Add multiboot2 protocol support for relocatable images. Only GRUB2 with
"multiboot2: Add support for relocatable images" patch understands
that feature. Older multiboot protocol (regardless of version)
compatible loaders ignore it and everything works as usual.
Signed-off-by: Daniel Kiper
Acked-by: Jan Beulich
Reviewed-by: Doug Goldstein
---
v12 - suggestions/fixes:
- replace TABs with spaces in xen/include/xen/multiboot2.h
(suggested by Doug Goldstein).
v9 - suggestions/fixes:
- use .L labels instead of numeric ones in multiboot2 data scanning loop
(suggested by Jan Beulich).
v4 - suggestions/fixes:
- do not get Xen image load base address from
multiboot2 information in x86_64 code
(suggested by Jan Beulich),
- improve label names
(suggested by Jan Beulich),
- improve comments,
(suggested by Jan Beulich).
v3 - suggestions/fixes:
- use %esi and %r15d instead of %ebp to store
Xen image load base address,
- rename some types and constants,
- reformat xen/include/xen/multiboot2.h
(suggested by Konrad Rzeszutek Wilk),
- improve comments,
- improve commit message
(suggested by Konrad Rzeszutek Wilk).
---
xen/arch/x86/boot/head.S | 16
xen/arch/x86/x86_64/asm-offsets.c |1 +
xen/include/xen/multiboot2.h | 13 +
3 files changed, 30 insertions(+)
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index bbc7cdd..fd0238b 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -82,6 +82,13 @@ multiboot2_header_start:
/* Align modules at page boundry. */
mb2ht_init MB2_HT(MODULE_ALIGN), MB2_HT(REQUIRED)
+/* Load address preference. */
+mb2ht_init MB2_HT(RELOCATABLE), MB2_HT(OPTIONAL), \
+ sym_offs(start), /* Min load address. */ \
+ 0x, /* The end of image max load address (4 GiB -
1). */ \
+ 0x20, /* Load address alignment (2 MiB). */ \
+ MULTIBOOT2_LOAD_PREFERENCE_HIGH
+
/* Console flags tag. */
mb2ht_init MB2_HT(CONSOLE_FLAGS), MB2_HT(OPTIONAL), \
MULTIBOOT2_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED
@@ -383,6 +390,15 @@ __start:
cmp %edi,MB2_fixed_total_size(%ebx)
jbe trampoline_bios_setup
+/* Get Xen image load base address from Multiboot2 information. */
+cmpl$MULTIBOOT2_TAG_TYPE_LOAD_BASE_ADDR,MB2_tag_type(%ecx)
+jne .Lmb2_mem_lower
+
+mov MB2_load_base_addr(%ecx),%esi
+sub $XEN_IMG_OFFSET,%esi
+jmp .Lmb2_next_tag
+
+.Lmb2_mem_lower:
/* Get mem_lower from Multiboot2 information. */
cmpl$MULTIBOOT2_TAG_TYPE_BASIC_MEMINFO,MB2_tag_type(%ecx)
cmove MB2_mem_lower(%ecx),%edx
diff --git a/xen/arch/x86/x86_64/asm-offsets.c
b/xen/arch/x86/x86_64/asm-offsets.c
index 87e573a..85639e4 100644
--- a/xen/arch/x86/x86_64/asm-offsets.c
+++ b/xen/arch/x86/x86_64/asm-offsets.c
@@ -174,6 +174,7 @@ void __dummy__(void)
OFFSET(MB2_fixed_total_size, multiboot2_fixed_t, total_size);
OFFSET(MB2_tag_type, multiboot2_tag_t, type);
OFFSET(MB2_tag_size, multiboot2_tag_t, size);
+OFFSET(MB2_load_base_addr, multiboot2_tag_load_base_addr_t,
load_base_addr);
OFFSET(MB2_mem_lower, multiboot2_tag_basic_meminfo_t, mem_lower);
OFFSET(MB2_efi64_st, multiboot2_tag_efi64_t, pointer);
OFFSET(MB2_efi64_ih, multiboot2_tag_efi64_ih_t, pointer);
diff --git a/xen/include/xen/multiboot2.h b/xen/include/xen/multiboot2.h
index a3e3119..5acd225 100644
--- a/xen/include/xen/multiboot2.h
+++ b/xen/include/xen/multiboot2.h
@@ -59,11 +59,17 @@
#define MULTIBOOT2_HEADER_TAG_EFI_BS7
#define MULTIBOOT2_HEADER_TAG_ENTRY_ADDRESS_EFI32 8
#define MULTIBOOT2_HEADER_TAG_ENTRY_ADDRESS_EFI64 9
+#define MULTIBOOT2_HEADER_TAG_RELOCATABLE 10
/* Header tag flags. */
#define MULTIBOOT2_HEADER_TAG_REQUIRED 0
#define MULTIBOOT2_HEADER_TAG_OPTIONAL 1
+/* Where image should be loaded (suggestion not requirement). */
+#define MULTIBOOT2_LOAD_PREFERENCE_NONE 0
+#define MULTIBOOT2_LOAD_PREFERENCE_LOW 1
+#define MULTIBOOT2_LOAD_PREFERENCE_HIGH 2
+
/* Header console tag console_flags. */
#define MULTIBOOT2_CONSOLE_FLAGS_CONSOLE_REQUIRED 1
#define MULTIBOOT2_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED 2
@@ -90,6 +96,7 @@
#define MULTIBOOT2_TAG_TYPE_EFI_BS 18
#define MULTIBOOT2_TAG_TYPE_EFI32_IH19
#define MULTIBOOT2_TAG_TYPE_EFI64_IH20
+#define MULTIBOOT2_TAG_TYPE_LOAD_BASE_ADDR 21
/* Multiboot 2 tag alignment. */
#define MULTIBOOT2_TAG_ALIGN8
@@ -120,6 +127,12 @@ typedef struct {
typedef struct {
u32 type;
u32 size;
+u32 load_base_addr;
+} multiboot2_tag_loa
