From c191920f737a09a7252088f018f6747f0d2f484d Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Fri, 30 May 2014 17:03:22 -0700 Subject: [PATCH] x86/vdso, build: Make LE access macros clearer, host-safe Make it a little clearer what the littleendian access macros in vdso2c.[ch] actually do. This way they can probably also be moved to a central location (e.g. tools/include) for the benefit of other host tools. We should avoid implementation namespace symbols when writing code that is compiling for the compiler host, so avoid names starting with double underscore or underscore-capital. Signed-off-by: H. Peter Anvin Cc: Andy Lutomirski Link: http://lkml.kernel.org/r/2cf258df123cb24bad63c274c8563c050547d99d.1401464755.git.luto@amacapital.net --- arch/x86/vdso/vdso2c.c | 16 +++++------ arch/x86/vdso/vdso2c.h | 65 ++++++++++++++++++++++-------------------- 2 files changed, 42 insertions(+), 39 deletions(-) diff --git a/arch/x86/vdso/vdso2c.c b/arch/x86/vdso/vdso2c.c index de19ced6c87d..deabaf5bfb89 100644 --- a/arch/x86/vdso/vdso2c.c +++ b/arch/x86/vdso/vdso2c.c @@ -54,17 +54,17 @@ static void fail(const char *format, ...) /* * Evil macros to do a little-endian read. */ -#define __GET_TYPE(x, type, bits, ifnot) \ +#define GLE(x, bits, ifnot) \ __builtin_choose_expr( \ - __builtin_types_compatible_p(typeof(x), type), \ - le##bits##toh((x)), ifnot) + (sizeof(x) == bits/8), \ + (__typeof__(x))le##bits##toh(x), ifnot) -extern void bad_get(uint64_t); +extern void bad_get_le(uint64_t); +#define LAST_LE(x) \ + __builtin_choose_expr(sizeof(x) == 1, (x), bad_get_le(x)) -#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 GET_LE(x) \ + GLE(x, 64, GLE(x, 32, GLE(x, 16, LAST_LE(x)))) #define NSYMS (sizeof(required_syms) / sizeof(required_syms[0])) diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h index f0475dad2286..d1e99e1892c4 100644 --- a/arch/x86/vdso/vdso2c.h +++ b/arch/x86/vdso/vdso2c.h @@ -18,27 +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 + GET(hdr->e_phoff)); + Elf_Phdr *pt = (Elf_Phdr *)(addr + GET_LE(hdr->e_phoff)); /* Walk the segment table. */ - for (i = 0; i < GET(hdr->e_phnum); i++) { - if (GET(pt[i].p_type) == PT_LOAD) { + for (i = 0; i < GET_LE(hdr->e_phnum); i++) { + if (GET_LE(pt[i].p_type) == PT_LOAD) { if (found_load) fail("multiple PT_LOAD segs\n"); - if (GET(pt[i].p_offset) != 0 || - GET(pt[i].p_vaddr) != 0) + if (GET_LE(pt[i].p_offset) != 0 || + GET_LE(pt[i].p_vaddr) != 0) fail("PT_LOAD in wrong place\n"); - if (GET(pt[i].p_memsz) != GET(pt[i].p_filesz)) + if (GET_LE(pt[i].p_memsz) != GET_LE(pt[i].p_filesz)) fail("cannot handle memsz != filesz\n"); - load_size = GET(pt[i].p_memsz); + load_size = GET_LE(pt[i].p_memsz); found_load = 1; - } 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); + } else if (GET_LE(pt[i].p_type) == PT_DYNAMIC) { + dyn = addr + GET_LE(pt[i].p_offset); + dyn_end = addr + GET_LE(pt[i].p_offset) + + GET_LE(pt[i].p_memsz); } } if (!found_load) @@ -46,48 +46,51 @@ 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 && GET(dyn[i].d_tag) != DT_NULL; i++) { - typeof(dyn[i].d_tag) tag = GET(dyn[i].d_tag); + for (i = 0; dyn + i < dyn_end && + GET_LE(dyn[i].d_tag) != DT_NULL; i++) { + typeof(dyn[i].d_tag) tag = GET_LE(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 + 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) + secstrings_hdr = addr + GET_LE(hdr->e_shoff) + + GET_LE(hdr->e_shentsize)*GET_LE(hdr->e_shstrndx); + secstrings = addr + GET_LE(secstrings_hdr->sh_offset); + for (i = 0; i < GET_LE(hdr->e_shnum); i++) { + Elf_Shdr *sh = addr + GET_LE(hdr->e_shoff) + + GET_LE(hdr->e_shentsize) * i; + if (GET_LE(sh->sh_type) == SHT_SYMTAB) symtab_hdr = sh; - if (!strcmp(secstrings + GET(sh->sh_name), ".altinstructions")) + if (!strcmp(secstrings + GET_LE(sh->sh_name), + ".altinstructions")) alt_sec = sh; } if (!symtab_hdr) fail("no symbol table\n"); - strtab_hdr = addr + GET(hdr->e_shoff) + - GET(hdr->e_shentsize) * GET(symtab_hdr->sh_link); + strtab_hdr = addr + GET_LE(hdr->e_shoff) + + GET_LE(hdr->e_shentsize) * GET_LE(symtab_hdr->sh_link); /* Walk the symbol table */ - for (i = 0; i < GET(symtab_hdr->sh_size) / GET(symtab_hdr->sh_entsize); + for (i = 0; + i < GET_LE(symtab_hdr->sh_size) / GET_LE(symtab_hdr->sh_entsize); i++) { int k; - Elf_Sym *sym = addr + GET(symtab_hdr->sh_offset) + - GET(symtab_hdr->sh_entsize) * i; - const char *name = addr + GET(strtab_hdr->sh_offset) + - GET(sym->st_name); + Elf_Sym *sym = addr + GET_LE(symtab_hdr->sh_offset) + + GET_LE(symtab_hdr->sh_entsize) * i; + const char *name = addr + GET_LE(strtab_hdr->sh_offset) + + GET_LE(sym->st_name); for (k = 0; k < NSYMS; k++) { if (!strcmp(name, required_syms[k])) { if (syms[k]) { fail("duplicate symbol %s\n", required_syms[k]); } - syms[k] = GET(sym->st_value); + syms[k] = GET_LE(sym->st_value); } } } @@ -147,9 +150,9 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) fprintf(outfile, "\t},\n"); if (alt_sec) { fprintf(outfile, "\t.alt = %lu,\n", - (unsigned long)GET(alt_sec->sh_offset)); + (unsigned long)GET_LE(alt_sec->sh_offset)); fprintf(outfile, "\t.alt_len = %lu,\n", - (unsigned long)GET(alt_sec->sh_size)); + (unsigned long)GET_LE(alt_sec->sh_size)); } for (i = 0; i < NSYMS; i++) { if (syms[i])