Date: Thu, 17 Sep 2015 00:43:21 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Gleb Smirnoff <glebius@FreeBSD.org> Cc: marcel@FreeBSD.org, Steve Kiernan <stevek@juniper.net>, brooks@FreeBSD.org, current@FreeBSD.org Subject: Re: r286727 breaks geom_md.ko loading Message-ID: <20150916214321.GI67105@kib.kiev.ua> In-Reply-To: <20150916140411.GN1023@glebius.int.ru> References: <20150916000019.GH1023@FreeBSD.org> <20150916051005.GF67105@kib.kiev.ua> <20150916131515.GL1023@glebius.int.ru> <20150916134249.GG67105@kib.kiev.ua> <20150916135003.GM1023@glebius.int.ru> <20150916135739.GH67105@kib.kiev.ua> <20150916140411.GN1023@glebius.int.ru>
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On Wed, Sep 16, 2015 at 05:04:11PM +0300, Gleb Smirnoff wrote:
> Yes, sorry for not being verbose enough. Kernel must not have 'device md'
> and must have 'options MD_ROOT'.
The following worked for me on i386 and amd64. Unless some objections are
raised against the approach, I will do the pass over other architectures
later.
diff --git a/sys/amd64/amd64/elf_machdep.c b/sys/amd64/amd64/elf_machdep.c
index d1cffd9..d961f09 100644
--- a/sys/amd64/amd64/elf_machdep.c
+++ b/sys/amd64/amd64/elf_machdep.c
@@ -168,6 +168,7 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
Elf_Size rtype, symidx;
const Elf_Rel *rel;
const Elf_Rela *rela;
+ int error;
switch (type) {
case ELF_RELOC_REL:
@@ -203,29 +204,29 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
break;
case R_X86_64_64: /* S + A */
- addr = lookup(lf, symidx, 1);
+ error = lookup(lf, symidx, 1, &addr);
val = addr + addend;
- if (addr == 0)
+ if (error != 0)
return -1;
if (*where != val)
*where = val;
break;
case R_X86_64_PC32: /* S + A - P */
- addr = lookup(lf, symidx, 1);
+ error = lookup(lf, symidx, 1, &addr);
where32 = (Elf32_Addr *)where;
val32 = (Elf32_Addr)(addr + addend - (Elf_Addr)where);
- if (addr == 0)
+ if (error != 0)
return -1;
if (*where32 != val32)
*where32 = val32;
break;
case R_X86_64_32S: /* S + A sign extend */
- addr = lookup(lf, symidx, 1);
+ error = lookup(lf, symidx, 1, &addr);
val32 = (Elf32_Addr)(addr + addend);
where32 = (Elf32_Addr *)where;
- if (addr == 0)
+ if (error != 0)
return -1;
if (*where32 != val32)
*where32 = val32;
@@ -242,8 +243,8 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
case R_X86_64_GLOB_DAT: /* S */
case R_X86_64_JMP_SLOT: /* XXX need addend + offset */
- addr = lookup(lf, symidx, 1);
- if (addr == 0)
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
return -1;
if (*where != addr)
*where = addr;
diff --git a/sys/i386/i386/elf_machdep.c b/sys/i386/i386/elf_machdep.c
index 03ab10f..81d6e35 100644
--- a/sys/i386/i386/elf_machdep.c
+++ b/sys/i386/i386/elf_machdep.c
@@ -178,6 +178,7 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
Elf_Word rtype, symidx;
const Elf_Rel *rel;
const Elf_Rela *rela;
+ int error;
switch (type) {
case ELF_RELOC_REL:
@@ -213,8 +214,8 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
break;
case R_386_32: /* S + A */
- addr = lookup(lf, symidx, 1);
- if (addr == 0)
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
return -1;
addr += addend;
if (*where != addr)
@@ -222,8 +223,8 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
break;
case R_386_PC32: /* S + A - P */
- addr = lookup(lf, symidx, 1);
- if (addr == 0)
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
return -1;
addr += addend - (Elf_Addr)where;
if (*where != addr)
@@ -240,8 +241,8 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
break;
case R_386_GLOB_DAT: /* S */
- addr = lookup(lf, symidx, 1);
- if (addr == 0)
+ error = lookup(lf, symidx, 1, &addr);
+ if (error != 0)
return -1;
if (*where != addr)
*where = addr;
diff --git a/sys/kern/link_elf.c b/sys/kern/link_elf.c
index 3b741cc..c931ae9 100644
--- a/sys/kern/link_elf.c
+++ b/sys/kern/link_elf.c
@@ -158,7 +158,7 @@ static int link_elf_each_function_nameval(linker_file_t,
static void link_elf_reloc_local(linker_file_t);
static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
static long link_elf_strtab_get(linker_file_t, caddr_t *);
-static Elf_Addr elf_lookup(linker_file_t, Elf_Size, int);
+static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
@@ -1548,8 +1548,8 @@ elf_get_symname(linker_file_t lf, Elf_Size symidx)
* This is not only more efficient, it's also more correct. It's not always
* the case that the symbol can be found through the hash table.
*/
-static Elf_Addr
-elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
+static int
+elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
{
elf_file_t ef = (elf_file_t)lf;
const Elf_Sym *sym;
@@ -1557,8 +1557,10 @@ elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
Elf_Addr addr, start, base;
/* Don't even try to lookup the symbol if the index is bogus. */
- if (symidx >= ef->nchains)
- return (0);
+ if (symidx >= ef->nchains) {
+ *res = 0;
+ return (EINVAL);
+ }
sym = ef->symtab + symidx;
@@ -1568,9 +1570,12 @@ elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
*/
if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
/* Force lookup failure when we have an insanity. */
- if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
- return (0);
- return ((Elf_Addr)ef->address + sym->st_value);
+ if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) {
+ *res = 0;
+ return (EINVAL);
+ }
+ *res = ((Elf_Addr)ef->address + sym->st_value);
+ return (0);
}
/*
@@ -1583,8 +1588,10 @@ elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
symbol = ef->strtab + sym->st_name;
/* Force a lookup failure if the symbol name is bogus. */
- if (*symbol == 0)
- return (0);
+ if (*symbol == 0) {
+ *res = 0;
+ return (EINVAL);
+ }
addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
@@ -1594,7 +1601,8 @@ elf_lookup(linker_file_t lf, Elf_Size symidx, int deps)
else if (elf_set_find(&set_vnet_list, addr, &start, &base))
addr = addr - start + base;
#endif
- return addr;
+ *res = addr;
+ return (0);
}
static void
diff --git a/sys/kern/link_elf_obj.c b/sys/kern/link_elf_obj.c
index 021381d..00fe1e4 100644
--- a/sys/kern/link_elf_obj.c
+++ b/sys/kern/link_elf_obj.c
@@ -144,7 +144,8 @@ static void link_elf_reloc_local(linker_file_t);
static long link_elf_symtab_get(linker_file_t, const Elf_Sym **);
static long link_elf_strtab_get(linker_file_t, caddr_t *);
-static Elf_Addr elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps);
+static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
+ Elf_Addr *);
static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
@@ -1253,38 +1254,46 @@ elf_obj_cleanup_globals_cache(elf_file_t ef)
* This is not only more efficient, it's also more correct. It's not always
* the case that the symbol can be found through the hash table.
*/
-static Elf_Addr
-elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps)
+static int
+elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
{
elf_file_t ef = (elf_file_t)lf;
Elf_Sym *sym;
const char *symbol;
- Elf_Addr ret;
+ Elf_Addr res1;
/* Don't even try to lookup the symbol if the index is bogus. */
- if (symidx >= ef->ddbsymcnt)
- return (0);
+ if (symidx >= ef->ddbsymcnt) {
+ *res = 0;
+ return (EINVAL);
+ }
sym = ef->ddbsymtab + symidx;
/* Quick answer if there is a definition included. */
- if (sym->st_shndx != SHN_UNDEF)
- return (sym->st_value);
+ if (sym->st_shndx != SHN_UNDEF) {
+ *res = sym->st_value;
+ return (0);
+ }
/* If we get here, then it is undefined and needs a lookup. */
switch (ELF_ST_BIND(sym->st_info)) {
case STB_LOCAL:
/* Local, but undefined? huh? */
- return (0);
+ *res = 0;
+ return (EINVAL);
case STB_GLOBAL:
+ case STB_WEAK:
/* Relative to Data or Function name */
symbol = ef->ddbstrtab + sym->st_name;
/* Force a lookup failure if the symbol name is bogus. */
- if (*symbol == 0)
- return (0);
- ret = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
+ if (*symbol == 0) {
+ *res = 0;
+ return (EINVAL);
+ }
+ res1 = (Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps);
/*
* Cache global lookups during module relocation. The failure
@@ -1296,18 +1305,20 @@ elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps)
* restored to SHN_UNDEF in elf_obj_cleanup_globals_cache(),
* above.
*/
- if (ret != 0) {
+ if (res1 != 0) {
sym->st_shndx = SHN_FBSD_CACHED;
- sym->st_value = ret;
+ sym->st_value = res1;
+ *res = res1;
+ return (0);
+ } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
+ sym->st_value = 0;
+ *res = 0;
+ return (0);
}
- return (ret);
-
- case STB_WEAK:
- printf("link_elf_obj: Weak symbols not supported\n");
- return (0);
+ return (EINVAL);
default:
- return (0);
+ return (EINVAL);
}
}
diff --git a/sys/sys/linker.h b/sys/sys/linker.h
index 5d24f00..7e562a6 100644
--- a/sys/sys/linker.h
+++ b/sys/sys/linker.h
@@ -264,7 +264,7 @@ extern int kld_debug;
#endif
-typedef Elf_Addr elf_lookup_fn(linker_file_t, Elf_Size, int);
+typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);
/* Support functions */
int elf_reloc(linker_file_t _lf, Elf_Addr base, const void *_rel, int _type, elf_lookup_fn _lu);
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