| From 59d4b8c48e5040af7e02b34eb26ea602ec82a38e Mon Sep 17 00:00:00 2001 |
| From: James Cowgill <james410@cowgill.org.uk> |
| Date: Mon, 5 Jan 2015 15:17:02 +0000 |
| Subject: [PATCH 3/3] Add mips n64 relocation format hack |
| |
| MIPSEL N64 ELF files use a slightly different format for storing relocation |
| entries which is incompatible with the normal R_SYM / R_INFO macros. |
| To workaround this, we rearrange the bytes in the relocation's r_info field |
| when reading and writing the relocations. |
| |
| This patch also ensures that strip.c sets the correct value of e_machine |
| before manipulating relocations so that these changes take effect. |
| |
| Signed-off-by: James Cowgill <james410@cowgill.org.uk> |
| --- |
| libelf/gelf_getrel.c | 25 +++++++++++++++++++++++-- |
| libelf/gelf_getrela.c | 25 +++++++++++++++++++++++-- |
| libelf/gelf_update_rel.c | 20 +++++++++++++++++++- |
| libelf/gelf_update_rela.c | 20 +++++++++++++++++++- |
| src/strip.c | 17 +++++++++++++++++ |
| 5 files changed, 101 insertions(+), 6 deletions(-) |
| |
| Index: elfutils-0.164/libelf/gelf_getrel.c |
| =================================================================== |
| --- elfutils-0.164.orig/libelf/gelf_getrel.c |
| +++ elfutils-0.164/libelf/gelf_getrel.c |
| @@ -36,6 +36,7 @@ |
| |
| #include "libelfP.h" |
| |
| +#define EF_MIPS_ABI 0x0000F000 |
| |
| GElf_Rel * |
| gelf_getrel (Elf_Data *data, int ndx, GElf_Rel *dst) |
| @@ -89,8 +90,28 @@ gelf_getrel (Elf_Data *data, int ndx, GE |
| result = NULL; |
| } |
| else |
| - result = memcpy (dst, &((Elf64_Rel *) data_scn->d.d_buf)[ndx], |
| - sizeof (Elf64_Rel)); |
| + { |
| + GElf_Ehdr hdr; |
| + result = memcpy (dst, &((Elf64_Rel *) data_scn->d.d_buf)[ndx], |
| + sizeof (Elf64_Rel)); |
| + |
| + if (gelf_getehdr(scn->elf, &hdr) != NULL && |
| + hdr.e_ident[EI_DATA] == ELFDATA2LSB && |
| + hdr.e_machine == EM_MIPS && |
| + (hdr.e_flags & EF_MIPS_ABI) == 0) |
| + { |
| + /* |
| + * The relocation format is mangled on MIPSEL N64 |
| + * We'll adjust it so at least R_SYM will work on it |
| + */ |
| + GElf_Xword r_info = dst->r_info; |
| + dst->r_info = (r_info << 32) | |
| + ((r_info >> 8) & 0xFF000000) | |
| + ((r_info >> 24) & 0x00FF0000) | |
| + ((r_info >> 40) & 0x0000FF00) | |
| + ((r_info >> 56) & 0x000000FF); |
| + } |
| + } |
| } |
| |
| rwlock_unlock (scn->elf->lock); |
| Index: elfutils-0.164/libelf/gelf_getrela.c |
| =================================================================== |
| --- elfutils-0.164.orig/libelf/gelf_getrela.c |
| +++ elfutils-0.164/libelf/gelf_getrela.c |
| @@ -36,6 +36,7 @@ |
| |
| #include "libelfP.h" |
| |
| +#define EF_MIPS_ABI 0x0000F000 |
| |
| GElf_Rela * |
| gelf_getrela (Elf_Data *data, int ndx, GElf_Rela *dst) |
| @@ -90,8 +91,28 @@ gelf_getrela (Elf_Data *data, int ndx, G |
| result = NULL; |
| } |
| else |
| - result = memcpy (dst, &((Elf64_Rela *) data_scn->d.d_buf)[ndx], |
| - sizeof (Elf64_Rela)); |
| + { |
| + GElf_Ehdr hdr; |
| + result = memcpy (dst, &((Elf64_Rela *) data_scn->d.d_buf)[ndx], |
| + sizeof (Elf64_Rela)); |
| + |
| + if (gelf_getehdr(scn->elf, &hdr) != NULL && |
| + hdr.e_ident[EI_DATA] == ELFDATA2LSB && |
| + hdr.e_machine == EM_MIPS && |
| + (hdr.e_flags & EF_MIPS_ABI) == 0) |
| + { |
| + /* |
| + * The relocation format is mangled on MIPSEL N64 |
| + * We'll adjust it so at least R_SYM will work on it |
| + */ |
| + GElf_Xword r_info = dst->r_info; |
| + dst->r_info = (r_info << 32) | |
| + ((r_info >> 8) & 0xFF000000) | |
| + ((r_info >> 24) & 0x00FF0000) | |
| + ((r_info >> 40) & 0x0000FF00) | |
| + ((r_info >> 56) & 0x000000FF); |
| + } |
| + } |
| } |
| |
| rwlock_unlock (scn->elf->lock); |
| Index: elfutils-0.164/libelf/gelf_update_rel.c |
| =================================================================== |
| --- elfutils-0.164.orig/libelf/gelf_update_rel.c |
| +++ elfutils-0.164/libelf/gelf_update_rel.c |
| @@ -36,6 +36,7 @@ |
| |
| #include "libelfP.h" |
| |
| +#define EF_MIPS_ABI 0x0000F000 |
| |
| int |
| gelf_update_rel (Elf_Data *dst, int ndx, GElf_Rel *src) |
| @@ -86,6 +87,9 @@ gelf_update_rel (Elf_Data *dst, int ndx, |
| } |
| else |
| { |
| + GElf_Ehdr hdr; |
| + GElf_Rel value = *src; |
| + |
| /* Check whether we have to resize the data buffer. */ |
| if (INVALID_NDX (ndx, Elf64_Rel, &data_scn->d)) |
| { |
| @@ -93,7 +97,21 @@ gelf_update_rel (Elf_Data *dst, int ndx, |
| goto out; |
| } |
| |
| - ((Elf64_Rel *) data_scn->d.d_buf)[ndx] = *src; |
| + if (gelf_getehdr(scn->elf, &hdr) != NULL && |
| + hdr.e_ident[EI_DATA] == ELFDATA2LSB && |
| + hdr.e_machine == EM_MIPS && |
| + (hdr.e_flags & EF_MIPS_ABI) == 0) |
| + { |
| + /* Undo the MIPSEL N64 hack from gelf_getrel */ |
| + GElf_Xword r_info = value.r_info; |
| + value.r_info = (r_info >> 32) | |
| + ((r_info << 8) & 0x000000FF00000000) | |
| + ((r_info << 24) & 0x0000FF0000000000) | |
| + ((r_info << 40) & 0x00FF000000000000) | |
| + ((r_info << 56) & 0xFF00000000000000); |
| + } |
| + |
| + ((Elf64_Rel *) data_scn->d.d_buf)[ndx] = value; |
| } |
| |
| result = 1; |
| Index: elfutils-0.164/libelf/gelf_update_rela.c |
| =================================================================== |
| --- elfutils-0.164.orig/libelf/gelf_update_rela.c |
| +++ elfutils-0.164/libelf/gelf_update_rela.c |
| @@ -36,6 +36,7 @@ |
| |
| #include "libelfP.h" |
| |
| +#define EF_MIPS_ABI 0x0000F000 |
| |
| int |
| gelf_update_rela (Elf_Data *dst, int ndx, GElf_Rela *src) |
| @@ -89,6 +90,9 @@ gelf_update_rela (Elf_Data *dst, int ndx |
| } |
| else |
| { |
| + GElf_Ehdr hdr; |
| + GElf_Rela value = *src; |
| + |
| /* Check whether we have to resize the data buffer. */ |
| if (INVALID_NDX (ndx, Elf64_Rela, &data_scn->d)) |
| { |
| @@ -96,7 +100,21 @@ gelf_update_rela (Elf_Data *dst, int ndx |
| goto out; |
| } |
| |
| - ((Elf64_Rela *) data_scn->d.d_buf)[ndx] = *src; |
| + if (gelf_getehdr(scn->elf, &hdr) != NULL && |
| + hdr.e_ident[EI_DATA] == ELFDATA2LSB && |
| + hdr.e_machine == EM_MIPS && |
| + (hdr.e_flags & EF_MIPS_ABI) == 0) |
| + { |
| + /* Undo the MIPSEL N64 hack from gelf_getrel */ |
| + GElf_Xword r_info = value.r_info; |
| + value.r_info = (r_info >> 32) | |
| + ((r_info << 8) & 0x000000FF00000000) | |
| + ((r_info << 24) & 0x0000FF0000000000) | |
| + ((r_info << 40) & 0x00FF000000000000) | |
| + ((r_info << 56) & 0xFF00000000000000); |
| + } |
| + |
| + ((Elf64_Rela *) data_scn->d.d_buf)[ndx] = value; |
| } |
| |
| result = 1; |
| Index: elfutils-0.164/src/strip.c |
| =================================================================== |
| --- elfutils-0.164.orig/src/strip.c |
| +++ elfutils-0.164/src/strip.c |
| @@ -546,6 +546,23 @@ handle_elf (int fd, Elf *elf, const char |
| goto fail; |
| } |
| |
| + /* Copy identity part of the ELF header now */ |
| + newehdr = gelf_getehdr (newelf, &newehdr_mem); |
| + if (newehdr == NULL) |
| + INTERNAL_ERROR (fname); |
| + |
| + memcpy (newehdr->e_ident, ehdr->e_ident, EI_NIDENT); |
| + newehdr->e_type = ehdr->e_type; |
| + newehdr->e_machine = ehdr->e_machine; |
| + newehdr->e_version = ehdr->e_version; |
| + |
| + if (gelf_update_ehdr (newelf, newehdr) == 0) |
| + { |
| + error (0, 0, gettext ("%s: error while creating ELF header: %s"), |
| + fname, elf_errmsg (-1)); |
| + return 1; |
| + } |
| + |
| /* Copy over the old program header if needed. */ |
| if (ehdr->e_type != ET_REL) |
| for (cnt = 0; cnt < phnum; ++cnt) |