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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 16/16] x86: add multiboot2 protocol support for relocatable images
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 <daniel.kiper@xxxxxxxxxx>
---
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 | 46 +++++++++++++++++++++++++++++--------
xen/arch/x86/x86_64/asm-offsets.c | 1 +
xen/include/xen/multiboot2.h | 13 +++++++++++
3 files changed, 50 insertions(+), 10 deletions(-)
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index e322270..dbf2555 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -79,6 +79,13 @@ 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_offset(start), /* Min load address. */ \
+ 0xffffffff, /* Max load address (4 GiB - 1). */ \
+ 0x200000, /* 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
@@ -178,30 +185,39 @@ efi_multiboot2_proto:
and $~(MULTIBOOT2_TAG_ALIGN-1),%rcx
0:
+ /* Get Xen image load base address from Multiboot2 information. */
+ cmpl $MULTIBOOT2_TAG_TYPE_LOAD_BASE_ADDR,MB2_tag_type(%rcx)
+ jne 1f
+
+ mov MB2_load_base_addr(%rcx),%r15d
+ sub $XEN_IMG_OFFSET,%r15
+ jmp 4f
+
+1:
/* Get EFI SystemTable address from Multiboot2 information. */
cmpl $MULTIBOOT2_TAG_TYPE_EFI64,MB2_tag_type(%rcx)
- jne 1f
+ jne 2f
mov MB2_efi64_st(%rcx),%rsi
/* Do not clear BSS twice and do not go into real mode. */
movb $1,skip_realmode(%rip)
- jmp 3f
+ jmp 4f
-1:
+2:
/* Get EFI ImageHandle address from Multiboot2 information. */
cmpl $MULTIBOOT2_TAG_TYPE_EFI64_IH,MB2_tag_type(%rcx)
- jne 2f
+ jne 3f
mov MB2_efi64_ih(%rcx),%rdi
- jmp 3f
+ jmp 4f
-2:
+3:
/* Is it the end of Multiboot2 information? */
cmpl $MULTIBOOT2_TAG_TYPE_END,MB2_tag_type(%rcx)
je run_bs
-3:
+4:
/* Go to next Multiboot2 information tag. */
add MB2_tag_size(%rcx),%ecx
add $(MULTIBOOT2_TAG_ALIGN-1),%rcx
@@ -313,14 +329,23 @@ multiboot2_proto:
and $~(MULTIBOOT2_TAG_ALIGN-1),%ecx
0:
+ /* Get Xen image load base address from Multiboot2 information. */
+ cmpl $MULTIBOOT2_TAG_TYPE_LOAD_BASE_ADDR,MB2_tag_type(%ecx)
+ jne 1f
+
+ mov MB2_load_base_addr(%ecx),%esi
+ sub $XEN_IMG_OFFSET,%esi
+ jmp 3f
+
+1:
/* Get mem_lower from Multiboot2 information. */
cmpl $MULTIBOOT2_TAG_TYPE_BASIC_MEMINFO,MB2_tag_type(%ecx)
- jne 1f
+ jne 2f
mov MB2_mem_lower(%ecx),%edx
- jmp trampoline_bios_setup
+ jmp 3f
-1:
+2:
/* EFI mode is not supported via legacy BIOS path. */
cmpl $MULTIBOOT2_TAG_TYPE_EFI32,MB2_tag_type(%ecx)
je mb2_too_old
@@ -332,6 +357,7 @@ multiboot2_proto:
cmpl $MULTIBOOT2_TAG_TYPE_END,MB2_tag_type(%ecx)
je trampoline_bios_setup
+3:
/* Go to next Multiboot2 information tag. */
add MB2_tag_size(%ecx),%ecx
add $(MULTIBOOT2_TAG_ALIGN-1),%ecx
diff --git a/xen/arch/x86/x86_64/asm-offsets.c
b/xen/arch/x86/x86_64/asm-offsets.c
index b7aed49..d227f28 100644
--- a/xen/arch/x86/x86_64/asm-offsets.c
+++ b/xen/arch/x86/x86_64/asm-offsets.c
@@ -172,6 +172,7 @@ void __dummy__(void)
DEFINE(MB2_fixed_sizeof, sizeof(multiboot2_fixed_t));
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 0f113f1..a1d355c 100644
--- a/xen/include/xen/multiboot2.h
+++ b/xen/include/xen/multiboot2.h
@@ -59,11 +59,17 @@
#define MULTIBOOT2_HEADER_TAG_EFI_BS 7
#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_IH 19
#define MULTIBOOT2_TAG_TYPE_EFI64_IH 20
+#define MULTIBOOT2_TAG_TYPE_LOAD_BASE_ADDR 21
/* Multiboot 2 tag alignment. */
#define MULTIBOOT2_TAG_ALIGN 8
@@ -120,6 +127,12 @@ typedef struct {
typedef struct {
u32 type;
u32 size;
+ u32 load_base_addr;
+} multiboot2_tag_load_base_addr_t;
+
+typedef struct {
+ u32 type;
+ u32 size;
char string[0];
} multiboot2_tag_string_t;
--
1.7.10.4
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