arm64: Check DMAP address is valid in PHYS_IN_DMAP

When checking if a physical address is in the DMAP region we assume
all physical addresses between DMAP_MIN_PHYSADDR and DMAP_MAX_PHYSADDR
are able to be accesses through the DMAP. It may be the case that
there is device memory in this range that shouldn't be accessed through
the DMAP mappings.

Add a check to PHYS_IN_DMAP that the translated virtual address is a
valid kernel address. To support code that already checks the address
is valid add PHYS_IN_DMAP_RANGE.

PR:		278233
Reviewed by:	alc, markj
Sponsored by:	Arm Ltd
Differential Revision:	https://reviews.freebsd.org/D44677

4 files changed, 22 insertions, 14 deletions

diff --git a/sys/arm64/arm64/efirt_machdep.c b/sys/arm64/arm64/efirt_machdep.c
index 52906779dfb9..0c46d2e6dcc6 100644
--- a/sys/arm64/arm64/efirt_machdep.c
+++ b/sys/arm64/arm64/efirt_machdep.c
@@ -144,13 +144,8 @@ efi_1t1_l3(vm_offset_t va)
 vm_offset_t
 efi_phys_to_kva(vm_paddr_t paddr)
 {
-	vm_offset_t vaddr;
-
-	if (PHYS_IN_DMAP(paddr)) {
-		vaddr = PHYS_TO_DMAP(paddr);
-		if (pmap_klookup(vaddr, NULL))
-			return (vaddr);
-	}
+	if (PHYS_IN_DMAP(paddr))
+		return (PHYS_TO_DMAP(paddr));
 
 	/* TODO: Map memory not in the DMAP */
 
diff --git a/sys/arm64/arm64/machdep.c b/sys/arm64/arm64/machdep.c
index d566a8e2298c..517f4e7c2e23 100644
--- a/sys/arm64/arm64/machdep.c
+++ b/sys/arm64/arm64/machdep.c
@@ -444,7 +444,7 @@ arm64_get_writable_addr(void *addr, void **out)
 	/*
 	 * If it is within the DMAP region and is writable use that.
 	 */
-	if (PHYS_IN_DMAP(pa)) {
+	if (PHYS_IN_DMAP_RANGE(pa)) {
 		addr = (void *)PHYS_TO_DMAP(pa);
 		if (PAR_SUCCESS(arm64_address_translate_s1e1w(
 		    (vm_offset_t)addr))) {
diff --git a/sys/arm64/arm64/minidump_machdep.c b/sys/arm64/arm64/minidump_machdep.c
index 87bf41b27fdf..8ee626953aef 100644
--- a/sys/arm64/arm64/minidump_machdep.c
+++ b/sys/arm64/arm64/minidump_machdep.c
@@ -202,7 +202,8 @@ cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 				if ((l3e & ATTR_DESCR_MASK) != L3_PAGE)
 					continue;
 				pa = PTE_TO_PHYS(l3e);
-				if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa))
+				if (PHYS_IN_DMAP_RANGE(pa) &&
+				    vm_phys_is_dumpable(pa))
 					vm_page_dump_add(state->dump_bitset,
 					    pa);
 			}
@@ -216,7 +217,7 @@ cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 	dumpsize += round_page(sizeof(dump_avail));
 	dumpsize += round_page(BITSET_SIZE(vm_page_dump_pages));
 	VM_PAGE_DUMP_FOREACH(state->dump_bitset, pa) {
-		if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa))
+		if (PHYS_IN_DMAP_RANGE(pa) && vm_phys_is_dumpable(pa))
 			dumpsize += PAGE_SIZE;
 		else
 			vm_page_dump_drop(state->dump_bitset, pa);
@@ -347,7 +348,7 @@ cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
 			 * We always write a page, even if it is zero. If pa
 			 * is malformed, write the zeroed tmpbuffer.
 			 */
-			if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa))
+			if (PHYS_IN_DMAP_RANGE(pa) && vm_phys_is_dumpable(pa))
 				error = blk_write(di, NULL, pa, PAGE_SIZE);
 			else
 				error = blk_write(di, (char *)&tmpbuffer, 0,
diff --git a/sys/arm64/include/vmparam.h b/sys/arm64/include/vmparam.h
index d5d4a5691f37..83c55913f56e 100644
--- a/sys/arm64/include/vmparam.h
+++ b/sys/arm64/include/vmparam.h
@@ -223,9 +223,21 @@
 #define	DMAP_MIN_PHYSADDR	(dmap_phys_base)
 #define	DMAP_MAX_PHYSADDR	(dmap_phys_max)
 
-/* True if pa is in the dmap range */
-#define	PHYS_IN_DMAP(pa)	((pa) >= DMAP_MIN_PHYSADDR && \
+/*
+ * Checks to see if a physical address is in the DMAP range.
+ * - PHYS_IN_DMAP_RANGE will return true that may be within the DMAP range
+ *   but not accessible through the DMAP, e.g. device memory between two
+ *   DMAP physical address regions.
+ * - PHYS_IN_DMAP will check if DMAP address is mapped before returning true.
+ *
+ * PHYS_IN_DMAP_RANGE should only be used when a check on the address is
+ * performed, e.g. by checking the physical address is within phys_avail,
+ * or checking the virtual address is mapped.
+ */
+#define	PHYS_IN_DMAP_RANGE(pa)	((pa) >= DMAP_MIN_PHYSADDR && \
     (pa) < DMAP_MAX_PHYSADDR)
+#define	PHYS_IN_DMAP(pa)	(PHYS_IN_DMAP_RANGE(pa) && \
+    pmap_klookup(PHYS_TO_DMAP(pa), NULL))
 /* True if va is in the dmap range */
 #define	VIRT_IN_DMAP(va)	((va) >= DMAP_MIN_ADDRESS && \
     (va) < (dmap_max_addr))
@@ -233,7 +245,7 @@
 #define	PMAP_HAS_DMAP	1
 #define	PHYS_TO_DMAP(pa)						\
 ({									\
-	KASSERT(PHYS_IN_DMAP(pa),					\
+	KASSERT(PHYS_IN_DMAP_RANGE(pa),					\
 	    ("%s: PA out of range, PA: 0x%lx", __func__,		\
 	    (vm_paddr_t)(pa)));						\
 	((pa) - dmap_phys_base) + DMAP_MIN_ADDRESS;			\