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[Xen-devel] [GRUB2 PATCH v3 1/4] 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.

If idea is accepted I will prepare grub_relocator32_efi relocator too.

Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
---
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/lib/i386/relocator.c    |   48 ++++++++++++++++++++++++++++++++++
 grub-core/lib/i386/relocator64.S  |    3 +++
 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 +
 7 files changed, 145 insertions(+), 9 deletions(-)

diff --git a/grub-core/lib/i386/relocator.c b/grub-core/lib/i386/relocator.c
index 71dd4f0..2b0c260 100644
--- a/grub-core/lib/i386/relocator.c
+++ b/grub-core/lib/i386/relocator.c
@@ -69,6 +69,13 @@ extern grub_uint64_t grub_relocator64_rsi;
 extern grub_addr_t grub_relocator64_cr3;
 extern struct grub_i386_idt grub_relocator16_idt;
 
+#ifdef GRUB_MACHINE_EFI
+#ifdef __x86_64__
+extern grub_uint8_t grub_relocator64_efi_start;
+extern grub_uint8_t grub_relocator64_efi_end;
+#endif
+#endif
+
 #define RELOCATOR_SIZEOF(x)    (&grub_relocator##x##_end - 
&grub_relocator##x##_start)
 
 grub_err_t
@@ -214,3 +221,44 @@ grub_relocator64_boot (struct grub_relocator *rel,
   /* Not reached.  */
   return GRUB_ERR_NONE;
 }
+
+#ifdef GRUB_MACHINE_EFI
+#ifdef __x86_64__
+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;
+}
+#endif
+#endif
diff --git a/grub-core/lib/i386/relocator64.S b/grub-core/lib/i386/relocator64.S
index e4648d8..7a06b16 100644
--- a/grub-core/lib/i386/relocator64.S
+++ b/grub-core/lib/i386/relocator64.S
@@ -73,6 +73,7 @@ VARIABLE(grub_relocator64_rsp)
 
        movq    %rax, %rsp
 
+VARIABLE(grub_relocator64_efi_start)
        /* mov imm64, %rax */
        .byte   0x48
        .byte   0xb8
@@ -120,6 +121,8 @@ LOCAL(jump_addr):
 VARIABLE(grub_relocator64_rip)
        .quad   0
 
+VARIABLE(grub_relocator64_efi_end)
+
 #ifndef __x86_64__
        .p2align        4
 LOCAL(gdt):
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 9d48627..d96aa40 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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