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[PR22764][LD][AARCH64]Allow R_AARCH64_ABS16 and R_AARCH64_ABS32 against absolution symbol or undefine symbol in shared object under LP64 abi.
- From: Renlin Li <renlin dot li at foss dot arm dot com>
- To: "binutils at sourceware dot org" <binutils at sourceware dot org>, Matthias Klose <doko at ubuntu dot com>, ard dot biesheuvel at linaro dot org, arnd at arndb dot de, Ramana Radhakrishnan <Ramana dot Radhakrishnan at arm dot com>, Nicholas Clifton <nickc at redhat dot com>
- Date: Mon, 5 Feb 2018 12:39:06 +0000
- Subject: [PR22764][LD][AARCH64]Allow R_AARCH64_ABS16 and R_AARCH64_ABS32 against absolution symbol or undefine symbol in shared object under LP64 abi.
- Authentication-results: sourceware.org; auth=none
Hi all,
The assumption that R_AARCH64_ABS16 and R_AARCH64_ABS32 relocation in LP64 abi
will be used to generate an address does not hold for absolute symbol.
In this case, it is a value fixed at static linking time.
The condition to check the relocations is relax to allow absolute symbol and
undefined symbol case.
aarch64 binutils cross/native regression test Okay. Linux kernel link Okay.
Okay to commit and backport to 2.30 branch?
Regards,
Renlin
bfd/ChangeLog:
2018-02-03 Renlin Li <renlin.li@arm.com>
PR ld/22764
* elfnn-aarch64.c (elfNN_aarch64_check_relocs): Relax the
R_AARCH64_ABS32 and R_AARCH64_ABS16 for absolute symbol. Apply the
check for writable section as well.
ld/ChangeLog:
2018-02-03 Renlin Li <renlin.li@arm.com>
PR ld/22764
* testsuite/ld-aarch64/emit-relocs-258.s: Define symbol as an address.
* testsuite/ld-aarch64/emit-relocs-259.s: Likewise.
* ld/testsuite/ld-aarch64/aarch64-elf.exp: Run new test.
* testsuite/ld-aarch64/pr22764.s: New.
* testsuite/ld-aarch64/pr22764.d: New.
diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index af448f98aef6fb39081d932a22951b58d8fc6515..2737773d1ccfa33c661f10b99a4937e43b46dfda 100644
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -7189,10 +7189,19 @@ elfNN_aarch64_check_relocs (bfd *abfd, struct bfd_link_info *info,
#if ARCH_SIZE == 64
case BFD_RELOC_AARCH64_32:
#endif
- if (bfd_link_pic (info)
- && (sec->flags & SEC_ALLOC) != 0
- && (sec->flags & SEC_READONLY) != 0)
+ if (bfd_link_pic (info) && (sec->flags & SEC_ALLOC) != 0)
{
+ if (h != NULL
+ /* This is an absolute symbol. It represents a value instead
+ of an address. */
+ && ((h->root.type == bfd_link_hash_defined
+ && bfd_is_abs_section (h->root.u.def.section))
+ /* This is an undefined symbol. */
+ || h->root.type == bfd_link_hash_undefined))
+ break;
+
+ /* For local symbols, defined global symbols in a non-ABS section,
+ it is assumed that the value is an address. */
int howto_index = bfd_r_type - BFD_RELOC_AARCH64_RELOC_START;
_bfd_error_handler
/* xgettext:c-format */
diff --git a/ld/testsuite/ld-aarch64/aarch64-elf.exp b/ld/testsuite/ld-aarch64/aarch64-elf.exp
index 2602a43dd90558e80c0f384abe393b7f41fd850f..c67ffb19ebfa074bdd4d203a5ef11bd0a61cb25e 100644
--- a/ld/testsuite/ld-aarch64/aarch64-elf.exp
+++ b/ld/testsuite/ld-aarch64/aarch64-elf.exp
@@ -285,6 +285,7 @@ run_dump_test "pr17415"
run_dump_test_lp64 "tprel_g2_overflow"
run_dump_test "tprel_add_lo12_overflow"
run_dump_test "protected-data"
+run_dump_test_lp64 "pr22764"
# ifunc tests
run_dump_test "ifunc-1"
diff --git a/ld/testsuite/ld-aarch64/emit-relocs-258.s b/ld/testsuite/ld-aarch64/emit-relocs-258.s
index f724776243199f4a9ff94b634b0998b963f92cf6..87bb657c5d99e739f7845869c4d221e4a485497a 100644
--- a/ld/testsuite/ld-aarch64/emit-relocs-258.s
+++ b/ld/testsuite/ld-aarch64/emit-relocs-258.s
@@ -1,5 +1,6 @@
+.global dummy
.text
-
+dummy:
ldr x0, .L1
.L1:
diff --git a/ld/testsuite/ld-aarch64/emit-relocs-259.s b/ld/testsuite/ld-aarch64/emit-relocs-259.s
index 7e1ba3ceb400b582350aa43d3c7d925ef22efd53..0977c9d869f3bfd224c439310d1f0b34073dbcd0 100644
--- a/ld/testsuite/ld-aarch64/emit-relocs-259.s
+++ b/ld/testsuite/ld-aarch64/emit-relocs-259.s
@@ -1,5 +1,6 @@
+.global dummy
.text
-
+dummy:
ldr x0, .L1
.L1:
diff --git a/ld/testsuite/ld-aarch64/pr22764.d b/ld/testsuite/ld-aarch64/pr22764.d
new file mode 100644
index 0000000000000000000000000000000000000000..46a063dea8565726b6d99c510462b2c1a6d608a3
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/pr22764.d
@@ -0,0 +1,17 @@
+#source: pr22764.s
+#ld: -shared -T relocs.ld -defsym sym_abs1=0x1 -defsym sym_abs2=0x2 -defsym sym_abs3=0x3 -e0 --emit-relocs
+#objdump: -dr
+#...
+
+Disassembly of section \.text:
+
+0000000000010000 \<\.text\>:
+ 10000: d503201f nop
+ ...
+ 10004: R_AARCH64_ABS64 sym_abs1
+ 1000c: 00000002 \.word 0x00000002
+ 1000c: R_AARCH64_ABS32 sym_abs2
+ 10010: 0003 \.short 0x0003
+ 10010: R_AARCH64_ABS16 sym_abs3
+ 10012: 0000 \.short 0x0000
+ 10014: d503201f nop
diff --git a/ld/testsuite/ld-aarch64/pr22764.s b/ld/testsuite/ld-aarch64/pr22764.s
new file mode 100644
index 0000000000000000000000000000000000000000..25e36b4a1290b8e84c8c18c55c69bb9f8e8a686b
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/pr22764.s
@@ -0,0 +1,6 @@
+ .text
+ nop
+ .xword sym_abs1
+ .word sym_abs2
+ .short sym_abs3
+ nop