From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1W1i8o-0006QC-6a for mharc-grub-devel@gnu.org; Fri, 10 Jan 2014 14:53:14 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56572) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W1i8e-0006OZ-9t for grub-devel@gnu.org; Fri, 10 Jan 2014 14:53:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W1i8V-00007h-Jv for grub-devel@gnu.org; Fri, 10 Jan 2014 14:53:04 -0500 Received: from mail-lb0-x22a.google.com ([2a00:1450:4010:c04::22a]:35062) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W1i8V-000073-7w for grub-devel@gnu.org; Fri, 10 Jan 2014 14:52:55 -0500 Received: by mail-lb0-f170.google.com with SMTP id c11so3760452lbj.15 for ; Fri, 10 Jan 2014 11:52:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-type:content-transfer-encoding; bh=Rj86MyTDqdW+HzSa4unDOmN4emchdURZZgbSBjteJCI=; b=MLCi6zl25k2mEqrQmCQ8JLvXhzV/uaU2pBDnufggrxbTnVGHwzS9V3hTeoAkQZwzsY fNpErNBgakcXONqzWRTKrWFobUgbGwsehvi8gcqol5JYcB2O29hS4UG+PxAafMXWjX6Q FZYvRdZ9BAz0FeGhNyt2WEG/zRGLK3WVHrEjIuk+z68GRa+1Nj9kHJeCL3160dXlBlpj BOmwGBahVirCanFj4g9MSpW3fEWhX1ECAG1y0oB1gYlG+b3TTZkPLrJIge33wQ3eTIte pMozyAqURjUwC+M8sFqHZ8nCUgUfe/8ylvTEYfSo3+kFvlUHpZYYEuHgWuivlKGajRN5 HJFQ== X-Received: by 10.112.151.42 with SMTP id un10mr4403854lbb.7.1389383573896; Fri, 10 Jan 2014 11:52:53 -0800 (PST) Received: from opensuse.site (ppp91-76-163-241.pppoe.mtu-net.ru. [91.76.163.241]) by mx.google.com with ESMTPSA id mk6sm2117072lac.0.2014.01.10.11.52.53 for (version=SSLv3 cipher=RC4-SHA bits=128/128); Fri, 10 Jan 2014 11:52:53 -0800 (PST) Date: Fri, 10 Jan 2014 23:52:52 +0400 From: Andrey Borzenkov To: The development of GNU GRUB Subject: Re: [PATCH] Adding Bi-Endian 32-bit and 64-bit Support to the Grub ELF Parser Message-ID: <20140110235252.2e009052@opensuse.site> In-Reply-To: References: X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.22; x86_64-suse-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 8bit X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2a00:1450:4010:c04::22a Cc: tbberry@us.ibm.com X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 Jan 2014 19:53:12 -0000 В Fri, 10 Jan 2014 11:58:58 -0600 Tomohiro B Berry 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. */