[GRUB2 PATCH v5 1/4] i386/relocator: Add grub_relocator64_efi relocator

[GRUB2 PATCH v5 1/4] i386/relocator: Add grub_relocator64_efi relocator

[Daniel Kiper]

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>
---
v4 - suggestions/fixes:
   - move EFI platform specific C code to separate file
     (suggested by Vladimir 'phcoder' Serbinenko),
   - add some comments
     (suggested by Vladimir 'phcoder' Serbinenko).

v3 - suggestions/fixes:
   - reuse grub-core/lib/i386/relocator64.S code
     instead of creating separate assembly file
     (suggested by Vladimir 'phcoder' Serbinenko),
   - grub_multiboot_boot() cleanup
     (suggested by Vladimir 'phcoder' Serbinenko),
   - reuse multiboot_header_tag_entry_address struct instead
     of creating new one for EFI 64-bit entry point
     (suggested by Vladimir 'phcoder' Serbinenko).
---
 grub-core/Makefile.core.def          |    1 +
 grub-core/lib/i386/relocator64.S     |   11 +++++
 grub-core/lib/x86_64/efi/relocator.c |   76 ++++++++++++++++++++++++++++++++++
 grub-core/loader/multiboot.c         |   51 ++++++++++++++++++++---
 grub-core/loader/multiboot_mbi2.c    |   19 +++++++--
 include/grub/i386/multiboot.h        |   11 +++++
 include/grub/i386/relocator.h        |   21 ++++++++++
 include/multiboot2.h                 |    1 +
 8 files changed, 182 insertions(+), 9 deletions(-)
 create mode 100644 grub-core/lib/x86_64/efi/relocator.c

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 58b4208..21ad0dd 100644
--- a/grub-core/Makefile.core.def
+++ b/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;
diff --git a/grub-core/lib/i386/relocator64.S b/grub-core/lib/i386/relocator64.S
index e4648d8..75725cf 100644
--- a/grub-core/lib/i386/relocator64.S
+++ b/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):
diff --git a/grub-core/lib/x86_64/efi/relocator.c b/grub-core/lib/x86_64/efi/relocator.c
new file mode 100644
index 0000000..c93d061
--- /dev/null
+++ b/grub-core/lib/x86_64/efi/relocator.c
@@ -0,0 +1,76 @@
+/*
+ *  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;
+
+  err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
+					  0x40000000 - 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;
+}
diff --git a/grub-core/loader/multiboot.c b/grub-core/loader/multiboot.c
index 73aa0aa..18038fd 100644
--- a/grub-core/loader/multiboot.c
+++ b/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__)
-  grub_relocator32_boot (grub_multiboot_relocator, state, 0);
-#else
-  grub_relocator32_boot (grub_multiboot_relocator, state);
-#endif
+  if (grub_efi_is_finished)
+    normal_boot (grub_multiboot_relocator, state);
+  else
+    efi_boot (grub_multiboot_relocator, state.MULTIBOOT_MBI_REGISTER);
 
   /* Not reached.  */
   return GRUB_ERR_NONE;
diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index f147d67..a3dca90 100644
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/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;
-  grub_addr_t entry = 0;
+  int entry_specified = 0, efi_entry_specified = 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)
diff --git a/include/grub/i386/multiboot.h b/include/grub/i386/multiboot.h
index a1b9488..807a1de 100644
--- a/include/grub/i386/multiboot.h
+++ b/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
 
diff --git a/include/grub/i386/relocator.h b/include/grub/i386/relocator.h
index 5f89a7e..2a56c3b 100644
--- a/include/grub/i386/relocator.h
+++ b/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 */
diff --git a/include/multiboot2.h b/include/multiboot2.h
index 8b8c156..46e7b71 100644
--- a/include/multiboot2.h
+++ b/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
-- 
1.7.10.4


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Re: [GRUB2 PATCH v5 1/4] i386/relocator: Add grub_relocator64_efi relocator

[Konrad Rzeszutek Wilk]

On Fri, Mar 18, 2016 at 06:00:23PM +0100, Daniel Kiper wrote:
> 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>

.. with one modification:
.. snip..
> diff --git a/grub-core/lib/x86_64/efi/relocator.c b/grub-core/lib/x86_64/efi/relocator.c
> new file mode 100644
> index 0000000..c93d061
> --- /dev/null
> +++ b/grub-core/lib/x86_64/efi/relocator.c
> +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;
> +
> +  err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
> +					  0x40000000 - RELOCATOR_SIZEOF (64_efi),
                                          ^^^^^^^^^^ - why the 1GB?

Could you give a bit details on it? Or preferrable have a comment right
above saying what that value is used?

Thanks.

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Re: [GRUB2 PATCH v5 1/4] i386/relocator: Add grub_relocator64_efi relocator

[Daniel Kiper]

On Fri, Mar 25, 2016 at 12:28:46PM -0400, Konrad Rzeszutek Wilk wrote:
> On Fri, Mar 18, 2016 at 06:00:23PM +0100, Daniel Kiper wrote:
> > 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>
>
> .. with one modification:
> .. snip..
> > diff --git a/grub-core/lib/x86_64/efi/relocator.c b/grub-core/lib/x86_64/efi/relocator.c
> > new file mode 100644
> > index 0000000..c93d061
> > --- /dev/null
> > +++ b/grub-core/lib/x86_64/efi/relocator.c
> > +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;
> > +
> > +  err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
> > +					  0x40000000 - RELOCATOR_SIZEOF (64_efi),
>                                           ^^^^^^^^^^ - why the 1GB?
>
> Could you give a bit details on it? Or preferrable have a comment right
> above saying what that value is used?

I took this from BSD loader. I assumed that if it uses this value then
it is safe to do the same here. However, it looks that we can safely use
"4 GiB - RELOCATOR_SIZEOF (64_efi)" too (probably higher value is also
good but I do not think we should go that way). If there are not
objections then I will repost fixed patch series next week.

Daniel

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[GRUB2 PATCH v5 2/4] multiboot2: Add tags used to pass ImageHandle to loaded image

[Daniel Kiper]

Add tags used to pass ImageHandle to loaded image if requested.
It is used by at least ExitBootServices() function.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
v4 - suggestions/fixes:
   - reduce number of #ifdefs in grub_multiboot_get_mbi_size()
     (suggested by Vladimir 'phcoder' Serbinenko).

v3 - suggestions/fixes:
   - mbi EFI related stuff size calculation
     should depend on target architecture
     (suggested by Konrad Rzeszutek Wilk),
   - use plain type instead of pointer
     dereference as sizeof() argument
     (suggested by Konrad Rzeszutek Wilk),
   - improve commit message
     (suggested by Konrad Rzeszutek Wilk).
---
 grub-core/loader/multiboot_mbi2.c |   42 ++++++++++++++++++++++++++++++-------
 include/multiboot2.h              |   16 ++++++++++++++
 2 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index a3dca90..6c04402 100644
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -172,6 +172,8 @@ grub_multiboot_load (grub_file_t file, const char *filename)
 	      case MULTIBOOT_TAG_TYPE_NETWORK:
 	      case MULTIBOOT_TAG_TYPE_EFI_MMAP:
 	      case MULTIBOOT_TAG_TYPE_EFI_BS:
+	      case MULTIBOOT_TAG_TYPE_EFI32_IH:
+	      case MULTIBOOT_TAG_TYPE_EFI64_IH:
 		break;
 
 	      default:
@@ -407,13 +409,15 @@ grub_multiboot_get_mbi_size (void)
 		 + grub_get_multiboot_mmap_count ()
 		 * sizeof (struct multiboot_mmap_entry)), MULTIBOOT_TAG_ALIGN)
     + ALIGN_UP (sizeof (struct multiboot_tag_framebuffer), MULTIBOOT_TAG_ALIGN)
-    + ALIGN_UP (sizeof (struct multiboot_tag_efi32), MULTIBOOT_TAG_ALIGN)
-    + ALIGN_UP (sizeof (struct multiboot_tag_efi64), MULTIBOOT_TAG_ALIGN)
     + ALIGN_UP (sizeof (struct multiboot_tag_old_acpi)
 		+ sizeof (struct grub_acpi_rsdp_v10), MULTIBOOT_TAG_ALIGN)
     + acpiv2_size ()
     + net_size ()
 #ifdef GRUB_MACHINE_EFI
+    + ALIGN_UP (sizeof (struct multiboot_tag_efi32), MULTIBOOT_TAG_ALIGN)
+    + ALIGN_UP (sizeof (struct multiboot_tag_efi32_ih), MULTIBOOT_TAG_ALIGN)
+    + ALIGN_UP (sizeof (struct multiboot_tag_efi64), MULTIBOOT_TAG_ALIGN)
+    + ALIGN_UP (sizeof (struct multiboot_tag_efi64_ih), MULTIBOOT_TAG_ALIGN)
     + ALIGN_UP (sizeof (struct multiboot_tag_efi_mmap)
 		+ efi_mmap_size, MULTIBOOT_TAG_ALIGN)
 #endif
@@ -907,11 +911,35 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
 
   if (keep_bs)
     {
-      struct multiboot_tag *tag = (struct multiboot_tag *) ptrorig;
-      tag->type = MULTIBOOT_TAG_TYPE_EFI_BS;
-      tag->size = sizeof (struct multiboot_tag);
-      ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
-	/ sizeof (grub_properly_aligned_t);
+      {
+	struct multiboot_tag *tag = (struct multiboot_tag *) ptrorig;
+	tag->type = MULTIBOOT_TAG_TYPE_EFI_BS;
+	tag->size = sizeof (struct multiboot_tag);
+	ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
+	  / sizeof (grub_properly_aligned_t);
+      }
+
+#ifdef __i386__
+      {
+	struct multiboot_tag_efi32_ih *tag = (struct multiboot_tag_efi32_ih *) ptrorig;
+	tag->type = MULTIBOOT_TAG_TYPE_EFI32_IH;
+	tag->size = sizeof (struct multiboot_tag_efi32_ih);
+	tag->pointer = (grub_addr_t) grub_efi_image_handle;
+	ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
+	  / sizeof (grub_properly_aligned_t);
+      }
+#endif
+
+#ifdef __x86_64__
+      {
+	struct multiboot_tag_efi64_ih *tag = (struct multiboot_tag_efi64_ih *) ptrorig;
+	tag->type = MULTIBOOT_TAG_TYPE_EFI64_IH;
+	tag->size = sizeof (struct multiboot_tag_efi64_ih);
+	tag->pointer = (grub_addr_t) grub_efi_image_handle;
+	ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
+	  / sizeof (grub_properly_aligned_t);
+      }
+#endif
     }
 #endif
 
diff --git a/include/multiboot2.h b/include/multiboot2.h
index 46e7b71..f5bebe1 100644
--- a/include/multiboot2.h
+++ b/include/multiboot2.h
@@ -60,6 +60,8 @@
 #define MULTIBOOT_TAG_TYPE_NETWORK           16
 #define MULTIBOOT_TAG_TYPE_EFI_MMAP          17
 #define MULTIBOOT_TAG_TYPE_EFI_BS            18
+#define MULTIBOOT_TAG_TYPE_EFI32_IH          19
+#define MULTIBOOT_TAG_TYPE_EFI64_IH          20
 
 #define MULTIBOOT_HEADER_TAG_END  0
 #define MULTIBOOT_HEADER_TAG_INFORMATION_REQUEST  1
@@ -371,6 +373,20 @@ struct multiboot_tag_efi_mmap
   multiboot_uint8_t efi_mmap[0];
 }; 
 
+struct multiboot_tag_efi32_ih
+{
+  multiboot_uint32_t type;
+  multiboot_uint32_t size;
+  multiboot_uint32_t pointer;
+};
+
+struct multiboot_tag_efi64_ih
+{
+  multiboot_uint32_t type;
+  multiboot_uint32_t size;
+  multiboot_uint64_t pointer;
+};
+
 #endif /* ! ASM_FILE */
 
 #endif /* ! MULTIBOOT_HEADER */
-- 
1.7.10.4


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[GRUB2 PATCH v5 3/4 - FOR REVIEW ONLY] multiboot2: Do not pass memory maps to image if EFI boot services are enabled

[Daniel Kiper]

If image requested EFI boot services then skip multiboot2 memory maps.
Main reason for not providing maps is because they will likely be
invalid. We do a few allocations after filling them, e.g. for relocator
needs. Usually we do not care as we would have finished boot services.
If we keep boot services then it is easier/safer to not provide maps.
However, if image needs memory maps and they are not provided by bootloader
then it should get itself just before ExitBootServices() call.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
v5 - suggestions/fixes:
   - improve commit message
     (suggested by Konrad Rzeszutek Wilk).

v3 - suggestions/fixes:
   - improve commit message
     (suggested by Konrad Rzeszutek Wilk and Vladimir 'phcoder' Serbinenko).
---
 grub-core/loader/multiboot_mbi2.c |   17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index 6c04402..ad1553b 100644
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -390,7 +390,7 @@ static grub_size_t
 grub_multiboot_get_mbi_size (void)
 {
 #ifdef GRUB_MACHINE_EFI
-  if (!efi_mmap_size)
+  if (!keep_bs && !efi_mmap_size)
     find_efi_mmap_size ();    
 #endif
   return 2 * sizeof (grub_uint32_t) + sizeof (struct multiboot_tag)
@@ -755,6 +755,7 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
       }
   }
 
+  if (!keep_bs)
     {
       struct multiboot_tag_mmap *tag = (struct multiboot_tag_mmap *) ptrorig;
       grub_fill_multiboot_mmap (tag);
@@ -776,6 +777,7 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
       / sizeof (grub_properly_aligned_t);
   }
 
+  if (!keep_bs)
     {
       struct multiboot_tag_basic_meminfo *tag
 	= (struct multiboot_tag_basic_meminfo *) ptrorig;
@@ -886,21 +888,17 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
     grub_efi_uintn_t efi_desc_size;
     grub_efi_uint32_t efi_desc_version;
 
+    if (!keep_bs)
+      {
 	tag->type = MULTIBOOT_TAG_TYPE_EFI_MMAP;
 	tag->size = sizeof (*tag) + efi_mmap_size;
 
-    if (!keep_bs)
 	err = grub_efi_finish_boot_services (&efi_mmap_size, tag->efi_mmap, NULL,
 					     &efi_desc_size, &efi_desc_version);
-    else
-      {
-	if (grub_efi_get_memory_map (&efi_mmap_size, (void *) tag->efi_mmap,
-				     NULL,
-				     &efi_desc_size, &efi_desc_version) <= 0)
-	  err = grub_error (GRUB_ERR_IO, "couldn't retrieve memory map");
-      }
+
 	if (err)
 	  return err;
+
 	tag->descr_size = efi_desc_size;
 	tag->descr_vers = efi_desc_version;
 	tag->size = sizeof (*tag) + efi_mmap_size;
@@ -908,6 +906,7 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
 	ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
 	  / sizeof (grub_properly_aligned_t);
       }
+  }
 
   if (keep_bs)
     {
-- 
1.7.10.4


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[GRUB2 PATCH v5 3/4 - FOR COMMIT] multiboot2: Do not pass memory maps to image if EFI boot services are enabled

[Daniel Kiper]

If image requested EFI boot services then skip multiboot2 memory maps.
Main reason for not providing maps is because they will likely be
invalid. We do a few allocations after filling them, e.g. for relocator
needs. Usually we do not care as we would have finished boot services.
If we keep boot services then it is easier/safer to not provide maps.
However, if image needs memory maps and they are not provided by bootloader
then it should get itself just before ExitBootServices() call.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
v5 - suggestions/fixes:
   - improve commit message
     (suggested by Konrad Rzeszutek Wilk).

v3 - suggestions/fixes:
   - improve commit message
     (suggested by Konrad Rzeszutek Wilk and Vladimir 'phcoder' Serbinenko).
---
 grub-core/loader/multiboot_mbi2.c |   71 ++++++++++++++++++-------------------
 1 file changed, 35 insertions(+), 36 deletions(-)

diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index 6c04402..ad1553b 100644
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -390,7 +390,7 @@ static grub_size_t
 grub_multiboot_get_mbi_size (void)
 {
 #ifdef GRUB_MACHINE_EFI
-  if (!efi_mmap_size)
+  if (!keep_bs && !efi_mmap_size)
     find_efi_mmap_size ();    
 #endif
   return 2 * sizeof (grub_uint32_t) + sizeof (struct multiboot_tag)
@@ -755,12 +755,13 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
       }
   }
 
-  {
-    struct multiboot_tag_mmap *tag = (struct multiboot_tag_mmap *) ptrorig;
-    grub_fill_multiboot_mmap (tag);
-    ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
-      / sizeof (grub_properly_aligned_t);
-  }
+  if (!keep_bs)
+    {
+      struct multiboot_tag_mmap *tag = (struct multiboot_tag_mmap *) ptrorig;
+      grub_fill_multiboot_mmap (tag);
+      ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
+	/ sizeof (grub_properly_aligned_t);
+    }
 
   {
     struct multiboot_tag_elf_sections *tag
@@ -776,18 +777,19 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
       / sizeof (grub_properly_aligned_t);
   }
 
-  {
-    struct multiboot_tag_basic_meminfo *tag
-      = (struct multiboot_tag_basic_meminfo *) ptrorig;
-    tag->type = MULTIBOOT_TAG_TYPE_BASIC_MEMINFO;
-    tag->size = sizeof (struct multiboot_tag_basic_meminfo); 
+  if (!keep_bs)
+    {
+      struct multiboot_tag_basic_meminfo *tag
+	= (struct multiboot_tag_basic_meminfo *) ptrorig;
+      tag->type = MULTIBOOT_TAG_TYPE_BASIC_MEMINFO;
+      tag->size = sizeof (struct multiboot_tag_basic_meminfo);
 
-    /* Convert from bytes to kilobytes.  */
-    tag->mem_lower = grub_mmap_get_lower () / 1024;
-    tag->mem_upper = grub_mmap_get_upper () / 1024;
-    ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
-       / sizeof (grub_properly_aligned_t);
-  }
+      /* Convert from bytes to kilobytes.  */
+      tag->mem_lower = grub_mmap_get_lower () / 1024;
+      tag->mem_upper = grub_mmap_get_upper () / 1024;
+      ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
+	/ sizeof (grub_properly_aligned_t);
+    }
 
   {
     struct grub_net_network_level_interface *net;
@@ -886,27 +888,24 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
     grub_efi_uintn_t efi_desc_size;
     grub_efi_uint32_t efi_desc_version;
 
-    tag->type = MULTIBOOT_TAG_TYPE_EFI_MMAP;
-    tag->size = sizeof (*tag) + efi_mmap_size;
-
     if (!keep_bs)
-      err = grub_efi_finish_boot_services (&efi_mmap_size, tag->efi_mmap, NULL,
-					   &efi_desc_size, &efi_desc_version);
-    else
       {
-	if (grub_efi_get_memory_map (&efi_mmap_size, (void *) tag->efi_mmap,
-				     NULL,
-				     &efi_desc_size, &efi_desc_version) <= 0)
-	  err = grub_error (GRUB_ERR_IO, "couldn't retrieve memory map");
+	tag->type = MULTIBOOT_TAG_TYPE_EFI_MMAP;
+	tag->size = sizeof (*tag) + efi_mmap_size;
+
+	err = grub_efi_finish_boot_services (&efi_mmap_size, tag->efi_mmap, NULL,
+					     &efi_desc_size, &efi_desc_version);
+
+	if (err)
+	  return err;
+
+	tag->descr_size = efi_desc_size;
+	tag->descr_vers = efi_desc_version;
+	tag->size = sizeof (*tag) + efi_mmap_size;
+
+	ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
+	  / sizeof (grub_properly_aligned_t);
       }
-    if (err)
-      return err;
-    tag->descr_size = efi_desc_size;
-    tag->descr_vers = efi_desc_version;
-    tag->size = sizeof (*tag) + efi_mmap_size;
-
-    ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
-      / sizeof (grub_properly_aligned_t);
   }
 
   if (keep_bs)
-- 
1.7.10.4


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[GRUB2 PATCH v5 4/4] multiboot2: Add support for relocatable images

[Daniel Kiper]

Currently multiboot2 protocol loads image exactly at address specified in
ELF or multiboot2 header. This solution works quite well on legacy BIOS
platforms. It is possible because memory regions are placed at predictable
addresses (though I was not able to find any spec which says that it is
strong requirement, so, it looks that it is just a goodwill of hardware
designers). However, EFI platforms are more volatile. Even if required
memory regions live at specific addresses then they are sometimes simply
not free (e.g. used by boot/runtime services on Dell PowerEdge R820 and
OVMF). This means that you are not able to just set up final image
destination on build time. You have to provide method to relocate image
contents to real load address which is usually different than load address
specified in ELF and multiboot2 headers.

This patch provides all needed machinery to do self relocation in image code.
First of all GRUB2 reads min_addr (min. load addr), max_addr (max. load addr),
align (required image alignment), preference (it says which memory regions are
preferred by image, e.g. none, low, high) from multiboot_header_tag_relocatable
header tag contained in binary (at this stage load addresses from multiboot2
and/or ELF headers are ignored). Later loader tries to fulfill request (not only
that one) and if it succeeds then it informs image about real load address via
multiboot_tag_load_base_addr tag. At this stage GRUB2 role is finished. Starting
from now executable must cope with relocations itself using whole static and
dynamic knowledge provided by boot loader.

This patch does not provide functionality which could do relocations using
ELF relocation data. However, I was asked by Konrad Rzeszutek Wilk and Vladimir
'phcoder' Serbinenko to investigate that thing. It looks that relevant machinery
could be added to existing code (including this patch) without huge effort.
Additionally, ELF relocation could live in parallel with self relocation provided
by this patch. However, during research I realized that first of all we should
establish the details how ELF relocatable image should look like and how it should
be build. At least to build proper test/example files.

So, this patch just provides support for self relocatable images. If ELF file
with relocs is loaded then GRUB2 complains loudly and ignores it. Support for
such files will be added later.

This patch was tested with Xen image which uses that functionality. However, this Xen
feature is still under development and new patchset will be released in about 3-4 weeks.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
---
v5 - suggestions/fixes:
   - fix support for multi segment ELF files
     (suggested by Vladimir 'phcoder' Serbinenko),
   - add some input data checks,
   - add some comments.

v4 - suggestions/fixes:
   - pack grub_multiboot_load_elf() arguments into struct
     (suggested by Juergen Gross, Konrad Rzeszutek Wilk
     and Vladimir 'phcoder' Serbinenko),
   - fix entry point address calculation
     (suggested by Vladimir 'phcoder' Serbinenko),
   - fail if ELF file has relocs sections
     (suggested by Vladimir 'phcoder' Serbinenko).

v3 - suggestions/fixes:
   - reduce number of casts
     (suggested by Konrad Rzeszutek Wilk),
   - remove unneeded space at the end of line
     (suggested by Konrad Rzeszutek Wilk),
   - improve commit message
     (suggested by Konrad Rzeszutek Wilk).
---
 grub-core/loader/i386/multiboot_mbi.c |   13 +++-
 grub-core/loader/multiboot.c          |   11 ++-
 grub-core/loader/multiboot_elfxx.c    |  127 ++++++++++++++++++++-------------
 grub-core/loader/multiboot_mbi2.c     |  114 +++++++++++++++++++++++------
 include/grub/multiboot.h              |   22 +++++-
 include/multiboot2.h                  |   24 +++++++
 6 files changed, 231 insertions(+), 80 deletions(-)

diff --git a/grub-core/loader/i386/multiboot_mbi.c b/grub-core/loader/i386/multiboot_mbi.c
index f60b702..fd7b41b 100644
--- a/grub-core/loader/i386/multiboot_mbi.c
+++ b/grub-core/loader/i386/multiboot_mbi.c
@@ -70,9 +70,18 @@ load_kernel (grub_file_t file, const char *filename,
 	     char *buffer, struct multiboot_header *header)
 {
   grub_err_t err;
+  mbi_load_data_t mld;
+
+  mld.file = file;
+  mld.filename = filename;
+  mld.buffer = buffer;
+  mld.mbi_ver = 1;
+  mld.relocatable = 0;
+  mld.avoid_efi_boot_services = 0;
+
   if (grub_multiboot_quirks & GRUB_MULTIBOOT_QUIRK_BAD_KLUDGE)
     {
-      err = grub_multiboot_load_elf (file, filename, buffer);
+      err = grub_multiboot_load_elf (&mld);
       if (err == GRUB_ERR_NONE) {
 	return GRUB_ERR_NONE;
       }
@@ -121,7 +130,7 @@ load_kernel (grub_file_t file, const char *filename,
       return GRUB_ERR_NONE;
     }
 
-  return grub_multiboot_load_elf (file, filename, buffer);
+  return grub_multiboot_load_elf (&mld);
 }
 
 static struct multiboot_header *
diff --git a/grub-core/loader/multiboot.c b/grub-core/loader/multiboot.c
index 18038fd..bd9d5b3 100644
--- a/grub-core/loader/multiboot.c
+++ b/grub-core/loader/multiboot.c
@@ -207,13 +207,12 @@ static grub_uint64_t highest_load;
 
 /* Load ELF32 or ELF64.  */
 grub_err_t
-grub_multiboot_load_elf (grub_file_t file, const char *filename,
-			 void *buffer)
+grub_multiboot_load_elf (mbi_load_data_t *mld)
 {
-  if (grub_multiboot_is_elf32 (buffer))
-    return grub_multiboot_load_elf32 (file, filename, buffer);
-  else if (grub_multiboot_is_elf64 (buffer))
-    return grub_multiboot_load_elf64 (file, filename, buffer);
+  if (grub_multiboot_is_elf32 (mld->buffer))
+    return grub_multiboot_load_elf32 (mld);
+  else if (grub_multiboot_is_elf64 (mld->buffer))
+    return grub_multiboot_load_elf64 (mld);
 
   return grub_error (GRUB_ERR_UNKNOWN_OS, N_("invalid arch-dependent ELF magic"));
 }
diff --git a/grub-core/loader/multiboot_elfxx.c b/grub-core/loader/multiboot_elfxx.c
index e3a39b6..8a9ab0c 100644
--- a/grub-core/loader/multiboot_elfxx.c
+++ b/grub-core/loader/multiboot_elfxx.c
@@ -51,11 +51,15 @@ CONCAT(grub_multiboot_is_elf, XX) (void *buffer)
 }
 
 static grub_err_t
-CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename, void *buffer)
+CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
 {
-  Elf_Ehdr *ehdr = (Elf_Ehdr *) buffer;
+  Elf_Ehdr *ehdr = (Elf_Ehdr *) mld->buffer;
   char *phdr_base;
+  grub_err_t err;
+  grub_relocator_chunk_t ch;
+  grub_uint32_t load_offset, load_size;
   int i;
+  void *source;
 
   if (ehdr->e_ident[EI_MAG0] != ELFMAG0
       || ehdr->e_ident[EI_MAG1] != ELFMAG1
@@ -75,54 +79,80 @@ CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename, voi
   if (ehdr->e_phoff + (grub_uint32_t) ehdr->e_phnum * ehdr->e_phentsize > MULTIBOOT_SEARCH)
     return grub_error (GRUB_ERR_BAD_OS, "program header at a too high offset");
 
-  phdr_base = (char *) buffer + ehdr->e_phoff;
+  phdr_base = (char *) mld->buffer + ehdr->e_phoff;
 #define phdr(i)			((Elf_Phdr *) (phdr_base + (i) * ehdr->e_phentsize))
 
+  mld->link_base_addr = ~0;
+
+  /* Calculate lowest and highest load address.  */
+  for (i = 0; i < ehdr->e_phnum; i++)
+    if (phdr(i)->p_type == PT_LOAD)
+      {
+	mld->link_base_addr = grub_min (mld->link_base_addr, phdr(i)->p_paddr);
+	highest_load = grub_max (highest_load, phdr(i)->p_paddr + phdr(i)->p_memsz);
+      }
+
+#ifdef MULTIBOOT_LOAD_ELF64
+  if (highest_load >= 0x100000000)
+    return grub_error (GRUB_ERR_BAD_OS, "segment cross 4 GiB border");
+#endif
+
+  load_size = highest_load - mld->link_base_addr;
+
+  if (mld->relocatable)
+    {
+      if (load_size > mld->max_addr || mld->min_addr > mld->max_addr - load_size)
+	return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size");
+
+      err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator, &ch,
+					      mld->min_addr, mld->max_addr - load_size,
+					      load_size, mld->align ? mld->align : 1,
+					      mld->preference, mld->avoid_efi_boot_services);
+    }
+  else
+    err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator, &ch,
+					   mld->link_base_addr, load_size);
+
+  if (err)
+    {
+      grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS image\n");
+      return err;
+    }
+
+  mld->load_base_addr = get_physical_target_address (ch);
+  source = get_virtual_current_address (ch);
+
   /* Load every loadable segment in memory.  */
   for (i = 0; i < ehdr->e_phnum; i++)
     {
       if (phdr(i)->p_type == PT_LOAD)
         {
-	  grub_err_t err;
-	  void *source;
 
-	  if (phdr(i)->p_paddr + phdr(i)->p_memsz > highest_load)
-	    highest_load = phdr(i)->p_paddr + phdr(i)->p_memsz;
+	  grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx, memsz=0x%lx, vaddr=0x%lx,"
+			"align=0x%lx, relocatable=%d, avoid_efi_boot_services=%d\n", i,
+			(long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz, (long) phdr(i)->p_vaddr,
+			(long) mld->align, mld->relocatable, mld->avoid_efi_boot_services);
 
-	  grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx, memsz=0x%lx, vaddr=0x%lx\n",
-			i, (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz, (long) phdr(i)->p_vaddr);
-
-	  {
-	    grub_relocator_chunk_t ch;
-	    err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator, 
-						   &ch, phdr(i)->p_paddr,
-						   phdr(i)->p_memsz);
-	    if (err)
-	      {
-		grub_dprintf ("multiboot_loader", "Error loading phdr %d\n", i);
-		return err;
-	      }
-	    source = get_virtual_current_address (ch);
-	  }
+	  load_offset = phdr(i)->p_paddr - mld->link_base_addr;
 
 	  if (phdr(i)->p_filesz != 0)
 	    {
-	      if (grub_file_seek (file, (grub_off_t) phdr(i)->p_offset)
+	      if (grub_file_seek (mld->file, (grub_off_t) phdr(i)->p_offset)
 		  == (grub_off_t) -1)
 		return grub_errno;
 
-	      if (grub_file_read (file, source, phdr(i)->p_filesz)
+	      if (grub_file_read (mld->file, (grub_uint8_t *) source + load_offset, phdr(i)->p_filesz)
 		  != (grub_ssize_t) phdr(i)->p_filesz)
 		{
 		  if (!grub_errno)
 		    grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
-				filename);
+				mld->filename);
 		  return grub_errno;
 		}
 	    }
 
           if (phdr(i)->p_filesz < phdr(i)->p_memsz)
-            grub_memset ((grub_uint8_t *) source + phdr(i)->p_filesz, 0,
+            grub_memset ((grub_uint8_t *) source + load_offset + phdr(i)->p_filesz, 0,
 			 phdr(i)->p_memsz - phdr(i)->p_filesz);
         }
     }
@@ -168,18 +198,18 @@ CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename, voi
       if (!shdr)
 	return grub_errno;
       
-      if (grub_file_seek (file, ehdr->e_shoff) == (grub_off_t) -1)
+      if (grub_file_seek (mld->file, ehdr->e_shoff) == (grub_off_t) -1)
 	{
 	  grub_free (shdr);
 	  return grub_errno;
 	}
 
-      if (grub_file_read (file, shdr, (grub_uint32_t) ehdr->e_shnum * ehdr->e_shentsize)
+      if (grub_file_read (mld->file, shdr, (grub_uint32_t) ehdr->e_shnum * ehdr->e_shentsize)
               != (grub_ssize_t) ehdr->e_shnum * ehdr->e_shentsize)
 	{
 	  if (!grub_errno)
 	    grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
-			filename);
+			mld->filename);
 	  return grub_errno;
 	}
       
@@ -189,7 +219,9 @@ CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename, voi
 	  Elf_Shdr *sh = (Elf_Shdr *) shdrptr;
 	  void *src;
 	  grub_addr_t target;
-	  grub_err_t err;
+
+	  if (mld->mbi_ver >= 2 && (sh->sh_type == SHT_REL || sh->sh_type == SHT_RELA))
+	    return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "ELF files with relocs are not supported yet");
 
 	  /* This section is a loaded section,
 	     so we don't care.  */
@@ -200,33 +232,28 @@ CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename, voi
 	  if (sh->sh_size == 0)
 	    continue;
 
-	  {
-	    grub_relocator_chunk_t ch;
-	    err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator,
-						    &ch, 0,
-						    (0xffffffff - sh->sh_size)
-						    + 1, sh->sh_size,
-						    sh->sh_addralign,
-						    GRUB_RELOCATOR_PREFERENCE_NONE,
-						    0);
-	    if (err)
-	      {
-		grub_dprintf ("multiboot_loader", "Error loading shdr %d\n", i);
-		return err;
-	      }
-	    src = get_virtual_current_address (ch);
-	    target = get_physical_target_address (ch);
-	  }
+	  err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator, &ch, 0,
+						  (0xffffffff - sh->sh_size) + 1,
+						  sh->sh_size, sh->sh_addralign,
+						  GRUB_RELOCATOR_PREFERENCE_NONE,
+						  mld->avoid_efi_boot_services);
+	  if (err)
+	    {
+	      grub_dprintf ("multiboot_loader", "Error loading shdr %d\n", i);
+	      return err;
+	    }
+	  src = get_virtual_current_address (ch);
+	  target = get_physical_target_address (ch);
 
-	  if (grub_file_seek (file, sh->sh_offset) == (grub_off_t) -1)
+	  if (grub_file_seek (mld->file, sh->sh_offset) == (grub_off_t) -1)
 	    return grub_errno;
 
-          if (grub_file_read (file, src, sh->sh_size)
+          if (grub_file_read (mld->file, src, sh->sh_size)
               != (grub_ssize_t) sh->sh_size)
 	    {
 	      if (!grub_errno)
 		grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
-			    filename);
+			    mld->filename);
 	      return grub_errno;
 	    }
 	  sh->sh_addr = target;
diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index ad1553b..655a911 100644
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -68,6 +68,7 @@ static grub_size_t elf_sec_num, elf_sec_entsize;
 static unsigned elf_sec_shstrndx;
 static void *elf_sections;
 static int keep_bs = 0;
+static grub_uint32_t load_base_addr;
 
 void
 grub_multiboot_add_elfsyms (grub_size_t num, grub_size_t entsize,
@@ -101,36 +102,40 @@ find_header (grub_properly_aligned_t *buffer, grub_ssize_t len)
 grub_err_t
 grub_multiboot_load (grub_file_t file, const char *filename)
 {
-  grub_properly_aligned_t *buffer;
   grub_ssize_t len;
   struct multiboot_header *header;
   grub_err_t err;
   struct multiboot_header_tag *tag;
   struct multiboot_header_tag_address *addr_tag = NULL;
+  struct multiboot_header_tag_relocatable *rel_tag;
   int entry_specified = 0, efi_entry_specified = 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;
+  mbi_load_data_t mld;
 
-  buffer = grub_malloc (MULTIBOOT_SEARCH);
-  if (!buffer)
+  mld.mbi_ver = 2;
+  mld.relocatable = 0;
+
+  mld.buffer = grub_malloc (MULTIBOOT_SEARCH);
+  if (!mld.buffer)
     return grub_errno;
 
-  len = grub_file_read (file, buffer, MULTIBOOT_SEARCH);
+  len = grub_file_read (file, mld.buffer, MULTIBOOT_SEARCH);
   if (len < 32)
     {
-      grub_free (buffer);
+      grub_free (mld.buffer);
       return grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"), filename);
     }
 
   COMPILE_TIME_ASSERT (MULTIBOOT_HEADER_ALIGN % 4 == 0);
 
-  header = find_header (buffer, len);
+  header = find_header (mld.buffer, len);
 
   if (header == 0)
     {
-      grub_free (buffer);
+      grub_free (mld.buffer);
       return grub_error (GRUB_ERR_BAD_ARGUMENT, "no multiboot header found");
     }
 
@@ -174,10 +179,11 @@ grub_multiboot_load (grub_file_t file, const char *filename)
 	      case MULTIBOOT_TAG_TYPE_EFI_BS:
 	      case MULTIBOOT_TAG_TYPE_EFI32_IH:
 	      case MULTIBOOT_TAG_TYPE_EFI64_IH:
+	      case MULTIBOOT_TAG_TYPE_LOAD_BASE_ADDR:
 		break;
 
 	      default:
-		grub_free (buffer);
+		grub_free (mld.buffer);
 		return grub_error (GRUB_ERR_UNKNOWN_OS,
 				   "unsupported information tag: 0x%x",
 				   request_tag->requests[i]);
@@ -215,6 +221,27 @@ grub_multiboot_load (grub_file_t file, const char *filename)
 	accepted_consoles |= GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER;
 	break;
 
+      case MULTIBOOT_HEADER_TAG_RELOCATABLE:
+	mld.relocatable = 1;
+	rel_tag = (struct multiboot_header_tag_relocatable *) tag;
+	mld.min_addr = rel_tag->min_addr;
+	mld.max_addr = rel_tag->max_addr;
+	mld.align = rel_tag->align;
+	switch (rel_tag->preference)
+	  {
+	  case MULTIBOOT_LOAD_PREFERENCE_LOW:
+	    mld.preference = GRUB_RELOCATOR_PREFERENCE_LOW;
+	    break;
+
+	  case MULTIBOOT_LOAD_PREFERENCE_HIGH:
+	    mld.preference = GRUB_RELOCATOR_PREFERENCE_HIGH;
+	    break;
+
+	  default:
+	    mld.preference = GRUB_RELOCATOR_PREFERENCE_NONE;
+	  }
+	break;
+
 	/* GRUB always page-aligns modules.  */
       case MULTIBOOT_HEADER_TAG_MODULE_ALIGN:
 	break;
@@ -228,7 +255,7 @@ grub_multiboot_load (grub_file_t file, const char *filename)
       default:
 	if (! (tag->flags & MULTIBOOT_HEADER_TAG_OPTIONAL))
 	  {
-	    grub_free (buffer);
+	    grub_free (mld.buffer);
 	    return grub_error (GRUB_ERR_UNKNOWN_OS,
 			       "unsupported tag: 0x%x", tag->type);
 	  }
@@ -237,7 +264,7 @@ grub_multiboot_load (grub_file_t file, const char *filename)
 
   if (addr_tag && !entry_specified && !(keep_bs && efi_entry_specified))
     {
-      grub_free (buffer);
+      grub_free (mld.buffer);
       return grub_error (GRUB_ERR_UNKNOWN_OS,
 			 "load address tag without entry address tag");
     }
@@ -246,8 +273,8 @@ grub_multiboot_load (grub_file_t file, const char *filename)
     {
       grub_uint64_t load_addr = (addr_tag->load_addr + 1)
 	? addr_tag->load_addr : (addr_tag->header_addr
-				 - ((char *) header - (char *) buffer));
-      int offset = ((char *) header - (char *) buffer -
+				 - ((char *) header - (char *) mld.buffer));
+      int offset = ((char *) header - (char *) mld.buffer -
 	   (addr_tag->header_addr - load_addr));
       int load_size = ((addr_tag->load_end_addr == 0) ? file->size - offset :
 		       addr_tag->load_end_addr - addr_tag->load_addr);
@@ -260,27 +287,42 @@ grub_multiboot_load (grub_file_t file, const char *filename)
       else
 	code_size = load_size;
 
-      err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator, 
-					     &ch, load_addr,
-					     code_size);
+      if (mld.relocatable)
+	{	      
+	  if (code_size > mld.max_addr || mld.min_addr > mld.max_addr - code_size)
+	    {
+	      grub_free (mld.buffer);
+	      return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size");
+	    }
+
+	  err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator, &ch,
+						  mld.min_addr, mld.max_addr - code_size,
+						  code_size, mld.align ? mld.align : 1,
+						  mld.preference, keep_bs);
+	}	      
+      else
+	err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator,
+					       &ch, load_addr, code_size);
       if (err)
 	{
 	  grub_dprintf ("multiboot_loader", "Error loading aout kludge\n");
-	  grub_free (buffer);
+	  grub_free (mld.buffer);
 	  return err;
 	}
+      mld.link_base_addr = load_addr;
+      mld.load_base_addr = get_physical_target_address (ch);
       source = get_virtual_current_address (ch);
 
       if ((grub_file_seek (file, offset)) == (grub_off_t) -1)
 	{
-	  grub_free (buffer);
+	  grub_free (mld.buffer);
 	  return grub_errno;
 	}
 
       grub_file_read (file, source, load_size);
       if (grub_errno)
 	{
-	  grub_free (buffer);
+	  grub_free (mld.buffer);
 	  return grub_errno;
 	}
 
@@ -290,19 +332,41 @@ grub_multiboot_load (grub_file_t file, const char *filename)
     }
   else
     {
-      err = grub_multiboot_load_elf (file, filename, buffer);
+      mld.file = file;
+      mld.filename = filename;
+      mld.avoid_efi_boot_services = keep_bs;
+      err = grub_multiboot_load_elf (&mld);
       if (err)
 	{
-	  grub_free (buffer);
+	  grub_free (mld.buffer);
 	  return err;
 	}
     }
 
+  load_base_addr = mld.load_base_addr;
+
   if (keep_bs && efi_entry_specified)
     grub_multiboot_payload_eip = efi_entry;
   else if (entry_specified)
     grub_multiboot_payload_eip = entry;
 
+  if (mld.relocatable)
+    {
+      /*
+       * Both branches are mathematically equivalent. However, it looks
+       * that real life (C?) is more complicated. I am trying to avoid
+       * wrap around here if mld.load_base_addr < mld.link_base_addr.
+       * If you look at C operator precedence then everything should work.
+       * However, I am not 100% sure that a given compiler will not
+       * optimize/break this stuff. So, maybe we should use signed
+       * 64-bit int here.
+       */
+      if (mld.load_base_addr >= mld.link_base_addr)
+	grub_multiboot_payload_eip += mld.load_base_addr - mld.link_base_addr;
+      else
+	grub_multiboot_payload_eip -= mld.link_base_addr - mld.load_base_addr;
+    }
+
   if (fbtag)
     err = grub_multiboot_set_console (GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER,
 				      accepted_consoles,
@@ -411,6 +475,7 @@ grub_multiboot_get_mbi_size (void)
     + ALIGN_UP (sizeof (struct multiboot_tag_framebuffer), MULTIBOOT_TAG_ALIGN)
     + ALIGN_UP (sizeof (struct multiboot_tag_old_acpi)
 		+ sizeof (struct grub_acpi_rsdp_v10), MULTIBOOT_TAG_ALIGN)
+    + ALIGN_UP (sizeof (struct multiboot_tag_load_base_addr), MULTIBOOT_TAG_ALIGN)
     + acpiv2_size ()
     + net_size ()
 #ifdef GRUB_MACHINE_EFI
@@ -694,6 +759,15 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
   ptrorig += (2 * sizeof (grub_uint32_t)) / sizeof (grub_properly_aligned_t);
 
   {
+    struct multiboot_tag_load_base_addr *tag = (struct multiboot_tag_load_base_addr *) ptrorig;
+    tag->type = MULTIBOOT_TAG_TYPE_LOAD_BASE_ADDR;
+    tag->size = sizeof (struct multiboot_tag_load_base_addr);
+    tag->load_base_addr = load_base_addr;
+    ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
+       / sizeof (grub_properly_aligned_t);
+  }
+
+  {
     struct multiboot_tag_string *tag = (struct multiboot_tag_string *) ptrorig;
     tag->type = MULTIBOOT_TAG_TYPE_CMDLINE;
     tag->size = sizeof (struct multiboot_tag_string) + cmdline_size; 
diff --git a/include/grub/multiboot.h b/include/grub/multiboot.h
index e13c084..c96492b 100644
--- a/include/grub/multiboot.h
+++ b/include/grub/multiboot.h
@@ -91,10 +91,28 @@ grub_multiboot_set_console (int console_type, int accepted_consoles,
 			    int console_required);
 grub_err_t
 grub_multiboot_load (grub_file_t file, const char *filename);
+
+struct mbi_load_data
+{
+  grub_file_t file;
+  const char *filename;
+  void *buffer;
+  unsigned int mbi_ver;
+  int relocatable;
+  grub_uint32_t min_addr;
+  grub_uint32_t max_addr;
+  grub_size_t align;
+  grub_uint32_t preference;
+  grub_uint32_t link_base_addr;
+  grub_uint32_t load_base_addr;
+  int avoid_efi_boot_services;
+};
+typedef struct mbi_load_data mbi_load_data_t;
+
 /* Load ELF32 or ELF64.  */
 grub_err_t
-grub_multiboot_load_elf (grub_file_t file, const char *filename,
-			 void *buffer);
+grub_multiboot_load_elf (mbi_load_data_t *mld);
+
 extern grub_size_t grub_multiboot_pure_size;
 extern grub_size_t grub_multiboot_alloc_mbi;
 extern grub_uint32_t grub_multiboot_payload_eip;
diff --git a/include/multiboot2.h b/include/multiboot2.h
index f5bebe1..5a3db5a 100644
--- a/include/multiboot2.h
+++ b/include/multiboot2.h
@@ -62,6 +62,7 @@
 #define MULTIBOOT_TAG_TYPE_EFI_BS            18
 #define MULTIBOOT_TAG_TYPE_EFI32_IH          19
 #define MULTIBOOT_TAG_TYPE_EFI64_IH          20
+#define MULTIBOOT_TAG_TYPE_LOAD_BASE_ADDR    21
 
 #define MULTIBOOT_HEADER_TAG_END  0
 #define MULTIBOOT_HEADER_TAG_INFORMATION_REQUEST  1
@@ -72,11 +73,16 @@
 #define MULTIBOOT_HEADER_TAG_MODULE_ALIGN  6
 #define MULTIBOOT_HEADER_TAG_EFI_BS  7
 #define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS_EFI64  9
+#define MULTIBOOT_HEADER_TAG_RELOCATABLE  10
 
 #define MULTIBOOT_ARCHITECTURE_I386  0
 #define MULTIBOOT_ARCHITECTURE_MIPS32  4
 #define MULTIBOOT_HEADER_TAG_OPTIONAL 1
 
+#define MULTIBOOT_LOAD_PREFERENCE_NONE 0
+#define MULTIBOOT_LOAD_PREFERENCE_LOW 1
+#define MULTIBOOT_LOAD_PREFERENCE_HIGH 2
+
 #define MULTIBOOT_CONSOLE_FLAGS_CONSOLE_REQUIRED 1
 #define MULTIBOOT_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED 2
 
@@ -161,6 +167,17 @@ struct multiboot_header_tag_module_align
   multiboot_uint32_t size;
 };
 
+struct multiboot_header_tag_relocatable
+{
+  multiboot_uint16_t type;
+  multiboot_uint16_t flags;
+  multiboot_uint32_t size;
+  multiboot_uint32_t min_addr;
+  multiboot_uint32_t max_addr;
+  multiboot_uint32_t align;
+  multiboot_uint32_t preference;
+};
+
 struct multiboot_color
 {
   multiboot_uint8_t red;
@@ -387,6 +404,13 @@ struct multiboot_tag_efi64_ih
   multiboot_uint64_t pointer;
 };
 
+struct multiboot_tag_load_base_addr
+{
+  multiboot_uint32_t type;
+  multiboot_uint32_t size;
+  multiboot_uint32_t load_base_addr;
+};
+
 #endif /* ! ASM_FILE */
 
 #endif /* ! MULTIBOOT_HEADER */
-- 
1.7.10.4


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Re: [GRUB2 PATCH v5 4/4] multiboot2: Add support for relocatable images

[Konrad Rzeszutek Wilk]

On Fri, Mar 18, 2016 at 06:00:27PM +0100, Daniel Kiper wrote:
> Currently multiboot2 protocol loads image exactly at address specified in
> ELF or multiboot2 header. This solution works quite well on legacy BIOS
> platforms. It is possible because memory regions are placed at predictable
> addresses (though I was not able to find any spec which says that it is
> strong requirement, so, it looks that it is just a goodwill of hardware
> designers). However, EFI platforms are more volatile. Even if required
> memory regions live at specific addresses then they are sometimes simply
> not free (e.g. used by boot/runtime services on Dell PowerEdge R820 and
> OVMF). This means that you are not able to just set up final image
> destination on build time. You have to provide method to relocate image
> contents to real load address which is usually different than load address
> specified in ELF and multiboot2 headers.
> 
> This patch provides all needed machinery to do self relocation in image code.
> First of all GRUB2 reads min_addr (min. load addr), max_addr (max. load addr),
> align (required image alignment), preference (it says which memory regions are
> preferred by image, e.g. none, low, high) from multiboot_header_tag_relocatable
> header tag contained in binary (at this stage load addresses from multiboot2
> and/or ELF headers are ignored). Later loader tries to fulfill request (not only
> that one) and if it succeeds then it informs image about real load address via
> multiboot_tag_load_base_addr tag. At this stage GRUB2 role is finished. Starting
> from now executable must cope with relocations itself using whole static and
> dynamic knowledge provided by boot loader.
> 
> This patch does not provide functionality which could do relocations using
> ELF relocation data. However, I was asked by Konrad Rzeszutek Wilk and Vladimir
> 'phcoder' Serbinenko to investigate that thing. It looks that relevant machinery
> could be added to existing code (including this patch) without huge effort.
> Additionally, ELF relocation could live in parallel with self relocation provided
> by this patch. However, during research I realized that first of all we should
> establish the details how ELF relocatable image should look like and how it should
> be build. At least to build proper test/example files.
> 
> So, this patch just provides support for self relocatable images. If ELF file
> with relocs is loaded then GRUB2 complains loudly and ignores it. Support for
> such files will be added later.
> 
> This patch was tested with Xen image which uses that functionality. However, this Xen
> feature is still under development and new patchset will be released in about 3-4 weeks.

> index e3a39b6..8a9ab0c 100644
> --- a/grub-core/loader/multiboot_elfxx.c
> +++ b/grub-core/loader/multiboot_elfxx.c

..snip..
>  static grub_err_t
> -CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename, void *buffer)
> +CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
>  {
> +#ifdef MULTIBOOT_LOAD_ELF64
> +  if (highest_load >= 0x100000000)
> +    return grub_error (GRUB_ERR_BAD_OS, "segment cross 4 GiB border");

segment crosses 4GiB border!

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