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[BFD, AArch64, x86] Improve warning for --force-bti 

The AArch64 linker option to turn on BTI (--force-bti) warns in case there are
input objects which have a missing GNU NOTE section for BTI. This patch is trying
to improve the warnings that come out.

In order to do so, I propose adding a new argument to elf_merge_gnu_properties
and the backend function merge_gnu_properties. This new argument makes sure
that we now pass both the objects along with the properties to which they
belong to. The x86 backend function has also been updated to match this
change.

*** bfd/ChangeLog ***

2019-03-21  Sudakshina Das  <sudi.das@arm.com>

	* elf-bfd.h (struct elf_backend_data): Add argument to
	merge_gnu_properties.
	* elf-properties.c (elf_merge_gnu_properties): Add argument to
	itself and while calling bed->merge_gnu_properties.
	(elf_merge_gnu_property_list): Update the calls for
	elf_merge_gnu_properties.
	* elfnn-aarch64.c (elfNN_aarch64_merge_gnu_properties): Update handling
	of --force-bti warning and add argument.
	* elfxx-aarch64.c (_bfd_aarch64_elf_link_setup_gnu_properties): Add
	warning.
	* elfxx-x86.c (_bfd_x86_elf_merge_gnu_properties): Add argument.
	* elfxx-x86.h (_bfd_x86_elf_merge_gnu_properties): Likewise in
	declaration.

*** ld/ChangeLog ***

2019-03-21  Sudakshina Das  <sudi.das@arm.com>

	* testsuite/ld-aarch64/aarch64-elf.exp: Add new test.
	* testsuite/ld-aarch64/bti-plt-1.s: Add .ifdef for PAC note section.
	* testsuite/ld-aarch64/bti-plt-6.d: Update warning.
	* testsuite/ld-aarch64/bti-plt-7.d: Likewise.
	* testsuite/ld-aarch64/bti-warn.d: New test.
This commit is contained in:
Sudakshina Das 2019-03-21 16:20:21 +00:00
parent f84bd4655c
commit 4e5391148d
13 changed files with 93 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
bfd/ChangeLog
View File

@ -1,3 +1,19 @@
2019-03-21 Sudakshina Das <sudi.das@arm.com>
* elf-bfd.h (struct elf_backend_data): Add argument to
merge_gnu_properties.
* elf-properties.c (elf_merge_gnu_properties): Add argument to
itself and while calling bed->merge_gnu_properties.
(elf_merge_gnu_property_list): Update the calls for
elf_merge_gnu_properties.
* elfnn-aarch64.c (elfNN_aarch64_merge_gnu_properties): Update handling
of --force-bti warning and add argument.
* elfxx-aarch64.c (_bfd_aarch64_elf_link_setup_gnu_properties): Add
warning.
* elfxx-x86.c (_bfd_x86_elf_merge_gnu_properties): Add argument.
* elfxx-x86.h (_bfd_x86_elf_merge_gnu_properties): Likewise in
declaration.
2019-03-20 Sudakshina Das <sudi.das@arm.com>
* elfxx-aarch64.c (_bfd_aarch64_elf_link_fixup_gnu_properties): Define.

2
bfd/elf-bfd.h
View File

@ -1473,7 +1473,7 @@ struct elf_backend_data
unsigned int);
/* Merge GNU properties. Return TRUE if property is updated. */
bfd_boolean (*merge_gnu_properties) (struct bfd_link_info *, bfd *,
bfd_boolean (*merge_gnu_properties) (struct bfd_link_info *, bfd *, bfd *,
elf_property *, elf_property *);
/* Set up GNU properties. */

8
bfd/elf-properties.c
View File

@ -198,7 +198,7 @@ next:
with ABFD. */
static bfd_boolean
elf_merge_gnu_properties (struct bfd_link_info *info, bfd *abfd,
elf_merge_gnu_properties (struct bfd_link_info *info, bfd *abfd, bfd *bbfd,
elf_property *aprop, elf_property *bprop)
{
const struct elf_backend_data *bed = get_elf_backend_data (abfd);
@ -207,7 +207,7 @@ elf_merge_gnu_properties (struct bfd_link_info *info, bfd *abfd,
if (bed->merge_gnu_properties != NULL
&& pr_type >= GNU_PROPERTY_LOPROC
&& pr_type < GNU_PROPERTY_LOUSER)
return bed->merge_gnu_properties (info, abfd, aprop, bprop);
return bed->merge_gnu_properties (info, abfd, bbfd, aprop, bprop);
switch (pr_type)
{
@ -289,7 +289,7 @@ elf_merge_gnu_property_list (struct bfd_link_info *info, bfd *first_pbfd,
TRUE);
/* Pass NULL to elf_merge_gnu_properties for the property which
isn't on *LISTP. */
elf_merge_gnu_properties (info, first_pbfd, &p->property, pr);
elf_merge_gnu_properties (info, first_pbfd, abfd, &p->property, pr);
if (p->property.pr_kind == property_remove)
{
if (info->has_map_file)
@ -365,7 +365,7 @@ elf_merge_gnu_property_list (struct bfd_link_info *info, bfd *first_pbfd,
else
number_p = FALSE;
if (elf_merge_gnu_properties (info, first_pbfd, NULL, &p->property))
if (elf_merge_gnu_properties (info, first_pbfd, abfd, NULL, &p->property))
{
if (p->property.pr_type == GNU_PROPERTY_NO_COPY_ON_PROTECTED)
elf_has_no_copy_on_protected (first_pbfd) = TRUE;

25
bfd/elfnn-aarch64.c
View File

@ -9968,7 +9968,7 @@ elfNN_aarch64_link_setup_gnu_properties (struct bfd_link_info *info)
for the effect of GNU properties of the output_bfd. */
static bfd_boolean
elfNN_aarch64_merge_gnu_properties (struct bfd_link_info *info,
bfd *abfd,
bfd *abfd, bfd *bbfd,
elf_property *aprop,
elf_property *bprop)
{
@ -9977,17 +9977,26 @@ elfNN_aarch64_merge_gnu_properties (struct bfd_link_info *info,
/* If output has been marked with BTI using command line argument, give out
warning if necessary. */
if ((prop & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)
/* Properties are merged per type, hence only check for warnings when merging
GNU_PROPERTY_AARCH64_FEATURE_1_AND. */
if (((aprop && aprop->pr_type == GNU_PROPERTY_AARCH64_FEATURE_1_AND)
|| (bprop && bprop->pr_type == GNU_PROPERTY_AARCH64_FEATURE_1_AND))
&& (prop & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)
&& (!elf_aarch64_tdata (info->output_bfd)->no_bti_warn))
{
if ((aprop && !(aprop->u.number & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
|| (bprop && !(bprop->u.number & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
/* If either property is NULL, it means its bfd did not have any
property. */
|| !aprop || !bprop)
|| !aprop)
{
_bfd_error_handler (_("warning: BTI turned on by --force-bti when "
"all inputs do not have BTI in NOTE section."));
_bfd_error_handler (_("%pB: warning: BTI turned on by --force-bti when "
"all inputs do not have BTI in NOTE section."),
abfd);
}
if ((bprop && !(bprop->u.number & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
|| !bprop)
{
_bfd_error_handler (_("%pB: warning: BTI turned on by --force-bti when "
"all inputs do not have BTI in NOTE section."),
bbfd);
}
}

5
bfd/elfxx-aarch64.c
View File

@ -719,6 +719,11 @@ _bfd_aarch64_elf_link_setup_gnu_properties (struct bfd_link_info *info,
prop = _bfd_elf_get_property (ebfd,
GNU_PROPERTY_AARCH64_FEATURE_1_AND,
4);
if (gnu_prop & GNU_PROPERTY_AARCH64_FEATURE_1_BTI
&& !(prop->u.number & GNU_PROPERTY_AARCH64_FEATURE_1_BTI))
_bfd_error_handler (_("%pB: warning: BTI turned on by --force-bti "
"when all inputs do not have BTI in NOTE "
"section."), ebfd);
prop->u.number |= gnu_prop;
prop->pr_kind = property_number;

1
bfd/elfxx-x86.c
View File

@ -2401,6 +2401,7 @@ _bfd_x86_elf_parse_gnu_properties (bfd *abfd, unsigned int type,
bfd_boolean
_bfd_x86_elf_merge_gnu_properties (struct bfd_link_info *info,
bfd *abfd ATTRIBUTE_UNUSED,
bfd *bbfd ATTRIBUTE_UNUSED,
elf_property *aprop,
elf_property *bprop)
{

2
bfd/elfxx-x86.h
View File

@ -691,7 +691,7 @@ extern enum elf_property_kind _bfd_x86_elf_parse_gnu_properties
(bfd *, unsigned int, bfd_byte *, unsigned int);
extern bfd_boolean _bfd_x86_elf_merge_gnu_properties
(struct bfd_link_info *, bfd *, elf_property *, elf_property *);
(struct bfd_link_info *, bfd *, bfd *, elf_property *, elf_property *);
extern void _bfd_x86_elf_link_fixup_gnu_properties
(struct bfd_link_info *, elf_property_list **);

8
ld/ChangeLog
View File

@ -1,3 +1,11 @@
2019-03-21 Sudakshina Das <sudi.das@arm.com>
* testsuite/ld-aarch64/aarch64-elf.exp: Add new test.
* testsuite/ld-aarch64/bti-plt-1.s: Add .ifdef for PAC note section.
* testsuite/ld-aarch64/bti-plt-6.d: Update warning.
* testsuite/ld-aarch64/bti-plt-7.d: Likewise.
* testsuite/ld-aarch64/bti-warn.d: New test.
2019-03-21 Alan Modra <amodra@gmail.com>
* testsuite/ld-elf/fini2.s: Reduce alignment.

2
ld/testsuite/ld-aarch64/aarch64-elf.exp
View File

@ -407,3 +407,5 @@ run_dump_test "pac-plt-1"
run_dump_test "pac-plt-2"
run_dump_test "bti-pac-plt-1"
run_dump_test "bti-pac-plt-2"
run_dump_test "bti-warn"

17
ld/testsuite/ld-aarch64/bti-plt-1.s
View File

@ -21,3 +21,20 @@ _start:
.p2align 3
5:
.endif
.ifdef __property_pac__
.section ".note.gnu.property", "a"
.p2align 3
.long 1f - 0f /* name length */
.long 5f - 2f /* data length */
.long 5 /* note type */
0: .asciz "GNU" /* vendor name */
1:
.p2align 3
2: .long 0xc0000000 /* pr_type. */
.long 4f - 3f /* pr_datasz. */
3:
.long 0x2 /* PAC. */
4:
.p2align 3
5:
.endif

4
ld/testsuite/ld-aarch64/bti-plt-6.d
View File

@ -1,9 +1,9 @@
#name: Warn with one missing GNU NOTE BTI input
#source: property-bti-pac1.s
#source: property-bti-pac2.s
#source: property-bti-pac1.s
#as: -mabi=lp64 -defsym __property_pac__=1
#ld: -shared --force-bti
#warning: .*: warning: BTI turned on by --force-bti.*$
#warning: .*property-bti-pac2.*: warning: BTI turned on by --force-bti.*$
#readelf: -n
# Should warn about the missing input BTI NOTE but should

5
ld/testsuite/ld-aarch64/bti-plt-7.d
View File

@ -1,9 +1,10 @@
#name: Warn when neither inputs has GNU NOTE BTI
#source: property-bti-pac1.s
#source: property-bti-pac2.s
#source: plt_mapping_symbol.s
#as: -mabi=lp64
#ld: -shared --force-bti
#warning: .*: warning: BTI turned on by --force-bti.*$
#warning: .*plt_mapping_symbol.*: warning: BTI turned on by --force-bti.*
#warning: .*property-bti-pac2.*: warning: BTI turned on by --force-bti.*
#readelf: -n
# Should warn about the missing input BTI NOTE but should

16
ld/testsuite/ld-aarch64/bti-warn.d Normal file
View File

@ -0,0 +1,16 @@
#name: Warn when both have GNU prop but neither BTI
#source: property-bti-pac2.s
#source: bti-plt-1.s
#as: -mabi=lp64 --defsym __guard_property_bti__=1 --defsym __property_pac__=1
#ld: -shared --force-bti
#warning: .*property-bti-pac2.*: warning: BTI turned on by --force-bti.*
#warning: .*bti-plt-1.*: warning: BTI turned on by --force-bti.*
#readelf: -n
# Should warn about the missing input BTI NOTE but should
# still mark output as BTI
Displaying notes found in: .note.gnu.property
Owner Data size Description
GNU 0x00000010 NT_GNU_PROPERTY_TYPE_0
Properties: AArch64 feature: BTI, PAC