[PATCH] loader/i386/linux: Add device tree support

* [PATCH] loader/i386/linux: Add device tree support
@ 2021-09-21 15:37 Mislav Stublić
  2021-09-21 19:05 ` Vladimir 'phcoder' Serbinenko
  2021-10-06 12:29 ` Daniel Kiper
  0 siblings, 2 replies; 6+ messages in thread
From: Mislav Stublić @ 2021-09-21 15:37 UTC (permalink / raw)
  To: grub-devel

Hi,

This implements device tree support for x86. Unfortunately I haven't been able to test this on latest master but I have tested against 2.04 and it works fine. I will test on master later but I wanted to get some initial comments if this is going in the right direction. What I haven't tested is firmware DTB loading support which only calls grub_efi_get_firmware_fdt from kern/efi implementation as I don't have hardware to test this scenario.

Mislav

Signed-off-by: Mislav Stublić <mislav.stublic@logicbricks.com>
---
 grub-core/Makefile.am         |   1 +
 grub-core/Makefile.core.def   |   2 +
 grub-core/loader/i386/linux.c | 159 ++++++++++++++++++++++++++++++++++++++++--
 include/grub/efi/efi.h        |   5 +-
 include/grub/i386/linux.h     |  21 +++++-
 5 files changed, 181 insertions(+), 7 deletions(-)

diff --git a/grub-core/Makefile.am b/grub-core/Makefile.am
index ee88e44..1b9ba1f 100644
--- a/grub-core/Makefile.am
+++ b/grub-core/Makefile.am
@@ -186,6 +186,7 @@ KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/i386/tsc.h
 KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/pci.h
 KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/acpi.h
 KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/i386/pmtimer.h
+KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/fdt.h
 endif

 if COND_ia64_efi
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 8022e1c..e499057 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -227,7 +227,9 @@ kernel = {
   x86_64_xen = kern/x86_64/dl.c;
   x86_64_efi = kern/x86_64/efi/callwrap.S;
   x86_64_efi = kern/i386/efi/init.c;
+  x86_64_efi = kern/efi/fdt.c;
   x86_64_efi = bus/pci.c;
+  x86_64_efi = lib/fdt.c;

   xen = kern/i386/tsc.c;
   xen = kern/i386/xen/tsc.c;
diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c
index 9f74a96..9c67a54 100644
--- a/grub-core/loader/i386/linux.c
+++ b/grub-core/loader/i386/linux.c
@@ -37,6 +37,7 @@
 #include <grub/linux.h>
 #include <grub/machine/kernel.h>
 #include <grub/safemath.h>
+#include <grub/fdt.h>

 GRUB_MOD_LICENSE ("GPLv3+");

@@ -77,6 +78,7 @@ static void *efi_mmap_buf;
 static grub_size_t maximal_cmdline_size;
 static struct linux_kernel_params linux_params;
 static char *linux_cmdline;
+static void *current_fdt = NULL;
 #ifdef GRUB_MACHINE_EFI
 static grub_efi_uintn_t efi_mmap_size;
 #else
@@ -398,6 +400,38 @@ grub_linux_boot_mmap_fill (grub_uint64_t addr, grub_uint64_t size,
   return 0;
 }

+struct grub_fdt_ctx
+{
+  grub_addr_t fdt_target;
+  grub_memory_type_t mem_type;
+};
+
+static int
+grub_linux_boot_acpi_find (grub_uint64_t addr, grub_uint64_t size,
+                          grub_memory_type_t type, void *data)
+{
+  struct grub_fdt_ctx *fdt_ctx = data;
+  grub_uint64_t fdt_size = grub_fdt_get_totalsize(current_fdt);
+  grub_uint64_t setup_data_header = sizeof(struct linux_i386_kernel_header_setup_data);
+
+
+  if (type != fdt_ctx->mem_type)
+    return 0;
+
+  if (size < setup_data_header + fdt_size)
+    return 0;
+
+  grub_dprintf ("fdt", "addr = 0x%lx, size = 0x%x, need_size = 0x%x, type = %d\n",
+               (unsigned long) addr,
+               (unsigned) size,
+               (unsigned) setup_data_header + fdt_size,
+               fdt_ctx->mem_type);
+
+  fdt_ctx->fdt_target = addr;
+
+  return 1;
+}
+
 static grub_err_t
 grub_linux_boot (void)
 {
@@ -411,6 +445,10 @@ grub_linux_boot (void)
   };
   grub_size_t mmap_size;
   grub_size_t cl_offset;
+  struct grub_fdt_ctx fdt_ctx = {0};
+  grub_uint64_t target_setup_data;
+  struct linux_i386_kernel_header_setup_data *tmp_setup_data;
+  grub_size_t fdt_size;

 #ifdef GRUB_MACHINE_IEEE1275
   {
@@ -579,6 +617,57 @@ grub_linux_boot (void)
     return grub_errno;
   ctx.params->mmap_size = ctx.e820_num;

+  if (current_fdt)
+    {
+      fdt_ctx.mem_type = GRUB_MEMORY_ACPI;
+#ifdef GRUB_MACHINE_EFI
+      grub_efi_mmap_iterate (grub_linux_boot_acpi_find, &fdt_ctx, 0);
+#else
+      grub_mmap_iterate (grub_linux_boot_acpi_find, &fdt_ctx);
+#endif
+      if (!fdt_ctx.fdt_target)
+        {
+          fdt_ctx.mem_type = GRUB_MEMORY_NVS;
+#ifdef GRUB_MACHINE_EFI
+          grub_efi_mmap_iterate (grub_linux_boot_acpi_find, &fdt_ctx, 0);
+#else
+          grub_mmap_iterate (grub_linux_boot_acpi_find, &fdt_ctx);
+#endif
+        }
+    }
+
+  if (fdt_ctx.fdt_target)
+    {
+      grub_relocator_chunk_t ch;
+
+      fdt_size = grub_fdt_get_totalsize (current_fdt);
+
+      err = grub_relocator_alloc_chunk_addr (relocator, &ch,
+                                            fdt_ctx.fdt_target,
+                                            sizeof(*tmp_setup_data) +
+                                            fdt_size);
+      if (!err)
+        {
+          tmp_setup_data = grub_zalloc (sizeof (*tmp_setup_data) + fdt_size);
+          if (tmp_setup_data)
+            {
+              target_setup_data = get_virtual_current_address (ch);
+              tmp_setup_data->next = 0;
+              tmp_setup_data->type = GRUB_SETUP_DTB;
+              tmp_setup_data->len = fdt_size;
+              grub_memcpy (tmp_setup_data->data, current_fdt, fdt_size);
+              grub_memcpy (target_setup_data, tmp_setup_data,
+                          sizeof (*tmp_setup_data) + fdt_size);
+
+              /* finalize FDT kernel target */
+              ctx.params->setup_data = target_setup_data;
+
+              grub_free (tmp_setup_data);
+              grub_free (current_fdt);
+            }
+        }
+    }
+
 #ifdef GRUB_MACHINE_EFI
   {
     grub_efi_uintn_t efi_desc_size;
@@ -591,9 +680,9 @@ grub_linux_boot (void)
                                         &efi_desc_size, &efi_desc_version);
     if (err)
       return err;
-
+
     /* Note that no boot services are available from here.  */
-    efi_mmap_target = ctx.real_mode_target
+    efi_mmap_target = ctx.real_mode_target
       + ((grub_uint8_t *) efi_mmap_buf - (grub_uint8_t *) real_mode_mem);
     /* Pass EFI parameters.  */
     if (grub_le_to_cpu16 (ctx.params->version) >= 0x0208)
@@ -743,7 +832,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
       align = 0;
       relocatable = 0;
     }
-
+
   if (grub_le_to_cpu16 (lh.version) >= 0x020a)
     {
       min_align = lh.min_alignment;
@@ -1123,7 +1212,66 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
   return grub_errno;
 }

-static grub_command_t cmd_linux, cmd_initrd;
+static grub_err_t
+grub_cmd_devicetree (grub_command_t cmd __attribute__ ((unused)),
+                    int argc, char *argv[])
+{
+  grub_file_t dtb;
+  void *new_fdt;
+  int size;
+
+  if (current_fdt)
+    grub_free (current_fdt);
+  current_fdt = NULL;
+
+#ifdef GRUB_MACHINE_EFI
+  /* no dtb file, try firmware */
+  if (argc == 0)
+    {
+      current_fdt = grub_efi_get_firmware_fdt();
+      if (current_fdt)
+        return GRUB_ERR_NONE;
+
+      return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("firmware dtb not found"));
+    }
+#endif
+
+  if (argc != 1)
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("dtb filename expected"));
+
+  dtb = grub_file_open (argv[0], GRUB_FILE_TYPE_DEVICE_TREE_IMAGE);
+  if (!dtb)
+    return grub_errno;
+
+  size = grub_file_size (dtb);
+  new_fdt = grub_zalloc (size);
+  if (!new_fdt)
+    return grub_errno;
+
+  grub_dprintf ("loader", "Loading device tree to %p\n",
+               new_fdt);
+  if (grub_file_read (dtb, new_fdt, size) < size)
+    {
+      grub_free (new_fdt);
+      return grub_error (GRUB_ERR_FILE_READ_ERROR,
+                        N_("unable to read dtb file %s"),
+                        argv[0]);
+    }
+
+  if (grub_fdt_check_header (new_fdt, size) != 0)
+    {
+      grub_free (new_fdt);
+      return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("invalid device tree"));
+    }
+
+  current_fdt = new_fdt;
+
+  grub_file_close (dtb);
+
+  return grub_errno;
+}
+
+static grub_command_t cmd_linux, cmd_initrd, cmd_devicetree;

 GRUB_MOD_INIT(linux)
 {
@@ -1131,6 +1279,9 @@ GRUB_MOD_INIT(linux)
                                     0, N_("Load Linux."));
   cmd_initrd = grub_register_command ("initrd", grub_cmd_initrd,
                                      0, N_("Load initrd."));
+  cmd_devicetree = grub_register_command_lockdown ("devicetree", grub_cmd_devicetree,
+                                                  /* TRANSLATORS: DTB stands for device tree blob.  */
+                                                  0, N_("Load DTB file."));
   my_mod = mod;
 }

diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index 83d958f..a095925 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -96,8 +96,11 @@ extern void (*EXPORT_VAR(grub_efi_net_config)) (grub_efi_handle_t hnd,
                                                char **device,
                                                char **path);

-#if defined(__arm__) || defined(__aarch64__) || defined(__riscv)
+#if defined(__arm__) || defined(__aarch64__) || defined(__riscv) || defined(__x86_64__)
 void *EXPORT_FUNC(grub_efi_get_firmware_fdt)(void);
+#endif
+
+#if defined(__arm__) || defined(__aarch64__) || defined(__riscv)
 grub_err_t EXPORT_FUNC(grub_efi_get_ram_base)(grub_addr_t *);
 #include <grub/cpu/linux.h>
 grub_err_t grub_arch_efi_linux_check_image(struct linux_arch_kernel_header *lh);
diff --git a/include/grub/i386/linux.h b/include/grub/i386/linux.h
index eddf925..b66413d 100644
--- a/include/grub/i386/linux.h
+++ b/include/grub/i386/linux.h
@@ -84,6 +84,23 @@ struct grub_e820_mmap
   grub_uint32_t type;
 } GRUB_PACKED;

+/* taken from linux kernel bootparam.h */
+#define GRUB_SETUP_NONE                      0
+#define GRUB_SETUP_E820_EXT                  1
+#define GRUB_SETUP_DTB                       2
+#define GRUB_SETUP_PCI                       3
+#define GRUB_SETUP_EFI                       4
+#define GRUB_SETUP_APPLE_PROPERTIES          5
+#define GRUB_SETUP_JAILHOUSE                 6
+#define GRUB_SETUP_INDIRECT                  (1<<31)
+
+struct linux_i386_kernel_header_setup_data {
+  grub_uint64_t next;
+  grub_uint32_t type;
+  grub_uint32_t len;
+  grub_uint8_t data[0];
+};
+
 enum
   {
     GRUB_VIDEO_LINUX_TYPE_TEXT = 0x01,
@@ -134,7 +151,7 @@ struct linux_i386_kernel_header
   grub_uint16_t heap_end_ptr;          /* Free memory after setup end */
   grub_uint16_t pad1;                  /* Unused */
   grub_uint32_t cmd_line_ptr;          /* Points to the kernel command line */
-  grub_uint32_t initrd_addr_max;        /* Highest address for initrd */
+  grub_uint32_t initrd_addr_max;       /* Highest address for initrd */
   grub_uint32_t kernel_alignment;
   grub_uint8_t relocatable;
   grub_uint8_t min_alignment;
@@ -144,7 +161,7 @@ struct linux_i386_kernel_header
   grub_uint64_t hardware_subarch_data;
   grub_uint32_t payload_offset;
   grub_uint32_t payload_length;
-  grub_uint64_t setup_data;
+  grub_uint64_t setup_data;            /* linked list of additional boot parameters (E820, DTB, PCI)*/
   grub_uint64_t pref_address;
   grub_uint32_t init_size;
   grub_uint32_t handover_offset;
--
1.8.3.1


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