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.

1 files changed, 1 insertions, 0 deletions

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);