Write back affected pages in pmap_qremove() as well. This removes the need

to change the DACR when switching to a kernel thread, thus making
userland thread => kernel thread => same userland thread switch cheaper by
totally avoiding data cache and TLB invalidation.

2 files changed, 12 insertions, 6 deletions

diff --git a/sys/arm/arm/pmap.c b/sys/arm/arm/pmap.c
index 8d4d24b..c3ab3e0 100644
--- a/sys/arm/arm/pmap.c
+++ b/sys/arm/arm/pmap.c
@@ -2965,12 +2965,12 @@ pmap_map(vm_offset_t *virt, vm_offset_t start, vm_offset_t end, int prot)
 }
 
 static void
-pmap_wb_page(vm_page_t m)
+pmap_wb_page(vm_page_t m, boolean_t do_inv)
 {
 	struct pv_entry *pv;
 
 	TAILQ_FOREACH(pv, &m->md.pv_list, pv_list)
-	    pmap_dcache_wb_range(pv->pv_pmap, pv->pv_va, PAGE_SIZE, FALSE,
+	    pmap_dcache_wb_range(pv->pv_pmap, pv->pv_va, PAGE_SIZE, do_inv,
 		(pv->pv_flags & PVF_WRITE) == 0);
 }
 
@@ -2988,7 +2988,7 @@ pmap_qenter(vm_offset_t va, vm_page_t *m, int count)
 	int i;
 
 	for (i = 0; i < count; i++) {
-		pmap_wb_page(m[i]);
+		pmap_wb_page(m[i], TRUE);
 		pmap_kenter_internal(va, VM_PAGE_TO_PHYS(m[i]), 
 		    KENTER_CACHE);
 		va += PAGE_SIZE;
@@ -3003,10 +3003,15 @@ pmap_qenter(vm_offset_t va, vm_page_t *m, int count)
 void
 pmap_qremove(vm_offset_t va, int count)
 {
+	vm_paddr_t pa;
 	int i;
 
 	for (i = 0; i < count; i++) {
-		pmap_kremove(va);
+		pa = vtophys(va);
+		if (pa) {
+			pmap_wb_page(PHYS_TO_VM_PAGE(pa), TRUE);
+			pmap_kremove(va);
+		}
 		va += PAGE_SIZE;
 	}
 }
@@ -3516,7 +3521,7 @@ pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_page_t mpte)
 	VM_OBJECT_UNLOCK(m->object);
 	mtx_lock(&Giant);
 	pmap_enter(pmap, va, m, VM_PROT_READ|VM_PROT_EXECUTE, FALSE);
-	pmap_dcache_wbinv_all(pmap);
+	pmap_idcache_wbinv_all(pmap);
 	mtx_unlock(&Giant);
 	VM_OBJECT_LOCK(m->object);
 	vm_page_lock_queues();
@@ -4277,6 +4282,7 @@ pmap_copy_page_xscale(vm_paddr_t src, vm_paddr_t dst)
 void
 pmap_copy_page(vm_page_t src, vm_page_t dst)
 {
+	cpu_dcache_wbinv_all();
 	pmap_copy_page_func(VM_PAGE_TO_PHYS(src), VM_PAGE_TO_PHYS(dst));
 }
 
diff --git a/sys/arm/arm/swtch.S b/sys/arm/arm/swtch.S
index 4470065..63b20b6 100644
--- a/sys/arm/arm/swtch.S
+++ b/sys/arm/arm/swtch.S
@@ -298,7 +298,6 @@ ENTRY(cpu_switch)
 	ldr	r5, [r9, #(PCB_DACR)]		/* r5 = new DACR */
 	mov	r2, #DOMAIN_CLIENT
 	cmp     r5, r2, lsl #(PMAP_DOMAIN_KERNEL * 2) /* Sw to kernel thread? */
-	mcreq	p15, 0, r5, c3, c0, 0	/* Update DACR for new context */
 	beq     .Lcs_context_switched        /* Yup. Don't flush cache */
 	mrc	p15, 0, r0, c3, c0, 0		/* r0 = old DACR */
 	/*
@@ -462,6 +461,7 @@ ENTRY(fork_trampoline)
 	mrs	r0, cpsr
 	orr	r0, r0, #(I32_bit)
 	msr	cpsr_c, r0
+	DO_AST
 	PULLFRAME
 
 	movs	pc, lr			/* Exit */