[PATCH v4 23/33] bootstd: Add an implementation of distro PXE boot

Simon Glass
2022-03-06T13:00:54Z

Add a bootmeth driver which handles distro boot from a network device, so
we can boot a bootflow using this commonly used mechanism.

In effect, this provides the same functionality as the 'pxe' command
and shares the same code. But the interface into it is via a bootmeth.

For now this requires the 'pxe' command be enabled. Future work may tidy
this up so that it can be used without CONFIG_CMDLINE being enabled.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

(no changes since v3)

Changes in v3:
- Add a log category
- Use a short name when BOOTSTD_FULL is not enabled

boot/Kconfig | 10 +++
boot/Makefile | 1 +
boot/bootmeth_pxe.c | 186 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 197 insertions(+)
create mode 100644 boot/bootmeth_pxe.c

diff --git a/boot/Kconfig b/boot/Kconfig
index 5f9fca4ffa..15b5e2e99b 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -339,6 +339,16 @@ config BOOTMETH_DISTRO

This provides a way to try out standard boot on an existing boot flow.

+config BOOTMETH_DISTRO_PXE
+ bool "Bootdev support for distro boot over network"
+ depends on CMD_PXE && CMD_NET && DM_ETH
+ default y
+ help
+ Enables support for distro boot using bootdevs. This makes the
+ bootdevs look for a 'extlinux/extlinux.conf' on the tftp server.
+
+ This provides a way to try out standard boot on an existing boot flow.
+
endif

config LEGACY_IMAGE_FORMAT
diff --git a/boot/Makefile b/boot/Makefile
index d8f5c340b8..170fcac8ec 100644
--- a/boot/Makefile
+++ b/boot/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += bootmeth-uclass.o
obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += bootstd-uclass.o

obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_DISTRO) += bootmeth_distro.o
+obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_DISTRO_PXE) += bootmeth_pxe.o

obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += image-fdt.o
obj-$(CONFIG_$(SPL_TPL_)FIT_SIGNATURE) += fdt_region.o
diff --git a/boot/bootmeth_pxe.c b/boot/bootmeth_pxe.c
new file mode 100644
index 0000000000..f1e2b4c776
--- /dev/null
+++ b/boot/bootmeth_pxe.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootmethod for distro boot using PXE (network boot)
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#define LOG_CATEGORY UCLASS_BOOTSTD
+
+#include <common.h>
+#include <bootdev.h>
+#include <bootflow.h>
+#include <bootmeth.h>
+#include <command.h>
+#include <distro.h>
+#include <dm.h>
+#include <fs.h>
+#include <log.h>
+#include <malloc.h>
+#include <mapmem.h>
+#include <mmc.h>
+#include <net.h>
+#include <pxe_utils.h>
+
+static int disto_pxe_getfile(struct pxe_context *ctx, const char *file_path,
+ char *file_addr, ulong *sizep)
+{
+ struct distro_info *info = ctx->userdata;
+ ulong addr;
+ int ret;
+
+ addr = simple_strtoul(file_addr, NULL, 16);
+ ret = bootmeth_read_file(info->dev, info->bflow, file_path, addr,
+ sizep);
+ if (ret)
+ return log_msg_ret("read", ret);
+
+ return 0;
+}
+
+static int distro_pxe_check(struct udevice *dev, struct bootflow_iter *iter)
+{
+ int ret;
+
+ /* This only works on network devices */
+ ret = bootflow_iter_uses_network(iter);
+ if (ret)
+ return log_msg_ret("net", ret);
+
+ return 0;
+}
+
+static int distro_pxe_read_bootflow(struct udevice *dev, struct bootflow *bflow)
+{
+ const char *addr_str;
+ char fname[200];
+ char *bootdir;
+ ulong addr;
+ ulong size;
+ char *buf;
+ int ret;
+
+ addr_str = env_get("pxefile_addr_r");
+ if (!addr_str)
+ return log_msg_ret("pxeb", -EPERM);
+ addr = simple_strtoul(addr_str, NULL, 16);
+
+ log_debug("calling pxe_get()\n");
+ ret = pxe_get(addr, &bootdir, &size);
+ log_debug("pxe_get() returned %d\n", ret);
+ if (ret)
+ return log_msg_ret("pxeb", ret);
+ bflow->size = size;
+
+ /* Use the directory of the dhcp bootdir as our subdir, if provided */
+ if (bootdir) {
+ const char *last_slash;
+ int path_len;
+
+ last_slash = strrchr(bootdir, '/');
+ if (last_slash) {
+ path_len = (last_slash - bootdir) + 1;
+ bflow->subdir = malloc(path_len + 1);
+ memcpy(bflow->subdir, bootdir, path_len);
+ bflow->subdir[path_len] = '\0';
+ }
+ }
+ snprintf(fname, sizeof(fname), "%s%s",
+ bflow->subdir ? bflow->subdir : "", DISTRO_FNAME);
+
+ bflow->fname = strdup(fname);
+ if (!bflow->fname)
+ return log_msg_ret("name", -ENOMEM);
+
+ bflow->state = BOOTFLOWST_READY;
+
+ /* Allocate the buffer, including the \0 byte added by get_pxe_file() */
+ buf = malloc(size + 1);
+ if (!buf)
+ return log_msg_ret("buf", -ENOMEM);
+ memcpy(buf, map_sysmem(addr, 0), size + 1);
+ bflow->buf = buf;
+
+ return 0;
+}
+
+static int distro_pxe_read_file(struct udevice *dev, struct bootflow *bflow,
+ const char *file_path, ulong addr, ulong *sizep)
+{
+ char *tftp_argv[] = {"tftp", NULL, NULL, NULL};
+ struct pxe_context *ctx = dev_get_priv(dev);
+ char file_addr[17];
+ ulong size;
+ int ret;
+
+ sprintf(file_addr, "%lx", addr);
+ tftp_argv[1] = file_addr;
+ tftp_argv[2] = (void *)file_path;
+
+ if (do_tftpb(ctx->cmdtp, 0, 3, tftp_argv))
+ return -ENOENT;
+ ret = pxe_get_file_size(&size);
+ if (ret)
+ return log_msg_ret("tftp", ret);
+ if (size > *sizep)
+ return log_msg_ret("spc", -ENOSPC);
+ *sizep = size;
+
+ return 0;
+}
+
+static int distro_pxe_boot(struct udevice *dev, struct bootflow *bflow)
+{
+ struct pxe_context *ctx = dev_get_priv(dev);
+ struct cmd_tbl cmdtp = {}; /* dummy */
+ struct distro_info info;
+ ulong addr;
+ int ret;
+
+ addr = map_to_sysmem(bflow->buf);
+ info.dev = dev;
+ info.bflow = bflow;
+ info.cmdtp = &cmdtp;
+ ret = pxe_setup_ctx(ctx, &cmdtp, disto_pxe_getfile, &info, false,
+ bflow->subdir);
+ if (ret)
+ return log_msg_ret("ctx", -EINVAL);
+
+ ret = pxe_process(ctx, addr, false);
+ if (ret)
+ return log_msg_ret("bread", -EINVAL);
+
+ return 0;
+}
+
+static int distro_bootmeth_pxe_bind(struct udevice *dev)
+{
+ struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
+
+ plat->desc = IS_ENABLED(CONFIG_BOOTSTD_FULL) ?
+ "PXE boot from a network device" : "PXE";
+
+ return 0;
+}
+
+static struct bootmeth_ops distro_bootmeth_pxe_ops = {
+ .check = distro_pxe_check,
+ .read_bootflow = distro_pxe_read_bootflow,
+ .read_file = distro_pxe_read_file,
+ .boot = distro_pxe_boot,
+};
+
+static const struct udevice_id distro_bootmeth_pxe_ids[] = {
+ { .compatible = "u-boot,distro-pxe" },
+ { }
+};
+
+U_BOOT_DRIVER(bootmeth_pxe) = {
+ .name = "bootmeth_pxe",
+ .id = UCLASS_BOOTMETH,
+ .of_match = distro_bootmeth_pxe_ids,
+ .ops = &distro_bootmeth_pxe_ops,
+ .bind = distro_bootmeth_pxe_bind,
+ .priv_auto = sizeof(struct pxe_context),
+};
--
2.35.1.616.g0bdcbb4464-goog