From bdfb9bcc25005d06a9c301830bdeb7ca5a0b6ef7 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Fri, 6 Jun 2014 14:30:37 -0700 Subject: [PATCH] x86, vdso: Use for littleendian access There are no standard functions for littleendian data (unlike bigendian data.) Thus, use to access littleendian data members. Those are fairly inefficient, but it doesn't matter for this purpose (and can be optimized later.) This avoids portability problems. Reported-by: Andrew Morton Signed-off-by: H. Peter Anvin Tested-by: Andy Lutomirski Link: http://lkml.kernel.org/r/20140606140017.afb7f91142f66cb3dd13c186@linux-foundation.org --- arch/x86/vdso/Makefile | 1 + arch/x86/vdso/vdso2c.c | 10 ++++---- arch/x86/vdso/vdso2c.h | 62 +++++++++++++++++++++++++------------------------- 3 files changed, 38 insertions(+), 35 deletions(-) diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile index 895d4b1..9769df0 100644 --- a/arch/x86/vdso/Makefile +++ b/arch/x86/vdso/Makefile @@ -59,6 +59,7 @@ VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \ $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE $(call if_changed,vdso) +HOST_EXTRACFLAGS += -I$(srctree)/tools/include hostprogs-y += vdso2c quiet_cmd_vdso2c = VDSO2C $@ diff --git a/arch/x86/vdso/vdso2c.c b/arch/x86/vdso/vdso2c.c index deabaf5..450ac6e 100644 --- a/arch/x86/vdso/vdso2c.c +++ b/arch/x86/vdso/vdso2c.c @@ -11,6 +11,8 @@ #include #include +#include + #include #include @@ -56,12 +58,12 @@ static void fail(const char *format, ...) */ #define GLE(x, bits, ifnot) \ __builtin_choose_expr( \ - (sizeof(x) == bits/8), \ - (__typeof__(x))le##bits##toh(x), ifnot) + (sizeof(*(x)) == bits/8), \ + (__typeof__(*(x)))get_unaligned_le##bits(x), ifnot) -extern void bad_get_le(uint64_t); +extern void bad_get_le(void); #define LAST_LE(x) \ - __builtin_choose_expr(sizeof(x) == 1, (x), bad_get_le(x)) + __builtin_choose_expr(sizeof(*(x)) == 1, *(x), bad_get_le()) #define GET_LE(x) \ GLE(x, 64, GLE(x, 32, GLE(x, 16, LAST_LE(x)))) diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h index d1e99e1..8a07463 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_LE(hdr->e_phoff)); + Elf_Phdr *pt = (Elf_Phdr *)(addr + GET_LE(&hdr->e_phoff)); /* Walk the segment table. */ - for (i = 0; i < GET_LE(hdr->e_phnum); i++) { - if (GET_LE(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_LE(pt[i].p_offset) != 0 || - GET_LE(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_LE(pt[i].p_memsz) != GET_LE(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_LE(pt[i].p_memsz); + load_size = GET_LE(&pt[i].p_memsz); found_load = 1; - } 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); + } 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) @@ -47,24 +47,24 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) /* Walk the dynamic table */ 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); + 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_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) + 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_LE(sh->sh_name), + if (!strcmp(secstrings + GET_LE(&sh->sh_name), ".altinstructions")) alt_sec = sh; } @@ -72,25 +72,25 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) if (!symtab_hdr) fail("no symbol table\n"); - strtab_hdr = addr + GET_LE(hdr->e_shoff) + - GET_LE(hdr->e_shentsize) * GET_LE(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_LE(symtab_hdr->sh_size) / GET_LE(symtab_hdr->sh_entsize); + i < GET_LE(&symtab_hdr->sh_size) / GET_LE(&symtab_hdr->sh_entsize); i++) { int k; - 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); + 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_LE(sym->st_value); + syms[k] = GET_LE(&sym->st_value); } } } @@ -150,9 +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_LE(alt_sec->sh_offset)); + (unsigned long)GET_LE(&alt_sec->sh_offset)); fprintf(outfile, "\t.alt_len = %lu,\n", - (unsigned long)GET_LE(alt_sec->sh_size)); + (unsigned long)GET_LE(&alt_sec->sh_size)); } for (i = 0; i < NSYMS; i++) { if (syms[i]) -- 2.7.4