drm/nouveau/bios: pointers beyond end of first image need special handling

Makes common the code that was previously used by the PMU table parsing,
as it appears other tables need this too.

Not much of an idea what this is all about...
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvkm/subdev/bios.h

@@ -7,6 +7,9 @@ struct nvkm_bios {
 	u32 size;
 	u8 *data;
 
+	u32 image0_size;
+	u32 imaged_addr;
+
 	u32 bmp_offset;
 	u32 bit_offset;
 

drivers/gpu/drm/nouveau/nvkm/subdev/bios/base.c

@@ -26,14 +26,23 @@
 #include <subdev/bios.h>
 #include <subdev/bios/bmp.h>
 #include <subdev/bios/bit.h>
+#include <subdev/bios/image.h>
 
 static bool
 nvbios_addr(struct nvkm_bios *bios, u32 *addr, u8 size)
 {
+	u32 p = *addr;
+
+	if (*addr > bios->image0_size && bios->imaged_addr) {
+		*addr -= bios->image0_size;
+		*addr += bios->imaged_addr;
+	}
+
 	if (unlikely(*addr + size >= bios->size)) {
-		nvkm_error(&bios->subdev, "OOB %d %08x\n", size, *addr);
+		nvkm_error(&bios->subdev, "OOB %d %08x %08x\n", size, p, *addr);
 		return false;
 	}
+
 	return true;
 }
 
@@ -134,8 +143,9 @@ int
 nvkm_bios_new(struct nvkm_device *device, int index, struct nvkm_bios **pbios)
 {
 	struct nvkm_bios *bios;
+	struct nvbios_image image;
 	struct bit_entry bit_i;
-	int ret;
+	int ret, idx = 0;
 
 	if (!(bios = *pbios = kzalloc(sizeof(*bios), GFP_KERNEL)))
 		return -ENOMEM;
@@ -145,6 +155,19 @@ nvkm_bios_new(struct nvkm_device *device, int index, struct nvkm_bios **pbios)
 	if (ret)
 		return ret;
 
+	/* Some tables have weird pointers that need adjustment before
+	 * they're dereferenced.  I'm not entirely sure why...
+	 */
+	if (nvbios_image(bios, idx++, &image)) {
+		bios->image0_size = image.size;
+		while (nvbios_image(bios, idx++, &image)) {
+			if (image.type == 0xe0) {
+				bios->imaged_addr = image.base;
+				break;
+			}
+		}
+	}
+
 	/* detect type of vbios we're dealing with */
 	bios->bmp_offset = nvbios_findstr(bios->data, bios->size,
 					  "\xff\x7f""NV\0", 5);

drivers/gpu/drm/nouveau/nvkm/subdev/bios/image.c

@@ -68,11 +68,16 @@ nvbios_imagen(struct nvkm_bios *bios, struct nvbios_image *image)
 bool
 nvbios_image(struct nvkm_bios *bios, int idx, struct nvbios_image *image)
 {
+	u32 imaged_addr = bios->imaged_addr;
 	memset(image, 0x00, sizeof(*image));
+	bios->imaged_addr = 0;
 	do {
 		image->base += image->size;
-		if (image->last || !nvbios_imagen(bios, image))
+		if (image->last || !nvbios_imagen(bios, image)) {
+			bios->imaged_addr = imaged_addr;
 			return false;
+		}
 	} while(idx--);
+	bios->imaged_addr = imaged_addr;
 	return true;
 }

drivers/gpu/drm/nouveau/nvkm/subdev/bios/pmu.c

@@ -26,21 +26,6 @@
 #include <subdev/bios/image.h>
 #include <subdev/bios/pmu.h>
 
-static u32
-weirdo_pointer(struct nvkm_bios *bios, u32 data)
-{
-	struct nvbios_image image;
-	int idx = 0;
-	if (nvbios_image(bios, idx++, &image)) {
-		data -= image.size;
-		while (nvbios_image(bios, idx++, &image)) {
-			if (image.type == 0xe0)
-				return image.base + data;
-		}
-	}
-	return 0;
-}
-
 u32
 nvbios_pmuTe(struct nvkm_bios *bios, u8 *ver, u8 *hdr, u8 *cnt, u8 *len)
 {
@@ -50,7 +35,7 @@ nvbios_pmuTe(struct nvkm_bios *bios, u8 *ver, u8 *hdr, u8 *cnt, u8 *len)
 	if (!bit_entry(bios, 'p', &bit_p)) {
 		if (bit_p.version == 2 && bit_p.length >= 4)
 			data = nvbios_rd32(bios, bit_p.offset + 0x00);
-		if ((data = weirdo_pointer(bios, data))) {
+		if (data) {
 			*ver = nvbios_rd08(bios, data + 0x00); /* maybe? */
 			*hdr = nvbios_rd08(bios, data + 0x01);
 			*len = nvbios_rd08(bios, data + 0x02);
@@ -97,8 +82,7 @@ nvbios_pmuRm(struct nvkm_bios *bios, u8 type, struct nvbios_pmuR *info)
 	u32 data;
 	memset(info, 0x00, sizeof(*info));
 	while ((data = nvbios_pmuEp(bios, idx++, &ver, &hdr, &pmuE))) {
-		if ( pmuE.type == type &&
-		    (data = weirdo_pointer(bios, pmuE.data))) {
+		if (pmuE.type == type && (data = pmuE.data)) {
 			info->init_addr_pmu = nvbios_rd32(bios, data + 0x08);
 			info->args_addr_pmu = nvbios_rd32(bios, data + 0x0c);
 			info->boot_addr     = data + 0x30;