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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2012-10-25 16:18:20 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2012-10-25 16:18:20 +0000 |
commit | 630862cd04e0f807f9d1d9d2ed8ba8f044dcedfa (patch) | |
tree | eef8d62f4f6b69c9377ef1814144713d434eb43c /nuttx/binfmt/libelf/libelf_bind.c | |
parent | a91b6552cdb1b147461b75128576012192d9e933 (diff) | |
download | px4-firmware-630862cd04e0f807f9d1d9d2ed8ba8f044dcedfa.tar.gz px4-firmware-630862cd04e0f807f9d1d9d2ed8ba8f044dcedfa.tar.bz2 px4-firmware-630862cd04e0f807f9d1d9d2ed8ba8f044dcedfa.zip |
A little more ELF loader logic
git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5257 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/binfmt/libelf/libelf_bind.c')
-rw-r--r-- | nuttx/binfmt/libelf/libelf_bind.c | 171 |
1 files changed, 169 insertions, 2 deletions
diff --git a/nuttx/binfmt/libelf/libelf_bind.c b/nuttx/binfmt/libelf/libelf_bind.c index 74b713b9e..dd75809ec 100644 --- a/nuttx/binfmt/libelf/libelf_bind.c +++ b/nuttx/binfmt/libelf/libelf_bind.c @@ -49,6 +49,8 @@ #include <nuttx/binfmt/elf.h> #include <nuttx/binfmt/symtab.h> +#include "libelf.h" + /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ @@ -80,6 +82,120 @@ ****************************************************************************/ /**************************************************************************** + * Name: elf_readsym + * + * Description: + * Read the ELFT symbol structure at the specfied index into memory. + * + ****************************************************************************/ + +static inline int elf_readrel(FAR struct elf_loadinfo_s *loadinfo, + FAR const Elf32_Shdr *relsec, + int index, FAR Elf32_Rel *rel) +{ + off_t offset; + + /* Verify that the symbol table index lies within symbol table */ + + if (index < 0 || index > (relsec->sh_size / sizeof(Elf32_Rel))) + { + bdbg("Bad relocation symbol index: %d\n", index); + return -EINVAL; + } + + /* Get the file offset to the symbol table entry */ + + offset = relsec->sh_offset + sizeof(Elf32_Rel) * index; + + /* And, finally, read the symbol table entry into memory */ + + return elf_read(loadinfo, (FAR uint8_t*)rel, sizeof(Elf32_Rel), offset); +} + +/**************************************************************************** + * Name: elf_relocate and elf_relocateadd + * + * Description: + * Perform all relocations associated with a section. + * + * Returned Value: + * 0 (OK) is returned on success and a negated errno is returned on + * failure. + * + ****************************************************************************/ + +static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx) +{ + FAR Elf32_Shdr *relsec = &loadinfo->shdr[relidx]; + FAR Elf32_Shdr *dstsec = &loadinfo->shdr[relsec->sh_info]; + Elf32_Rel rel; + Elf32_Sym sym; + uintptr_t addr; + int symidx; + int ret; + int i; + + /* Examine each relocation in the section */ + + for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++) + { + /* Read the relocation entry into memory */ + + ret = elf_readrel(loadinfo, relsec, i, &rel); + if (ret < 0) + { + bdbg("Section %d reloc %d: Failed to read relocation entry: %d\n", + relidx, i, ret); + return ret; + } + + /* Get the symbol table index for the relocation. This is contained + * in a bit-field within the r_info element. + */ + + symidx = ELF32_R_SYM(rel.r_info); + + /* Read the symbol table entry into memory */ + + ret = elf_readsym(loadinfo, symidx, &sym); + if (ret < 0) + { + bdbg("Section %d reloc %d: Failed to read symbol[%d]: %d\n", + relidx, i, symidx, ret); + return ret; + } + + /* Calculate the relocation address */ + + if (rel.r_offset < 0 || rel.r_offset > dstsec->sh_size - sizeof(uint32_t)) + { + bdbg("Section %d reloc %d: Relocation address out of range, offset %d size %d\n", + relidx, i, rel.r_offset, dstsec->sh_size); + return -EINVAL; + } + + addr = dstsec->sh_addr + rel.r_offset; + + /* Now perform the architecture-specific relocation */ + + ret = arch_relocate(&rel, &sym, addr); + if (ret < 0) + { + bdbg("Section %d reloc %d: Relocation failed: %d\n", ret); + return ret; + } + } + + return OK; +} + +static int elf_relocateadd(FAR struct elf_loadinfo_s *loadinfo, int relidx) +{ + bdbg("Not implemented\n"); + return -ENOSYS; +} + +/**************************************************************************** * Public Functions ****************************************************************************/ @@ -99,7 +215,58 @@ int elf_bind(FAR struct elf_loadinfo_s *loadinfo, FAR const struct symtab_s *exports, int nexports) { -#warning "Missing logic" - return -ENOSYS; + int ret; + int i; + + /* Find the symbol and string tables */ + + ret = elf_findsymtab(loadinfo); + if (ret < 0) + { + return ret; + } + + /* Process relocations in every allocated section */ + + for (i = 1; i < loadinfo->ehdr.e_shnum; i++) + { + /* Get the index to the relocation section */ + + int infosec = loadinfo->shdr[i].sh_info; + if (infosec >= loadinfo->ehdr.e_shnum) + { + continue; + } + + /* Make sure that the section is allocated. We can't relocated + * sections that were not loaded into memory. + */ + + if ((loadinfo->shdr[infosec].sh_flags & SHF_ALLOC) == 0) + { + continue; + } + + /* Process the relocations by type */ + + if (loadinfo->shdr[i].sh_type == SHT_REL) + { + ret = elf_relocate(loadinfo, i); + } + else if (loadinfo->shdr[i].sh_type == SHT_RELA) + { + ret = elf_relocateadd(loadinfo, i); + } + + if (ret < 0) + { + break; + } + } + + /* Flush the instruction cache before starting the newly loaded module */ + + arch_flushicache((FAR void*)loadinfo->alloc, loadinfo->allocsize); + return ret; } |