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, 5 insertions, 0 deletions

diff --git a/sys/i386/xen/pmap.c b/sys/i386/xen/pmap.c
index 1d9c9c1..5bf1331 100644
--- a/sys/i386/xen/pmap.c
+++ b/sys/i386/xen/pmap.c
@@ -4175,6 +4175,11 @@ pmap_activate(struct thread *td)
 	critical_exit();
 }
 
+void
+pmap_sync_icache(pmap_t pm, vm_offset_t va, vm_size_t sz)
+{
+}
+
 /*
  *	Increase the starting virtual address of the given mapping if a
  *	different alignment might result in more superpage mappings.