[PATCH 2/2] RISC-V: Allow to boot Linux with EFI stub on riscv64

[Nikita Ermakov]

- Split a riscv loader to the riscv32 and riscv64 loaders.

- Add loader to boot Linux with EFI stub on riscv64. It is based on the
  grub-core/loader/arm64/linux.c

Signed-off-by: Nikita Ermakov <arei@altlinux.org>
---
 grub-core/Makefile.core.def                 |   4 +-
 grub-core/loader/{riscv => riscv32}/linux.c |   0
 grub-core/loader/riscv64/linux.c            | 380 ++++++++++++++++++++
 3 files changed, 382 insertions(+), 2 deletions(-)
 rename grub-core/loader/{riscv => riscv32}/linux.c (100%)
 create mode 100644 grub-core/loader/riscv64/linux.c

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 8022e1c0a..655a45de7 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1809,8 +1809,8 @@ module = {
   arm_efi = loader/arm64/linux.c;
   arm_uboot = loader/arm/linux.c;
   arm64 = loader/arm64/linux.c;
-  riscv32 = loader/riscv/linux.c;
-  riscv64 = loader/riscv/linux.c;
+  riscv32 = loader/riscv32/linux.c;
+  riscv64 = loader/riscv64/linux.c;
   common = loader/linux.c;
   common = lib/cmdline.c;
   enable = noemu;
diff --git a/grub-core/loader/riscv/linux.c b/grub-core/loader/riscv32/linux.c
similarity index 100%
rename from grub-core/loader/riscv/linux.c
rename to grub-core/loader/riscv32/linux.c
diff --git a/grub-core/loader/riscv64/linux.c b/grub-core/loader/riscv64/linux.c
new file mode 100644
index 000000000..630015495
--- /dev/null
+++ b/grub-core/loader/riscv64/linux.c
@@ -0,0 +1,380 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2018  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/charset.h>
+#include <grub/command.h>
+#include <grub/err.h>
+#include <grub/file.h>
+#include <grub/fdt.h>
+#include <grub/linux.h>
+#include <grub/loader.h>
+#include <grub/mm.h>
+#include <grub/types.h>
+#include <grub/cpu/linux.h>
+#include <grub/efi/efi.h>
+#include <grub/efi/fdtload.h>
+#include <grub/efi/memory.h>
+#include <grub/efi/pe32.h>
+#include <grub/i18n.h>
+#include <grub/lib/cmdline.h>
+#include <grub/verify.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_dl_t my_mod;
+static int loaded;
+
+static void *kernel_addr;
+static grub_uint64_t kernel_size;
+
+static char *linux_args;
+static grub_uint32_t cmdline_size;
+
+static grub_addr_t initrd_start;
+static grub_addr_t initrd_end;
+
+grub_err_t
+grub_arch_efi_linux_check_image (struct linux_arch_kernel_header * lh)
+{
+  if (lh->magic != GRUB_LINUX_RISCV_MAGIC_SIGNATURE)
+    return grub_error(GRUB_ERR_BAD_OS, "invalid magic number");
+
+  if ((lh->code0 & 0xffff) != GRUB_PE32_MAGIC)
+    return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
+                       N_("plain image kernel not supported - rebuild with 
CONFIG_(U)EFI_STUB enabled"));
+
+  grub_dprintf ("linux", "UEFI stub kernel:\n");
+  grub_dprintf ("linux", "PE/COFF header @ %08x\n", lh->hdr_offset);
+
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+finalize_params_linux (void)
+{
+  int node, retval;
+
+  void *fdt;
+
+  fdt = grub_fdt_load (GRUB_EFI_LINUX_FDT_EXTRA_SPACE);
+
+  if (!fdt)
+    goto failure;
+
+  node = grub_fdt_find_subnode (fdt, 0, "chosen");
+  if (node < 0)
+    node = grub_fdt_add_subnode (fdt, 0, "chosen");
+
+  if (node < 1)
+    goto failure;
+
+  /* Set initrd info */
+  if (initrd_start && initrd_end > initrd_start)
+    {
+      grub_dprintf ("linux", "Initrd @ %p-%p\n",
+                    (void *) initrd_start, (void *) initrd_end);
+
+      retval = grub_fdt_set_prop64 (fdt, node, "linux,initrd-start",
+                                    initrd_start);
+      if (retval)
+        goto failure;
+      retval = grub_fdt_set_prop64 (fdt, node, "linux,initrd-end",
+                                    initrd_end);
+      if (retval)
+        goto failure;
+    }
+
+  if (grub_fdt_install() != GRUB_ERR_NONE)
+    goto failure;
+
+  return GRUB_ERR_NONE;
+
+failure:
+  grub_fdt_unload();
+  return grub_error(GRUB_ERR_BAD_OS, "failed to install/update FDT");
+}
+
+grub_err_t
+grub_arch_efi_linux_boot_image (grub_addr_t addr, grub_size_t size, char *args)
+{
+  grub_efi_loaded_image_t *loaded_image = NULL;
+  grub_efi_memory_mapped_device_path_t *mempath;
+  grub_efi_handle_t image_handle;
+  grub_efi_boot_services_t *b;
+  grub_efi_status_t status;
+  int len;
+
+  mempath = grub_malloc (2 * sizeof (grub_efi_memory_mapped_device_path_t));
+  if (!mempath)
+    return grub_errno;
+
+  mempath[0].header.type = GRUB_EFI_HARDWARE_DEVICE_PATH_TYPE;
+  mempath[0].header.subtype = GRUB_EFI_MEMORY_MAPPED_DEVICE_PATH_SUBTYPE;
+  mempath[0].header.length = grub_cpu_to_le16_compile_time (sizeof (*mempath));
+  mempath[0].memory_type = GRUB_EFI_LOADER_DATA;
+  mempath[0].start_address = addr;
+  mempath[0].end_address = addr + size;
+
+  mempath[1].header.type = GRUB_EFI_END_DEVICE_PATH_TYPE;
+  mempath[1].header.subtype = GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE;
+  mempath[1].header.length = sizeof (grub_efi_device_path_t);
+
+  b = grub_efi_system_table->boot_services;
+  status = b->load_image (0, grub_efi_image_handle,
+                          (grub_efi_device_path_t *) mempath,
+                          (void *) addr, size, &image_handle);
+  if (status != GRUB_EFI_SUCCESS)
+    return grub_error (GRUB_ERR_BAD_OS, "cannot load image");
+
+  grub_dprintf ("linux", "linux command line: '%s'\n", args);
+
+  /* Convert command line to UCS-2 */
+  loaded_image = grub_efi_get_loaded_image (image_handle);
+  if (!loaded_image)
+    return grub_error(GRUB_ERR_BAD_OS, "cannot get image");
+  loaded_image->load_options_size = len =
+    (grub_strlen (args) + 1) * sizeof (grub_efi_char16_t);
+  loaded_image->load_options =
+    grub_efi_allocate_any_pages (GRUB_EFI_BYTES_TO_PAGES 
(loaded_image->load_options_size));
+  if (!loaded_image->load_options)
+    return grub_errno;
+
+  loaded_image->load_options_size =
+    2 * grub_utf8_to_utf16 (loaded_image->load_options, len,
+                            (grub_uint8_t *) args, len, NULL);
+
+  grub_dprintf ("linux", "starting image %p\n", image_handle);
+  status = b->start_image (image_handle, 0, NULL);
+
+  /* When successful, not reached */
+  b->unload_image (image_handle);
+  grub_efi_free_pages ((grub_addr_t) loaded_image->load_options,
+                       GRUB_EFI_BYTES_TO_PAGES 
(loaded_image->load_options_size));
+
+  return grub_errno;
+}
+
+static grub_err_t
+grub_linux_boot (void)
+{
+  if (finalize_params_linux () != GRUB_ERR_NONE)
+    return grub_errno;
+
+  return (grub_arch_efi_linux_boot_image((grub_addr_t)kernel_addr,
+                                         kernel_size, linux_args));
+}
+
+static grub_err_t
+grub_linux_unload (void)
+{
+  grub_dl_unref (my_mod);
+  loaded = 0;
+  if (initrd_start)
+    grub_efi_free_pages ((grub_efi_physical_address_t) initrd_start,
+                         GRUB_EFI_BYTES_TO_PAGES (initrd_end - initrd_start));
+  initrd_start = initrd_end = 0;
+  grub_free (linux_args);
+  if (kernel_addr)
+    grub_efi_free_pages ((grub_addr_t) kernel_addr,
+                         GRUB_EFI_BYTES_TO_PAGES (kernel_size));
+  grub_fdt_unload ();
+  return GRUB_ERR_NONE;
+}
+
+/* According to the Linux arch/riscv/include/asm/efi.h */
+#define INITRD_MAX_ADDRESS_OFFSET (256ULL << 20)
+
+/*
+ * This function returns a pointer to a legally allocated initrd buffer,
+ * or NULL if unsuccessful
+ */
+static void *
+allocate_initrd_mem (int initrd_pages)
+{
+  grub_addr_t max_addr;
+
+  if (grub_efi_get_ram_base (&max_addr) != GRUB_ERR_NONE)
+    return NULL;
+
+  max_addr += INITRD_MAX_ADDRESS_OFFSET - 1;
+
+  return grub_efi_allocate_pages_real (max_addr, initrd_pages,
+                                       GRUB_EFI_ALLOCATE_MAX_ADDRESS,
+                                       GRUB_EFI_LOADER_DATA);
+}
+
+static grub_err_t
+grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
+                 int argc, char *argv[])
+{
+  struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 };
+  int initrd_size, initrd_pages;
+  void *initrd_mem = NULL;
+
+  if (argc == 0)
+    {
+      grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
+      goto fail;
+    }
+
+  if (!loaded)
+    {
+      grub_error (GRUB_ERR_BAD_ARGUMENT,
+                  N_("you need to load the kernel first"));
+      goto fail;
+    }
+
+  if (grub_initrd_init (argc, argv, &initrd_ctx))
+    goto fail;
+
+  initrd_size = grub_get_initrd_size (&initrd_ctx);
+  grub_dprintf ("linux", "Loading initrd\n");
+
+  initrd_pages = (GRUB_EFI_BYTES_TO_PAGES (initrd_size));
+  initrd_mem = allocate_initrd_mem (initrd_pages);
+
+  if (!initrd_mem)
+    {
+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
+      goto fail;
+    }
+
+  if (grub_initrd_load (&initrd_ctx, argv, initrd_mem))
+    goto fail;
+
+  initrd_start = (grub_addr_t) initrd_mem;
+  initrd_end = initrd_start + initrd_size;
+  grub_dprintf ("linux", "[addr=%p, size=0x%x]\n",
+                (void *) initrd_start, initrd_size);
+
+fail:
+  grub_initrd_close (&initrd_ctx);
+  if (initrd_mem && !initrd_start)
+    grub_efi_free_pages ((grub_addr_t) initrd_mem, initrd_pages);
+
+  return grub_errno;
+}
+
+static grub_err_t
+grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
+                int argc, char *argv[])
+{
+  grub_file_t file = 0;
+  struct linux_arch_kernel_header lh;
+  grub_err_t err;
+
+  grub_dl_ref (my_mod);
+
+  if (argc == 0)
+    {
+      grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
+      goto fail;
+    }
+
+  file = grub_file_open (argv[0], GRUB_FILE_TYPE_LINUX_KERNEL);
+  if (!file)
+    goto fail;
+
+  kernel_size = grub_file_size (file);
+
+  if (grub_file_read (file, &lh, sizeof (lh)) < (long) sizeof (lh))
+    return grub_errno;
+
+  if (grub_arch_efi_linux_check_image (&lh) != GRUB_ERR_NONE)
+    goto fail;
+
+  grub_loader_unset();
+
+  grub_dprintf ("linux", "kernel file size: %lld\n", (long long) kernel_size);
+  kernel_addr = grub_efi_allocate_any_pages (GRUB_EFI_BYTES_TO_PAGES 
(kernel_size));
+  grub_dprintf ("linux", "kernel numpages: %lld\n",
+                (long long) GRUB_EFI_BYTES_TO_PAGES (kernel_size));
+  if (!kernel_addr)
+    {
+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
+      goto fail;
+    }
+
+  grub_file_seek (file, 0);
+  if (grub_file_read (file, kernel_addr, kernel_size)
+      < (grub_int64_t) kernel_size)
+    {
+      if (!grub_errno)
+        grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"), argv[0]);
+      goto fail;
+    }
+
+  grub_dprintf ("linux", "kernel @ %p\n", kernel_addr);
+
+  cmdline_size = grub_loader_cmdline_size (argc, argv) + sizeof (LINUX_IMAGE);
+  linux_args = grub_malloc (cmdline_size);
+  if (!linux_args)
+    {
+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
+      goto fail;
+    }
+  grub_memcpy (linux_args, LINUX_IMAGE, sizeof (LINUX_IMAGE));
+  err = grub_create_loader_cmdline (argc, argv,
+                                    linux_args + sizeof (LINUX_IMAGE) - 1,
+                                    cmdline_size,
+                                    GRUB_VERIFY_KERNEL_CMDLINE);
+  if (err)
+    goto fail;
+
+  if (grub_errno == GRUB_ERR_NONE)
+    {
+      grub_loader_set (grub_linux_boot, grub_linux_unload, 0);
+      loaded = 1;
+    }
+
+fail:
+  if (file)
+    grub_file_close (file);
+
+  if (grub_errno != GRUB_ERR_NONE)
+    {
+      grub_dl_unref (my_mod);
+      loaded = 0;
+    }
+
+  if (linux_args && !loaded)
+    grub_free (linux_args);
+
+  if (kernel_addr && !loaded)
+    grub_efi_free_pages ((grub_addr_t) kernel_addr,
+                         GRUB_EFI_BYTES_TO_PAGES (kernel_size));
+
+  return grub_errno;
+}
+
+static grub_command_t cmd_linux, cmd_initrd;
+
+GRUB_MOD_INIT (linux)
+{
+  cmd_linux = grub_register_command ("linux", grub_cmd_linux, 0,
+                                     N_("Load Linux."));
+  cmd_initrd = grub_register_command ("initrd", grub_cmd_initrd, 0,
+                                      N_("Load initrd."));
+  my_mod = mod;
+}
+
+GRUB_MOD_FINI (linux)
+{
+  grub_unregister_command (cmd_linux);
+  grub_unregister_command (cmd_initrd);
+}
-- 
2.25.4