct proc *, vm_offset_t, vm_offset_t);
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c
index 851c733..8882565 100644
--- a/sys/vm/vm_glue.c
+++ b/sys/vm/vm_glue.c
@@ -309,6 +309,13 @@ vm_imgact_unmap_page(struct sf_buf *sf)
 	vm_page_unlock_queues();
 }
 
+void
+vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz)
+{
+
+	pmap_sync_icache(map->pmap, va, sz);
+}
+
 struct kstack_cache_entry {
 	vm_object_t ksobj;
 	struct kstack_cache_entry *next_ks_entry;