[RFC,4/7] xen/x86: Add some addresses to the Multiboot2 header

Commit Message

Daniel Kiper July 8, 2017, 9:53 p.m. UTC

In comparison to ELF the PE format is not supported by the Multiboot2
protocol. So, if we wish to load xen.efi using this protocol we have
to add MULTIBOOT2_HEADER_TAG_ADDRESS and MULTIBOOT2_HEADER_TAG_ENTRY_ADDRESS
tags into Multiboot2 header.

Additionally, put MULTIBOOT2_HEADER_TAG_ENTRY_ADDRESS and
MULTIBOOT2_HEADER_TAG_ENTRY_ADDRESS_EFI64 tags close to each other.

Signed-off-by: Daniel Kiper <[e-mail]>
---
 xen/arch/x86/boot/head.S |   19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

Patch

diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index 0c603a5..90db661 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -237,6 +237,13 @@  multiboot2_header_start:
         /* Align modules at page boundry. */
         mb2ht_init MB2_HT(MODULE_ALIGN), MB2_HT(REQUIRED)
 
+        /* The address tag. */
+        mb2ht_init MB2_HT(ADDRESS), MB2_HT(REQUIRED), \
+                   sym_offs(multiboot2_header_start), /* header_addr */ \
+                   sym_offs(start),                   /* load_addr */ \
+                   sym_offs(__bss_start),             /* load_end_addr */ \
+                   sym_offs(__2M_rwdata_end)          /* bss_end_addr */
+
         /* Load address preference. */
         mb2ht_init MB2_HT(RELOCATABLE), MB2_HT(OPTIONAL), \
                    sym_offs(start), /* Min load address. */ \
@@ -244,6 +251,14 @@  multiboot2_header_start:
                    0x200000, /* Load address alignment (2 MiB). */ \
                    MULTIBOOT2_LOAD_PREFERENCE_HIGH
 
+        /* Multiboot2 entry point. */
+        mb2ht_init MB2_HT(ENTRY_ADDRESS), MB2_HT(REQUIRED), \
+                   sym_offs(__start)
+
+        /* EFI64 Multiboot2 entry point. */
+        mb2ht_init MB2_HT(ENTRY_ADDRESS_EFI64), MB2_HT(OPTIONAL), \
+                   sym_offs(__efi64_mb2_start)
+
         /* Console flags tag. */
         mb2ht_init MB2_HT(CONSOLE_FLAGS), MB2_HT(OPTIONAL), \
                    MULTIBOOT2_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED
@@ -257,10 +272,6 @@  multiboot2_header_start:
         /* Request that ExitBootServices() not be called. */
         mb2ht_init MB2_HT(EFI_BS), MB2_HT(OPTIONAL)
 
-        /* EFI64 Multiboot2 entry point. */
-        mb2ht_init MB2_HT(ENTRY_ADDRESS_EFI64), MB2_HT(OPTIONAL), \
-                   sym_offs(__efi64_mb2_start)
-
         /* Multiboot2 header end tag. */
         mb2ht_init MB2_HT(END), MB2_HT(REQUIRED)
 .Lmultiboot2_header_end: