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.

2 files changed, 9 insertions, 3 deletions

diff --git a/sys/arm/arm/pmap.c b/sys/arm/arm/pmap.c
index 5e55f8e..3b70a41 100644
--- a/sys/arm/arm/pmap.c
+++ b/sys/arm/arm/pmap.c
@@ -2863,14 +2863,14 @@ pmap_kenter_internal(vm_offset_t va, vm_offset_t pa, int flags)
 	if (pvzone != NULL && (m = vm_phys_paddr_to_vm_page(pa))) {
 		vm_page_lock_queues();
 		if (!TAILQ_EMPTY(&m->md.pv_list) || m->md.pv_kva) {
-				/* release vm_page lock for pv_entry UMA */
+			/* release vm_page lock for pv_entry UMA */
 			vm_page_unlock_queues();
 			if ((pve = pmap_get_pv_entry()) == NULL)
 				panic("pmap_kenter_internal: no pv entries");	
 			vm_page_lock_queues();
 			PMAP_LOCK(pmap_kernel());
 			pmap_enter_pv(m, pve, pmap_kernel(), va,
-					 PVF_WRITE | PVF_UNMAN);
+			    PVF_WRITE | PVF_UNMAN);
 			pmap_fix_cache(m, pmap_kernel(), va);
 			PMAP_UNLOCK(pmap_kernel());
 		} else {
@@ -4567,6 +4567,12 @@ pmap_mincore(pmap_t pmap, vm_offset_t addr)
 }
 
 
+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.
diff --git a/sys/arm/mv/mv_machdep.c b/sys/arm/mv/mv_machdep.c
index 2dc20ce..c348e24 100644
--- a/sys/arm/mv/mv_machdep.c
+++ b/sys/arm/mv/mv_machdep.c
@@ -408,7 +408,7 @@ initarm(void *mdp, void *unused __unused)
 		availmem_regions_sz = i;
 	} else {
 		/* Fall back to hardcoded boothowto flags and metadata. */
-		boothowto = RB_VERBOSE | RB_SINGLE;
+		boothowto = 0; // RB_VERBOSE | RB_SINGLE;
 		lastaddr = fake_preload_metadata();
 
 		/*