From bd4161fcbafb72b4df7da643e9639b897fafbc5b Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Thu, 20 Aug 2009 16:09:38 -0700 Subject: [PATCH] FFI step 2: can ask for libc.so.6. introduced explicit "data" symbol instead of etext to mark beginning of data, so that using larger alignment (i.e. 4MB like GNU loader) doesn't confuse garbage collector. split dodata into dodata and dobss in preparation for putting the dynamic data + headers in the data segment instead of stuffed at the beginning of the binary. R=r DELTA=52 (37 added, 3 deleted, 12 changed) OCL=33610 CL=33618 --- src/cmd/6l/asm.c | 28 +++++++++++++++++++++++----- src/cmd/6l/l.h | 1 + src/cmd/6l/obj.c | 1 + src/cmd/6l/pass.c | 9 +++++++++ src/cmd/ld/elf64.c | 19 +++++++++++-------- src/cmd/ld/elf64.h | 1 + src/pkg/runtime/mgc0.c | 3 ++- 7 files changed, 48 insertions(+), 14 deletions(-) diff --git a/src/cmd/6l/asm.c b/src/cmd/6l/asm.c index 7e0bd9191d..5acaaae5f1 100644 --- a/src/cmd/6l/asm.c +++ b/src/cmd/6l/asm.c @@ -128,7 +128,7 @@ asmb(void) int32 v, magic; int a, nl; uchar *op1; - vlong vl, va, startva, fo, w, symo, hashoff; + vlong vl, va, startva, fo, w, symo, hashoff, dstrtab, off; vlong symdatva = 0x99LL<<32; Elf64Hdr *eh; Elf64PHdr *ph, *pph; @@ -431,6 +431,7 @@ asmb(void) sh = newElf64SHdr(""); pph = nil; /* silence compiler */ + dstrtab = 0; /* Dynamic linking sections */ if (!debug['d']) { /* -d suppresses dynamic loader format */ @@ -443,7 +444,7 @@ asmb(void) pph->off = ELF64HDRSIZE; pph->vaddr = startva + pph->off; pph->paddr = startva + pph->off; - pph->align = 8; + pph->align = INITRND; /* interpreter */ ph = newElf64PHdr(); @@ -503,13 +504,19 @@ asmb(void) sh->addr = startva + sh->off; sh->off = startelf(); elf64writedynent(DT_HASH, startva+hashoff); - elf64writedynent(DT_STRTAB, startva+ELF64FULLHDRSIZE-STRTABSIZE); elf64writedynent(DT_SYMTAB, startva); elf64writedynent(DT_RELA, startva); elf64writedynent(DT_RELASZ, 0); // size of the whole rela in bytes elf64writedynent(DT_RELAENT, ELF64RELASIZE); - elf64writedynent(DT_STRSZ, STRTABSIZE); elf64writedynent(DT_SYMENT, 0); +// elf64writedynent(DT_NEEDED, elf64addstr("libc.so.6")); + + /* make space for these now but fill them in later */ + cflush(); + dstrtab = seek(cout, 0, 1); + elf64writedynent(DT_STRTAB, -1); + elf64writedynent(DT_STRSZ, -1); + elf64writedynent(DT_NULL, 0); sh->size = endelf() - sh->off; sh->addralign = 8; @@ -534,7 +541,7 @@ asmb(void) ph->paddr = startva + ph->off; ph->filesz = sh->off + sh->size - ph->off; ph->memsz = ph->filesz; - ph->align = 8; + ph->align = INITRND; } ph = newElf64PHdr(); @@ -644,6 +651,17 @@ asmb(void) elf64writestrtable(); sh->size = endelf() - sh->off; + if(dstrtab != 0) { + // update DT_STRTAB entry + cflush(); + off = seek(cout, 0, 1); + seek(cout, dstrtab, 0); + elf64writedynent(DT_STRTAB, sh->addr); + elf64writedynent(DT_STRSZ, sh->size); + cflush(); + seek(cout, off, 0); + } + /* Main header */ eh = getElf64Hdr(); eh->ident[EI_MAG0] = '\177'; diff --git a/src/cmd/6l/l.h b/src/cmd/6l/l.h index 8f72812bcc..0490bc1db1 100644 --- a/src/cmd/6l/l.h +++ b/src/cmd/6l/l.h @@ -390,6 +390,7 @@ double cputime(void); void datblk(int32, int32); void deadcode(void); void diag(char*, ...); +void dobss(void); void dodata(void); void doinit(void); void doprof1(void); diff --git a/src/cmd/6l/obj.c b/src/cmd/6l/obj.c index d9630fe333..98318d94b1 100644 --- a/src/cmd/6l/obj.c +++ b/src/cmd/6l/obj.c @@ -390,6 +390,7 @@ main(int argc, char *argv[]) patch(); follow(); dodata(); + dobss(); dostkoff(); paramspace = "SP"; /* (FP) now (SP) on output */ if(debug['p']) diff --git a/src/cmd/6l/pass.c b/src/cmd/6l/pass.c index 3917ac5423..540063568f 100644 --- a/src/cmd/6l/pass.c +++ b/src/cmd/6l/pass.c @@ -124,6 +124,14 @@ dodata(void) } datsize += u; } +} + +void +dobss(void) +{ + int i; + Sym *s; + int32 t; /* now the bss */ bsssize = 0; @@ -137,6 +145,7 @@ dodata(void) s->value = bsssize + datsize; bsssize += t; } + xdefine("data", SBSS, 0); xdefine("edata", SBSS, datsize); xdefine("end", SBSS, bsssize + datsize); } diff --git a/src/cmd/ld/elf64.c b/src/cmd/ld/elf64.c index dc9f4196b1..d6a2f7f3c2 100644 --- a/src/cmd/ld/elf64.c +++ b/src/cmd/ld/elf64.c @@ -13,7 +13,7 @@ static Elf64Hdr hdr; static Elf64PHdr *phdr[NSECT]; static Elf64SHdr *shdr[NSECT]; static char *sname[NSECT]; -static char *str[NSECT]; +static char *str[20]; /* Initialize the global variable that describes the ELF header. It will be updated as @@ -80,15 +80,19 @@ elf64writestrtable(void) diag("elf64 string table overflow"); } -void -e64addstr(char *name) +uint32 +elf64addstr(char *name) { - if (numstr >= NSECT) { + int r; + + if (numstr >= nelem(str)) { diag("too many elf strings"); - return; + return 0; } str[numstr++] = strdup(name); + r = stroffset; stroffset += strlen(name)+1; + return r; } uint32 @@ -135,11 +139,10 @@ newElf64SHdr(char *name) hdr.shstrndx = hdr.shnum; e = malloc(sizeof *e); memset(e, 0, sizeof *e); - e->name = stroffset; + e->name = elf64addstr(name); if (hdr.shnum >= NSECT) { diag("too many shdrs"); } else { - e64addstr(name); shdr[hdr.shnum++] = e; } return e; @@ -152,7 +155,7 @@ getElf64Hdr(void) } uint32 -elf64writehdr() +elf64writehdr(void) { int i; diff --git a/src/cmd/ld/elf64.h b/src/cmd/ld/elf64.h index 55d0ca3098..bde6376783 100644 --- a/src/cmd/ld/elf64.h +++ b/src/cmd/ld/elf64.h @@ -274,6 +274,7 @@ Elf64PHdr *newElf64PHdr(); uint32 elf64writehdr(void); uint32 elf64writephdrs(void); uint32 elf64writeshdrs(void); +uint32 elf64addstr(char*); void elf64writestrtable(void); void elf64writedynent(int, uint64); uint32 elf64_hash(uchar*); diff --git a/src/pkg/runtime/mgc0.c b/src/pkg/runtime/mgc0.c index d27c186f41..b5b2b48a3e 100644 --- a/src/pkg/runtime/mgc0.c +++ b/src/pkg/runtime/mgc0.c @@ -19,6 +19,7 @@ enum { Debug = 0 }; +extern byte data[]; extern byte etext[]; extern byte end[]; @@ -84,7 +85,7 @@ mark(void) G *gp; // mark data+bss - scanblock(0, etext, end - etext); + scanblock(0, data, end - data); // mark stacks for(gp=allg; gp!=nil; gp=gp->alllink) { -- 2.48.1