4 Jul
2018
4 Jul
'18
3:55 p.m.
Implements __gnu_Unwind_Find_got(), which is called from libgcc while
unwinding.
* libc/sysdeps/linux/arm/Makefile.arch (CSRC): Add find._got.c.
* libc/sysdeps/linux/arm/find_got.c: New file.
Signed-off-by: Mickaël Guêné <mickael.guene(a)st.com>
Signed-off-by: Christophe Lyon <christophe.lyon(a)st.com>
diff --git a/libc/sysdeps/linux/arm/Makefile.arch b/libc/sysdeps/linux/arm/Makefile.arch
index f9ac88b..40a0184 100644
--- a/libc/sysdeps/linux/arm/Makefile.arch
+++ b/libc/sysdeps/linux/arm/Makefile.arch
@@ -23,7 +23,7 @@ $(eval $(call cache-output-var,IS_EABI,$(CC_IS_EABI_CHECK) -x c - -E -dM
</dev/n
CSRC-$(IS_EABI) += aeabi_assert.c aeabi_atexit.c aeabi_errno_addr.c \
aeabi_localeconv.c aeabi_memclr.c aeabi_memcpy.c \
- aeabi_memmove.c aeabi_memset.c find_exidx.c
+ aeabi_memmove.c aeabi_memset.c find_exidx.c find_got.c
SSRC-$(IS_EABI) += syscall-eabi.S
CSRC-$(if $(IS_EABI),,y)) += syscall.c
ARCH_OBJ_FILTEROUT-$(IS_EABI) := syscall.c
diff --git a/libc/sysdeps/linux/arm/find_got.c b/libc/sysdeps/linux/arm/find_got.c
new file mode 100644
index 0000000..1292388
--- /dev/null
+++ b/libc/sysdeps/linux/arm/find_got.c
@@ -0,0 +1,72 @@
+/* Copyright (C) 2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <link.h>
+#include <unwind.h>
+
+#if __FDPIC__
+#include <bits/elf-fdpic.h>
+
+struct got_callback_data
+{
+ _Unwind_Ptr pc;
+ _Unwind_Ptr got;
+};
+
+static __always_inline int
+__dl_addr_in_loadaddr(void *p, struct elf32_fdpic_loadaddr loadaddr)
+{
+ struct elf32_fdpic_loadmap *map = loadaddr.map;
+ int c;
+
+ for (c = 0; c < map->nsegs; c++)
+ if ((void *)map->segs[c].addr <= p &&
+ (char *)p < (char *)map->segs[c].addr + map->segs[c].p_memsz)
+ return 1;
+
+ return 0;
+}
+
+/* Callback to return the GOT value if the module contains PC. */
+static int
+find_got_callback (struct dl_phdr_info * info, size_t size, void * ptr)
+{
+ int match = 0;
+ struct got_callback_data *data = (struct got_callback_data *) ptr;
+
+ if (__dl_addr_in_loadaddr((void *) data->pc, info->dlpi_addr)) {
+ match = 1;
+ data->got = (_Unwind_Ptr) info->dlpi_addr.got_value;
+ }
+
+ return match;
+}
+
+/* Find the GOT that corresponds to the module containing PC. */
+_Unwind_Ptr __gnu_Unwind_Find_got (_Unwind_Ptr pc);
+_Unwind_Ptr __gnu_Unwind_Find_got (_Unwind_Ptr pc)
+{
+ struct got_callback_data data;
+
+ data.pc = pc;
+ if (dl_iterate_phdr (find_got_callback, &data) <= 0)
+ return 0;
+
+ return data.got;
+}
+#endif
+
--
2.6.3