IFUNC: Update IFUNC resolver check with DT_TEXTREL

Add ifunc_resolvers to elf_link_hash_table and use it for both x86 and
ppc64.  Before glibc commit b5c45e837, DT_TEXTREL is incompatible with
IFUNC resolvers.  Set ifunc_resolvers if there are IFUNC resolvers and
issue a warning for IFUNC resolvers with DT_TEXTREL.

bfd/

	PR ld/18801
	* elf-bfd.h (elf_link_hash_table): Add ifunc_resolvers.
	(_bfd_elf_allocate_ifunc_dyn_relocs): Remove the
	bfd_boolean * argument.  Set ifunc_resolvers if there are IFUNC
	resolvers.
	* elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Updated.
	Set ifunc_resolvers if there are FUNC resolvers.
	* elf64-ppc.c (ppc_link_hash_table): Remove local_ifunc_resolver.
	(build_global_entry_stubs_and_plt): Replace local_ifunc_resolver
	with elf.ifunc_resolvers.
	(write_plt_relocs_for_local_syms): Likewise.
	(ppc64_elf_relocate_section): Likewise.
	(ppc64_elf_finish_dynamic_sections): Likewise.
	* elfnn-aarch64.c (elfNN_aarch64_allocate_ifunc_dynrelocs):
	Updated.
	* elfxx-x86.c (elf_x86_allocate_dynrelocs): Likewise.
	(_bfd_x86_elf_size_dynamic_sections): Check elf.ifunc_resolvers
	instead of readonly_dynrelocs_against_ifunc.
	* elfxx-x86.h (elf_x86_link_hash_table): Remove
	readonly_dynrelocs_against_ifunc.

ld/

	PR ld/18801
	* testsuite/ld-i386/i386.exp: Run ifunc-textrel-1a,
	ifunc-textrel-1b, ifunc-textrel-2a and ifunc-textrel-2b.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-i386/ifunc-textrel-1a.d: Likewise.
	* testsuite/ld-i386/ifunc-textrel-1b.d: Likewise.
	* testsuite/ld-i386/ifunc-textrel-2a.d: Likewise.
	* testsuite/ld-i386/ifunc-textrel-2b.d: Likewise.
	* testsuite/ld-x86-64/ifunc-textrel-1.s: Likewise.
	* testsuite/ld-x86-64/ifunc-textrel-1a.d: Likewise.
	* testsuite/ld-x86-64/ifunc-textrel-1b.d: Likewise.
	* testsuite/ld-x86-64/ifunc-textrel-2.s: Likewise.
	* testsuite/ld-x86-64/ifunc-textrel-2a.d: Likewise.
	* testsuite/ld-x86-64/ifunc-textrel-2b.d: Likewise.
	* testsuite/ld-i386/pr18801a.d: Expect warning for IFUNC
	resolvers.
	* testsuite/ld-i386/pr18801b.d: Likewise.
	* estsuite/ld-x86-64/pr18801a.d: Likewise.
	* estsuite/ld-x86-64/pr18801b.d: Likewise.
This commit is contained in:
H.J. Lu 2020-06-09 06:56:55 -07:00
parent f9630fa654
commit cebd6b8ac1
24 changed files with 179 additions and 44 deletions

View File

@ -1,3 +1,26 @@
2020-06-09 H.J. Lu <hongjiu.lu@intel.com>
PR ld/18801
* elf-bfd.h (elf_link_hash_table): Add ifunc_resolvers.
(_bfd_elf_allocate_ifunc_dyn_relocs): Remove the
bfd_boolean * argument. Set ifunc_resolvers if there are IFUNC
resolvers.
* elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Updated.
Set ifunc_resolvers if there are FUNC resolvers.
* elf64-ppc.c (ppc_link_hash_table): Remove local_ifunc_resolver.
(build_global_entry_stubs_and_plt): Replace local_ifunc_resolver
with elf.ifunc_resolvers.
(write_plt_relocs_for_local_syms): Likewise.
(ppc64_elf_relocate_section): Likewise.
(ppc64_elf_finish_dynamic_sections): Likewise.
* elfnn-aarch64.c (elfNN_aarch64_allocate_ifunc_dynrelocs):
Updated.
* elfxx-x86.c (elf_x86_allocate_dynrelocs): Likewise.
(_bfd_x86_elf_size_dynamic_sections): Check elf.ifunc_resolvers
instead of readonly_dynrelocs_against_ifunc.
* elfxx-x86.h (elf_x86_link_hash_table): Remove
readonly_dynrelocs_against_ifunc.
2020-06-09 Alan Modra <amodra@gmail.com>
* elf64-ppc.c (struct ppc_link_hash_table): Delete

View File

@ -570,6 +570,9 @@ struct elf_link_hash_table
section symbols. */
bfd_boolean is_relocatable_executable;
/* TRUE if there are IFUNC resolvers. */
bfd_boolean ifunc_resolvers;
/* The BFD used to hold special sections created by the linker.
This will be the first BFD found which requires these sections to
be created. */
@ -2875,8 +2878,8 @@ extern bfd_boolean _bfd_elf_create_ifunc_sections
(bfd *, struct bfd_link_info *);
extern bfd_boolean _bfd_elf_allocate_ifunc_dyn_relocs
(struct bfd_link_info *, struct elf_link_hash_entry *,
struct elf_dyn_relocs **, bfd_boolean *, unsigned int,
unsigned int, unsigned int, bfd_boolean);
struct elf_dyn_relocs **, unsigned int, unsigned int,
unsigned int, bfd_boolean);
extern void elf_append_rela (bfd *, asection *, Elf_Internal_Rela *);
extern void elf_append_rel (bfd *, asection *, Elf_Internal_Rela *);

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@ -107,7 +107,6 @@ bfd_boolean
_bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
struct elf_link_hash_entry *h,
struct elf_dyn_relocs **head,
bfd_boolean *readonly_dynrelocs_against_ifunc_p,
unsigned int plt_entry_size,
unsigned int plt_header_size,
unsigned int got_entry_size,
@ -118,7 +117,6 @@ _bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
unsigned int sizeof_reloc;
const struct elf_backend_data *bed;
struct elf_link_hash_table *htab;
bfd_boolean readonly_dynrelocs_against_ifunc;
/* If AVOID_PLT is TRUE, don't use PLT if possible. */
bfd_boolean use_plt = !avoid_plt || h->plt.refcount > 0;
bfd_boolean need_dynreloc = !use_plt || bfd_link_pic (info);
@ -255,8 +253,6 @@ _bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
if (!need_dynreloc || !h->non_got_ref)
*head = NULL;
readonly_dynrelocs_against_ifunc = FALSE;
/* Finally, allocate space. */
p = *head;
if (p != NULL)
@ -264,17 +260,13 @@ _bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
bfd_size_type count = 0;
do
{
if (!readonly_dynrelocs_against_ifunc)
{
asection *s = p->sec->output_section;
if (s != NULL && (s->flags & SEC_READONLY) != 0)
readonly_dynrelocs_against_ifunc = TRUE;
}
count += p->count;
p = p->next;
}
while (p != NULL);
htab->ifunc_resolvers = count != 0;
/* Dynamic relocations are stored in
1. .rel[a].ifunc section in PIC object.
2. .rel[a].got section in dynamic executable.
@ -290,9 +282,6 @@ _bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
}
}
if (readonly_dynrelocs_against_ifunc_p)
*readonly_dynrelocs_against_ifunc_p = readonly_dynrelocs_against_ifunc;
/* For STT_GNU_IFUNC symbol, .got.plt has the real function address
and .got has the PLT entry adddress. We will load the GOT entry
with the PLT entry in finish_dynamic_symbol if it is used. For

View File

@ -3239,10 +3239,6 @@ struct ppc_link_hash_table
/* Whether func_desc_adjust needs to be run over symbols. */
unsigned int need_func_desc_adj:1;
/* Whether there exist local gnu indirect function resolvers,
referenced by dynamic relocations. */
unsigned int local_ifunc_resolver:1;
/* Whether plt calls for ELFv2 localentry:0 funcs have been optimized. */
unsigned int has_plt_localentry0:1;
@ -13880,7 +13876,7 @@ build_global_entry_stubs_and_plt (struct elf_link_hash_entry *h, void *inf)
{
plt = htab->elf.iplt;
relplt = htab->elf.irelplt;
htab->local_ifunc_resolver = 1;
htab->elf.ifunc_resolvers = TRUE;
if (htab->opd_abi)
rela.r_info = ELF64_R_INFO (0, R_PPC64_JMP_IREL);
else
@ -13934,7 +13930,7 @@ build_global_entry_stubs_and_plt (struct elf_link_hash_entry *h, void *inf)
+ ((ent->plt.offset - PLT_INITIAL_ENTRY_SIZE (htab))
/ PLT_ENTRY_SIZE (htab) * sizeof (Elf64_External_Rela)));
if (h->type == STT_GNU_IFUNC && is_static_defined (h))
htab->local_ifunc_resolver = 1;
htab->elf.ifunc_resolvers = TRUE;
bfd_elf64_swap_reloca_out (info->output_bfd, &rela, loc);
}
}
@ -14076,7 +14072,7 @@ write_plt_relocs_for_local_syms (struct bfd_link_info *info)
if (ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC)
{
htab->local_ifunc_resolver = 1;
htab->elf.ifunc_resolvers = TRUE;
plt = htab->elf.iplt;
relplt = htab->elf.irelplt;
}
@ -16103,7 +16099,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
{
relgot = htab->elf.irelplt;
if (indx == 0 || is_static_defined (&h->elf))
htab->local_ifunc_resolver = 1;
htab->elf.ifunc_resolvers = TRUE;
}
else if (indx != 0
|| (bfd_link_pic (info)
@ -16633,7 +16629,7 @@ ppc64_elf_relocate_section (bfd *output_bfd,
{
sreloc = htab->elf.irelplt;
if (indx == 0 || is_static_defined (&h->elf))
htab->local_ifunc_resolver = 1;
htab->elf.ifunc_resolvers = TRUE;
}
if (sreloc == NULL)
abort ();
@ -17397,7 +17393,7 @@ ppc64_elf_finish_dynamic_sections (bfd *output_bfd,
break;
case DT_TEXTREL:
if (htab->local_ifunc_resolver)
if (htab->elf.ifunc_resolvers)
info->callbacks->einfo
(_("%P: warning: text relocations and GNU indirect "
"functions may result in a segfault at runtime\n"));

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@ -8818,7 +8818,6 @@ elfNN_aarch64_allocate_ifunc_dynrelocs (struct elf_link_hash_entry *h,
&& h->def_regular)
return _bfd_elf_allocate_ifunc_dyn_relocs (info, h,
&h->dyn_relocs,
NULL,
htab->plt_entry_size,
htab->plt_header_size,
GOT_ENTRY_SIZE,

View File

@ -132,7 +132,6 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
&& h->def_regular)
{
if (_bfd_elf_allocate_ifunc_dyn_relocs (info, h, &h->dyn_relocs,
&htab->readonly_dynrelocs_against_ifunc,
plt_entry_size,
(htab->plt.has_plt0
* plt_entry_size),
@ -1416,15 +1415,11 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd,
if ((info->flags & DF_TEXTREL) != 0)
{
if (htab->readonly_dynrelocs_against_ifunc)
{
info->callbacks->einfo
(_("%P%X: read-only segment has dynamic IFUNC relocations;"
" recompile with %s\n"),
bfd_link_dll (info) ? "-fPIC" : "-fPIE");
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
if (htab->elf.ifunc_resolvers)
info->callbacks->einfo
(_("%P: warning: GNU indirect functions with DT_TEXTREL "
"may result in a segfault at runtime; recompile with %s\n"),
bfd_link_dll (info) ? "-fPIC" : "-fPIE");
if (!add_dynamic_entry (DT_TEXTREL, 0))
return FALSE;

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@ -483,10 +483,6 @@ struct elf_x86_link_hash_table
/* The index of the next R_X86_64_IRELATIVE entry in .rela.plt. */
bfd_vma next_irelative_index;
/* TRUE if there are dynamic relocs against IFUNC symbols that apply
to read-only sections. */
bfd_boolean readonly_dynrelocs_against_ifunc;
/* The (unloaded but important) .rel.plt.unloaded section on VxWorks.
This is used for i386 only. */
asection *srelplt2;

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@ -1,3 +1,25 @@
2020-06-09 H.J. Lu <hongjiu.lu@intel.com>
PR ld/18801
* testsuite/ld-i386/i386.exp: Run ifunc-textrel-1a,
ifunc-textrel-1b, ifunc-textrel-2a and ifunc-textrel-2b.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/ifunc-textrel-1a.d: Likewise.
* testsuite/ld-i386/ifunc-textrel-1b.d: Likewise.
* testsuite/ld-i386/ifunc-textrel-2a.d: Likewise.
* testsuite/ld-i386/ifunc-textrel-2b.d: Likewise.
* testsuite/ld-x86-64/ifunc-textrel-1.s: Likewise.
* testsuite/ld-x86-64/ifunc-textrel-1a.d: Likewise.
* testsuite/ld-x86-64/ifunc-textrel-1b.d: Likewise.
* testsuite/ld-x86-64/ifunc-textrel-2.s: Likewise.
* testsuite/ld-x86-64/ifunc-textrel-2a.d: Likewise.
* testsuite/ld-x86-64/ifunc-textrel-2b.d: Likewise.
* testsuite/ld-i386/pr18801a.d: Expect warning for IFUNC
resolvers.
* testsuite/ld-i386/pr18801b.d: Likewise.
* estsuite/ld-x86-64/pr18801a.d: Likewise.
* estsuite/ld-x86-64/pr18801b.d: Likewise.
2020-06-09 Alan Modra <amodra@gmail.com>
PR 26065

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@ -519,6 +519,10 @@ run_dump_test "pr17935-1"
run_dump_test "pr17935-2"
run_dump_test "pr18801a"
run_dump_test "pr18801b"
run_dump_test "ifunc-textrel-1a"
run_dump_test "ifunc-textrel-1b"
run_dump_test "ifunc-textrel-2a"
run_dump_test "ifunc-textrel-2b"
run_dump_test "pr18815"
run_dump_test "pr19939a"
run_dump_test "pr19939b"

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@ -0,0 +1,4 @@
#source: ../ld-x86-64/ifunc-textrel-1.s
#as: --32
#ld: -m elf_i386 -pie
#warning: GNU indirect functions with DT_TEXTREL may result in a segfault at runtime; recompile with -fPIE

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@ -0,0 +1,4 @@
#source: ../ld-x86-64/ifunc-textrel-1.s
#as: --32
#ld: -m elf_i386 -shared
#warning: GNU indirect functions with DT_TEXTREL may result in a segfault at runtime; recompile with -fPIC

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@ -0,0 +1,8 @@
#source: ../ld-x86-64/ifunc-textrel-2.s
#as: --32
#ld: -m elf_i386 -pie -z notext
#readelf: -r --wide
#failif
[0-9a-f]+ +[0-9a-f]+ +R_386_IRELATIVE +
#..

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@ -0,0 +1,8 @@
#source: ../ld-x86-64/ifunc-textrel-2.s
#as: --32
#ld: -m elf_i386 -shared -z notext
#readelf: -r --wide
#failif
[0-9a-f]+ +[0-9a-f]+ +R_386_IRELATIVE +
#..

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@ -1,4 +1,4 @@
#source: pr18801.s
#as: --32
#ld: -m elf_i386 -pie
#error: read-only segment has dynamic IFUNC relocations; recompile with -fPIE
#warning: GNU indirect functions with DT_TEXTREL may result in a segfault at runtime; recompile with -fPIE

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@ -1,4 +1,4 @@
#source: pr18801.s
#as: --32
#ld: -m elf_i386 -shared
#error: read-only segment has dynamic IFUNC relocations; recompile with -fPIC
#warning: GNU indirect functions with DT_TEXTREL may result in a segfault at runtime; recompile with -fPIC

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@ -0,0 +1,28 @@
.text
.type selector, %function
foo:
movl $0, %eax
ret
selector:
.ifdef __x86_64__
leaq foo(%rip), %rax
.else
leal foo@GOTOFF(%eax), %eax
.endif
ret
.type selector, %gnu_indirect_function
.globl _start
_start:
.ifdef __x86_64__
movabs ptr, %rax
call *%rax
.else
mov ptr, %eax
call *%eax
.endif
ret
.data
.type ptr, @object
ptr:
.dc.a selector
.section .note.GNU-stack,"",@progbits

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@ -0,0 +1,4 @@
#source: ifunc-textrel-1.s
#as: --64 -defsym __x86_64__=1
#ld: -m elf_x86_64 -pie
#warning: GNU indirect functions with DT_TEXTREL may result in a segfault at runtime; recompile with -fPIE

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@ -0,0 +1,4 @@
#source: ifunc-textrel-1.s
#as: --64 -defsym __x86_64__=1
#ld: -m elf_x86_64 -shared
#warning: GNU indirect functions with DT_TEXTREL may result in a segfault at runtime; recompile with -fPIC

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@ -0,0 +1,28 @@
.text
.type selector, %function
foo:
movl $0, %eax
ret
selector:
.ifdef __x86_64__
leaq foo(%rip), %rax
.else
leal foo@GOTOFF(%eax), %eax
.endif
ret
.type selector, %gnu_indirect_function
.globl _start
_start:
.ifdef __x86_64__
movabs ptr, %rax
call *%rax
.else
mov ptr, %eax
call *%eax
.endif
ret
.data
.type ptr, @object
ptr:
.dc.a foo
.section .note.GNU-stack,"",@progbits

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@ -0,0 +1,8 @@
#source: ifunc-textrel-2.s
#as: --64 -defsym __x86_64__=1
#ld: -m elf_x86_64 -pie -z notext
#readelf: -r --wide
#failif
[0-9a-f]+ +[0-9a-f]+ +R_X86_64_IRELATIVE +[0-9a-f]+
#..

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@ -0,0 +1,8 @@
#source: ifunc-textrel-2.s
#as: --64 -defsym __x86_64__=1
#ld: -m elf_x86_64 -shared -z notext
#readelf: -r --wide
#failif
[0-9a-f]+ +[0-9a-f]+ +R_X86_64_IRELATIVE +[0-9a-f]+
#..

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@ -1,4 +1,4 @@
#source: pr18801.s
#as: --64
#ld: -melf_x86_64 -pie
#error: read-only segment has dynamic IFUNC relocations; recompile with -fPIE
#warning: GNU indirect functions with DT_TEXTREL may result in a segfault at runtime; recompile with -fPIE

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@ -1,4 +1,4 @@
#source: pr18801.s
#as: --64
#ld: -melf_x86_64 -shared
#error: read-only segment has dynamic IFUNC relocations; recompile with -fPIC
#warning: GNU indirect functions with DT_TEXTREL may result in a segfault at runtime; recompile with -fPIC

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@ -581,6 +581,10 @@ run_dump_test "pr18160"
run_dump_test "pr18176"
run_dump_test "pr18801a"
run_dump_test "pr18801b"
run_dump_test "ifunc-textrel-1a"
run_dump_test "ifunc-textrel-1b"
run_dump_test "ifunc-textrel-2a"
run_dump_test "ifunc-textrel-2b"
run_dump_test "pr18815"
run_dump_test "pr19013"
run_dump_test "pr19013-x32"