[PATCH 2/2] x86,vdso: Fix cross-compilation from big-endian architectures
This adds a macro GET(x) to convert x from big-endian to little-endian. Hopefully I put it everywhere it needs to go and got all the cases needed for everyone's linux/elf.h. Signed-off-by: Andy Lutomirski --- arch/x86/vdso/vdso2c.c | 15 + arch/x86/vdso/vdso2c.h | 59 -- 2 files changed, 48 insertions(+), 26 deletions(-) diff --git a/arch/x86/vdso/vdso2c.c b/arch/x86/vdso/vdso2c.c index fe8bfbf..de19ced 100644 --- a/arch/x86/vdso/vdso2c.c +++ b/arch/x86/vdso/vdso2c.c @@ -51,6 +51,21 @@ static void fail(const char *format, ...) va_end(ap); } +/* + * Evil macros to do a little-endian read. + */ +#define __GET_TYPE(x, type, bits, ifnot) \ + __builtin_choose_expr( \ + __builtin_types_compatible_p(typeof(x), type), \ + le##bits##toh((x)), ifnot) + +extern void bad_get(uint64_t); + +#define GET(x) \ + __GET_TYPE((x), __u32, 32, __GET_TYPE((x), __u64, 64, \ + __GET_TYPE((x), __s32, 32, __GET_TYPE((x), __s64, 64, \ + __GET_TYPE((x), __u16, 16, bad_get(x)) + #define NSYMS (sizeof(required_syms) / sizeof(required_syms[0])) #define BITS 64 diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h index 26a7c1f..dadecb9 100644 --- a/arch/x86/vdso/vdso2c.h +++ b/arch/x86/vdso/vdso2c.h @@ -18,25 +18,27 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) const char *secstrings; uint64_t syms[NSYMS] = {}; - Elf_Phdr *pt = (Elf_Phdr *)(addr + hdr->e_phoff); + Elf_Phdr *pt = (Elf_Phdr *)(addr + GET(hdr->e_phoff)); /* Walk the segment table. */ - for (i = 0; i < hdr->e_phnum; i++) { - if (pt[i].p_type == PT_LOAD) { + for (i = 0; i < GET(hdr->e_phnum); i++) { + if (GET(pt[i].p_type) == PT_LOAD) { if (found_load) fail("multiple PT_LOAD segs\n"); - if (pt[i].p_offset != 0 || pt[i].p_vaddr != 0) + if (GET(pt[i].p_offset) != 0 || + GET(pt[i].p_vaddr) != 0) fail("PT_LOAD in wrong place\n"); - if (pt[i].p_memsz != pt[i].p_filesz) + if (GET(pt[i].p_memsz) != GET(pt[i].p_filesz)) fail("cannot handle memsz != filesz\n"); - load_size = pt[i].p_memsz; + load_size = GET(pt[i].p_memsz); found_load = 1; - } else if (pt[i].p_type == PT_DYNAMIC) { - dyn = addr + pt[i].p_offset; - dyn_end = addr + pt[i].p_offset + pt[i].p_memsz; + } else if (GET(pt[i].p_type) == PT_DYNAMIC) { + dyn = addr + GET(pt[i].p_offset); + dyn_end = addr + GET(pt[i].p_offset) + + GET(pt[i].p_memsz); } } if (!found_load) @@ -44,43 +46,48 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) data_size = (load_size + 4095) / 4096 * 4096; /* Walk the dynamic table */ - for (i = 0; dyn + i < dyn_end && dyn[i].d_tag != DT_NULL; i++) { - if (dyn[i].d_tag == DT_REL || dyn[i].d_tag == DT_RELSZ || - dyn[i].d_tag == DT_RELENT || dyn[i].d_tag == DT_TEXTREL) + for (i = 0; dyn + i < dyn_end && GET(dyn[i].d_tag) != DT_NULL; i++) { + typeof(dyn[i].d_tag) tag = GET(dyn[i].d_tag); + if (tag == DT_REL || tag == DT_RELSZ || + tag == DT_RELENT || tag == DT_TEXTREL) fail("vdso image contains dynamic relocations\n"); } /* Walk the section table */ - secstrings_hdr = addr + hdr->e_shoff + hdr->e_shentsize*hdr->e_shstrndx; - secstrings = addr + secstrings_hdr->sh_offset; - for (i = 0; i < hdr->e_shnum; i++) { - Elf_Shdr *sh = addr + hdr->e_shoff + hdr->e_shentsize * i; - if (sh->sh_type == SHT_SYMTAB) + secstrings_hdr = addr + GET(hdr->e_shoff) + + GET(hdr->e_shentsize)*GET(hdr->e_shstrndx); + secstrings = addr + GET(secstrings_hdr->sh_offset); + for (i = 0; i < GET(hdr->e_shnum); i++) { + Elf_Shdr *sh = addr + GET(hdr->e_shoff) + + GET(hdr->e_shentsize) * i; + if (GET(sh->sh_type) == SHT_SYMTAB) symtab_hdr = sh; - if (!strcmp(secstrings + sh->sh_name, ".altinstructions")) + if (!strcmp(secstrings + GET(sh->sh_name), ".altinstructions")) alt_sec = sh; } if (!symtab_hdr) fail("no symbol table\n"); -
[PATCH 2/2] x86,vdso: Fix cross-compilation from big-endian architectures
This adds a macro GET(x) to convert x from big-endian to little-endian. Hopefully I put it everywhere it needs to go and got all the cases needed for everyone's linux/elf.h. Signed-off-by: Andy Lutomirski l...@amacapital.net --- arch/x86/vdso/vdso2c.c | 15 + arch/x86/vdso/vdso2c.h | 59 -- 2 files changed, 48 insertions(+), 26 deletions(-) diff --git a/arch/x86/vdso/vdso2c.c b/arch/x86/vdso/vdso2c.c index fe8bfbf..de19ced 100644 --- a/arch/x86/vdso/vdso2c.c +++ b/arch/x86/vdso/vdso2c.c @@ -51,6 +51,21 @@ static void fail(const char *format, ...) va_end(ap); } +/* + * Evil macros to do a little-endian read. + */ +#define __GET_TYPE(x, type, bits, ifnot) \ + __builtin_choose_expr( \ + __builtin_types_compatible_p(typeof(x), type), \ + le##bits##toh((x)), ifnot) + +extern void bad_get(uint64_t); + +#define GET(x) \ + __GET_TYPE((x), __u32, 32, __GET_TYPE((x), __u64, 64, \ + __GET_TYPE((x), __s32, 32, __GET_TYPE((x), __s64, 64, \ + __GET_TYPE((x), __u16, 16, bad_get(x)) + #define NSYMS (sizeof(required_syms) / sizeof(required_syms[0])) #define BITS 64 diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h index 26a7c1f..dadecb9 100644 --- a/arch/x86/vdso/vdso2c.h +++ b/arch/x86/vdso/vdso2c.h @@ -18,25 +18,27 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) const char *secstrings; uint64_t syms[NSYMS] = {}; - Elf_Phdr *pt = (Elf_Phdr *)(addr + hdr-e_phoff); + Elf_Phdr *pt = (Elf_Phdr *)(addr + GET(hdr-e_phoff)); /* Walk the segment table. */ - for (i = 0; i hdr-e_phnum; i++) { - if (pt[i].p_type == PT_LOAD) { + for (i = 0; i GET(hdr-e_phnum); i++) { + if (GET(pt[i].p_type) == PT_LOAD) { if (found_load) fail(multiple PT_LOAD segs\n); - if (pt[i].p_offset != 0 || pt[i].p_vaddr != 0) + if (GET(pt[i].p_offset) != 0 || + GET(pt[i].p_vaddr) != 0) fail(PT_LOAD in wrong place\n); - if (pt[i].p_memsz != pt[i].p_filesz) + if (GET(pt[i].p_memsz) != GET(pt[i].p_filesz)) fail(cannot handle memsz != filesz\n); - load_size = pt[i].p_memsz; + load_size = GET(pt[i].p_memsz); found_load = 1; - } else if (pt[i].p_type == PT_DYNAMIC) { - dyn = addr + pt[i].p_offset; - dyn_end = addr + pt[i].p_offset + pt[i].p_memsz; + } else if (GET(pt[i].p_type) == PT_DYNAMIC) { + dyn = addr + GET(pt[i].p_offset); + dyn_end = addr + GET(pt[i].p_offset) + + GET(pt[i].p_memsz); } } if (!found_load) @@ -44,43 +46,48 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) data_size = (load_size + 4095) / 4096 * 4096; /* Walk the dynamic table */ - for (i = 0; dyn + i dyn_end dyn[i].d_tag != DT_NULL; i++) { - if (dyn[i].d_tag == DT_REL || dyn[i].d_tag == DT_RELSZ || - dyn[i].d_tag == DT_RELENT || dyn[i].d_tag == DT_TEXTREL) + for (i = 0; dyn + i dyn_end GET(dyn[i].d_tag) != DT_NULL; i++) { + typeof(dyn[i].d_tag) tag = GET(dyn[i].d_tag); + if (tag == DT_REL || tag == DT_RELSZ || + tag == DT_RELENT || tag == DT_TEXTREL) fail(vdso image contains dynamic relocations\n); } /* Walk the section table */ - secstrings_hdr = addr + hdr-e_shoff + hdr-e_shentsize*hdr-e_shstrndx; - secstrings = addr + secstrings_hdr-sh_offset; - for (i = 0; i hdr-e_shnum; i++) { - Elf_Shdr *sh = addr + hdr-e_shoff + hdr-e_shentsize * i; - if (sh-sh_type == SHT_SYMTAB) + secstrings_hdr = addr + GET(hdr-e_shoff) + + GET(hdr-e_shentsize)*GET(hdr-e_shstrndx); + secstrings = addr + GET(secstrings_hdr-sh_offset); + for (i = 0; i GET(hdr-e_shnum); i++) { + Elf_Shdr *sh = addr + GET(hdr-e_shoff) + + GET(hdr-e_shentsize) * i; + if (GET(sh-sh_type) == SHT_SYMTAB) symtab_hdr = sh; - if (!strcmp(secstrings + sh-sh_name, .altinstructions)) + if (!strcmp(secstrings + GET(sh-sh_name), .altinstructions)) alt_sec = sh; } if (!symtab_hdr) fail(no symbol table\n); - strtab_hdr = addr + hdr-e_shoff +