From: Will Newton <will.newton@linaro.org>
To: libc-ports@sourceware.org
Cc: Patch Tracking <patches@linaro.org>
Subject: [PATCH] aarch64: Enable ifunc support.
Date: Tue, 26 Nov 2013 11:14:00 -0000 [thread overview]
Message-ID: <5294628E.30507@linaro.org> (raw)
Add support for handling the R_AARCH64_IRELATIVE relocation and
STT_GNU_IFUNC symbols to the aarch64 port.
ports/ChangeLog.aarch64:
2013-11-25 Will Newton <will.newton@linaro.org>
* sysdeps/aarch64/dl-irel.h: Include ldsodefs.h.
(ELF_MACHINE_IRELA): Define. (elf_ifunc_invoke): Pass
hwcap to ifunc resolver function. (elf_irela): New function.
* sysdeps/aarch64/dl-machine.h: Include dl-irel.h.
(elf_machine_rela) Handle STT_GNU_IFUNC symbols and
R_AARCH64_IRELATIVE relocations. (elf_machine_lazy_rel):
Handle R_AARCH64_IRELATIVE relocations.
---
ports/sysdeps/aarch64/dl-irel.h | 22 +++++++++++++++++++---
ports/sysdeps/aarch64/dl-machine.h | 20 ++++++++++++++++++++
2 files changed, 39 insertions(+), 3 deletions(-)
diff --git a/ports/sysdeps/aarch64/dl-irel.h b/ports/sysdeps/aarch64/dl-irel.h
index 1a3811e..f37ee39 100644
--- a/ports/sysdeps/aarch64/dl-irel.h
+++ b/ports/sysdeps/aarch64/dl-irel.h
@@ -22,15 +22,31 @@
#include <stdio.h>
#include <unistd.h>
+#include <ldsodefs.h>
-/* AArch64 does not yet implement IFUNC support. However since
- 2011-06-20 provision of a elf_ifunc_invoke has been mandatory. */
+#define ELF_MACHINE_IRELA 1
static inline ElfW(Addr)
__attribute ((always_inline))
elf_ifunc_invoke (ElfW(Addr) addr)
{
- return ((ElfW(Addr) (*) (void)) (addr)) ();
+ return ((ElfW(Addr) (*) (unsigned long int)) (addr)) (GLRO(dl_hwcap));
+}
+
+static inline void
+__attribute ((always_inline))
+elf_irela (const ElfW(Rela) *reloc)
+{
+ ElfW(Addr) *const reloc_addr = (void *) reloc->r_offset;
+ const unsigned long int r_type = ELFW(R_TYPE) (reloc->r_info);
+
+ if (__glibc_likely (r_type == R_AARCH64_IRELATIVE))
+ {
+ ElfW(Addr) value = elf_ifunc_invoke (reloc->r_addend);
+ *reloc_addr = value;
+ }
+ else
+ __libc_fatal ("unexpected reloc type in static binary");
}
#endif
diff --git a/ports/sysdeps/aarch64/dl-machine.h b/ports/sysdeps/aarch64/dl-machine.h
index 71dd6b3..01a214f 100644
--- a/ports/sysdeps/aarch64/dl-machine.h
+++ b/ports/sysdeps/aarch64/dl-machine.h
@@ -23,6 +23,7 @@
#include <tls.h>
#include <dl-tlsdesc.h>
+#include <dl-irel.h>
/* Return nonzero iff ELF header is compatible with the running host. */
static inline int __attribute__ ((unused))
@@ -243,6 +244,12 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
ElfW(Addr) value = sym_map == NULL ? 0 : sym_map->l_addr + sym->st_value;
+ if (sym != NULL
+ && __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
+ && __glibc_likely (sym->st_shndx != SHN_UNDEF)
+ && __glibc_likely (!skip_ifunc))
+ value = elf_ifunc_invoke (value);
+
switch (r_type)
{
case R_AARCH64_COPY:
@@ -331,6 +338,12 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
}
break;
+ case R_AARCH64_IRELATIVE:
+ value = map->l_addr + reloc->r_addend;
+ value = elf_ifunc_invoke (value);
+ *reloc_addr = value;
+ break;
+
default:
_dl_reloc_bad_type (map, r_type, 0);
break;
@@ -374,6 +387,13 @@ elf_machine_lazy_rel (struct link_map *map,
td->entry = (void*)(D_PTR (map, l_info[ADDRIDX (DT_TLSDESC_PLT)])
+ map->l_addr);
}
+ else if (__glibc_unlikely (r_type == R_AARCH64_IRELATIVE))
+ {
+ ElfW(Addr) value = map->l_addr + reloc->r_addend;
+ if (__glibc_likely (!skip_ifunc))
+ value = elf_ifunc_invoke (value);
+ *reloc_addr = value;
+ }
else
_dl_reloc_bad_type (map, r_type, 1);
}
--
1.8.1.4
next reply other threads:[~2013-11-26 8:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-26 11:14 Will Newton [this message]
2013-11-26 15:05 ` Marcus Shawcroft
2013-11-26 15:08 ` Will Newton
2013-11-26 15:17 ` Marcus Shawcroft
2013-11-26 15:19 ` Carlos O'Donell
2013-11-26 15:24 ` Carlos O'Donell
2013-11-26 15:41 ` Carlos O'Donell
2013-11-26 16:21 ` Will Newton
2013-11-26 16:37 ` Carlos O'Donell
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