[PATCH 2/2] RISC-V: Implement linux image loader

[Chester Lin]

An image loader for booting RISC-V linux. The major idea is based on
loader/arm64/linux.c but still follows the the current boot procedure of
RISC-V Linux. [boot-entry = dram-base + text-offset]

Signed-off-by: Chester Lin <address@hidden>
---
 grub-core/loader/riscv/linux.c | 311 ++++++++++++++++++++++++++++++++-
 1 file changed, 307 insertions(+), 4 deletions(-)

diff --git a/grub-core/loader/riscv/linux.c b/grub-core/loader/riscv/linux.c
index d17c488e1..e1960356e 100644
--- a/grub-core/loader/riscv/linux.c
+++ b/grub-core/loader/riscv/linux.c
@@ -15,21 +15,240 @@
  *  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/dl.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_size_t kernel_size;
+
+static char *linux_args;
+static grub_size_t cmdline_size;
+
+static grub_addr_t initrd_start;
+static grub_addr_t initrd_end;
+
+#if __riscv_xlen == 64
+#define INITRD_MAX_ADDRESS_OFFSET (32ULL * 1024 * 1024 * 1024)
+#else
+#define INITRD_MAX_ADDRESS_OFFSET (512U * 1024 * 1024)
+#endif
+
+#define get_hartid(__v)                        \
+{                                      \
+  __asm__ __volatile__ ("mv %0, tp"    \
+                       : "=r" (__v) :  \
+                       : "memory");    \
+}
+
+typedef void (*kernel_entry_t) (int, void *);
+
+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");
+
+  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
+prepare_fdt (void **fdt_addr)
+{
+  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;
+
+  *fdt_addr = fdt;
+
+  return GRUB_ERR_NONE;
+
+failure:
+  grub_fdt_unload();
+  return grub_error(GRUB_ERR_BAD_OS, "failed to install/update FDT");
+}
+
+static grub_err_t
+grub_linux_boot (void)
+{
+  register unsigned long hartid;
+  kernel_entry_t boot_kernel;
+  void *fdt_addr = NULL;
+
+  if(!kernel_addr)
+    return grub_error(GRUB_ERR_BAD_OS, "kernel image is not loaded");
+
+  boot_kernel = (kernel_entry_t) kernel_addr;
+
+  if(prepare_fdt(&fdt_addr) != GRUB_ERR_NONE)
+       goto failure;
+
+  get_hartid(hartid);
+
+  grub_dprintf ("linux", "Boot Hart: %lu\n", hartid);
+
+  boot_kernel(hartid, fdt_addr);
+
+failure:
+  return grub_error(GRUB_ERR_BAD_OS, "failed to boot kernel");
+}
+
+
+
+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;
+}
+
+/*
+ * This function returns a pointer to a legally allocated initrd buffer,
+ * or NULL if unsuccessful
+ */
+static void *
+allocate_kernel_mem (int kernel_pages, grub_addr_t offset)
+{
+  grub_addr_t max_addr;
+
+  if (grub_efi_get_ram_base (&max_addr) != GRUB_ERR_NONE)
+    return NULL;
+
+  max_addr += offset;
+
+  return grub_efi_allocate_pages_real (max_addr, kernel_pages,
+                                      GRUB_EFI_ALLOCATE_ADDRESS,
+                                      GRUB_EFI_LOADER_DATA);
+}
+
+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 __attribute__ ((unused)),
                 char *argv[] __attribute__ ((unused)))
 {
-  grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, N_("Linux not supported yet"));
+  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;
+
+ 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
@@ -37,9 +256,92 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
                int argc __attribute__ ((unused)),
                char *argv[] __attribute__ ((unused)))
 {
-  grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, N_("Linux not supported yet"));
+  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();
+
+  kernel_addr = allocate_kernel_mem (
+               GRUB_EFI_BYTES_TO_PAGES (kernel_size), lh.text_offset);
+
+  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_ssize_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;
@@ -50,6 +352,7 @@ GRUB_MOD_INIT (linux)
                                     N_("Load Linux."));
   cmd_initrd = grub_register_command ("initrd", grub_cmd_initrd, 0,
                                      N_("Load initrd."));
+  my_mod = mod;
 }
 
 GRUB_MOD_FINI (linux)
-- 
2.24.0