This is the mail archive of the
binutils@sourceware.org
mailing list for the binutils project.
[ARM-FDPIC 04/12] [ARM] Implement FDPIC relocations.
- From: Christophe Lyon <christophe dot lyon at st dot com>
- To: <binutils at sourceware dot org>
- Date: Thu, 22 Mar 2018 15:38:22 +0100
- Subject: [ARM-FDPIC 04/12] [ARM] Implement FDPIC relocations.
- References: <20180322143850.1766-1-christophe.lyon@st.com>
This is the main BFD patch, that enables the linker to actually handle
the FDPIC relocation.
2018-XX-XX Christophe Lyon <christophe.lyon@st.com>
Mickaël Guêné <mickael.guene@st.com>
bfd/
* elf32-arm.c (struct fdpic_local): New.
(elf_arm_obj_tdata): Add local_fdpic_cnts field.
(elf32_arm_local_fdpic_cnts): New.
(struct fdpic_global): New.
(elf32_arm_link_hash_entry): Add fdpic_cnts field.
(elf32_arm_link_hash_table): Add srofixup field.
(arm_elf_add_rofixup): New.
(arm_elf_fill_funcdesc): New.
(elf32_arm_link_hash_newfunc): Handle fdpic_cnts.
(elf32_arm_allocate_local_sym_info): Likewise.
(create_got_section): Create .rofixup section.
(elf32_arm_copy_indirect_symbol): Handle fdpic_cnts.
(bfd_elf32_arm_set_target_params): Handle FDPIC.
(elf32_arm_final_link_relocate): Likewise.
(elf32_arm_check_relocs): Likewise.
(allocate_dynrelocs_for_symbol): Likewise.
(elf32_arm_size_dynamic_sections): Likewise.
(elf32_arm_finish_dynamic_sections): Likewise.
(elf32_arm_output_arch_local_syms): Likewise.
(elf32_arm_fdpic_omit_section_dynsym): New.
ld/
* emulparams/armelf_linux_fdpiceabi.sh: Add .rofixup section.
---
bfd/elf32-arm.c | 728 ++++++++++++++++++++++++++++++--
ld/emulparams/armelf_linux_fdpiceabi.sh | 8 +-
2 files changed, 705 insertions(+), 31 deletions(-)
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 3805f71..5892255 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -3001,6 +3001,13 @@ struct arm_local_iplt_info
struct elf_dyn_relocs *dyn_relocs;
};
+/* Structure to handle FDPIC support for local functions. */
+struct fdpic_local {
+ unsigned int funcdesc_cnt;
+ unsigned int gotofffuncdesc_cnt;
+ int funcdesc_offset;
+};
+
struct elf_arm_obj_tdata
{
struct elf_obj_tdata root;
@@ -3019,6 +3026,9 @@ struct elf_arm_obj_tdata
/* Zero to warn when linking objects with incompatible wchar_t sizes. */
int no_wchar_size_warning;
+
+ /* Maintains FDPIC counters and funcdesc info. */
+ struct fdpic_local *local_fdpic_cnts;
};
#define elf_arm_tdata(bfd) \
@@ -3033,6 +3043,9 @@ struct elf_arm_obj_tdata
#define elf32_arm_local_iplt(bfd) \
(elf_arm_tdata (bfd)->local_iplt)
+#define elf32_arm_local_fdpic_cnts(bfd) \
+ (elf_arm_tdata (bfd)->local_fdpic_cnts)
+
#define is_arm_elf(bfd) \
(bfd_get_flavour (bfd) == bfd_target_elf_flavour \
&& elf_tdata (bfd) != NULL \
@@ -3047,6 +3060,15 @@ elf32_arm_mkobject (bfd *abfd)
#define elf32_arm_hash_entry(ent) ((struct elf32_arm_link_hash_entry *)(ent))
+/* Structure to handle FDPIC support for extern functions. */
+struct fdpic_global {
+ unsigned int gotofffuncdesc_cnt;
+ unsigned int gotfuncdesc_cnt;
+ unsigned int funcdesc_cnt;
+ int funcdesc_offset;
+ int gotfuncdesc_offset;
+};
+
/* Arm ELF linker hash entry. */
struct elf32_arm_link_hash_entry
{
@@ -3082,6 +3104,9 @@ struct elf32_arm_link_hash_entry
/* A pointer to the most recently used stub hash entry against this
symbol. */
struct elf32_arm_stub_hash_entry *stub_cache;
+
+ /* Counter for FDPIC relocations against this symbol. */
+ struct fdpic_global fdpic_cnts;
};
/* Traverse an arm ELF linker hash table. */
@@ -3288,8 +3313,22 @@ struct elf32_arm_link_hash_table
/* True if the target system uses FDPIC. */
int fdpic_p;
+
+ /* Fixup section. Used for FDPIC. */
+ asection *srofixup;
};
+/* Add an FDPIC read-only fixup. */
+static void
+arm_elf_add_rofixup (bfd *output_bfd, asection *srofixup, bfd_vma offset)
+{
+ bfd_vma fixup_offset;
+
+ fixup_offset = srofixup->reloc_count++ * 4;
+ BFD_ASSERT (fixup_offset < srofixup->size);
+ bfd_put_32 (output_bfd, offset, srofixup->contents + fixup_offset);
+}
+
static inline int
ctz (unsigned int mask)
{
@@ -3327,6 +3366,57 @@ elf32_arm_popcount (unsigned int mask)
#endif
}
+static void elf32_arm_add_dynreloc (bfd *output_bfd, struct bfd_link_info *info,
+ asection *sreloc, Elf_Internal_Rela *rel);
+
+static void
+arm_elf_fill_funcdesc(bfd *output_bfd,
+ struct bfd_link_info *info,
+ int *funcdesc_offset,
+ int dynindx,
+ int offset,
+ bfd_vma addr,
+ bfd_vma dynreloc_value,
+ bfd_vma seg)
+{
+ if ((*funcdesc_offset & 1) == 0)
+ {
+ struct elf32_arm_link_hash_table *globals = elf32_arm_hash_table (info);
+ asection *sgot = globals->root.sgot;
+
+ if (bfd_link_pic(info))
+ {
+ asection *srelgot = globals->root.srelgot;
+ Elf_Internal_Rela outrel;
+
+ outrel.r_info = ELF32_R_INFO (dynindx, R_ARM_FUNCDESC_VALUE);
+ outrel.r_offset = sgot->output_section->vma + sgot->output_offset + offset;
+ outrel.r_addend = 0;
+
+ elf32_arm_add_dynreloc (output_bfd, info, srelgot, &outrel);
+ bfd_put_32 (output_bfd, addr, sgot->contents + offset);
+ bfd_put_32 (output_bfd, seg, sgot->contents + offset + 4);
+ }
+ else
+ {
+ struct elf_link_hash_entry *hgot = globals->root.hgot;
+ bfd_vma got_value = hgot->root.u.def.value
+ + hgot->root.u.def.section->output_section->vma
+ + hgot->root.u.def.section->output_offset;
+
+ arm_elf_add_rofixup(output_bfd, globals->srofixup,
+ sgot->output_section->vma + sgot->output_offset
+ + offset);
+ arm_elf_add_rofixup(output_bfd, globals->srofixup,
+ sgot->output_section->vma + sgot->output_offset
+ + offset + 4);
+ bfd_put_32 (output_bfd, dynreloc_value, sgot->contents + offset);
+ bfd_put_32 (output_bfd, got_value, sgot->contents + offset + 4);
+ }
+ *funcdesc_offset |= 1;
+ }
+}
+
/* Create an entry in an ARM ELF linker hash table. */
static struct bfd_hash_entry *
@@ -3362,6 +3452,12 @@ elf32_arm_link_hash_newfunc (struct bfd_hash_entry * entry,
ret->export_glue = NULL;
ret->stub_cache = NULL;
+
+ ret->fdpic_cnts.gotofffuncdesc_cnt = 0;
+ ret->fdpic_cnts.gotfuncdesc_cnt = 0;
+ ret->fdpic_cnts.funcdesc_cnt = 0;
+ ret->fdpic_cnts.funcdesc_offset = -1;
+ ret->fdpic_cnts.gotfuncdesc_offset = -1;
}
return (struct bfd_hash_entry *) ret;
@@ -3383,11 +3479,15 @@ elf32_arm_allocate_local_sym_info (bfd *abfd)
size = num_syms * (sizeof (bfd_signed_vma)
+ sizeof (struct arm_local_iplt_info *)
+ sizeof (bfd_vma)
- + sizeof (char));
+ + sizeof (char)
+ + sizeof (struct fdpic_local));
data = bfd_zalloc (abfd, size);
if (data == NULL)
return FALSE;
+ elf32_arm_local_fdpic_cnts (abfd) = (struct fdpic_local *) data;
+ data += num_syms * sizeof (struct fdpic_local);
+
elf_local_got_refcounts (abfd) = (bfd_signed_vma *) data;
data += num_syms * sizeof (bfd_signed_vma);
@@ -3569,6 +3669,16 @@ create_got_section (bfd *dynobj, struct bfd_link_info *info)
if (! _bfd_elf_create_got_section (dynobj, info))
return FALSE;
+ /* Also create .rofixup. */
+ if (htab->fdpic_p)
+ {
+ htab->srofixup = bfd_make_section_with_flags (dynobj, ".rofixup",
+ (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS
+ | SEC_IN_MEMORY | SEC_LINKER_CREATED | SEC_READONLY));
+ if (htab->srofixup == NULL || ! bfd_set_section_alignment (dynobj, htab->srofixup, 2))
+ return FALSE;
+ }
+
return TRUE;
}
@@ -3808,6 +3918,11 @@ elf32_arm_copy_indirect_symbol (struct bfd_link_info *info,
edir->plt.noncall_refcount += eind->plt.noncall_refcount;
eind->plt.noncall_refcount = 0;
+ /* Copy FDPIC counters. */
+ edir->fdpic_cnts.gotofffuncdesc_cnt += eind->fdpic_cnts.gotofffuncdesc_cnt;
+ edir->fdpic_cnts.gotfuncdesc_cnt += eind->fdpic_cnts.gotfuncdesc_cnt;
+ edir->fdpic_cnts.funcdesc_cnt += eind->fdpic_cnts.funcdesc_cnt;
+
/* We should only allocate a function to .iplt once the final
symbol information is known. */
BFD_ASSERT (!eind->is_iplt);
@@ -8788,7 +8903,10 @@ bfd_elf32_arm_set_target_params (struct bfd *output_bfd,
globals->use_blx |= params->use_blx;
globals->vfp11_fix = params->vfp11_denorm_fix;
globals->stm32l4xx_fix = params->stm32l4xx_fix;
- globals->pic_veneer = params->pic_veneer;
+ if (globals->fdpic_p)
+ globals->pic_veneer = 1;
+ else
+ globals->pic_veneer = params->pic_veneer;
globals->fix_cortex_a8 = params->fix_cortex_a8;
globals->fix_arm1176 = params->fix_arm1176;
globals->cmse_implib = params->cmse_implib;
@@ -10147,7 +10265,8 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
relocations are copied into the output file to be resolved at
run time. */
if ((bfd_link_pic (info)
- || globals->root.is_relocatable_executable)
+ || globals->root.is_relocatable_executable
+ || globals->fdpic_p)
&& (input_section->flags & SEC_ALLOC)
&& !(globals->vxworks_p
&& strcmp (input_section->output_section->name,
@@ -10168,6 +10287,7 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
{
Elf_Internal_Rela outrel;
bfd_boolean skip, relocate;
+ int isrofixup = 0;
if ((r_type == R_ARM_REL32 || r_type == R_ARM_REL32_NOI)
&& !h->def_regular)
@@ -10223,7 +10343,8 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
int symbol;
/* This symbol is local, or marked to become local. */
- BFD_ASSERT (r_type == R_ARM_ABS32 || r_type == R_ARM_ABS32_NOI);
+ BFD_ASSERT (r_type == R_ARM_ABS32 || r_type == R_ARM_ABS32_NOI
+ || (globals->fdpic_p && !bfd_link_pic(info)));
if (globals->symbian_p)
{
asection *osec;
@@ -10269,6 +10390,8 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
must use an R_ARM_IRELATIVE relocation to obtain the
correct run-time address. */
outrel.r_info = ELF32_R_INFO (symbol, R_ARM_IRELATIVE);
+ else if (globals->fdpic_p && !bfd_link_pic(info))
+ isrofixup = 1;
else
outrel.r_info = ELF32_R_INFO (symbol, R_ARM_RELATIVE);
if (globals->use_rel)
@@ -10277,7 +10400,10 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
outrel.r_addend += dynreloc_value;
}
- elf32_arm_add_dynreloc (output_bfd, info, sreloc, &outrel);
+ if (isrofixup)
+ arm_elf_add_rofixup(output_bfd, globals->srofixup, outrel.r_offset);
+ else
+ elf32_arm_add_dynreloc (output_bfd, info, sreloc, &outrel);
/* If this reloc is against an external symbol, we do not want to
fiddle with the addend. Otherwise, we need to include the symbol
@@ -11153,8 +11279,10 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
else
{
Elf_Internal_Rela outrel;
+ int isrofixup = 0;
- if (h->dynindx != -1 && !SYMBOL_REFERENCES_LOCAL (info, h))
+ if (((h->dynindx != -1) || globals->fdpic_p)
+ && !SYMBOL_REFERENCES_LOCAL (info, h))
{
/* If the symbol doesn't resolve locally in a static
object, we have an undefined reference. If the
@@ -11177,6 +11305,8 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
&& (ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
|| h->root.type != bfd_link_hash_undefweak))
outrel.r_info = ELF32_R_INFO (0, R_ARM_RELATIVE);
+ else if (globals->fdpic_p)
+ isrofixup = 1;
else
outrel.r_info = 0;
outrel.r_addend = dynreloc_value;
@@ -11185,20 +11315,27 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
/* The GOT entry is initialized to zero by default.
See if we should install a different value. */
if (outrel.r_addend != 0
- && (outrel.r_info == 0 || globals->use_rel))
+ && (outrel.r_info == 0 || globals->use_rel || isrofixup))
{
bfd_put_32 (output_bfd, outrel.r_addend,
sgot->contents + off);
outrel.r_addend = 0;
}
- if (outrel.r_info != 0)
+ if (outrel.r_info != 0 && !isrofixup)
{
outrel.r_offset = (sgot->output_section->vma
+ sgot->output_offset
+ off);
elf32_arm_add_dynreloc (output_bfd, info, srelgot, &outrel);
}
+ else if (isrofixup)
+ {
+ arm_elf_add_rofixup(output_bfd,
+ elf32_arm_hash_table(info)->srofixup,
+ sgot->output_section->vma
+ + sgot->output_offset + off);
+ }
h->got.offset |= 1;
}
value = sgot->output_offset + off;
@@ -11236,6 +11373,14 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
outrel.r_info = ELF32_R_INFO (0, R_ARM_RELATIVE);
elf32_arm_add_dynreloc (output_bfd, info, srelgot, &outrel);
}
+ else if (globals->fdpic_p)
+ {
+ /* For FDPIC executables, we use rofixup to fix
+ address at runtime. */
+ arm_elf_add_rofixup(output_bfd, globals->srofixup,
+ sgot->output_section->vma + sgot->output_offset
+ + off);
+ }
local_got_offsets[r_symndx] |= 1;
}
@@ -11295,12 +11440,24 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
globals->tls_ldm_got.offset |= 1;
}
- value = sgot->output_section->vma + sgot->output_offset + off
- - (input_section->output_section->vma + input_section->output_offset + rel->r_offset);
+ if (globals->fdpic_p)
+ {
+ bfd_put_32(output_bfd,
+ globals->root.sgot->output_offset + off,
+ contents + rel->r_offset);
+
+ return bfd_reloc_ok;
+ }
+ else
+ {
+ value = sgot->output_section->vma + sgot->output_offset + off
+ - (input_section->output_section->vma
+ + input_section->output_offset + rel->r_offset);
- return _bfd_final_link_relocate (howto, input_bfd, input_section,
- contents, rel->r_offset, value,
- rel->r_addend);
+ return _bfd_final_link_relocate (howto, input_bfd, input_section,
+ contents, rel->r_offset, value,
+ rel->r_addend);
+ }
}
case R_ARM_TLS_CALL:
@@ -11653,9 +11810,23 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
- (input_section->output_section->vma
+ input_section->output_offset + rel->r_offset));
- return _bfd_final_link_relocate (howto, input_bfd, input_section,
- contents, rel->r_offset, value,
- rel->r_addend);
+ if (globals->fdpic_p && (r_type == R_ARM_TLS_GD32 ||
+ r_type == R_ARM_TLS_IE32))
+ {
+ /* For FDPIC relocations, resolve to the offset of the GOT
+ entry from the start of GOT. */
+ bfd_put_32(output_bfd,
+ globals->root.sgot->output_offset + off,
+ contents + rel->r_offset);
+
+ return bfd_reloc_ok;
+ }
+ else
+ {
+ return _bfd_final_link_relocate (howto, input_bfd, input_section,
+ contents, rel->r_offset, value,
+ rel->r_addend);
+ }
}
case R_ARM_TLS_LE32:
@@ -12237,6 +12408,244 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
*unresolved_reloc_p = FALSE;
return bfd_reloc_ok;
+ case R_ARM_GOTOFFFUNCDESC:
+ {
+ if (h == NULL)
+ {
+ struct fdpic_local *local_fdpic_cnts = elf32_arm_local_fdpic_cnts(input_bfd);
+ int dynindx = elf_section_data (sym_sec->output_section)->dynindx;
+ int offset = local_fdpic_cnts[r_symndx].funcdesc_offset & ~1;
+ bfd_vma addr = dynreloc_value - sym_sec->output_section->vma;
+ bfd_vma seg = -1;
+
+ if (bfd_link_pic(info) && dynindx == 0)
+ abort();
+
+ /* Resolve relocation. */
+ bfd_put_32(output_bfd, (offset + sgot->output_offset)
+ , contents + rel->r_offset);
+ /* Emit R_ARM_FUNCDESC_VALUE or two fixups on funcdesc if
+ not done yet. */
+ arm_elf_fill_funcdesc(output_bfd, info,
+ &local_fdpic_cnts[r_symndx].funcdesc_offset,
+ dynindx, offset, addr, dynreloc_value, seg);
+ }
+ else
+ {
+ int dynindx;
+ int offset = eh->fdpic_cnts.funcdesc_offset & ~1;
+ bfd_vma addr;
+ bfd_vma seg = -1;
+
+ /* For static binaries, sym_sec can be null. */
+ if (sym_sec)
+ {
+ dynindx = elf_section_data (sym_sec->output_section)->dynindx;
+ addr = dynreloc_value - sym_sec->output_section->vma;
+ }
+ else
+ {
+ dynindx = 0;
+ addr = 0;
+ }
+
+ if (bfd_link_pic(info) && dynindx == 0)
+ abort();
+
+ /* This case cannot occur since funcdesc is allocated by
+ the dynamic loader so we cannot resolve the relocation. */
+ if (h->dynindx != -1)
+ abort();
+
+ /* Resolve relocation. */
+ bfd_put_32(output_bfd, (offset + sgot->output_offset),
+ contents + rel->r_offset);
+ /* Emit R_ARM_FUNCDESC_VALUE on funcdesc if not done yet. */
+ arm_elf_fill_funcdesc(output_bfd, info,
+ &eh->fdpic_cnts.funcdesc_offset,
+ dynindx, offset, addr, dynreloc_value, seg);
+ }
+ }
+ *unresolved_reloc_p = FALSE;
+ return bfd_reloc_ok;
+
+ case R_ARM_GOTFUNCDESC:
+ {
+ if (h != NULL)
+ {
+ Elf_Internal_Rela outrel;
+
+ /* Resolve relocation. */
+ bfd_put_32(output_bfd, ((eh->fdpic_cnts.gotfuncdesc_offset & ~1)
+ + sgot->output_offset),
+ contents + rel->r_offset);
+ /* Add funcdesc and associated R_ARM_FUNCDESC_VALUE. */
+ if(h->dynindx == -1)
+ {
+ int dynindx;
+ int offset = eh->fdpic_cnts.funcdesc_offset & ~1;
+ bfd_vma addr;
+ bfd_vma seg = -1;
+
+ /* For static binaries sym_sec can be null. */
+ if (sym_sec)
+ {
+ dynindx = elf_section_data (sym_sec->output_section)->dynindx;
+ addr = dynreloc_value - sym_sec->output_section->vma;
+ }
+ else
+ {
+ dynindx = 0;
+ addr = 0;
+ }
+
+ if (bfd_link_pic(info) && dynindx == 0)
+ abort();
+
+ /* Emit R_ARM_FUNCDESC_VALUE on funcdesc if not done yet. */
+ arm_elf_fill_funcdesc(output_bfd, info,
+ &eh->fdpic_cnts.funcdesc_offset,
+ dynindx, offset, addr, dynreloc_value, seg);
+ }
+
+ /* Add a dynamic relocation on GOT entry if not already done. */
+ if ((eh->fdpic_cnts.gotfuncdesc_offset & 1) == 0)
+ {
+ if (h->dynindx == -1)
+ {
+ outrel.r_info = ELF32_R_INFO (0, R_ARM_RELATIVE);
+ if (h->root.type == bfd_link_hash_undefweak)
+ bfd_put_32(output_bfd, 0, sgot->contents
+ + (eh->fdpic_cnts.gotfuncdesc_offset & ~1));
+ else
+ bfd_put_32(output_bfd, sgot->output_section->vma
+ + sgot->output_offset
+ + (eh->fdpic_cnts.funcdesc_offset & ~1),
+ sgot->contents
+ + (eh->fdpic_cnts.gotfuncdesc_offset & ~1));
+ }
+ else
+ {
+ outrel.r_info = ELF32_R_INFO (h->dynindx, R_ARM_FUNCDESC);
+ }
+ outrel.r_offset = sgot->output_section->vma
+ + sgot->output_offset
+ + (eh->fdpic_cnts.gotfuncdesc_offset & ~1);
+ outrel.r_addend = 0;
+ if (h->dynindx == -1 && !bfd_link_pic(info))
+ if (h->root.type == bfd_link_hash_undefweak)
+ arm_elf_add_rofixup(output_bfd, globals->srofixup, -1);
+ else
+ arm_elf_add_rofixup(output_bfd, globals->srofixup, outrel.r_offset);
+ else
+ elf32_arm_add_dynreloc (output_bfd, info, srelgot, &outrel);
+ eh->fdpic_cnts.gotfuncdesc_offset |= 1;
+ }
+ }
+ else
+ {
+ /* Such relocation on static function should not have been
+ emitted by the compiler. */
+ abort();
+ }
+ }
+ *unresolved_reloc_p = FALSE;
+ return bfd_reloc_ok;
+
+ case R_ARM_FUNCDESC:
+ {
+ if (h == NULL)
+ {
+ struct fdpic_local *local_fdpic_cnts = elf32_arm_local_fdpic_cnts(input_bfd);
+ Elf_Internal_Rela outrel;
+ int dynindx = elf_section_data (sym_sec->output_section)->dynindx;
+ int offset = local_fdpic_cnts[r_symndx].funcdesc_offset & ~1;
+ bfd_vma addr = dynreloc_value - sym_sec->output_section->vma;
+ bfd_vma seg = -1;
+
+ if (bfd_link_pic(info) && dynindx == 0)
+ abort();
+
+ /* Replace static FUNCDESC relocation with a
+ R_ARM_RELATIVE dynamic relocation or with a rofixup for
+ executable. */
+ outrel.r_info = ELF32_R_INFO (0, R_ARM_RELATIVE);
+ outrel.r_offset = input_section->output_section->vma
+ + input_section->output_offset + rel->r_offset;
+ outrel.r_addend = 0;
+ if (bfd_link_pic(info))
+ elf32_arm_add_dynreloc (output_bfd, info, srelgot, &outrel);
+ else
+ arm_elf_add_rofixup(output_bfd, globals->srofixup, outrel.r_offset);
+
+ bfd_put_32 (input_bfd, sgot->output_section->vma
+ + sgot->output_offset + offset, hit_data);
+
+ /* Emit R_ARM_FUNCDESC_VALUE on funcdesc if not done yet. */
+ arm_elf_fill_funcdesc(output_bfd, info,
+ &local_fdpic_cnts[r_symndx].funcdesc_offset,
+ dynindx, offset, addr, dynreloc_value, seg);
+ }
+ else
+ {
+ if (h->dynindx == -1)
+ {
+ int dynindx;
+ int offset = eh->fdpic_cnts.funcdesc_offset & ~1;
+ bfd_vma addr;
+ bfd_vma seg = -1;
+ Elf_Internal_Rela outrel;
+
+ /* For static binaries sym_sec can be null. */
+ if (sym_sec)
+ {
+ dynindx = elf_section_data (sym_sec->output_section)->dynindx;
+ addr = dynreloc_value - sym_sec->output_section->vma;
+ }
+ else
+ {
+ dynindx = 0;
+ addr = 0;
+ }
+
+ if (bfd_link_pic(info) && dynindx == 0)
+ abort();
+
+ /* Replace static FUNCDESC relocation with a
+ R_ARM_RELATIVE dynamic relocation. */
+ outrel.r_info = ELF32_R_INFO (0, R_ARM_RELATIVE);
+ outrel.r_offset = input_section->output_section->vma
+ + input_section->output_offset + rel->r_offset;
+ outrel.r_addend = 0;
+ if (bfd_link_pic(info))
+ elf32_arm_add_dynreloc (output_bfd, info, srelgot, &outrel);
+ else
+ arm_elf_add_rofixup(output_bfd, globals->srofixup, outrel.r_offset);
+
+ bfd_put_32 (input_bfd, sgot->output_section->vma
+ + sgot->output_offset + offset, hit_data);
+
+ /* Emit R_ARM_FUNCDESC_VALUE on funcdesc if not done yet. */
+ arm_elf_fill_funcdesc(output_bfd, info,
+ &eh->fdpic_cnts.funcdesc_offset,
+ dynindx, offset, addr, dynreloc_value, seg);
+ }
+ else
+ {
+ Elf_Internal_Rela outrel;
+
+ /* Add a dynamic relocation. */
+ outrel.r_info = ELF32_R_INFO (h->dynindx, R_ARM_FUNCDESC);
+ outrel.r_offset = input_section->output_section->vma
+ + input_section->output_offset + rel->r_offset;
+ outrel.r_addend = 0;
+ elf32_arm_add_dynreloc (output_bfd, info, srelgot, &outrel);
+ }
+ }
+ }
+ *unresolved_reloc_p = FALSE;
+ return bfd_reloc_ok;
+
default:
return bfd_reloc_notsupported;
}
@@ -14499,6 +14908,54 @@ elf32_arm_check_relocs (bfd *abfd, struct bfd_link_info *info,
r_type = elf32_arm_tls_transition (info, r_type, h);
switch (r_type)
{
+ case R_ARM_GOTOFFFUNCDESC:
+ {
+ if (h == NULL)
+ {
+ if (!elf32_arm_allocate_local_sym_info (abfd))
+ return FALSE;
+ elf32_arm_local_fdpic_cnts(abfd)[r_symndx].gotofffuncdesc_cnt += 1;
+ elf32_arm_local_fdpic_cnts(abfd)[r_symndx].funcdesc_offset = -1;
+ }
+ else
+ {
+ eh->fdpic_cnts.gotofffuncdesc_cnt++;
+ }
+ }
+ break;
+
+ case R_ARM_GOTFUNCDESC:
+ {
+ if (h == NULL)
+ {
+ /* Such a relocation is not supposed to be generated
+ by gcc on a static function. */
+ /* Anyway if needed it could be handled. */
+ abort();
+ }
+ else
+ {
+ eh->fdpic_cnts.gotfuncdesc_cnt++;
+ }
+ }
+ break;
+
+ case R_ARM_FUNCDESC:
+ {
+ if (h == NULL)
+ {
+ if (!elf32_arm_allocate_local_sym_info (abfd))
+ return FALSE;
+ elf32_arm_local_fdpic_cnts(abfd)[r_symndx].funcdesc_cnt += 1;
+ elf32_arm_local_fdpic_cnts(abfd)[r_symndx].funcdesc_offset = -1;
+ }
+ else
+ {
+ eh->fdpic_cnts.funcdesc_cnt++;
+ }
+ }
+ break;
+
case R_ARM_GOT32:
case R_ARM_GOT_PREL:
case R_ARM_TLS_GD32:
@@ -14640,7 +15097,8 @@ elf32_arm_check_relocs (bfd *abfd, struct bfd_link_info *info,
case R_ARM_THM_MOVT_PREL:
/* Should the interworking branches be listed here? */
- if ((bfd_link_pic (info) || htab->root.is_relocatable_executable)
+ if ((bfd_link_pic (info) || htab->root.is_relocatable_executable
+ || htab->fdpic_p)
&& (sec->flags & SEC_ALLOC) != 0)
{
if (h == NULL
@@ -14793,6 +15251,18 @@ elf32_arm_check_relocs (bfd *abfd, struct bfd_link_info *info,
if (elf32_arm_howto_from_type (r_type)->pc_relative)
p->pc_count += 1;
p->count += 1;
+ if (h == NULL && htab->fdpic_p && !bfd_link_pic(info)
+ && r_type != R_ARM_ABS32 && r_type != R_ARM_ABS32_NOI) {
+ /* Here we only support R_ARM_ABS32 and R_ARM_ABS32_NOI
+ that will become rofixup. */
+ /* This is due to the fact that we suppose all will become rofixup. */
+ fprintf(stderr, "FDPIC does not yet support %d relocation to become dynamic for executable\n", r_type);
+ _bfd_error_handler
+ (_("FDPIC does not yet support %s relocation"
+ " to become dynamic for executable"),
+ elf32_arm_howto_table_1[r_type].name);
+ abort();
+ }
}
}
@@ -15455,7 +15925,7 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
/* Make sure this symbol is output as a dynamic symbol.
Undefined weak syms won't yet be marked as dynamic. */
- if (h->dynindx == -1 && !h->forced_local
+ if (htab->root.dynamic_sections_created && h->dynindx == -1 && !h->forced_local
&& h->root.type == bfd_link_hash_undefweak)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
@@ -15535,7 +16005,8 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
if ((tls_type & GOT_TLS_GD) && indx != 0)
elf32_arm_allocate_dynrelocs (info, htab->root.srelgot, 1);
}
- else if (indx != -1 && !SYMBOL_REFERENCES_LOCAL (info, h))
+ else if (((indx != -1) || htab->fdpic_p)
+ && !SYMBOL_REFERENCES_LOCAL (info, h))
{
if (htab->root.dynamic_sections_created)
/* Reserve room for the GOT entry's R_ARM_GLOB_DAT relocation. */
@@ -15552,11 +16023,110 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
|| h->root.type != bfd_link_hash_undefweak))
/* Reserve room for the GOT entry's R_ARM_RELATIVE relocation. */
elf32_arm_allocate_dynrelocs (info, htab->root.srelgot, 1);
+ else if (htab->fdpic_p && tls_type == GOT_NORMAL)
+ /* Reserve room for rofixup for FDPIC executable. */
+ /* TLS relocs do not need space since they are completely
+ resolved. */
+ htab->srofixup->size += 4;
}
}
else
h->got.offset = (bfd_vma) -1;
+ /* FDPIC support. */
+ if (eh->fdpic_cnts.gotofffuncdesc_cnt > 0)
+ {
+ /* Symbol musn't be exported. */
+ if (h->dynindx != -1)
+ abort();
+
+ /* We only allocate one function descriptor with its associated relocation. */
+ if (eh->fdpic_cnts.funcdesc_offset == -1)
+ {
+ asection *s = htab->root.sgot;
+
+ eh->fdpic_cnts.funcdesc_offset = s->size;
+ s->size += 8;
+ /* We will add an R_ARM_FUNCDESC_VALUE relocation or two rofixups. */
+ if (bfd_link_pic(info))
+ elf32_arm_allocate_dynrelocs (info, htab->root.srelgot, 1);
+ else
+ htab->srofixup->size += 8;
+ }
+ }
+
+ if (eh->fdpic_cnts.gotfuncdesc_cnt > 0)
+ {
+ asection *s = htab->root.sgot;
+
+ if (htab->root.dynamic_sections_created && h->dynindx == -1
+ && !h->forced_local)
+ if (! bfd_elf_link_record_dynamic_symbol (info, h))
+ return FALSE;
+
+ if (h->dynindx == -1)
+ {
+ /* We only allocate one function descriptor with its associated relocation. q */
+ if (eh->fdpic_cnts.funcdesc_offset == -1)
+ {
+
+ eh->fdpic_cnts.funcdesc_offset = s->size;
+ s->size += 8;
+ /* We will add an R_ARM_FUNCDESC_VALUE relocation or two rofixups. */
+ if (bfd_link_pic(info))
+ elf32_arm_allocate_dynrelocs (info, htab->root.srelgot, 1);
+ else
+ htab->srofixup->size += 8;
+ }
+ }
+
+ /* Add one entry into the GOT and a R_ARM_FUNCDESC or
+ R_ARM_RELATIVE/rofixup relocation on it. */
+ eh->fdpic_cnts.gotfuncdesc_offset = s->size;
+ s->size += 4;
+ if (h->dynindx == -1 && !bfd_link_pic(info))
+ htab->srofixup->size += 4;
+ else
+ elf32_arm_allocate_dynrelocs (info, htab->root.srelgot, 1);
+ }
+
+ if (eh->fdpic_cnts.funcdesc_cnt > 0)
+ {
+ if (htab->root.dynamic_sections_created && h->dynindx == -1
+ && !h->forced_local)
+ if (! bfd_elf_link_record_dynamic_symbol (info, h))
+ return FALSE;
+
+ if (h->dynindx == -1)
+ {
+ /* We only allocate one function descriptor with its associated relocation. */
+ if (eh->fdpic_cnts.funcdesc_offset == -1)
+ {
+ asection *s = htab->root.sgot;
+
+ eh->fdpic_cnts.funcdesc_offset = s->size;
+ s->size += 8;
+ /* We will add an R_ARM_FUNCDESC_VALUE relocation or two rofixups. */
+ if (bfd_link_pic(info))
+ elf32_arm_allocate_dynrelocs (info, htab->root.srelgot, 1);
+ else
+ htab->srofixup->size += 8;
+ }
+ }
+ if (h->dynindx == -1 && !bfd_link_pic(info))
+ {
+ /* For FDPIC executable we replace R_ARM_RELATIVE with a rofixup. */
+ htab->srofixup->size += 4 * eh->fdpic_cnts.funcdesc_cnt;
+ }
+ else
+ {
+ /* Will need one dynamic reloc per reference. will be either
+ R_ARM_FUNCDESC or R_ARM_RELATIVE for hidden symbols. */
+ elf32_arm_allocate_dynrelocs (info, htab->root.srelgot,
+ eh->fdpic_cnts.funcdesc_cnt);
+ }
+ }
+
/* Allocate stubs for exported Thumb functions on v4t. */
if (!htab->use_blx && h->dynindx != -1
&& h->def_regular
@@ -15599,7 +16169,7 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
space for pc-relative relocs that have become local due to symbol
visibility changes. */
- if (bfd_link_pic (info) || htab->root.is_relocatable_executable)
+ if (bfd_link_pic (info) || htab->root.is_relocatable_executable || htab->fdpic_p)
{
/* Relocs that use pc_count are PC-relative forms, which will appear
on something like ".long foo - ." or "movw REG, foo - .". We want
@@ -15646,7 +16216,7 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
/* Make sure undefined weak symbols are output as a dynamic
symbol in PIEs. */
- else if (h->dynindx == -1
+ else if (htab->root.dynamic_sections_created && h->dynindx == -1
&& !h->forced_local)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
@@ -15702,10 +16272,15 @@ allocate_dynrelocs_for_symbol (struct elf_link_hash_entry *h, void * inf)
for (p = eh->dyn_relocs; p != NULL; p = p->next)
{
asection *sreloc = elf_section_data (p->sec)->sreloc;
+
if (h->type == STT_GNU_IFUNC
&& eh->plt.noncall_refcount == 0
&& SYMBOL_REFERENCES_LOCAL (info, h))
elf32_arm_allocate_irelocs (info, sreloc, p->count);
+ else if (h->dynindx != -1 && (!bfd_link_pic(info) || !info->symbolic || !h->def_regular))
+ elf32_arm_allocate_dynrelocs (info, sreloc, p->count);
+ else if (htab->fdpic_p && !bfd_link_pic(info))
+ htab->srofixup->size += 4 * p->count;
else
elf32_arm_allocate_dynrelocs (info, sreloc, p->count);
}
@@ -15800,6 +16375,7 @@ elf32_arm_size_dynamic_sections (bfd * output_bfd ATTRIBUTE_UNUSED,
asection *srel;
bfd_boolean is_vxworks = htab->vxworks_p;
unsigned int symndx;
+ struct fdpic_local *local_fdpic_cnts;
if (! is_arm_elf (ibfd))
continue;
@@ -15829,7 +16405,10 @@ elf32_arm_size_dynamic_sections (bfd * output_bfd ATTRIBUTE_UNUSED,
else if (p->count != 0)
{
srel = elf_section_data (p->sec)->sreloc;
- elf32_arm_allocate_dynrelocs (info, srel, p->count);
+ if (htab->fdpic_p && !bfd_link_pic(info))
+ htab->srofixup->size += 4 * p->count;
+ else
+ elf32_arm_allocate_dynrelocs (info, srel, p->count);
if ((p->sec->output_section->flags & SEC_READONLY) != 0)
info->flags |= DF_TEXTREL;
}
@@ -15846,15 +16425,54 @@ elf32_arm_size_dynamic_sections (bfd * output_bfd ATTRIBUTE_UNUSED,
local_iplt_ptr = elf32_arm_local_iplt (ibfd);
local_tls_type = elf32_arm_local_got_tls_type (ibfd);
local_tlsdesc_gotent = elf32_arm_local_tlsdesc_gotent (ibfd);
+ local_fdpic_cnts = elf32_arm_local_fdpic_cnts (ibfd);
symndx = 0;
s = htab->root.sgot;
srel = htab->root.srelgot;
for (; local_got < end_local_got;
++local_got, ++local_iplt_ptr, ++local_tls_type,
- ++local_tlsdesc_gotent, ++symndx)
+ ++local_tlsdesc_gotent, ++symndx, ++local_fdpic_cnts)
{
*local_tlsdesc_gotent = (bfd_vma) -1;
local_iplt = *local_iplt_ptr;
+
+ /* FDPIC support. */
+ if (local_fdpic_cnts->gotofffuncdesc_cnt > 0)
+ {
+ if (local_fdpic_cnts->funcdesc_offset == -1)
+ {
+ local_fdpic_cnts->funcdesc_offset = s->size;
+ s->size += 8;
+
+ /* We will add an R_ARM_FUNCDESC_VALUE relocation or two rofixups. */
+ if (bfd_link_pic(info))
+ elf32_arm_allocate_dynrelocs (info, srel, 1);
+ else
+ htab->srofixup->size += 8;
+ }
+ }
+
+ if (local_fdpic_cnts->funcdesc_cnt > 0)
+ {
+ if (local_fdpic_cnts->funcdesc_offset == -1)
+ {
+ local_fdpic_cnts->funcdesc_offset = s->size;
+ s->size += 8;
+
+ /* We will add an R_ARM_FUNCDESC_VALUE relocation or two rofixups. */
+ if (bfd_link_pic(info))
+ elf32_arm_allocate_dynrelocs (info, srel, 1);
+ else
+ htab->srofixup->size += 8;
+ }
+
+ /* We will add n R_ARM_RELATIVE relocations or n rofixups. */
+ if (bfd_link_pic(info))
+ elf32_arm_allocate_dynrelocs (info, srel, local_fdpic_cnts->funcdesc_cnt);
+ else
+ htab->srofixup->size += 4 * local_fdpic_cnts->funcdesc_cnt;
+ }
+
if (local_iplt != NULL)
{
struct elf_dyn_relocs *p;
@@ -15929,13 +16547,15 @@ elf32_arm_size_dynamic_sections (bfd * output_bfd ATTRIBUTE_UNUSED,
&& (local_iplt == NULL
|| local_iplt->arm.noncall_refcount == 0))
elf32_arm_allocate_irelocs (info, srel, 1);
- else if (bfd_link_pic (info) || output_bfd->flags & DYNAMIC)
+ else if (bfd_link_pic (info) || output_bfd->flags & DYNAMIC || htab->fdpic_p)
{
- if ((bfd_link_pic (info) && !(*local_tls_type & GOT_TLS_GDESC))
- || *local_tls_type & GOT_TLS_GD)
+ if ((bfd_link_pic (info) && !(*local_tls_type & GOT_TLS_GDESC)))
elf32_arm_allocate_dynrelocs (info, srel, 1);
+ else if (htab->fdpic_p && *local_tls_type & GOT_NORMAL)
+ htab->srofixup->size += 4;
- if (bfd_link_pic (info) && *local_tls_type & GOT_TLS_GDESC)
+ if ((bfd_link_pic (info) || htab->fdpic_p)
+ && *local_tls_type & GOT_TLS_GDESC)
{
elf32_arm_allocate_dynrelocs (info,
htab->root.srelplt, 1);
@@ -15960,6 +16580,11 @@ elf32_arm_size_dynamic_sections (bfd * output_bfd ATTRIBUTE_UNUSED,
else
htab->tls_ldm_got.offset = -1;
+ /* At the very end of the .rofixup section is a pointer to the GOT,
+ reserve space for it. */
+ if (htab->fdpic_p && htab->srofixup != NULL)
+ htab->srofixup->size += 4;
+
/* Allocate global sym .plt and .got entries, and space for global
sym dynamic relocs. */
elf_link_hash_traverse (& htab->root, allocate_dynrelocs_for_symbol, info);
@@ -16050,7 +16675,8 @@ elf32_arm_size_dynamic_sections (bfd * output_bfd ATTRIBUTE_UNUSED,
&& s != htab->root.iplt
&& s != htab->root.igotplt
&& s != htab->root.sdynbss
- && s != htab->root.sdynrelro)
+ && s != htab->root.sdynrelro
+ && s != htab->srofixup)
{
/* It's not one of our sections, so don't allocate space. */
continue;
@@ -16682,6 +17308,21 @@ elf32_arm_finish_dynamic_sections (bfd * output_bfd, struct bfd_link_info * info
elf_section_data (sgot->output_section)->this_hdr.sh_entsize = 4;
}
+ /* At the very end of the .rofixup section is a pointer to the GOT. */
+ if (htab->fdpic_p && htab->srofixup != NULL)
+ {
+ struct elf_link_hash_entry *hgot = htab->root.hgot;
+
+ bfd_vma got_value = hgot->root.u.def.value
+ + hgot->root.u.def.section->output_section->vma
+ + hgot->root.u.def.section->output_offset;
+
+ arm_elf_add_rofixup(output_bfd, htab->srofixup, got_value);
+
+ /* Make sure we allocated and generated the same number of fixups. */
+ BFD_ASSERT (htab->srofixup->reloc_count * 4 == htab->srofixup->size);
+ }
+
return TRUE;
}
@@ -17301,7 +17942,7 @@ elf32_arm_output_arch_local_syms (bfd *output_bfd,
if (!elf32_arm_output_map_sym (&osi, ARM_MAP_THUMB, 16))
return FALSE;
}
- else if (!htab->symbian_p)
+ else if (!htab->symbian_p && !htab->fdpic_p)
{
if (!elf32_arm_output_map_sym (&osi, ARM_MAP_ARM, 0))
return FALSE;
@@ -19514,15 +20155,44 @@ elf32_arm_fdpic_link_hash_table_create (bfd *abfd)
return ret;
}
+/* We need dynamic symbols for every section, since segments can
+ relocate independently. */
+static bfd_boolean
+elf32_arm_fdpic_omit_section_dynsym (bfd *output_bfd ATTRIBUTE_UNUSED,
+ struct bfd_link_info *info
+ ATTRIBUTE_UNUSED,
+ asection *p ATTRIBUTE_UNUSED)
+{
+ switch (elf_section_data (p)->this_hdr.sh_type)
+ {
+ case SHT_PROGBITS:
+ case SHT_NOBITS:
+ /* If sh_type is yet undecided, assume it could be
+ SHT_PROGBITS/SHT_NOBITS. */
+ case SHT_NULL:
+ return FALSE;
+
+ /* There shouldn't be section relative relocations
+ against any other section. */
+ default:
+ return TRUE;
+ }
+}
+
#undef elf32_bed
#define elf32_bed elf32_arm_fdpic_bed
#undef bfd_elf32_bfd_link_hash_table_create
#define bfd_elf32_bfd_link_hash_table_create elf32_arm_fdpic_link_hash_table_create
+#undef elf_backend_omit_section_dynsym
+#define elf_backend_omit_section_dynsym elf32_arm_fdpic_omit_section_dynsym
+
#include "elf32-target.h"
+
#undef elf_match_priority
#undef ELF_OSABI
+#undef elf_backend_omit_section_dynsym
/* VxWorks Targets. */
diff --git a/ld/emulparams/armelf_linux_fdpiceabi.sh b/ld/emulparams/armelf_linux_fdpiceabi.sh
index 104cf38..aa604aa 100644
--- a/ld/emulparams/armelf_linux_fdpiceabi.sh
+++ b/ld/emulparams/armelf_linux_fdpiceabi.sh
@@ -9,5 +9,9 @@ OTHER_READONLY_SECTIONS="
.ARM.extab ${RELOCATING-0} : { *(.ARM.extab${RELOCATING+* .gnu.linkonce.armextab.*}) }
${RELOCATING+ PROVIDE_HIDDEN (__exidx_start = .); }
.ARM.exidx ${RELOCATING-0} : { *(.ARM.exidx${RELOCATING+* .gnu.linkonce.armexidx.*}) }
- ${RELOCATING+ PROVIDE_HIDDEN (__exidx_end = .); }"
-
+ ${RELOCATING+ PROVIDE_HIDDEN (__exidx_end = .); }
+ .rofixup : {
+ ${RELOCATING+__ROFIXUP_LIST__ = .;}
+ *(.rofixup)
+ ${RELOCATING+__ROFIXUP_END__ = .;}
+}"
--
2.6.3