[U-Boot] [PATCH v3 05/21] efi_loader: add device-path utils

Rob Clark
2017-09-13T22:05:28Z

Helpers to construct device-paths from devices, partitions, files, and
for parsing and manipulating device-paths.

For non-legacy devices, this will use u-boot's device-model to construct
device-paths which include bus hierarchy to construct device-paths. For
legacy devices we still fake it, but slightly more convincingly.

Signed-off-by: Rob Clark <robdclark@gmail.com>
---
include/efi_api.h | 10 +
include/efi_loader.h | 26 ++
lib/efi_loader/Makefile | 2 +-
lib/efi_loader/efi_boottime.c | 13 +-
lib/efi_loader/efi_device_path.c | 563 +++++++++++++++++++++++++++++++++++++++
5 files changed, 611 insertions(+), 3 deletions(-)
create mode 100644 lib/efi_loader/efi_device_path.c

diff --git a/include/efi_api.h b/include/efi_api.h
index b761cf4822..4e27c82129 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -314,6 +314,7 @@ struct efi_device_path_acpi_path {
#define DEVICE_PATH_TYPE_MESSAGING_DEVICE 0x03
# define DEVICE_PATH_SUB_TYPE_MSG_USB 0x05
# define DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR 0x0b
+# define DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS 0x0f
# define DEVICE_PATH_SUB_TYPE_MSG_SD 0x1a
# define DEVICE_PATH_SUB_TYPE_MSG_MMC 0x1d

@@ -329,6 +330,15 @@ struct efi_device_path_mac_addr {
u8 if_type;
} __packed;

+struct efi_device_path_usb_class {
+ struct efi_device_path dp;
+ u16 vendor_id;
+ u16 product_id;
+ u8 device_class;
+ u8 device_subclass;
+ u8 device_protocol;
+} __packed;
+
struct efi_device_path_sd_mmc_path {
struct efi_device_path dp;
u8 slot_number;
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 1179234f68..d052b03ab7 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -197,6 +197,32 @@ extern void *efi_bounce_buffer;
#define EFI_LOADER_BOUNCE_BUFFER_SIZE (64 * 1024 * 1024)
#endif

+
+struct efi_device_path *efi_dp_next(const struct efi_device_path *dp);
+int efi_dp_match(struct efi_device_path *a, struct efi_device_path *b);
+struct efi_object *efi_dp_find_obj(struct efi_device_path *dp,
+ struct efi_device_path **rem);
+unsigned efi_dp_size(const struct efi_device_path *dp);
+struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp);
+struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
+ const struct efi_device_path *dp2);
+struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
+ const struct efi_device_path *node);
+
+
+struct efi_device_path *efi_dp_from_dev(struct udevice *dev);
+struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part);
+struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
+ const char *path);
+struct efi_device_path *efi_dp_from_eth(void);
+void efi_dp_split_file_path(struct efi_device_path *full_path,
+ struct efi_device_path **device_path,
+ struct efi_device_path **file_path);
+
+#define EFI_DP_TYPE(_dp, _type, _subtype) \
+ (((_dp)->type == DEVICE_PATH_TYPE_##_type) && \
+ ((_dp)->sub_type == DEVICE_PATH_SUB_TYPE_##_subtype))
+
/* Convert strings from normal C strings to uEFI strings */
static inline void ascii2unicode(u16 *unicode, const char *ascii)
{
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index 30bf343a36..f35e5ce8a8 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -15,7 +15,7 @@ always := $(efiprogs-y)

obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
obj-y += efi_image_loader.o efi_boottime.o efi_runtime.o efi_console.o
-obj-y += efi_memory.o efi_device_path_to_text.o
+obj-y += efi_memory.o efi_device_path_to_text.o efi_device_path.o
obj-$(CONFIG_LCD) += efi_gop.o
obj-$(CONFIG_DM_VIDEO) += efi_gop.o
obj-$(CONFIG_PARTITIONS) += efi_disk.o
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 43f32385fa..b962b62a97 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -665,8 +665,17 @@ static efi_status_t EFIAPI efi_locate_device_path(efi_guid_t *protocol,
struct efi_device_path **device_path,
efi_handle_t *device)
{
- EFI_ENTRY("%p, %p, %p", protocol, device_path, device);
- return EFI_EXIT(EFI_NOT_FOUND);
+ struct efi_object *efiobj;
+
+ EFI_ENTRY("%pUl, %p, %p", protocol, device_path, device);
+
+ efiobj = efi_dp_find_obj(*device_path, device_path);
+ if (!efiobj)
+ return EFI_EXIT(EFI_NOT_FOUND);
+
+ *device = efiobj->handle;
+
+ return EFI_EXIT(EFI_SUCCESS);
}

/* Collapses configuration table entries, removing index i */
diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
new file mode 100644
index 0000000000..5d5c3b3464
--- /dev/null
+++ b/lib/efi_loader/efi_device_path.c
@@ -0,0 +1,563 @@
+/*
+ * EFI device path from u-boot device-model mapping
+ *
+ * (C) Copyright 2017 Rob Clark
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <blk.h>
+#include <dm.h>
+#include <usb.h>
+#include <mmc.h>
+#include <efi_loader.h>
+#include <inttypes.h>
+#include <part.h>
+
+/* template END node: */
+static const struct efi_device_path END = {
+ .type = DEVICE_PATH_TYPE_END,
+ .sub_type = DEVICE_PATH_SUB_TYPE_END,
+ .length = sizeof(END),
+};
+
+#define U_BOOT_GUID \
+ EFI_GUID(0xe61d73b9, 0xa384, 0x4acc, \
+ 0xae, 0xab, 0x82, 0xe8, 0x28, 0xf3, 0x62, 0x8b)
+
+/* template ROOT node: */
+static const struct efi_device_path_vendor ROOT = {
+ .dp = {
+ .type = DEVICE_PATH_TYPE_HARDWARE_DEVICE,
+ .sub_type = DEVICE_PATH_SUB_TYPE_VENDOR,
+ .length = sizeof(ROOT),
+ },
+ .guid = U_BOOT_GUID,
+};
+
+static void *dp_alloc(size_t sz)
+{
+ void *buf;
+
+ if (efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, sz, &buf) != EFI_SUCCESS)
+ return NULL;
+
+ return buf;
+}
+
+/*
+ * Iterate to next block in device-path, terminating (returning NULL)
+ * at /End* node.
+ */
+struct efi_device_path *efi_dp_next(const struct efi_device_path *dp)
+{
+ if (dp == NULL)
+ return NULL;
+ if (dp->type == DEVICE_PATH_TYPE_END)
+ return NULL;
+ dp = ((void *)dp) + dp->length;
+ if (dp->type == DEVICE_PATH_TYPE_END)
+ return NULL;
+ return (struct efi_device_path *)dp;
+}
+
+/*
+ * Compare two device-paths, stopping when the shorter of the two hits
+ * an End* node. This is useful to, for example, compare a device-path
+ * representing a device with one representing a file on the device, or
+ * a device with a parent device.
+ */
+int efi_dp_match(struct efi_device_path *a, struct efi_device_path *b)
+{
+ while (1) {
+ int ret;
+
+ ret = memcmp(&a->length, &b->length, sizeof(a->length));
+ if (ret)
+ return ret;
+
+ ret = memcmp(a, b, a->length);
+ if (ret)
+ return ret;
+
+ a = efi_dp_next(a);
+ b = efi_dp_next(b);
+
+ if (!a || !b)
+ return 0;
+ }
+}
+
+
+/*
+ * See UEFI spec (section 3.1.2, about short-form device-paths..
+ * tl;dr: we can have a device-path that starts with a USB WWID
+ * or USB Class node, and a few other cases which don't encode
+ * the full device path with bus hierarchy:
+ *
+ * - MESSAGING:USB_WWID
+ * - MESSAGING:USB_CLASS
+ * - MEDIA:FILE_PATH
+ * - MEDIA:HARD_DRIVE
+ * - MESSAGING:URI
+ */
+static struct efi_device_path *shorten_path(struct efi_device_path *dp)
+{
+ while (dp) {
+ /*
+ * TODO: Add MESSAGING:USB_WWID and MESSAGING:URI..
+ * in practice fallback.efi just uses MEDIA:HARD_DRIVE
+ * so not sure when we would see these other cases.
+ */
+ if (EFI_DP_TYPE(dp, MESSAGING_DEVICE, MSG_USB_CLASS) ||
+ EFI_DP_TYPE(dp, MEDIA_DEVICE, HARD_DRIVE_PATH) ||
+ EFI_DP_TYPE(dp, MEDIA_DEVICE, FILE_PATH))
+ return dp;
+
+ dp = efi_dp_next(dp);
+ }
+
+ return dp;
+}
+
+static struct efi_object *find_obj(struct efi_device_path *dp, bool short_path,
+ struct efi_device_path **rem)
+{
+ struct efi_object *efiobj;
+
+ list_for_each_entry(efiobj, &efi_obj_list, link) {
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(efiobj->protocols); i++) {
+ struct efi_handler *handler = &efiobj->protocols[i];
+ struct efi_device_path *obj_dp;
+
+ if (!handler->guid)
+ break;
+
+ if (guidcmp(handler->guid, &efi_guid_device_path))
+ continue;
+
+ obj_dp = handler->protocol_interface;
+
+ do {
+ if (efi_dp_match(dp, obj_dp) == 0) {
+ if (rem) {
+ *rem = ((void *)dp) +
+ efi_dp_size(obj_dp);
+ }
+ return efiobj;
+ }
+
+ obj_dp = shorten_path(efi_dp_next(obj_dp));
+ } while (short_path && obj_dp);
+ }
+ }
+
+ return NULL;
+}
+
+
+/*
+ * Find an efiobj from device-path, if 'rem' is not NULL, returns the
+ * remaining part of the device path after the matched object.
+ */
+struct efi_object *efi_dp_find_obj(struct efi_device_path *dp,
+ struct efi_device_path **rem)
+{
+ struct efi_object *efiobj;
+
+ efiobj = find_obj(dp, false, rem);
+
+ if (!efiobj)
+ efiobj = find_obj(dp, true, rem);
+
+ return efiobj;
+}
+
+/* return size not including End node: */
+unsigned efi_dp_size(const struct efi_device_path *dp)
+{
+ unsigned sz = 0;
+
+ while (dp) {
+ sz += dp->length;
+ dp = efi_dp_next(dp);
+ }
+
+ return sz;
+}
+
+struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp)
+{
+ struct efi_device_path *ndp;
+ unsigned sz = efi_dp_size(dp) + sizeof(END);
+
+ if (!dp)
+ return NULL;
+
+ ndp = dp_alloc(sz);
+ memcpy(ndp, dp, sz);
+
+ return ndp;
+}
+
+struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
+ const struct efi_device_path *dp2)
+{
+ struct efi_device_path *ret;
+
+ if (!dp1) {
+ ret = efi_dp_dup(dp2);
+ } else if (!dp2) {
+ ret = efi_dp_dup(dp1);
+ } else {
+ /* both dp1 and dp2 are non-null */
+ unsigned sz1 = efi_dp_size(dp1);
+ unsigned sz2 = efi_dp_size(dp2);
+ void *p = dp_alloc(sz1 + sz2 + sizeof(END));
+ memcpy(p, dp1, sz1);
+ memcpy(p + sz1, dp2, sz2);
+ memcpy(p + sz1 + sz2, &END, sizeof(END));
+ ret = p;
+ }
+
+ return ret;
+}
+
+struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
+ const struct efi_device_path *node)
+{
+ struct efi_device_path *ret;
+
+ if (!node && !dp) {
+ ret = efi_dp_dup(&END);
+ } else if (!node) {
+ ret = efi_dp_dup(dp);
+ } else if (!dp) {
+ unsigned sz = node->length;
+ void *p = dp_alloc(sz + sizeof(END));
+ memcpy(p, node, sz);
+ memcpy(p + sz, &END, sizeof(END));
+ ret = p;
+ } else {
+ /* both dp and node are non-null */
+ unsigned sz = efi_dp_size(dp);
+ void *p = dp_alloc(sz + node->length + sizeof(END));
+ memcpy(p, dp, sz);
+ memcpy(p + sz, node, node->length);
+ memcpy(p + sz + node->length, &END, sizeof(END));
+ ret = p;
+ }
+
+ return ret;
+}
+
+#ifdef CONFIG_DM
+/* size of device-path not including END node for device and all parents
+ * up to the root device.
+ */
+static unsigned dp_size(struct udevice *dev)
+{
+ if (!dev || !dev->driver)
+ return sizeof(ROOT);
+
+ switch (dev->driver->id) {
+ case UCLASS_ROOT:
+ case UCLASS_SIMPLE_BUS:
+ /* stop traversing parents at this point: */
+ return sizeof(ROOT);
+ case UCLASS_MMC:
+ return dp_size(dev->parent) +
+ sizeof(struct efi_device_path_sd_mmc_path);
+ case UCLASS_MASS_STORAGE:
+ case UCLASS_USB_HUB:
+ return dp_size(dev->parent) +
+ sizeof(struct efi_device_path_usb_class);
+ default:
+ /* just skip over unknown classes: */
+ return dp_size(dev->parent);
+ }
+}
+
+static void *dp_fill(void *buf, struct udevice *dev)
+{
+ if (!dev || !dev->driver)
+ return buf;
+
+ switch (dev->driver->id) {
+ case UCLASS_ROOT:
+ case UCLASS_SIMPLE_BUS: {
+ /* stop traversing parents at this point: */
+ struct efi_device_path_vendor *vdp = buf;
+ *vdp = ROOT;
+ return &vdp[1];
+ }
+#if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
+ case UCLASS_MMC: {
+ struct efi_device_path_sd_mmc_path *sddp =
+ dp_fill(buf, dev->parent);
+ struct mmc *mmc = mmc_get_mmc_dev(dev);
+ struct blk_desc *desc = mmc_get_blk_desc(mmc);
+
+ sddp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
+ sddp->dp.sub_type = (desc->if_type == IF_TYPE_MMC) ?
+ DEVICE_PATH_SUB_TYPE_MSG_MMC :
+ DEVICE_PATH_SUB_TYPE_MSG_SD;
+ sddp->dp.length = sizeof(*sddp);
+ sddp->slot_number = dev->seq;
+
+ return &sddp[1];
+ }
+#endif
+ case UCLASS_MASS_STORAGE:
+ case UCLASS_USB_HUB: {
+ struct efi_device_path_usb_class *udp =
+ dp_fill(buf, dev->parent);
+ struct usb_device *udev = dev_get_parent_priv(dev);
+ struct usb_device_descriptor *desc = &udev->descriptor;
+
+ udp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
+ udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS;
+ udp->dp.length = sizeof(*udp);
+ udp->vendor_id = desc->idVendor;
+ udp->product_id = desc->idProduct;
+ udp->device_class = desc->bDeviceClass;
+ udp->device_subclass = desc->bDeviceSubClass;
+ udp->device_protocol = desc->bDeviceProtocol;
+
+ return &udp[1];
+ }
+ default:
+ debug("unhandled device class: %s (%u)\n",
+ dev->name, dev->driver->id);
+ return dp_fill(buf, dev->parent);
+ }
+}
+
+/* Construct a device-path from a device: */
+struct efi_device_path *efi_dp_from_dev(struct udevice *dev)
+{
+ void *buf, *start;
+
+ start = buf = dp_alloc(dp_size(dev) + sizeof(END));
+ buf = dp_fill(buf, dev);
+ *((struct efi_device_path *)buf) = END;
+
+ return start;
+}
+#endif
+
+static unsigned dp_part_size(struct blk_desc *desc, int part)
+{
+ unsigned dpsize;
+
+#ifdef CONFIG_BLK
+ dpsize = dp_size(desc->bdev->parent);
+#else
+ dpsize = sizeof(ROOT) + sizeof(struct efi_device_path_usb);
+#endif
+
+ if (part == 0) /* the actual disk, not a partition */
+ return dpsize;
+
+ if (desc->part_type == PART_TYPE_ISO)
+ dpsize += sizeof(struct efi_device_path_cdrom_path);
+ else
+ dpsize += sizeof(struct efi_device_path_hard_drive_path);
+
+ return dpsize;
+}
+
+static void *dp_part_fill(void *buf, struct blk_desc *desc, int part)
+{
+ disk_partition_t info;
+
+#ifdef CONFIG_BLK
+ buf = dp_fill(buf, desc->bdev->parent);
+#else
+ /*
+ * We *could* make a more accurate path, by looking at if_type
+ * and handling all the different cases like we do for non-
+ * legacy (ie CONFIG_BLK=y) case. But most important thing
+ * is just to have a unique device-path for if_type+devnum.
+ * So map things to a fictional USB device:
+ */
+ struct efi_device_path_usb *udp;
+
+ memcpy(buf, &ROOT, sizeof(ROOT));
+ buf += sizeof(ROOT);
+
+ udp = buf;
+ udp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
+ udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB;
+ udp->dp.length = sizeof(*udp);
+ udp->parent_port_number = desc->if_type;
+ udp->usb_interface = desc->devnum;
+ buf = &udp[1];
+#endif
+
+ if (part == 0) /* the actual disk, not a partition */
+ return buf;
+
+ part_get_info(desc, part, &info);
+
+ if (desc->part_type == PART_TYPE_ISO) {
+ struct efi_device_path_cdrom_path *cddp = buf;
+
+ cddp->boot_entry = part - 1;
+ cddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
+ cddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_CDROM_PATH;
+ cddp->dp.length = sizeof(*cddp);
+ cddp->partition_start = info.start;
+ cddp->partition_end = info.size;
+
+ buf = &cddp[1];
+ } else {
+ struct efi_device_path_hard_drive_path *hddp = buf;
+
+ hddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
+ hddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH;
+ hddp->dp.length = sizeof(*hddp);
+ hddp->partition_number = part - 1;
+ hddp->partition_start = info.start;
+ hddp->partition_end = info.size;
+ if (desc->part_type == PART_TYPE_EFI)
+ hddp->partmap_type = 2;
+ else
+ hddp->partmap_type = 1;
+ hddp->signature_type = desc->sig_type;
+ if (hddp->signature_type != 0)
+ memcpy(hddp->partition_signature, &desc->guid_sig,
+ sizeof(hddp->partition_signature));
+
+ buf = &hddp[1];
+ }
+
+ return buf;
+}
+
+
+/* Construct a device-path from a partition on a blk device: */
+struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part)
+{
+ void *buf, *start;
+
+ start = buf = dp_alloc(dp_part_size(desc, part) + sizeof(END));
+
+ buf = dp_part_fill(buf, desc, part);
+
+ *((struct efi_device_path *)buf) = END;
+
+ return start;
+}
+
+/* convert path to an UEFI style path (ie. DOS style backslashes and utf16) */
+static void path_to_uefi(u16 *uefi, const char *path)
+{
+ while (*path) {
+ char c = *(path++);
+ if (c == '/')
+ c = '\\';
+ *(uefi++) = c;
+ }
+ *uefi = '\0';
+}
+
+/*
+ * If desc is NULL, this creates a path with only the file component,
+ * otherwise it creates a full path with both device and file components
+ */
+struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
+ const char *path)
+{
+ struct efi_device_path_file_path *fp;
+ void *buf, *start;
+ unsigned dpsize = 0, fpsize;
+
+ if (desc)
+ dpsize = dp_part_size(desc, part);
+
+ fpsize = sizeof(struct efi_device_path) + 2 * (strlen(path) + 1);
+ dpsize += fpsize;
+
+ start = buf = dp_alloc(dpsize + sizeof(END));
+
+ if (desc)
+ buf = dp_part_fill(buf, desc, part);
+
+ /* add file-path: */
+ fp = buf;
+ fp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
+ fp->dp.sub_type = DEVICE_PATH_SUB_TYPE_FILE_PATH;
+ fp->dp.length = fpsize;
+ path_to_uefi(fp->str, path);
+ buf += fpsize;
+
+ *((struct efi_device_path *)buf) = END;
+
+ return start;
+}
+
+#ifdef CONFIG_NET
+struct efi_device_path *efi_dp_from_eth(void)
+{
+ struct efi_device_path_mac_addr *ndp;
+ void *buf, *start;
+ unsigned dpsize = 0;
+
+ assert(eth_get_dev());
+
+#ifdef CONFIG_DM_ETH
+ dpsize += dp_size(eth_get_dev());
+#else
+ dpsize += sizeof(ROOT);
+#endif
+ dpsize += sizeof(*ndp);
+
+ start = buf = dp_alloc(dpsize + sizeof(END));
+
+#ifdef CONFIG_DM_ETH
+ buf = dp_fill(buf, eth_get_dev());
+#else
+ memcpy(buf, &ROOT, sizeof(ROOT));
+ buf += sizeof(ROOT);
+#endif
+
+ ndp = buf;
+ ndp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
+ ndp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
+ ndp->dp.length = sizeof(*ndp);
+ memcpy(ndp->mac.addr, eth_get_ethaddr(), ARP_HLEN);
+ buf = &ndp[1];
+
+ *((struct efi_device_path *)buf) = END;
+
+ return start;
+}
+#endif
+
+/*
+ * Helper to split a full device path (containing both device and file
+ * parts) into it's constituent parts.
+ */
+void efi_dp_split_file_path(struct efi_device_path *full_path,
+ struct efi_device_path **device_path,
+ struct efi_device_path **file_path)
+{
+ struct efi_device_path *p, *dp, *fp;
+
+ dp = efi_dp_dup(full_path);
+ p = dp;
+ while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH))
+ p = efi_dp_next(p);
+ fp = efi_dp_dup(p);
+
+ p->type = DEVICE_PATH_TYPE_END;
+ p->sub_type = DEVICE_PATH_SUB_TYPE_END;
+ p->length = sizeof(*p);
+
+ *device_path = dp;
+ *file_path = fp;
+}
--
2.13.5