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.ki...@oracle.com> Acked-by: Jan Beulich <jbeul...@suse.com> Reviewed-by: Doug Goldstein <car...@cardoe.com> --- 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. */ \ + 0xffffffff, /* The end of image 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 @@ -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_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[]; } multiboot2_tag_string_t; -- 1.7.10.4 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel