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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 5/6] multiboot2: Add support for relocatable images
On Mon, Jul 20, 2015 at 04:35:53PM +0200, Daniel Kiper wrote:
This parts needs a bit of details I think.
As in why can't the ELF note that is present in the binary
be satisfied. Or under what conditions would the existing code
not work?
> Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
> ---
> grub-core/loader/i386/multiboot_mbi.c | 6 ++--
> grub-core/loader/multiboot.c | 12 +++++--
> grub-core/loader/multiboot_elfxx.c | 28 +++++++++++----
> grub-core/loader/multiboot_mbi2.c | 63
> +++++++++++++++++++++++++++++----
> include/grub/multiboot.h | 4 ++-
> include/multiboot2.h | 24 +++++++++++++
> 6 files changed, 118 insertions(+), 19 deletions(-)
>
> diff --git a/grub-core/loader/i386/multiboot_mbi.c
> b/grub-core/loader/i386/multiboot_mbi.c
> index 956d0e3..abdb98b 100644
> --- a/grub-core/loader/i386/multiboot_mbi.c
> +++ b/grub-core/loader/i386/multiboot_mbi.c
> @@ -72,7 +72,8 @@ load_kernel (grub_file_t file, const char *filename,
> grub_err_t err;
> if (grub_multiboot_quirks & GRUB_MULTIBOOT_QUIRK_BAD_KLUDGE)
> {
> - err = grub_multiboot_load_elf (file, filename, buffer);
> + err = grub_multiboot_load_elf (file, filename, buffer, 0, 0, 0, 0,
> + GRUB_RELOCATOR_PREFERENCE_NONE, NULL, 0);
> if (err == GRUB_ERR_UNKNOWN_OS && (header->flags &
> MULTIBOOT_AOUT_KLUDGE))
> grub_errno = err = GRUB_ERR_NONE;
> }
> @@ -118,7 +119,8 @@ load_kernel (grub_file_t file, const char *filename,
> return GRUB_ERR_NONE;
> }
>
> - return grub_multiboot_load_elf (file, filename, buffer);
> + return grub_multiboot_load_elf (file, filename, buffer, 0, 0, 0, 0,
> + GRUB_RELOCATOR_PREFERENCE_NONE, NULL, 0);
Oh boy. That is a bit hard to read. Perhaps another function could be
introduced?
grub_multiboot_load_elf_ignore_reloc ? which would just pass the three
parameters and set the rest to the 0 options?
> }
>
> static struct multiboot_header *
> diff --git a/grub-core/loader/multiboot.c b/grub-core/loader/multiboot.c
> index ca7154f..1b1f7a9 100644
> --- a/grub-core/loader/multiboot.c
> +++ b/grub-core/loader/multiboot.c
> @@ -190,12 +190,18 @@ static grub_uint64_t highest_load;
> /* Load ELF32 or ELF64. */
> grub_err_t
> grub_multiboot_load_elf (grub_file_t file, const char *filename,
> - void *buffer)
> + void *buffer, int relocatable, grub_uint32_t min_addr,
> + grub_uint32_t max_addr, grub_size_t align,
> grub_uint32_t preference,
> + grub_uint32_t *base_addr, int avoid_efi_boot_services)
s/int/bool/ ?
> {
> if (grub_multiboot_is_elf32 (buffer))
> - return grub_multiboot_load_elf32 (file, filename, buffer);
> + return grub_multiboot_load_elf32 (file, filename, buffer, relocatable,
> + min_addr, max_addr, align, preference,
> + base_addr, avoid_efi_boot_services);
> else if (grub_multiboot_is_elf64 (buffer))
> - return grub_multiboot_load_elf64 (file, filename, buffer);
> + return grub_multiboot_load_elf64 (file, filename, buffer, relocatable,
> + min_addr, max_addr, align, preference,
> + base_addr, avoid_efi_boot_services);
>
> return grub_error (GRUB_ERR_UNKNOWN_OS, N_("invalid arch-dependent ELF
> magic"));
> }
> diff --git a/grub-core/loader/multiboot_elfxx.c
> b/grub-core/loader/multiboot_elfxx.c
> index 6a220bd..4fce685 100644
> --- a/grub-core/loader/multiboot_elfxx.c
> +++ b/grub-core/loader/multiboot_elfxx.c
> @@ -51,7 +51,10 @@ CONCAT(grub_multiboot_is_elf, XX) (void *buffer)
> }
>
> static grub_err_t
> -CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename,
> void *buffer)
> +CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file, const char *filename,
> + void *buffer, int relocatable,
> grub_uint32_t min_addr,
> + grub_uint32_t max_addr, grub_size_t align,
> grub_uint32_t preference,
> + grub_uint32_t *base_addr, int
> avoid_efi_boot_services)
> {
> Elf_Ehdr *ehdr = (Elf_Ehdr *) buffer;
> char *phdr_base;
> @@ -89,19 +92,30 @@ CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file,
> const char *filename, voi
> if (phdr(i)->p_paddr + phdr(i)->p_memsz > highest_load)
> highest_load = phdr(i)->p_paddr + phdr(i)->p_memsz;
>
> - grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx,
> memsz=0x%lx, vaddr=0x%lx\n",
> - i, (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz,
> (long) phdr(i)->p_vaddr);
> + grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx,
> memsz=0x%lx, vaddr=0x%lx,"
> + "align=0x%lx, relocatable=%d,
> avoid_efi_boot_services=%d\n", i,
%d to %s
> + (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz,
> (long) phdr(i)->p_vaddr,
> + (long) align, relocatable, avoid_efi_boot_services);
and then
avoid_efi_boot_services ? "yes" : "no"
>
> {
> grub_relocator_chunk_t ch;
> - err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator,
> - &ch, phdr(i)->p_paddr,
> - phdr(i)->p_memsz);
> +
> + if (relocatable)
> + err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator,
> &ch,
> + min_addr, max_addr -
> phdr(i)->p_memsz,
> + phdr(i)->p_memsz, align ?
> align : 1,
> + preference,
> avoid_efi_boot_services);
> + else
> + err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator,
> + &ch, phdr(i)->p_paddr,
> + phdr(i)->p_memsz);
> if (err)
> {
> grub_dprintf ("multiboot_loader", "Error loading phdr %d\n", i);
> return err;
> }
> + if (base_addr)
> + *base_addr = get_physical_target_address (ch);
> source = get_virtual_current_address (ch);
> }
>
> @@ -208,7 +222,7 @@ CONCAT(grub_multiboot_load_elf, XX) (grub_file_t file,
> const char *filename, voi
> + 1, sh->sh_size,
> sh->sh_addralign,
>
> GRUB_RELOCATOR_PREFERENCE_NONE,
> - 0);
> + avoid_efi_boot_services);
> if (err)
> {
> grub_dprintf ("multiboot_loader", "Error loading shdr %d\n", i);
> diff --git a/grub-core/loader/multiboot_mbi2.c
> b/grub-core/loader/multiboot_mbi2.c
> index dc9c709..7ac64ec 100644
> --- a/grub-core/loader/multiboot_mbi2.c
> +++ b/grub-core/loader/multiboot_mbi2.c
> @@ -68,6 +68,7 @@ static grub_size_t elf_sec_num, elf_sec_entsize;
> static unsigned elf_sec_shstrndx;
> static void *elf_sections;
> static int keep_bs = 0;
> +static grub_uint32_t base_addr = 0;
>
> void
> grub_multiboot_add_elfsyms (grub_size_t num, grub_size_t entsize,
> @@ -107,11 +108,13 @@ grub_multiboot_load (grub_file_t file, const char
> *filename)
> grub_err_t err;
> struct multiboot_header_tag *tag;
> struct multiboot_header_tag_address *addr_tag = NULL;
> - int entry_specified = 0, efi_entry_specified = 0;
> + int entry_specified = 0, efi_entry_specified = 0, relocatable = 0;
> grub_addr_t entry = 0, efi_entry = 0;
> - grub_uint32_t console_required = 0;
> + grub_uint32_t console_required = 0, min_addr = 0;
> + grub_uint32_t max_addr = 0, preference = 0;
> struct multiboot_header_tag_framebuffer *fbtag = NULL;
> int accepted_consoles = GRUB_MULTIBOOT_CONSOLE_EGA_TEXT;
> + grub_size_t align = 0;
>
> buffer = grub_malloc (MULTIBOOT_SEARCH);
> if (!buffer)
> @@ -174,6 +177,7 @@ grub_multiboot_load (grub_file_t file, const char
> *filename)
> case MULTIBOOT_TAG_TYPE_EFI_BS:
> case MULTIBOOT_TAG_TYPE_EFI32_IH:
> case MULTIBOOT_TAG_TYPE_EFI64_IH:
> + case MULTIBOOT_TAG_TYPE_BASE_ADDR:
> break;
>
> default:
> @@ -215,6 +219,26 @@ grub_multiboot_load (grub_file_t file, const char
> *filename)
> accepted_consoles |= GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER;
> break;
>
> + case MULTIBOOT_HEADER_TAG_RELOCATABLE:
> + relocatable = 1;
How about:
struct multiboot_header_tag_relocatable *_tag = (struct
multiboot_header_tag_relocatable *)tag;
and then you don't have to use the casting?
> + min_addr = ((struct multiboot_header_tag_relocatable *) tag)->min_addr;
> + max_addr = ((struct multiboot_header_tag_relocatable *) tag)->max_addr;
> + align = ((struct multiboot_header_tag_relocatable *) tag)->align;
> + switch (((struct multiboot_header_tag_relocatable *) tag)->preference)
> + {
> + case MULTIBOOT_LOAD_PREFERENCE_LOW:
> + preference = GRUB_RELOCATOR_PREFERENCE_LOW;
> + break;
> +
> + case MULTIBOOT_LOAD_PREFERENCE_HIGH:
> + preference = GRUB_RELOCATOR_PREFERENCE_HIGH;
> + break;
> +
> + default:
> + preference = GRUB_RELOCATOR_PREFERENCE_NONE;
> + }
> + break;
> +
> /* GRUB always page-aligns modules. */
> case MULTIBOOT_HEADER_TAG_MODULE_ALIGN:
> break;
> @@ -260,15 +284,22 @@ grub_multiboot_load (grub_file_t file, const char
> *filename)
> else
> code_size = load_size;
>
> - err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator,
> - &ch, load_addr,
> - code_size);
> + if (relocatable)
> + err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator, &ch,
> + min_addr, max_addr - code_size,
> + code_size, align ? align : 1,
> + preference, keep_bs);
> + else
> + err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator,
> + &ch, load_addr,
> + code_size);
> if (err)
> {
> grub_dprintf ("multiboot_loader", "Error loading aout kludge\n");
> grub_free (buffer);
> return err;
> }
> + base_addr = get_physical_target_address (ch);
> source = get_virtual_current_address (ch);
>
> if ((grub_file_seek (file, offset)) == (grub_off_t) -1)
> @@ -290,7 +321,9 @@ grub_multiboot_load (grub_file_t file, const char
> *filename)
> }
> else
> {
> - err = grub_multiboot_load_elf (file, filename, buffer);
> + err = grub_multiboot_load_elf (file, filename, buffer,
> + relocatable, min_addr, max_addr,
> + align, preference, &base_addr, keep_bs);
> if (err)
> {
> grub_free (buffer);
> @@ -303,6 +336,14 @@ grub_multiboot_load (grub_file_t file, const char
> *filename)
> else if (entry_specified)
> grub_multiboot_payload_eip = entry;
>
> + if (relocatable)
> + {
> + if (base_addr > min_addr)
> + grub_multiboot_payload_eip += base_addr - min_addr;
> + else
> + grub_multiboot_payload_eip -= min_addr - base_addr;
> + }
> +
> if (fbtag)
> err = grub_multiboot_set_console (GRUB_MULTIBOOT_CONSOLE_FRAMEBUFFER,
> accepted_consoles,
> @@ -409,6 +450,7 @@ grub_multiboot_get_mbi_size (void)
> + grub_get_multiboot_mmap_count ()
> * sizeof (struct multiboot_mmap_entry)), MULTIBOOT_TAG_ALIGN)
> + ALIGN_UP (sizeof (struct multiboot_tag_framebuffer),
> MULTIBOOT_TAG_ALIGN)
> + + ALIGN_UP (sizeof (struct multiboot_tag_base_addr), MULTIBOOT_TAG_ALIGN)
> #ifdef GRUB_MACHINE_EFI
> + ALIGN_UP (sizeof (struct multiboot_tag_efi32), MULTIBOOT_TAG_ALIGN)
> + ALIGN_UP (sizeof (struct multiboot_tag_efi64), MULTIBOOT_TAG_ALIGN)
> @@ -693,6 +735,15 @@ grub_multiboot_make_mbi (grub_uint32_t *target)
> ptrorig += (2 * sizeof (grub_uint32_t)) / sizeof (grub_properly_aligned_t);
>
> {
> + struct multiboot_tag_base_addr *tag = (struct multiboot_tag_base_addr *)
> ptrorig;
> + tag->type = MULTIBOOT_TAG_TYPE_BASE_ADDR;
> + tag->size = sizeof (struct multiboot_tag_base_addr);
You have an extra space at the end.
> + tag->base_addr = base_addr;
> + ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
> + / sizeof (grub_properly_aligned_t);
> + }
> +
> + {
> struct multiboot_tag_string *tag = (struct multiboot_tag_string *)
> ptrorig;
> tag->type = MULTIBOOT_TAG_TYPE_CMDLINE;
> tag->size = sizeof (struct multiboot_tag_string) + cmdline_size;
> diff --git a/include/grub/multiboot.h b/include/grub/multiboot.h
> index e13c084..ec322b0 100644
> --- a/include/grub/multiboot.h
> +++ b/include/grub/multiboot.h
> @@ -94,7 +94,9 @@ grub_multiboot_load (grub_file_t file, const char
> *filename);
> /* Load ELF32 or ELF64. */
> grub_err_t
> grub_multiboot_load_elf (grub_file_t file, const char *filename,
> - void *buffer);
> + void *buffer, int relocatable, grub_uint32_t min_addr,
> + grub_uint32_t max_addr, grub_size_t align,
> grub_uint32_t preference,
> + grub_uint32_t *base_addr, int avoid_efi_boot_services);
> extern grub_size_t grub_multiboot_pure_size;
> extern grub_size_t grub_multiboot_alloc_mbi;
> extern grub_uint32_t grub_multiboot_payload_eip;
> diff --git a/include/multiboot2.h b/include/multiboot2.h
> index 9f97ddc..941a95d 100644
> --- a/include/multiboot2.h
> +++ b/include/multiboot2.h
> @@ -62,6 +62,7 @@
> #define MULTIBOOT_TAG_TYPE_EFI_BS 18
> #define MULTIBOOT_TAG_TYPE_EFI32_IH 19
> #define MULTIBOOT_TAG_TYPE_EFI64_IH 20
> +#define MULTIBOOT_TAG_TYPE_BASE_ADDR 21
>
> #define MULTIBOOT_HEADER_TAG_END 0
> #define MULTIBOOT_HEADER_TAG_INFORMATION_REQUEST 1
> @@ -72,11 +73,16 @@
> #define MULTIBOOT_HEADER_TAG_MODULE_ALIGN 6
> #define MULTIBOOT_HEADER_TAG_EFI_BS 7
> #define MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS_EFI64 9
> +#define MULTIBOOT_HEADER_TAG_RELOCATABLE 10
>
> #define MULTIBOOT_ARCHITECTURE_I386 0
> #define MULTIBOOT_ARCHITECTURE_MIPS32 4
> #define MULTIBOOT_HEADER_TAG_OPTIONAL 1
>
> +#define MULTIBOOT_LOAD_PREFERENCE_NONE 0
> +#define MULTIBOOT_LOAD_PREFERENCE_LOW 1
> +#define MULTIBOOT_LOAD_PREFERENCE_HIGH 2
> +
> #define MULTIBOOT_CONSOLE_FLAGS_CONSOLE_REQUIRED 1
> #define MULTIBOOT_CONSOLE_FLAGS_EGA_TEXT_SUPPORTED 2
>
> @@ -169,6 +175,17 @@ struct multiboot_header_tag_module_align
> multiboot_uint32_t size;
> };
>
> +struct multiboot_header_tag_relocatable
> +{
> + multiboot_uint16_t type;
> + multiboot_uint16_t flags;
> + multiboot_uint32_t size;
> + multiboot_uint32_t min_addr;
> + multiboot_uint32_t max_addr;
> + multiboot_uint32_t align;
> + multiboot_uint32_t preference;
> +};
> +
> struct multiboot_color
> {
> multiboot_uint8_t red;
> @@ -395,6 +412,13 @@ struct multiboot_tag_efi64_ih
> multiboot_uint64_t pointer;
> };
>
> +struct multiboot_tag_base_addr
> +{
> + multiboot_uint32_t type;
> + multiboot_uint32_t size;
> + multiboot_uint32_t base_addr;
> +};
> +
> #endif /* ! ASM_FILE */
>
> #endif /* ! MULTIBOOT_HEADER */
> --
> 1.7.10.4
>
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