i386/relocator: Add grub_relocator64_efi relocator

Add grub_relocator64_efi relocator. It will be used on EFI 64-bit platforms
when multiboot2 compatible image requests MULTIBOOT_TAG_TYPE_EFI_BS. Relocator
will set lower parts of %rax and %rbx accordingly to multiboot2 specification.
On the other hand processor mode, just before jumping into loaded image, will
be set accordingly to Unified Extensible Firmware Interface Specification,
Version 2.4 Errata B, section 2.3.4, x64 Platforms, boot services. This way
loaded image will be able to use EFI boot services without any issues.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>

grub-core/Makefile.core.def

@@ -1531,6 +1531,7 @@ module = {
   i386_xen = lib/i386/xen/relocator.S;
   x86_64_xen = lib/x86_64/xen/relocator.S;
   xen = lib/i386/relocator_common_c.c;
+  x86_64_efi = lib/x86_64/efi/relocator.c;
 
   extra_dist = lib/i386/relocator_common.S;
   extra_dist = kern/powerpc/cache_flush.S;

grub-core/lib/i386/relocator64.S

@@ -73,6 +73,14 @@ VARIABLE(grub_relocator64_rsp)
 
 	movq	%rax, %rsp
 
+	/*
+	 * Here is grub_relocator64_efi_start() entry point.
+	 * Following code is shared between grub_relocator64_efi_start()
+	 * and grub_relocator64_start().
+	 *
+	 * Think twice before changing anything below!!!
+	 */
+VARIABLE(grub_relocator64_efi_start)
 	/* mov imm64, %rax */
 	.byte 	0x48
 	.byte	0xb8
@@ -120,6 +128,9 @@ LOCAL(jump_addr):
 VARIABLE(grub_relocator64_rip)
 	.quad	0
 
+	/* Here grub_relocator64_efi_start() ends. Ufff... */
+VARIABLE(grub_relocator64_efi_end)
+
 #ifndef __x86_64__
 	.p2align	4
 LOCAL(gdt):

grub-core/lib/x86_64/efi/relocator.c

@@ -0,0 +1,80 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2009  Free Software Foundation, Inc.
+ *  Copyright (C) 2016  Oracle and/or its affiliates. All rights reserved.
+ *
+ *  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/mm.h>
+#include <grub/misc.h>
+
+#include <grub/types.h>
+#include <grub/err.h>
+
+#include <grub/i386/relocator.h>
+#include <grub/relocator_private.h>
+
+extern grub_uint64_t grub_relocator64_rax;
+extern grub_uint64_t grub_relocator64_rbx;
+extern grub_uint64_t grub_relocator64_rcx;
+extern grub_uint64_t grub_relocator64_rdx;
+extern grub_uint64_t grub_relocator64_rip;
+extern grub_uint64_t grub_relocator64_rsi;
+
+extern grub_uint8_t grub_relocator64_efi_start;
+extern grub_uint8_t grub_relocator64_efi_end;
+
+#define RELOCATOR_SIZEOF(x)	(&grub_relocator##x##_end - &grub_relocator##x##_start)
+
+grub_err_t
+grub_relocator64_efi_boot (struct grub_relocator *rel,
+			   struct grub_relocator64_efi_state state)
+{
+  grub_err_t err;
+  void *relst;
+  grub_relocator_chunk_t ch;
+
+  /*
+   * 64-bit relocator code may live above 4 GiB quite well.
+   * However, I do not want ask for problems. Just in case.
+   */
+  err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
+					  0x100000000 - RELOCATOR_SIZEOF (64_efi),
+					  RELOCATOR_SIZEOF (64_efi), 16,
+					  GRUB_RELOCATOR_PREFERENCE_NONE, 1);
+  if (err)
+    return err;
+
+  /* Do not touch %rsp! It points to EFI created stack. */
+  grub_relocator64_rax = state.rax;
+  grub_relocator64_rbx = state.rbx;
+  grub_relocator64_rcx = state.rcx;
+  grub_relocator64_rdx = state.rdx;
+  grub_relocator64_rip = state.rip;
+  grub_relocator64_rsi = state.rsi;
+
+  grub_memmove (get_virtual_current_address (ch), &grub_relocator64_efi_start,
+		RELOCATOR_SIZEOF (64_efi));
+
+  err = grub_relocator_prepare_relocs (rel, get_physical_target_address (ch),
+				       &relst, NULL);
+  if (err)
+    return err;
+
+  ((void (*) (void)) relst) ();
+
+  /* Not reached.  */
+  return GRUB_ERR_NONE;
+}

grub-core/loader/multiboot.c

@@ -118,6 +118,48 @@ grub_multiboot_set_video_mode (void)
   return err;
 }
 
+#ifdef GRUB_MACHINE_EFI
+#ifdef __x86_64__
+#define grub_relocator_efi_boot		grub_relocator64_efi_boot
+#define grub_relocator_efi_state	grub_relocator64_efi_state
+#endif
+#endif
+
+#ifdef grub_relocator_efi_boot
+static void
+efi_boot (struct grub_relocator *rel,
+	  grub_uint32_t target)
+{
+  struct grub_relocator_efi_state state_efi = MULTIBOOT_EFI_INITIAL_STATE;
+
+  state_efi.MULTIBOOT_EFI_ENTRY_REGISTER = grub_multiboot_payload_eip;
+  state_efi.MULTIBOOT_EFI_MBI_REGISTER = target;
+
+  grub_relocator_efi_boot (rel, state_efi);
+}
+#else
+#define grub_efi_is_finished	1
+static void
+efi_boot (struct grub_relocator *rel __attribute__ ((unused)),
+	  grub_uint32_t target __attribute__ ((unused)))
+{
+}
+#endif
+
+#if defined (__i386__) || defined (__x86_64__)
+static void
+normal_boot (struct grub_relocator *rel, struct grub_relocator32_state state)
+{
+  grub_relocator32_boot (rel, state, 0);
+}
+#else
+static void
+normal_boot (struct grub_relocator *rel, struct grub_relocator32_state state)
+{
+  grub_relocator32_boot (rel, state);
+}
+#endif
+
 static grub_err_t
 grub_multiboot_boot (void)
 {
@@ -131,11 +173,10 @@ grub_multiboot_boot (void)
   if (err)
     return err;
 
-#if defined (__i386__) || defined (__x86_64__)
+  if (grub_efi_is_finished)
-  grub_relocator32_boot (grub_multiboot_relocator, state, 0);
+    normal_boot (grub_multiboot_relocator, state);
-#else
+  else
-  grub_relocator32_boot (grub_multiboot_relocator, state);
+    efi_boot (grub_multiboot_relocator, state.MULTIBOOT_MBI_REGISTER);
-#endif
 
   /* Not reached.  */
   return GRUB_ERR_NONE;

grub-core/loader/multiboot_mbi2.c

@@ -107,8 +107,8 @@ grub_multiboot_load (grub_file_t file, const char *filename)
   grub_err_t err;
   struct multiboot_header_tag *tag;
   struct multiboot_header_tag_address *addr_tag = NULL;
-  int entry_specified = 0;
+  int entry_specified = 0, efi_entry_specified = 0;
-  grub_addr_t entry = 0;
+  grub_addr_t entry = 0, efi_entry = 0;
   grub_uint32_t console_required = 0;
   struct multiboot_header_tag_framebuffer *fbtag = NULL;
   int accepted_consoles = GRUB_MULTIBOOT_CONSOLE_EGA_TEXT;
@@ -192,6 +192,13 @@ grub_multiboot_load (grub_file_t file, const char *filename)
 	entry = ((struct multiboot_header_tag_entry_address *) tag)->entry_addr;
 	break;
 
+      case MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS_EFI64:
+#if defined (GRUB_MACHINE_EFI) && defined (__x86_64__)
+	efi_entry_specified = 1;
+	efi_entry = ((struct multiboot_header_tag_entry_address *) tag)->entry_addr;
+#endif
+	break;
+
       case MULTIBOOT_HEADER_TAG_CONSOLE_FLAGS:
 	if (!(((struct multiboot_header_tag_console_flags *) tag)->console_flags
 	    & MULTIBOOT_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED))
@@ -211,7 +218,9 @@ grub_multiboot_load (grub_file_t file, const char *filename)
 	break;
 
       case MULTIBOOT_HEADER_TAG_EFI_BS:
+#ifdef GRUB_MACHINE_EFI
 	keep_bs = 1;
+#endif
 	break;
 
       default:
@@ -224,7 +233,7 @@ grub_multiboot_load (grub_file_t file, const char *filename)
 	break;
       }
 
-  if (addr_tag && !entry_specified)
+  if (addr_tag && !entry_specified && !(keep_bs && efi_entry_specified))
     {
       grub_free (buffer);
       return grub_error (GRUB_ERR_UNKNOWN_OS,
@@ -287,7 +296,9 @@ grub_multiboot_load (grub_file_t file, const char *filename)
 	}
     }
 
-  if (entry_specified)
+  if (keep_bs && efi_entry_specified)
+    grub_multiboot_payload_eip = efi_entry;
+  else if (entry_specified)
     grub_multiboot_payload_eip = entry;
 
   if (fbtag)

include/grub/i386/multiboot.h

@@ -30,6 +30,17 @@
 #define MULTIBOOT_MBI_REGISTER ebx
 #define MULTIBOOT_ARCHITECTURE_CURRENT MULTIBOOT_ARCHITECTURE_I386
 
+#ifdef GRUB_MACHINE_EFI
+#ifdef __x86_64__
+#define MULTIBOOT_EFI_INITIAL_STATE  { .rax = MULTIBOOT_BOOTLOADER_MAGIC,	\
+    .rcx = 0,									\
+    .rdx = 0,									\
+      }
+#define MULTIBOOT_EFI_ENTRY_REGISTER rip
+#define MULTIBOOT_EFI_MBI_REGISTER rbx
+#endif
+#endif
+
 #define MULTIBOOT_ELF32_MACHINE EM_386
 #define MULTIBOOT_ELF64_MACHINE EM_X86_64
 

include/grub/i386/relocator.h

@@ -65,6 +65,20 @@ struct grub_relocator64_state
   grub_addr_t cr3;
 };
 
+#ifdef GRUB_MACHINE_EFI
+#ifdef __x86_64__
+struct grub_relocator64_efi_state
+{
+  grub_uint64_t rax;
+  grub_uint64_t rbx;
+  grub_uint64_t rcx;
+  grub_uint64_t rdx;
+  grub_uint64_t rip;
+  grub_uint64_t rsi;
+};
+#endif
+#endif
+
 grub_err_t grub_relocator16_boot (struct grub_relocator *rel,
 				  struct grub_relocator16_state state);
 
@@ -76,4 +90,11 @@ grub_err_t grub_relocator64_boot (struct grub_relocator *rel,
 				  struct grub_relocator64_state state,
 				  grub_addr_t min_addr, grub_addr_t max_addr);
 
+#ifdef GRUB_MACHINE_EFI
+#ifdef __x86_64__
+grub_err_t grub_relocator64_efi_boot (struct grub_relocator *rel,
+				      struct grub_relocator64_efi_state state);
+#endif
+#endif
+
 #endif /* ! GRUB_RELOCATOR_CPU_HEADER */

include/multiboot2.h

@@ -69,6 +69,7 @@
 #define MULTIBOOT_HEADER_TAG_FRAMEBUFFER  5
 #define MULTIBOOT_HEADER_TAG_MODULE_ALIGN  6
 #define MULTIBOOT_HEADER_TAG_EFI_BS  7
+#define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS_EFI64  9
 
 #define MULTIBOOT_ARCHITECTURE_I386  0
 #define MULTIBOOT_ARCHITECTURE_MIPS32  4