В Fri, 10 Jan 2014 11:58:58 -0600
Tomohiro B Berry <tbbe...@us.ibm.com> пишет:
> This patch adds bi-endian support for both 32-bit and 64-bit elf files.
>
> It compares the native endianness to the endianness of the elf file, and
> swaps the header bytes if necessary. This will allow, for example, 32-bit
> Big Endian grub to load a 64-bit Little Endian kernel.
>
I wonder - when big endian grub will pass boot parameters to little
endian kernel - won't there be endianness mismatch?
> Regards,
> Tomo Berry
>
> diff --git a/grub-core/kern/elf.c b/grub-core/kern/elf.c
> index 5f99c43..3326cd7 100644
> --- a/grub-core/kern/elf.c
> +++ b/grub-core/kern/elf.c
> @@ -28,20 +28,45 @@
>
> GRUB_MOD_LICENSE ("GPLv3+");
>
> +void grub_elf32_byteswap_header (grub_elf_t elf);
> +void grub_elf64_byteswap_header (grub_elf_t elf);
> +grub_err_t grub_elf32_check_version (grub_elf_t elf);
> +grub_err_t grub_elf64_check_version (grub_elf_t elf);
> +
> /* Check if EHDR is a valid ELF header. */
> static grub_err_t
> grub_elf_check_header (grub_elf_t elf)
> {
> - Elf32_Ehdr *e = &elf->ehdr.ehdr32;
> + /* e_ident is the same for both 64-bit and 32-bit so just load into a
> 32-bit struct for now */
> + Elf32_Ehdr *e = &elf->ehdr.ehdr32;
>
> + /* check if it is an ELF image at all */
> if (e->e_ident[EI_MAG0] != ELFMAG0
> || e->e_ident[EI_MAG1] != ELFMAG1
> || e->e_ident[EI_MAG2] != ELFMAG2
> || e->e_ident[EI_MAG3] != ELFMAG3
> - || e->e_ident[EI_VERSION] != EV_CURRENT
> - || e->e_version != EV_CURRENT)
> - return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-independent ELF
> magic"));
> -
> + || e->e_ident[EI_VERSION] != EV_CURRENT)
> + return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-independent ELF
> magic"));
> +
> + switch (e->e_ident[EI_CLASS])
> + {
> + case ELFCLASS32:
> + if (e->e_ident[EI_DATA] != ELFDATA_NATIVE)
> + grub_elf32_byteswap_header (elf);
> + if (grub_elf32_check_version (elf) != GRUB_ERR_NONE)
> + return grub_errno;
> + break;
> + case ELFCLASS64:
> + if (e->e_ident[EI_DATA] != ELFDATA_NATIVE)
> + grub_elf64_byteswap_header (elf);
> + if (grub_elf64_check_version (elf) != GRUB_ERR_NONE)
> + return grub_errno;
> + break;
> + default:
> + return grub_error (GRUB_ERR_BAD_OS, N_("unrecognized ELF
> class"));
> + break;
> + }
> +
> return GRUB_ERR_NONE;
> }
>
> @@ -127,7 +152,16 @@ grub_elf_open (const char *name)
> #define grub_elf_is_elfXX grub_elf_is_elf32
> #define grub_elfXX_load_phdrs grub_elf32_load_phdrs
> #define ElfXX_Phdr Elf32_Phdr
> +#define ElfXX_Ehdr Elf32_Ehdr
> #define grub_uintXX_t grub_uint32_t
> +/* for phdr/ehdr byte swaps */
> +#define byte_swap_halfXX grub_swap_bytes16
> +#define byte_swap_wordXX grub_swap_bytes32
> +#define byte_swap_addrXX grub_swap_bytes32
> +#define byte_swap_offXX grub_swap_bytes32
> +#define byte_swap_XwordXX byte_swap_wordXX /* the 64-bit phdr uses Xwords
> and the 32-bit uses words */
> +#define grub_elfXX_byteswap_header grub_elf32_byteswap_header
> +#define grub_elfXX_check_version grub_elf32_check_version
>
> #include "elfXX.c"
>
> @@ -140,7 +174,15 @@ grub_elf_open (const char *name)
> #undef grub_elf_is_elfXX
> #undef grub_elfXX_load_phdrs
> #undef ElfXX_Phdr
> +#undef ElfXX_Ehdr
> #undef grub_uintXX_t
> +#undef byte_swap_halfXX
> +#undef byte_swap_wordXX
> +#undef byte_swap_addrXX
> +#undef byte_swap_offXX
> +#undef byte_swap_XwordXX
> +#undef grub_elfXX_byteswap_header
> +#undef grub_elfXX_check_version
>
>
>
> /* 64-bit */
> @@ -153,6 +195,16 @@ grub_elf_open (const char *name)
> #define grub_elf_is_elfXX grub_elf_is_elf64
> #define grub_elfXX_load_phdrs grub_elf64_load_phdrs
> #define ElfXX_Phdr Elf64_Phdr
> +#define ElfXX_Ehdr Elf64_Ehdr
> #define grub_uintXX_t grub_uint64_t
> +/* for phdr/ehdr byte swaps */
> +#define byte_swap_halfXX grub_swap_bytes16
> +#define byte_swap_wordXX grub_swap_bytes32
> +#define byte_swap_addrXX grub_swap_bytes64
> +#define byte_swap_offXX grub_swap_bytes64
> +#define byte_swap_XwordXX grub_swap_bytes64
> +#define grub_elfXX_byteswap_header grub_elf64_byteswap_header
> +#define grub_elfXX_check_version grub_elf64_check_version
>
> #include "elfXX.c"
> +
> diff --git a/grub-core/kern/elfXX.c b/grub-core/kern/elfXX.c
> index 2e45449..09062ce 100644
> --- a/grub-core/kern/elfXX.c
> +++ b/grub-core/kern/elfXX.c
> @@ -154,3 +154,47 @@ grub_elfXX_load (grub_elf_t elf, const char
> *filename,
>
> return grub_errno;
> }
> +
> +void
> +grub_elfXX_byteswap_header (grub_elf_t elf)
> +{
> + ElfXX_Ehdr *e = &(elf->ehdr.ehdrXX);
> + ElfXX_Phdr *phdr;
> +
> + e->e_type = byte_swap_halfXX (e->e_type);
> + e->e_machine = byte_swap_halfXX (e->e_machine);
> + e->e_version = byte_swap_wordXX (e->e_version);
> + e->e_entry = byte_swap_addrXX (e->e_entry);
> + e->e_phoff = byte_swap_offXX (e->e_phoff);
> + e->e_shoff = byte_swap_offXX (e->e_shoff);
> + e->e_flags = byte_swap_wordXX (e->e_flags);
> + e->e_ehsize = byte_swap_halfXX (e->e_ehsize);
> + e->e_phentsize = byte_swap_halfXX (e->e_phentsize);
> + e->e_phnum = byte_swap_halfXX (e->e_phnum);
> + e->e_shentsize = byte_swap_halfXX (e->e_shentsize);
> + e->e_shnum = byte_swap_halfXX (e->e_shnum);
> + e->e_shstrndx = byte_swap_halfXX (e->e_shstrndx);
> +
> + FOR_ELFXX_PHDRS (elf,phdr)
> + {
> + phdr->p_type = byte_swap_wordXX (phdr->p_type);
> + phdr->p_flags = byte_swap_wordXX (phdr->p_flags);
> + phdr->p_offset = byte_swap_offXX (phdr->p_offset);
> + phdr->p_vaddr = byte_swap_addrXX (phdr->p_vaddr);
> + phdr->p_paddr = byte_swap_addrXX (phdr->p_paddr);
> + phdr->p_filesz = byte_swap_XwordXX (phdr->p_filesz);
> + phdr->p_memsz = byte_swap_XwordXX (phdr->p_memsz);
> + phdr->p_align = byte_swap_XwordXX (phdr->p_align);
> + }
> +
> +}
> +
> +grub_err_t
> +grub_elfXX_check_version (grub_elf_t elf)
> +{
> + if (elf->ehdr.ehdrXX.e_version != EV_CURRENT)
> + return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-independent ELF
> magic"));
> +
> + return GRUB_ERR_NONE;
> +}
> +
> diff --git a/include/grub/elf.h b/include/grub/elf.h
> index 140d24d..d5adf3f 100644
> --- a/include/grub/elf.h
> +++ b/include/grub/elf.h
> @@ -56,6 +56,13 @@ typedef grub_uint16_t Elf64_Section;
> typedef Elf32_Half Elf32_Versym;
> typedef Elf64_Half Elf64_Versym;
>
> +/* Define the native endianness */
> +
> +#ifdef GRUB_CPU_WORDS_BIGENDIAN
> +#define ELFDATA_NATIVE ELFDATA2MSB
> +#else
> +#define ELFDATA_NATIVE ELFDATA2LSB
> +#endif
>
> /* The ELF file header. This appears at the start of every ELF file. */
_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
