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authorChristophe Lyon <christophe.lyon@st.com>2013-01-18 15:08:04 +0100
committerWaldemar Brodkorb <wbrodkorb@conet.de>2018-08-10 16:01:58 +0200
commit5ec586eb37f61e57f19ac60b58af61f167ca054a (patch)
tree6c72d03d43e76a33eb5d6360d9bdb2573a048c42 /ldso
parentf88bb681ba22d77a19abfb4c1617c826298ed473 (diff)
rtld: Add FDPIC code for arm
Add FDPIC dynamic relocations support, similar to what other FDPIC targets do. Lazy binding is implemented in a folllow-up patch. Disable the SEND* macros because they involve relocations to access constant strings that are unsupported by the existing arm version. Define DL_START, START, ARCH_NEEDS_BOOTSTRAP_RELOCS, DL_CHECK_LIB_TYPE similarly to what other FDPIC targets do. Define raise() because _dl_find_hash references __aeabi_uidivmod, which uses __aeabi_idiv0 which in turn references raise. * include/elf.h (R_ARM_FUNCDESC): Define. (R_ARM_FUNCDESC_VALUE): Define. * ldso/include/dl-string.h (SEND_STDERR, SEND_ADDRESS_STDERR) (SEND_NUMBER_STDERR): Define empty for __FDPIC__. * ldso/ldso/arm/dl-inlines.h: New file. * ldso/ldso/arm/dl-startup.h (PERFORM_BOOTSTRAP_RELOC): Fix type of load_addr. Fix handling of R_ARM_RELATIVE, add support for R_ARM_FUNCDESC_VALUE. (DL_START, START): Define for __FDPIC__. (raise): Define. * ldso/ldso/arm/dl-sysdep.h (ARCH_NEEDS_BOOTSTRAP_RELOCS): Define. (DL_CHECK_LIB_TYPE): Define. (elf_machine_type_class): Take into account FDPIC related relocations. (elf_machine_load_address): Support __FDPIC__. (elf_machine_relative): Likewise. * ldso/ldso/arm/elfinterp.c (_dl_linux_resolver): Dummy support for __FDPIC__, implemented in a later patch. (_dl_do_reloc): Fix reloc_adr computation for __FDPIC__, fix handling of local symbols. Fix handling of R_ARM_RELATIVE, add support for R_ARM_FUNCDESC_VALUE, R_ARM_FUNCDESC. * ldso/ldso/arm/resolve.S: Make _dl_linux_resolve hidden. * ldso/ldso/fdpic/dl-inlines.h (htab_delete): Declare. * libc/sysdeps/linux/arm/bits/elf-fdpic.h: New file, similar to bfin's. * libc/sysdeps/linux/arm/crtreloc.c: Likewise. * libc/sysdeps/linux/arm/find_exidx.c (__dl_addr_in_loadaddr) Define. (find_exidx_callback): Support __FDPIC__. Signed-off-by: Mickaël Guêné <mickael.guene@st.com> Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
Diffstat (limited to 'ldso')
-rw-r--r--ldso/include/dl-string.h3
-rw-r--r--ldso/ldso/arm/dl-inlines.h1
-rw-r--r--ldso/ldso/arm/dl-startup.h47
-rw-r--r--ldso/ldso/arm/dl-sysdep.h67
-rw-r--r--ldso/ldso/arm/elfinterp.c85
-rw-r--r--ldso/ldso/arm/resolve.S1
-rw-r--r--ldso/ldso/fdpic/dl-inlines.h2
7 files changed, 176 insertions, 30 deletions
diff --git a/ldso/include/dl-string.h b/ldso/include/dl-string.h
index fc1d1fccd..bf6997188 100644
--- a/ldso/include/dl-string.h
+++ b/ldso/include/dl-string.h
@@ -256,7 +256,8 @@ static __always_inline char * _dl_simple_ltoahex(char *local, unsigned long i)
/* On some (wierd) arches, none of this stuff works at all, so
* disable the whole lot... */
-#if defined(__mips__)
+/* The same applies for ARM FDPIC at least for the moment. */
+#if defined(__mips__) || (__FDPIC__)
# define SEND_STDERR(X)
# define SEND_ADDRESS_STDERR(X, add_a_newline)
diff --git a/ldso/ldso/arm/dl-inlines.h b/ldso/ldso/arm/dl-inlines.h
new file mode 100644
index 000000000..8fdf6eb48
--- /dev/null
+++ b/ldso/ldso/arm/dl-inlines.h
@@ -0,0 +1 @@
+#include "../fdpic/dl-inlines.h"
diff --git a/ldso/ldso/arm/dl-startup.h b/ldso/ldso/arm/dl-startup.h
index 371dc2293..ea1e9f6f9 100644
--- a/ldso/ldso/arm/dl-startup.h
+++ b/ldso/ldso/arm/dl-startup.h
@@ -131,7 +131,7 @@ __asm__(
/* Handle relocation of the symbols in the dynamic loader. */
static __always_inline
void PERFORM_BOOTSTRAP_RELOC(ELF_RELOC *rpnt, unsigned long *reloc_addr,
- unsigned long symbol_addr, unsigned long load_addr, Elf32_Sym *symtab)
+ unsigned long symbol_addr, DL_LOADADDR_TYPE load_addr, Elf32_Sym *symtab)
{
switch (ELF_R_TYPE(rpnt->r_info)) {
case R_ARM_NONE:
@@ -176,12 +176,55 @@ void PERFORM_BOOTSTRAP_RELOC(ELF_RELOC *rpnt, unsigned long *reloc_addr,
*reloc_addr = symbol_addr;
break;
case R_ARM_RELATIVE:
- *reloc_addr += load_addr;
+ *reloc_addr = DL_RELOC_ADDR(load_addr, *reloc_addr);
break;
case R_ARM_COPY:
break;
+#ifdef __FDPIC__
+ case R_ARM_FUNCDESC_VALUE:
+ {
+ struct funcdesc_value *dst = (struct funcdesc_value *) reloc_addr;
+
+ dst->entry_point += symbol_addr;
+ dst->got_value = load_addr.got_value;
+ }
+ break;
+#endif
default:
SEND_STDERR("Unsupported relocation type\n");
_dl_exit(1);
}
}
+
+#ifdef __FDPIC__
+#undef DL_START
+#define DL_START(X) \
+static void __attribute__ ((used)) \
+_dl_start (Elf32_Addr dl_boot_got_pointer, \
+ struct elf32_fdpic_loadmap *dl_boot_progmap, \
+ struct elf32_fdpic_loadmap *dl_boot_ldsomap, \
+ Elf32_Dyn *dl_boot_ldso_dyn_pointer, \
+ struct funcdesc_value *dl_main_funcdesc, \
+ X)
+
+/*
+ * Transfer control to the user's application, once the dynamic loader
+ * is done. We return the address of the function's entry point to
+ * _dl_boot, see boot1_arch.h.
+ */
+#define START() do { \
+ struct elf_resolve *exec_mod = _dl_loaded_modules; \
+ dl_main_funcdesc->entry_point = _dl_elf_main; \
+ while (exec_mod->libtype != elf_executable) \
+ exec_mod = exec_mod->next; \
+ dl_main_funcdesc->got_value = exec_mod->loadaddr.got_value; \
+ return; \
+} while (0)
+
+/* We use __aeabi_idiv0 in _dl_find_hash, so we need to have the raise
+ symbol. */
+int raise(int sig)
+{
+ _dl_exit(1);
+}
+#endif /* __FDPIC__ */
diff --git a/ldso/ldso/arm/dl-sysdep.h b/ldso/ldso/arm/dl-sysdep.h
index a47a55213..0f783e1c4 100644
--- a/ldso/ldso/arm/dl-sysdep.h
+++ b/ldso/ldso/arm/dl-sysdep.h
@@ -10,6 +10,19 @@
/* Define this if the system uses RELOCA. */
#undef ELF_USES_RELOCA
#include <elf.h>
+
+#ifdef __FDPIC__
+/* Need bootstrap relocations */
+#define ARCH_NEEDS_BOOTSTRAP_RELOCS
+
+#define DL_CHECK_LIB_TYPE(epnt, piclib, _dl_progname, libname) \
+do \
+{ \
+ (piclib) = 2; \
+} \
+while (0)
+#endif /* __FDPIC__ */
+
/* Initialization sequence for the GOT. */
#define INIT_GOT(GOT_BASE,MODULE) \
{ \
@@ -63,11 +76,25 @@ unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, int reloc_entry);
ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
of the main executable's symbols, as for a COPY reloc. */
+
+#ifdef __FDPIC__
+/* Avoid R_ARM_ABS32 to go through the PLT so that R_ARM_TARGET1
+ translated to R_ARM_ABS32 doesn't use the PLT: otherwise, this
+ breaks init_array because functions are referenced through the
+ PLT. */
+#define elf_machine_type_class(type) \
+ ((((type) == R_ARM_JUMP_SLOT || (type) == R_ARM_TLS_DTPMOD32 \
+ || (type) == R_ARM_FUNCDESC_VALUE || (type) == R_ARM_FUNCDESC || (type) == R_ARM_ABS32 \
+ || (type) == R_ARM_TLS_DTPOFF32 || (type) == R_ARM_TLS_TPOFF32) \
+ * ELF_RTYPE_CLASS_PLT) \
+ | (((type) == R_ARM_COPY) * ELF_RTYPE_CLASS_COPY))
+#else
#define elf_machine_type_class(type) \
((((type) == R_ARM_JUMP_SLOT || (type) == R_ARM_TLS_DTPMOD32 \
|| (type) == R_ARM_TLS_DTPOFF32 || (type) == R_ARM_TLS_TPOFF32) \
* ELF_RTYPE_CLASS_PLT) \
| (((type) == R_ARM_COPY) * ELF_RTYPE_CLASS_COPY))
+#endif /* __FDPIC__ */
/* Return the link-time address of _DYNAMIC. Conveniently, this is the
first element of the GOT. We used to use the PIC register to do this
@@ -106,10 +133,24 @@ elf_machine_dynamic (void)
extern char __dl_start[] __asm__("_dl_start");
+#ifdef __FDPIC__
+/* We must force strings used early in the bootstrap into the data
+ segment. */
+#undef SEND_EARLY_STDERR
+#define SEND_EARLY_STDERR(S) \
+ do { /* FIXME: implement */; } while (0)
+
+#undef INIT_GOT
+#include "../fdpic/dl-sysdep.h"
+#endif /* __FDPIC__ */
+
/* Return the run-time load address of the shared object. */
static __always_inline Elf32_Addr __attribute__ ((unused))
elf_machine_load_address (void)
{
+#if defined(__FDPIC__)
+ return 0;
+#else
Elf32_Addr got_addr = (Elf32_Addr) &__dl_start;
Elf32_Addr pcrel_addr;
#if defined __OPTIMIZE__ && !defined __thumb__
@@ -128,19 +169,33 @@ elf_machine_load_address (void)
: "=r" (pcrel_addr), "=r" (tmp));
#endif
return pcrel_addr - got_addr;
+#endif
}
static __always_inline void
+#ifdef __FDPIC__
+elf_machine_relative (DL_LOADADDR_TYPE load_off, const Elf32_Addr rel_addr,
+#else
elf_machine_relative (Elf32_Addr load_off, const Elf32_Addr rel_addr,
+#endif
Elf32_Word relative_count)
{
- Elf32_Rel * rpnt = (void *) rel_addr;
- --rpnt;
- do {
- Elf32_Addr *const reloc_addr = (void *) (load_off + (++rpnt)->r_offset);
+#if defined(__FDPIC__)
+ Elf32_Rel *rpnt = (void *) rel_addr;
+
+ do {
+ unsigned long *reloc_addr = (unsigned long *) DL_RELOC_ADDR(load_off, rpnt->r_offset);
- *reloc_addr += load_off;
- } while (--relative_count);
+ *reloc_addr = DL_RELOC_ADDR(load_off, *reloc_addr);
+ rpnt++;
+#else
+ Elf32_Rel * rpnt = (void *) rel_addr;
+ --rpnt;
+ do {
+ Elf32_Addr *const reloc_addr = (void *) (load_off + (++rpnt)->r_offset);
+ *reloc_addr += load_off;
+#endif
+ } while(--relative_count);
}
#endif /* !_ARCH_DL_SYSDEP */
diff --git a/ldso/ldso/arm/elfinterp.c b/ldso/ldso/arm/elfinterp.c
index 96809a9ae..402ba9618 100644
--- a/ldso/ldso/arm/elfinterp.c
+++ b/ldso/ldso/arm/elfinterp.c
@@ -36,6 +36,11 @@ extern int _dl_linux_resolve(void);
unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
{
+#if __FDPIC__
+ /* FIXME: implement. */
+ while(1) ;
+ return 0;
+#else
ELF_RELOC *this_reloc;
char *strtab;
char *symname;
@@ -88,6 +93,7 @@ unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
#endif
return new_addr;
+#endif
}
static int
@@ -181,7 +187,7 @@ _dl_do_reloc (struct elf_resolve *tpnt,struct r_scope_elem *scope,
struct elf_resolve *def_mod = 0;
int goof = 0;
- reloc_addr = (unsigned long *) (tpnt->loadaddr + (unsigned long) rpnt->r_offset);
+ reloc_addr = (unsigned long *) DL_RELOC_ADDR(tpnt->loadaddr, rpnt->r_offset);
reloc_type = ELF_R_TYPE(rpnt->r_info);
symtab_index = ELF_R_SYM(rpnt->r_info);
@@ -191,25 +197,30 @@ _dl_do_reloc (struct elf_resolve *tpnt,struct r_scope_elem *scope,
symname = strtab + symtab[symtab_index].st_name;
if (symtab_index) {
- symbol_addr = (unsigned long)_dl_find_hash(symname, scope, tpnt,
- elf_machine_type_class(reloc_type), &sym_ref);
-
- /*
- * We want to allow undefined references to weak symbols - this might
- * have been intentional. We should not be linking local symbols
- * here, so all bases should be covered.
- */
- if (!symbol_addr && (ELF_ST_TYPE(symtab[symtab_index].st_info) != STT_TLS)
- && (ELF_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK)) {
- /* This may be non-fatal if called from dlopen. */
- return 1;
-
- }
- if (_dl_trace_prelink) {
- _dl_debug_lookup (symname, tpnt, &symtab[symtab_index],
- &sym_ref, elf_machine_type_class(reloc_type));
+ if (ELF_ST_BIND (symtab[symtab_index].st_info) == STB_LOCAL) {
+ symbol_addr = (unsigned long) DL_RELOC_ADDR(tpnt->loadaddr, symtab[symtab_index].st_value);
+ def_mod = tpnt;
+ } else {
+ symbol_addr = (unsigned long)_dl_find_hash(symname, scope, tpnt,
+ elf_machine_type_class(reloc_type), &sym_ref);
+
+ /*
+ * We want to allow undefined references to weak symbols - this might
+ * have been intentional. We should not be linking local symbols
+ * here, so all bases should be covered.
+ */
+ if (!symbol_addr && (ELF_ST_TYPE(symtab[symtab_index].st_info) != STT_TLS)
+ && (ELF_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK)) {
+ /* This may be non-fatal if called from dlopen. */
+ return 1;
+
+ }
+ if (_dl_trace_prelink) {
+ _dl_debug_lookup (symname, tpnt, &symtab[symtab_index],
+ &sym_ref, elf_machine_type_class(reloc_type));
+ }
+ def_mod = sym_ref.tpnt;
}
- def_mod = sym_ref.tpnt;
} else {
/*
* Relocs against STN_UNDEF are usually treated as using a
@@ -267,12 +278,42 @@ _dl_do_reloc (struct elf_resolve *tpnt,struct r_scope_elem *scope,
*reloc_addr = symbol_addr;
break;
case R_ARM_RELATIVE:
- *reloc_addr += (unsigned long) tpnt->loadaddr;
+ *reloc_addr = DL_RELOC_ADDR(tpnt->loadaddr, *reloc_addr);
break;
case R_ARM_COPY:
_dl_memcpy((void *) reloc_addr,
(void *) symbol_addr, symtab[symtab_index].st_size);
break;
+#ifdef __FDPIC__
+ case R_ARM_FUNCDESC_VALUE:
+ {
+ struct funcdesc_value funcval;
+ struct funcdesc_value *dst = (struct funcdesc_value *) reloc_addr;
+
+ funcval.entry_point = (void*)symbol_addr;
+ /* Add offset to section address for local symbols. */
+ if (ELF_ST_BIND(symtab[symtab_index].st_info) == STB_LOCAL)
+ funcval.entry_point += *reloc_addr;
+ funcval.got_value = def_mod->loadaddr.got_value;
+ *dst = funcval;
+ }
+ break;
+ case R_ARM_FUNCDESC:
+ {
+ unsigned long reloc_value = *reloc_addr;
+
+ if (symbol_addr)
+ reloc_value = (unsigned long) _dl_funcdesc_for(symbol_addr + reloc_value, sym_ref.tpnt->loadaddr.got_value);
+ else
+ /* Relocation against an
+ undefined weak symbol:
+ set funcdesc to zero. */
+ reloc_value = 0;
+
+ *reloc_addr = reloc_value;
+ }
+ break;
+#endif
#if defined USE_TLS && USE_TLS
case R_ARM_TLS_DTPMOD32:
*reloc_addr = def_mod->l_tls_modid;
@@ -330,7 +371,6 @@ _dl_do_lazy_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
#endif
return 0;
-
}
void _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
@@ -345,3 +385,6 @@ int _dl_parse_relocation_information(struct dyn_elf *rpnt,
return _dl_parse(rpnt->dyn, scope, rel_addr, rel_size, _dl_do_reloc);
}
+#ifndef IS_IN_libdl
+# include "../../libc/sysdeps/linux/arm/crtreloc.c"
+#endif
diff --git a/ldso/ldso/arm/resolve.S b/ldso/ldso/arm/resolve.S
index 7e0058e0d..2a516436e 100644
--- a/ldso/ldso/arm/resolve.S
+++ b/ldso/ldso/arm/resolve.S
@@ -102,6 +102,7 @@
.align 4 @ 16 byte boundary and there are 32 bytes below (arm case)
#if 1 /*(!defined(__thumb__) || defined __THUMB_INTERWORK__) || defined(__thumb2__)*/
.arm
+ .hidden _dl_linux_resolve
.globl _dl_linux_resolve
.type _dl_linux_resolve,%function
.align 4;
diff --git a/ldso/ldso/fdpic/dl-inlines.h b/ldso/ldso/fdpic/dl-inlines.h
index f59087568..89e7a9a68 100644
--- a/ldso/ldso/fdpic/dl-inlines.h
+++ b/ldso/ldso/fdpic/dl-inlines.h
@@ -7,6 +7,8 @@
#include <inline-hashtab.h>
+static __always_inline void htab_delete(struct funcdesc_ht *htab);
+
/* Initialize a DL_LOADADDR_TYPE given a got pointer and a complete load map. */
static __always_inline void
__dl_init_loadaddr_map(struct elf32_fdpic_loadaddr *loadaddr, Elf32_Addr dl_boot_got_pointer,