Author: kib
Date: Thu May 17 15:24:53 2018
New Revision: 333720
URL: https://svnweb.freebsd.org/changeset/base/333720
Log:
MFC r333228
Implement support for ifuncs in the kernel linker on x86.
MFC r333411:
Avoid calls to bzero() before ireloc
Approved by: re (marius)
Modified:
stable/11/sys/amd64/amd64/elf_machdep.c
stable/11/sys/amd64/amd64/machdep.c
stable/11/sys/i386/i386/elf_machdep.c
stable/11/sys/i386/i386/machdep.c
stable/11/sys/kern/link_elf.c
stable/11/sys/kern/link_elf_obj.c
stable/11/sys/sys/linker.h
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/amd64/amd64/elf_machdep.c
==============================================================================
--- stable/11/sys/amd64/amd64/elf_machdep.c Thu May 17 15:21:19 2018
(r333719)
+++ stable/11/sys/amd64/amd64/elf_machdep.c Thu May 17 15:24:53 2018
(r333720)
@@ -173,10 +173,13 @@ elf64_dump_thread(struct thread *td, void *dst, size_t
*off = len;
}
+#define ERI_LOCAL 0x0001
+#define ERI_ONLYIFUNC 0x0002
+
/* Process one elf relocation with addend. */
static int
elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
- int type, int local, elf_lookup_fn lookup)
+ int type, elf_lookup_fn lookup, int flags)
{
Elf64_Addr *where, val;
Elf32_Addr *where32, val32;
@@ -215,6 +218,9 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbas
panic("unknown reloc type %d\n", type);
}
+ if (((flags & ERI_ONLYIFUNC) == 0) ^ (rtype != R_X86_64_IRELATIVE))
+ return (0);
+
switch (rtype) {
case R_X86_64_NONE: /* none */
break;
@@ -273,6 +279,13 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbas
*where = val;
break;
+ case R_X86_64_IRELATIVE:
+ addr = relocbase + addend;
+ val = ((Elf64_Addr (*)(void))addr)();
+ if (*where != val)
+ *where = val;
+ break;
+
default:
printf("kldload: unexpected relocation type %ld\n",
rtype);
@@ -282,11 +295,20 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbas
}
int
+elf_reloc_ifunc(linker_file_t lf, Elf_Addr relocbase, const void *data,
+ int type, elf_lookup_fn lookup)
+{
+
+ return (elf_reloc_internal(lf, relocbase, data, type, lookup,
+ ERI_ONLYIFUNC));
+}
+
+int
elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
elf_lookup_fn lookup)
{
- return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup));
+ return (elf_reloc_internal(lf, relocbase, data, type, lookup, 0));
}
int
@@ -294,7 +316,8 @@ elf_reloc_local(linker_file_t lf, Elf_Addr relocbase,
int type, elf_lookup_fn lookup)
{
- return (elf_reloc_internal(lf, relocbase, data, type, 1, lookup));
+ return (elf_reloc_internal(lf, relocbase, data, type, lookup,
+ ERI_LOCAL));
}
int
Modified: stable/11/sys/amd64/amd64/machdep.c
==============================================================================
--- stable/11/sys/amd64/amd64/machdep.c Thu May 17 15:21:19 2018
(r333719)
+++ stable/11/sys/amd64/amd64/machdep.c Thu May 17 15:24:53 2018
(r333720)
@@ -1564,16 +1564,23 @@ hammer_time(u_int64_t modulep, u_int64_t physfree)
size_t kstack0_sz;
int late_console;
- /*
- * This may be done better later if it gets more high level
- * components in it. If so just link td->td_proc here.
- */
- proc_linkup0(&proc0, &thread0);
-
kmdp = init_ops.parse_preload_data(modulep);
identify_cpu1();
identify_hypervisor();
+ /*
+ * hw.cpu_stdext_disable is ignored by the call, it will be
+ * re-evaluted by the below call to finishidentcpu().
+ */
+ identify_cpu2();
+
+ link_elf_ireloc(kmdp);
+
+ /*
+ * This may be done better later if it gets more high level
+ * components in it. If so just link td->td_proc here.
+ */
+ proc_linkup0(&proc0, &thread0);
/* Init basic tunables, hz etc */
init_param1();
Modified: stable/11/sys/i386/i386/elf_machdep.c
==============================================================================
--- stable/11/sys/i386/i386/elf_machdep.c Thu May 17 15:21:19 2018
(r333719)
+++ stable/11/sys/i386/i386/elf_machdep.c Thu May 17 15:24:53 2018
(r333720)
@@ -158,10 +158,13 @@ elf32_dump_thread(struct thread *td, void *dst, size_t
*off = len;
}
+#define ERI_LOCAL 0x0001
+#define ERI_ONLYIFUNC 0x0002
+
/* Process one elf relocation with addend. */
static int
elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
- int type, int local, elf_lookup_fn lookup)
+ int type, elf_lookup_fn lookup, int flags)
{
Elf_Addr *where;
Elf_Addr addr;
@@ -190,7 +193,10 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbas
panic("unknown reloc type %d\n", type);
}
- if (local) {
+ if (((flags & ERI_ONLYIFUNC) == 0) ^ (rtype != R_386_IRELATIVE))
+ return (0);
+
+ if ((flags & ERI_LOCAL) != 0) {
if (rtype == R_386_RELATIVE) { /* A + B */
addr = elf_relocaddr(lf, relocbase + addend);
if (*where != addr)
@@ -242,6 +248,12 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbas
case R_386_RELATIVE:
break;
+ case R_386_IRELATIVE:
+ addr = relocbase + addend;
+ addr = ((Elf_Addr (*)(void))addr)();
+ if (*where != addr)
+ *where = addr;
+ break;
default:
printf("kldload: unexpected relocation type %d\n",
rtype);
@@ -251,11 +263,20 @@ elf_reloc_internal(linker_file_t lf, Elf_Addr relocbas
}
int
+elf_reloc_ifunc(linker_file_t lf, Elf_Addr relocbase, const void *data,
+ int type, elf_lookup_fn lookup)
+{
+
+ return (elf_reloc_internal(lf, relocbase, data, type, lookup,
+ ERI_ONLYIFUNC));
+}
+
+int
elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
elf_lookup_fn lookup)
{
- return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup));
+ return (elf_reloc_internal(lf, relocbase, data, type, lookup, 0));
}
int
@@ -263,7 +284,8 @@ elf_reloc_local(linker_file_t lf, Elf_Addr relocbase,
int type, elf_lookup_fn lookup)
{
- return (elf_reloc_internal(lf, relocbase, data, type, 1, lookup));
+ return (elf_reloc_internal(lf, relocbase, data, type, lookup,
+ ERI_LOCAL));
}
int
Modified: stable/11/sys/i386/i386/machdep.c
==============================================================================
--- stable/11/sys/i386/i386/machdep.c Thu May 17 15:21:19 2018
(r333719)
+++ stable/11/sys/i386/i386/machdep.c Thu May 17 15:24:53 2018
(r333720)
@@ -2441,6 +2441,7 @@ init386(int first)
int gsel_tss, metadata_missing, x, pa;
struct pcpu *pc;
struct xstate_hdr *xhdr;
+ caddr_t kmdp;
int late_console;
thread0.td_kstack = proc0kstack;
@@ -2687,6 +2688,9 @@ init386(int first)
cninit();
i386_kdb_init();
}
+
+ kmdp = preload_search_by_type("elf kernel");
+ link_elf_ireloc(kmdp);
vm86_initialize();
getmemsize(first);
Modified: stable/11/sys/kern/link_elf.c
==============================================================================
--- stable/11/sys/kern/link_elf.c Thu May 17 15:21:19 2018
(r333719)
+++ stable/11/sys/kern/link_elf.c Thu May 17 15:24:53 2018
(r333720)
@@ -188,6 +188,9 @@ static struct linker_class link_elf_class = {
static int parse_dynamic(elf_file_t);
static int relocate_file(elf_file_t);
+static int relocate_file1(elf_file_t ef, int (*elf_reloc_func)(
+ linker_file_t lf, Elf_Addr relocbase, const void *data,
+ int type, elf_lookup_fn lookup));
static int link_elf_preload_parse_symbols(elf_file_t);
static struct elf_set_head set_pcpu_list;
@@ -1183,7 +1186,8 @@ symbol_name(elf_file_t ef, Elf_Size r_info)
}
static int
-relocate_file(elf_file_t ef)
+relocate_file1(elf_file_t ef, int (*elf_reloc_func)(linker_file_t lf,
+ Elf_Addr relocbase, const void *data, int type, elf_lookup_fn lookup))
{
const Elf_Rel *rellim;
const Elf_Rel *rel;
@@ -1197,7 +1201,7 @@ relocate_file(elf_file_t ef)
rellim = (const Elf_Rel *)
((const char *)ef->rel + ef->relsize);
while (rel < rellim) {
- if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
+ if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rel,
ELF_RELOC_REL, elf_lookup)) {
symname = symbol_name(ef, rel->r_info);
printf("link_elf: symbol %s undefined\n",
symname);
@@ -1213,7 +1217,7 @@ relocate_file(elf_file_t ef)
relalim = (const Elf_Rela *)
((const char *)ef->rela + ef->relasize);
while (rela < relalim) {
- if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
+ if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rela,
ELF_RELOC_RELA, elf_lookup)) {
symname = symbol_name(ef, rela->r_info);
printf("link_elf: symbol %s undefined\n",
@@ -1230,7 +1234,7 @@ relocate_file(elf_file_t ef)
rellim = (const Elf_Rel *)
((const char *)ef->pltrel + ef->pltrelsize);
while (rel < rellim) {
- if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rel,
+ if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rel,
ELF_RELOC_REL, elf_lookup)) {
symname = symbol_name(ef, rel->r_info);
printf("link_elf: symbol %s undefined\n",
@@ -1247,7 +1251,7 @@ relocate_file(elf_file_t ef)
relalim = (const Elf_Rela *)
((const char *)ef->pltrela + ef->pltrelasize);
while (rela < relalim) {
- if (elf_reloc(&ef->lf, (Elf_Addr)ef->address, rela,
+ if (elf_reloc_func(&ef->lf, (Elf_Addr)ef->address, rela,
ELF_RELOC_RELA, elf_lookup)) {
symname = symbol_name(ef, rela->r_info);
printf("link_elf: symbol %s undefined\n",
@@ -1261,6 +1265,19 @@ relocate_file(elf_file_t ef)
return (0);
}
+static int
+relocate_file(elf_file_t ef)
+{
+ int e;
+
+ e = relocate_file1(ef, elf_reloc);
+#if defined(__i386__) || defined(__amd64__)
+ if (e == 0)
+ e = relocate_file1(ef, elf_reloc_ifunc);
+#endif
+ return (e);
+}
+
/*
* Hash function for symbol table lookup. Don't even think about changing
* this. It is specified by the System V ABI.
@@ -1318,7 +1335,8 @@ link_elf_lookup_symbol(linker_file_t lf, const char* n
if (strcmp(name, strp) == 0) {
if (symp->st_shndx != SHN_UNDEF ||
(symp->st_value != 0 &&
- ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
+ (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
+ ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
*sym = (c_linker_sym_t) symp;
return (0);
}
@@ -1338,7 +1356,8 @@ link_elf_lookup_symbol(linker_file_t lf, const char* n
if (strcmp(name, strp) == 0) {
if (symp->st_shndx != SHN_UNDEF ||
(symp->st_value != 0 &&
- ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
+ (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
+ ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) {
*sym = (c_linker_sym_t) symp;
return (0);
}
@@ -1353,12 +1372,18 @@ static int
link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval)
{
- elf_file_t ef = (elf_file_t) lf;
- const Elf_Sym* es = (const Elf_Sym*) sym;
+ elf_file_t ef;
+ const Elf_Sym *es;
+ caddr_t val;
+ ef = (elf_file_t)lf;
+ es = (const Elf_Sym *)sym;
if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) {
symval->name = ef->strtab + es->st_name;
- symval->value = (caddr_t) ef->address + es->st_value;
+ val = (caddr_t)ef->address + es->st_value;
+ if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
+ val = ((caddr_t (*)(void))val)();
+ symval->value = val;
symval->size = es->st_size;
return (0);
}
@@ -1366,7 +1391,10 @@ link_elf_symbol_values(linker_file_t lf, c_linker_sym_
return (ENOENT);
if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
symval->name = ef->ddbstrtab + es->st_name;
- symval->value = (caddr_t) ef->address + es->st_value;
+ val = (caddr_t)ef->address + es->st_value;
+ if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
+ val = ((caddr_t (*)(void))val)();
+ symval->value = val;
symval->size = es->st_size;
return (0);
}
@@ -1476,7 +1504,8 @@ link_elf_each_function_name(linker_file_t file,
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
- ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
+ (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
+ ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
error = callback(ef->ddbstrtab + symp->st_name, opaque);
if (error != 0)
return (error);
@@ -1497,7 +1526,8 @@ link_elf_each_function_nameval(linker_file_t file,
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
- ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
+ (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
+ ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
error = link_elf_symbol_values(file,
(c_linker_sym_t) symp, &symval);
if (error != 0)
@@ -1656,3 +1686,27 @@ link_elf_strtab_get(linker_file_t lf, caddr_t *strtab)
return (ef->ddbstrcnt);
}
+
+#if defined(__i386__) || defined(__amd64__)
+void
+link_elf_ireloc(caddr_t kmdp)
+{
+ struct elf_file eff;
+ elf_file_t ef;
+ volatile char *c;
+ size_t i;
+
+ ef = &eff;
+
+ /* Do not use bzero/memset before ireloc is done. */
+ for (c = (char *)ef, i = 0; i < sizeof(*ef); i++)
+ c[i] = 0;
+
+ ef->modptr = kmdp;
+ ef->dynamic = (Elf_Dyn *)&_DYNAMIC;
+ parse_dynamic(ef);
+ ef->address = 0;
+ link_elf_preload_parse_symbols(ef);
+ relocate_file1(ef, elf_reloc_ifunc);
+}
+#endif
Modified: stable/11/sys/kern/link_elf_obj.c
==============================================================================
--- stable/11/sys/kern/link_elf_obj.c Thu May 17 15:21:19 2018
(r333719)
+++ stable/11/sys/kern/link_elf_obj.c Thu May 17 15:24:53 2018
(r333720)
@@ -1194,12 +1194,19 @@ static int
link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval)
{
- elf_file_t ef = (elf_file_t) lf;
- const Elf_Sym *es = (const Elf_Sym*) sym;
+ elf_file_t ef;
+ const Elf_Sym *es;
+ caddr_t val;
+ ef = (elf_file_t) lf;
+ es = (const Elf_Sym*) sym;
+ val = (caddr_t)es->st_value;
if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) {
symval->name = ef->ddbstrtab + es->st_name;
- symval->value = (caddr_t)es->st_value;
+ val = (caddr_t)es->st_value;
+ if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC)
+ val = ((caddr_t (*)(void))val)();
+ symval->value = val;
symval->size = es->st_size;
return 0;
}
@@ -1284,7 +1291,8 @@ link_elf_each_function_name(linker_file_t file,
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
- ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
+ (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
+ ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
error = callback(ef->ddbstrtab + symp->st_name, opaque);
if (error)
return (error);
@@ -1305,8 +1313,10 @@ link_elf_each_function_nameval(linker_file_t file,
/* Exhaustive search */
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
if (symp->st_value != 0 &&
- ELF_ST_TYPE(symp->st_info) == STT_FUNC) {
- error = link_elf_symbol_values(file, (c_linker_sym_t)
symp, &symval);
+ (ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
+ ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) {
+ error = link_elf_symbol_values(file,
+ (c_linker_sym_t)symp, &symval);
if (error)
return (error);
error = callback(file, i, &symval, opaque);
Modified: stable/11/sys/sys/linker.h
==============================================================================
--- stable/11/sys/sys/linker.h Thu May 17 15:21:19 2018 (r333719)
+++ stable/11/sys/sys/linker.h Thu May 17 15:24:53 2018 (r333720)
@@ -269,11 +269,16 @@ extern int kld_debug;
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);
-int elf_reloc_local(linker_file_t _lf, Elf_Addr base, const void *_rel, int
_type, elf_lookup_fn _lu);
+int elf_reloc(linker_file_t _lf, Elf_Addr base, const void *_rel,
+ int _type, elf_lookup_fn _lu);
+int elf_reloc_ifunc(linker_file_t _lf, Elf_Addr base, const void *_rel,
+ int _type, elf_lookup_fn _lu);
+int elf_reloc_local(linker_file_t _lf, Elf_Addr base, const void *_rel,
+ int _type, elf_lookup_fn _lu);
Elf_Addr elf_relocaddr(linker_file_t _lf, Elf_Addr addr);
const Elf_Sym *elf_get_sym(linker_file_t _lf, Elf_Size _symidx);
const char *elf_get_symname(linker_file_t _lf, Elf_Size _symidx);
+void link_elf_ireloc(caddr_t kmdp);
typedef struct linker_ctf {
const uint8_t *ctftab; /* Decompressed CTF data. */
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