[PATCH RFC 5/7] xen/x86: Add multiboot2 protocol support

[Daniel Kiper <daniel.kiper@oracle.com>]

Add multiboot2 protocol support. This way we are laying the foundation
for EFI + GRUB2 + Xen development.

Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 xen/arch/x86/boot/head.S  |  112 ++++++++++++++++++++++++++++++++++++++++++++-
 xen/arch/x86/boot/reloc.c |  103 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 212 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 79bce3c..f0ea6d0 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -1,5 +1,6 @@
 #include <xen/config.h>
 #include <xen/multiboot.h>
+#include <xen/multiboot2.h>
 #include <public/xen.h>
 #include <asm/asm_defns.h>
 #include <asm/desc.h>
@@ -33,6 +34,68 @@ ENTRY(start)
         /* Checksum: must be the negated sum of the first two fields. */
         .long   -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
 
+/*** MULTIBOOT2 HEADER ****/
+/* Some ideas are taken from grub-2.00/grub-core/tests/boot/kernel-i386.S file. */
+        .align  MULTIBOOT2_HEADER_ALIGN
+
+multiboot2_header:
+        /* Magic number indicating a Multiboot2 header. */
+        .long   MULTIBOOT2_HEADER_MAGIC
+        /* Architecture: i386. */
+        .long   MULTIBOOT2_ARCHITECTURE_I386
+        /* Multiboot2 header length. */
+        .long   multiboot2_header_end - multiboot2_header
+        /* Multiboot2 header checksum. */
+        .long   -(MULTIBOOT2_HEADER_MAGIC + MULTIBOOT2_ARCHITECTURE_I386 + \
+                        (multiboot2_header_end - multiboot2_header))
+
+        /* Multiboot2 tags... */
+multiboot2_info_req:
+        /* Multiboot2 information request tag. */
+        .short  MULTIBOOT2_HEADER_TAG_INFORMATION_REQUEST
+        .short  MULTIBOOT2_HEADER_TAG_REQUIRED
+        .long   multiboot2_info_req_end - multiboot2_info_req
+        .long   MULTIBOOT2_TAG_TYPE_MMAP
+multiboot2_info_req_end:
+
+        /*
+         * Align Xen image and modules at page boundry.
+         *
+         * .balignl MULTIBOOT2_TAG_ALIGN, MULTIBOOT2_TAG_TYPE_END is a hack
+         * to avoid bug related to Multiboot2 information request tag in earlier
+         * versions of GRUB2.
+         *
+         * DO NOT MOVE THIS TAG! ANY CHANGE HERE MAY BREAK COMPATIBILITY
+         * WITH EARLIER GRUB2 VERSIONS!
+         */
+        .balignl MULTIBOOT2_TAG_ALIGN, MULTIBOOT2_TAG_TYPE_END
+        .short   MULTIBOOT2_HEADER_TAG_MODULE_ALIGN
+        .short   MULTIBOOT2_HEADER_TAG_REQUIRED
+        .long    8 /* Tag size. */
+
+        /* Console flags tag. */
+        .align  MULTIBOOT2_TAG_ALIGN
+        .short  MULTIBOOT2_HEADER_TAG_CONSOLE_FLAGS
+        .short  MULTIBOOT2_HEADER_TAG_OPTIONAL
+        .long   12 /* Tag size. */
+        .long   MULTIBOOT2_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED
+
+        /* Framebuffer tag. */
+        .align  MULTIBOOT2_TAG_ALIGN
+        .short  MULTIBOOT2_HEADER_TAG_FRAMEBUFFER
+        .short  MULTIBOOT2_HEADER_TAG_OPTIONAL
+        .long   20 /* Tag size. */
+        .long   0 /* Number of the columns - no preference. */
+        .long   0 /* Number of the lines - no preference. */
+        .long   0 /* Number of bits per pixel - no preference. */
+
+        /* Multiboot2 header end tag. */
+        .align  MULTIBOOT2_TAG_ALIGN
+        .short  MULTIBOOT2_HEADER_TAG_END
+        .short  0
+        .long   8 /* Tag size. */
+multiboot2_header_end:
+
         .section .init.rodata, "a", @progbits
         .align 4
 
@@ -81,10 +144,55 @@ __start:
         mov     %ecx,%es
         mov     %ecx,%ss
 
+        /* Set mem_lower to 0 */
+        xor     %edx,%edx
+
         /* Check for Multiboot bootloader */
-        cmp     $0x2BADB002,%eax
-        jne     not_multiboot
+        cmp     $MULTIBOOT_BOOTLOADER_MAGIC,%eax
+        je      1f
+
+        /* Check for Multiboot2 bootloader */
+        cmp     $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
+        je      2f
+
+        jmp     not_multiboot
+
+1:
+        /* Get mem_lower from Multiboot information */
+        testb   $MBI_MEMLIMITS,(%ebx)
+        jz      0f                  /* not available? BDA value will be fine */
 
+        mov     4(%ebx),%edx
+        shl     $10-4,%edx
+        jmp     0f
+
+2:
+        /* Get Multiboot2 information address */
+        mov     %ebx,%ecx
+        add     $8,%ecx
+
+3:
+        /* Get mem_lower from Multiboot2 information */
+        cmpl    $MULTIBOOT2_TAG_TYPE_BASIC_MEMINFO,(%ecx)
+        jne     4f
+
+        mov     8(%ecx),%edx
+        shl     $10-4,%edx
+        jmp     5f
+
+4:
+        /* Is it the end of Multiboot2 information? */
+        cmpl    $MULTIBOOT2_TAG_TYPE_END,(%ecx)
+        je      0f
+
+5:
+        /* Go to next Multiboot2 information tag */
+        add     4(%ecx),%ecx
+        add     $(MULTIBOOT2_TAG_ALIGN-1),%ecx
+        and     $~(MULTIBOOT2_TAG_ALIGN-1),%ecx
+        jmp     3b
+
+0:
         /* Set up trampoline segment 64k below EBDA */
         movzwl  0x40e,%ecx          /* EBDA segment */
         cmp     $0xa000,%ecx        /* sanity check (high) */
diff --git a/xen/arch/x86/boot/reloc.c b/xen/arch/x86/boot/reloc.c
index 29f4887..eaf3226 100644
--- a/xen/arch/x86/boot/reloc.c
+++ b/xen/arch/x86/boot/reloc.c
@@ -18,8 +18,12 @@ typedef unsigned long u32;
 typedef unsigned long long u64;
 
 #include "../../../include/xen/multiboot.h"
+#include "../../../include/xen/multiboot2.h"
 #include "../../../include/asm/mbd.h"
 
+#define ALIGN_UP(addr, align) \
+                ((addr + (typeof(addr))align - 1) & ~((typeof(addr))align - 1))
+
 /*
  * __HERE__ IS TRUE ENTRY POINT!!!
  *
@@ -144,6 +148,100 @@ static mbd_t *mb_mbd(mbd_t *mbd, multiboot_info_t *mbi)
     return mbd;
 }
 
+static mbd_t *mb2_mbd(mbd_t *mbd, void *mbi)
+{
+    int i, mod_idx = 0;
+    memory_map_t *mmap_dst;
+    multiboot2_memory_map_t *mmap_src;
+    multiboot2_tag_t *tag;
+    u32 ptr;
+    boot_module_t *mbd_mods;
+
+    /* Skip Multiboot2 information fixed part. */
+    tag = mbi + sizeof(u32) * 2;
+
+    while ( 1 )
+    {
+        if ( tag->type == MULTIBOOT2_TAG_TYPE_MODULE )
+            ++mbd->mods_nr;
+        else if ( tag->type == MULTIBOOT2_TAG_TYPE_END )
+        {
+            mbd->mods = alloc_struct(mbd->mods_nr * sizeof(boot_module_t));
+            mbd_mods = (boot_module_t *)mbd->mods;
+            break;
+        }
+
+        /* Go to next Multiboot2 information tag. */
+        tag = (multiboot2_tag_t *)(ALIGN_UP((u32)tag + tag->size, MULTIBOOT2_TAG_ALIGN));
+    }
+
+    /* Skip Multiboot2 information fixed part. */
+    tag = mbi + sizeof(u32) * 2;
+
+    while ( 1 )
+    {
+        switch ( tag->type )
+        {
+        case MULTIBOOT2_TAG_TYPE_BOOT_LOADER_NAME:
+            ptr = (u32)((multiboot2_tag_string_t *)tag)->string;
+            mbd->boot_loader_name = copy_string(ptr);
+            break;
+
+        case MULTIBOOT2_TAG_TYPE_CMDLINE:
+            ptr = (u32)((multiboot2_tag_string_t *)tag)->string;
+            mbd->cmdline = copy_string(ptr);
+            break;
+
+        case MULTIBOOT2_TAG_TYPE_BASIC_MEMINFO:
+            mbd->mem_lower = ((multiboot2_tag_basic_meminfo_t *)tag)->mem_lower;
+            mbd->mem_upper = ((multiboot2_tag_basic_meminfo_t *)tag)->mem_upper;
+            break;
+
+        case MULTIBOOT2_TAG_TYPE_MMAP:
+            mbd->mmap_size = ((multiboot2_tag_mmap_t *)tag)->size;
+            mbd->mmap_size -= sizeof(multiboot2_tag_mmap_t);
+            mbd->mmap_size += sizeof(((multiboot2_tag_mmap_t){0}).entries);
+            mbd->mmap_size /= ((multiboot2_tag_mmap_t *)tag)->entry_size;
+            mbd->mmap_size *= sizeof(memory_map_t);
+
+            mbd->mmap = alloc_struct(mbd->mmap_size);
+
+            mmap_src = ((multiboot2_tag_mmap_t *)tag)->entries;
+            mmap_dst = (memory_map_t *)mbd->mmap;
+
+            for (i = 0; i < mbd->mmap_size / sizeof(memory_map_t); ++i)
+            {
+                mmap_dst[i].size = sizeof(memory_map_t);
+                mmap_dst[i].size -= sizeof(((memory_map_t){0}).size);
+                mmap_dst[i].base_addr_low = (u32)mmap_src[i].addr;
+                mmap_dst[i].base_addr_high = (u32)(mmap_src[i].addr >> 32);
+                mmap_dst[i].length_low = (u32)mmap_src[i].len;
+                mmap_dst[i].length_high = (u32)(mmap_src[i].len >> 32);
+                mmap_dst[i].type = mmap_src[i].type;
+            }
+            break;
+
+        case MULTIBOOT2_TAG_TYPE_MODULE:
+            mbd_mods[mod_idx].start = (u32)((multiboot2_tag_module_t *)tag)->mod_start;
+            mbd_mods[mod_idx].end = (u32)((multiboot2_tag_module_t *)tag)->mod_end;
+            ptr = (u32)((multiboot2_tag_module_t *)tag)->cmdline;
+            mbd_mods[mod_idx].cmdline = copy_string(ptr);
+            mbd_mods[mod_idx].relocated = 0;
+            ++mod_idx;
+            break;
+
+        case MULTIBOOT2_TAG_TYPE_END:
+            return mbd;
+
+        default:
+            break;
+        }
+
+        /* Go to next Multiboot2 information tag. */
+        tag = (multiboot2_tag_t *)(ALIGN_UP((u32)tag + tag->size, MULTIBOOT2_TAG_ALIGN));
+    }
+}
+
 /*
  * __THIS__ IS NOT ENTRY POINT!!!
  * PLEASE LOOK AT THE BEGINNING OF THIS FILE!!!
@@ -158,5 +256,8 @@ mbd_t *__reloc(void *mbi, u32 mb_magic)
     mbd = (mbd_t *)alloc_struct(sizeof(mbd_t));
     zero_struct((u32)mbd, sizeof(mbd_t));
 
-    return mb_mbd(mbd, mbi);
+    if ( mb_magic == MULTIBOOT_BOOTLOADER_MAGIC )
+        return mb_mbd(mbd, mbi);
+    else
+        return mb2_mbd(mbd, mbi);
 }
-- 
1.7.10.4