Add pmap function pmap_copy_pages(), which copies the content of the

pages around, taking array of vm_page_t both for source and
destination.  Starting offsets and total transfer size are specified.

The function implements optimal algorithm for copying using the
platform-specific optimizations.  For instance, on the architectures
were the direct map is available, no transient mappings are created,
for i386 the per-cpu ephemeral page frame is used.  The code was
typically borrowed from the pmap_copy_page() for the same
architecture.

Only i386/amd64, powerpc aim and arm/arm-v6 implementations were
tested at the time of commit. High-level code, not committed yet to
the tree, ensures that the use of the function is only allowed after
explicit enablement.

For sparc64, the existing code has known issues and a stab is added
instead, to allow the kernel linking.

Sponsored by:	The FreeBSD Foundation
Tested by:	pho (i386, amd64), scottl (amd64), ian (arm and arm-v6)
MFC after:	2 weeks

1 files changed, 40 insertions, 0 deletions

diff --git a/sys/i386/xen/pmap.c b/sys/i386/xen/pmap.c
index 65e2e76..e8115b0 100644
--- a/sys/i386/xen/pmap.c
+++ b/sys/i386/xen/pmap.c
@@ -3447,6 +3447,46 @@ pmap_copy_page(vm_page_t src, vm_page_t dst)
 	mtx_unlock(&sysmaps->lock);
 }
 
+void
+pmap_copy_pages(vm_page_t ma[], vm_offset_t a_offset, vm_page_t mb[],
+    vm_offset_t b_offset, int xfersize)
+{
+	struct sysmaps *sysmaps;
+	vm_page_t a_pg, b_pg;
+	char *a_cp, *b_cp;
+	vm_offset_t a_pg_offset, b_pg_offset;
+	int cnt;
+
+	sysmaps = &sysmaps_pcpu[PCPU_GET(cpuid)];
+	mtx_lock(&sysmaps->lock);
+	if (*sysmaps->CMAP1 != 0)
+		panic("pmap_copy_pages: CMAP1 busy");
+	if (*sysmaps->CMAP2 != 0)
+		panic("pmap_copy_pages: CMAP2 busy");
+	sched_pin();
+	while (xfersize > 0) {
+		a_pg = ma[a_offset >> PAGE_SHIFT];
+		a_pg_offset = a_offset & PAGE_MASK;
+		cnt = min(xfersize, PAGE_SIZE - a_pg_offset);
+		b_pg = mb[b_offset >> PAGE_SHIFT];
+		b_pg_offset = b_offset & PAGE_MASK;
+		cnt = min(cnt, PAGE_SIZE - b_pg_offset);
+		PT_SET_MA(sysmaps->CADDR1, PG_V | VM_PAGE_TO_MACH(a_pg) | PG_A);
+		PT_SET_MA(sysmaps->CADDR2, PG_V | PG_RW |
+		    VM_PAGE_TO_MACH(b_pg) | PG_A | PG_M);
+		a_cp = sysmaps->CADDR1 + a_pg_offset;
+		b_cp = sysmaps->CADDR2 + b_pg_offset;
+		bcopy(a_cp, b_cp, cnt);
+		a_offset += cnt;
+		b_offset += cnt;
+		xfersize -= cnt;
+	}
+	PT_SET_MA(sysmaps->CADDR1, 0);
+	PT_SET_MA(sysmaps->CADDR2, 0);
+	sched_unpin();
+	mtx_unlock(&sysmaps->lock);
+}
+
 /*
  * Returns true if the pmap's pv is one of the first
  * 16 pvs linked to from this page.  This count may