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>

1 files changed, 38 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/arm/find_exidx.c b/libc/sysdeps/linux/arm/find_exidx.c
index 679d90c05..cd4d442cf 100644
--- a/libc/sysdeps/linux/arm/find_exidx.c
+++ b/libc/sysdeps/linux/arm/find_exidx.c
@@ -18,6 +18,23 @@
 #include <link.h>
 #include <unwind.h>
 
+#if __FDPIC__
+#include <bits/elf-fdpic.h>
+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;
+}
+#endif
+
 struct unw_eh_callback_data
 {
   _Unwind_Ptr pc;
@@ -32,6 +49,26 @@ struct unw_eh_callback_data
 static int
 find_exidx_callback (struct dl_phdr_info * info, size_t size, void * ptr)
 {
+#if __FDPIC__
+  struct unw_eh_callback_data * data;
+  const ElfW(Phdr) *phdr;
+  int i;
+  int match = 0;
+
+  data = (struct unw_eh_callback_data *) ptr;
+  if (__dl_addr_in_loadaddr((void *) data->pc, info->dlpi_addr)) {
+    match = 1;
+    phdr = info->dlpi_phdr;
+    for (i = info->dlpi_phnum; i > 0; i--, phdr++) {
+      if (phdr->p_type == PT_ARM_EXIDX) {
+        data->exidx_start = (_Unwind_Ptr) __RELOC_POINTER(phdr->p_vaddr, info->dlpi_addr);
+        data->exidx_len = phdr->p_memsz;
+      }
+    }
+  }
+
+  return match;
+#else
   struct unw_eh_callback_data * data;
   const ElfW(Phdr) *phdr;
   int i;
@@ -59,6 +96,7 @@ find_exidx_callback (struct dl_phdr_info * info, size_t size, void * ptr)
     }
 
   return match;
+#endif
 }