From eb23038d19295a783144ec266736d486e5671d96 Mon Sep 17 00:00:00 2001
From: Tamar Christina <tamar.christina@arm.com>
Date: Thu, 11 Apr 2019 11:27:28 +0100
Subject: [PATCH] AArch64: When DF_BIND_NOW don't use TLSDESC GOT value.
When using DF_BIND_NOW on AArch64 we don't reserve the GOT slot for a TLSDESC,
but we still emitted DT_TLSDESC_GOT and DT_TLSDESC_PLT. This caused random
memory corruption as the "special" value of (bfd_vma)-1 would be set for
dt_tlsdesc_got.
Since we don't have a value of dt_tlsdesc_got I also don't emit DT_TLSDESC_PLT
now becuase it would point to an incomplete PLT. To be able to write the PLT
entry DT_TLSDESC_GOT is needed and since we don't have one we can't write the
PLT entry either.
It is my understanding that GLIBC doesn't need these two entries when not lazy
loading. Conversely AArch32 does not reserve neither the GOT not the PLT slot
when doing DF_BIND_NOW.
AArch32 does not need these checks because these values are initialized to 0
and so the if (...) checks don't pass, but on AArch64 these are initialized
to (bfd_vma)-1 and thus we need some extra checks.
bfd/ChangeLog:
PR ld/24302
* elfnn-aarch64.c (elfNN_aarch64_size_dynamic_sections): Don't emit
DT_TLSDESC_GOT and DT_TLSDESC_PLT when DF_BIND_NOW.
(elfNN_aarch64_finish_dynamic_sections): Don't write PLT if DF_BIND_NOW.
ld/ChangeLog:
PR ld/24302
* testsuite/ld-aarch64/aarch64-elf.exp: Add new test.
* testsuite/ld-aarch64/tls-relax-gdesc-le-now.d: New test.
(cherry picked from commit ce12121b63145322b4961bbb2b94b939cb916ba7)
---
bfd/ChangeLog | 10 ++++++++++
bfd/elfnn-aarch64.c | 12 ++++++++----
ld/ChangeLog | 10 ++++++++++
ld/testsuite/ld-aarch64/aarch64-elf.exp | 1 +
.../ld-aarch64/tls-relax-gdesc-le-now.d | 19 +++++++++++++++++++
5 files changed, 48 insertions(+), 4 deletions(-)
create mode 100644 ld/testsuite/ld-aarch64/tls-relax-gdesc-le-now.d
#diff --git a/bfd/ChangeLog b/bfd/ChangeLog
#index 45255c0168..e6979c1a44 100644
#--- a/bfd/ChangeLog
#+++ b/bfd/ChangeLog
#@@ -1,3 +1,13 @@
#+2019-04-18 Tamar Christina <tamar.christina@arm.com>
#+
#+ Backport from mainline.
#+ 2019-04-11 Tamar Christina <tamar.christina@arm.com>
#+
#+ PR ld/24302
#+ * elfnn-aarch64.c (elfNN_aarch64_size_dynamic_sections): Don't emit
#+ DT_TLSDESC_GOT and DT_TLSDESC_PLT when DF_BIND_NOW.
#+ (elfNN_aarch64_finish_dynamic_sections): Don't write PLT if DF_BIND_NOW.
#+
# 2019-04-17 H.J. Lu <hongjiu.lu@intel.com>
#
# PR ld/24458
diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index faa27611d4..9652cf3878 100644
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -8848,13 +8848,14 @@ elfNN_aarch64_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
if (htab->root.splt->size == 0)
htab->root.splt->size += PLT_ENTRY_SIZE;
- htab->tlsdesc_plt = htab->root.splt->size;
- htab->root.splt->size += PLT_TLSDESC_ENTRY_SIZE;
/* If we're not using lazy TLS relocations, don't generate the
- GOT entry required. */
+ GOT and PLT entry required. */
if (!(info->flags & DF_BIND_NOW))
{
+ htab->tlsdesc_plt = htab->root.splt->size;
+ htab->root.splt->size += PLT_TLSDESC_ENTRY_SIZE;
+
htab->dt_tlsdesc_got = htab->root.sgot->size;
htab->root.sgot->size += GOT_ENTRY_SIZE;
}
@@ -8958,6 +8959,7 @@ elfNN_aarch64_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
return FALSE;
if (htab->tlsdesc_plt
+ && !(info->flags & DF_BIND_NOW)
&& (!add_dynamic_entry (DT_TLSDESC_PLT, 0)
|| !add_dynamic_entry (DT_TLSDESC_GOT, 0)))
return FALSE;
@@ -9445,6 +9447,7 @@ elfNN_aarch64_finish_dynamic_sections (bfd *output_bfd,
case DT_TLSDESC_GOT:
s = htab->root.sgot;
+ BFD_ASSERT (htab->dt_tlsdesc_got != (bfd_vma)-1);
dyn.d_un.d_ptr = s->output_section->vma + s->output_offset
+ htab->dt_tlsdesc_got;
break;
@@ -9464,8 +9467,9 @@ elfNN_aarch64_finish_dynamic_sections (bfd *output_bfd,
this_hdr.sh_entsize = htab->plt_entry_size;
- if (htab->tlsdesc_plt)
+ if (htab->tlsdesc_plt && !(info->flags & DF_BIND_NOW))
{
+ BFD_ASSERT (htab->dt_tlsdesc_got != (bfd_vma)-1);
bfd_put_NN (output_bfd, (bfd_vma) 0,
htab->root.sgot->contents + htab->dt_tlsdesc_got);
#diff --git a/ld/ChangeLog b/ld/ChangeLog
#index f4b12a2f0a..6add6bb031 100644
#--- a/ld/ChangeLog
#+++ b/ld/ChangeLog
#@@ -1,3 +1,13 @@
#+2019-04-18 Tamar Christina <tamar.christina@arm.com>
#+
#+ Backport from mainline.
#+ 2019-04-11 Tamar Christina <tamar.christina@arm.com>
#+
#+ PR ld/24302
#+ * testsuite/ld-aarch64/aarch64-elf.exp: Add new test.
#+ * testsuite/ld-aarch64/tls-relax-gdesc-le-now.d: New test.
#+
#+
# 2019-04-17 H.J. Lu <hongjiu.lu@intel.com>
#
# PR ld/24458
diff --git a/ld/testsuite/ld-aarch64/aarch64-elf.exp b/ld/testsuite/ld-aarch64/aarch64-elf.exp
index 2b9fad5604..ad0f8d9081 100644
--- a/ld/testsuite/ld-aarch64/aarch64-elf.exp
+++ b/ld/testsuite/ld-aarch64/aarch64-elf.exp
@@ -256,6 +256,7 @@ run_dump_test "tls-relax-all-ilp32"
run_dump_test "tls-relax-gd-le"
run_dump_test "tls-relax-gd-le-ilp32"
run_dump_test "tls-relax-gdesc-le"
+run_dump_test "tls-relax-gdesc-le-now"
run_dump_test "tls-relax-gdesc-le-ilp32"
run_dump_test "tls-relax-gd-ie"
run_dump_test "tls-relax-gd-ie-ilp32"
diff --git a/ld/testsuite/ld-aarch64/tls-relax-gdesc-le-now.d b/ld/testsuite/ld-aarch64/tls-relax-gdesc-le-now.d
new file mode 100644
index 0000000000..f1565e9c11
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/tls-relax-gdesc-le-now.d
@@ -0,0 +1,19 @@
+#source: tls-relax-gdesc-le.s
+#ld: -shared -z now
+#readelf: -dr
+#...
+ 0x.+ \(STRTAB\) \s+0x.+
+ 0x.+ \(SYMTAB\) \s+0x.+
+ 0x.+ \(STRSZ\) \s+.+ \(bytes\)
+ 0x.+ \(SYMENT\) \s+.+ \(bytes\)
+ 0x.+ \(PLTGOT\) \s+0x.+
+ 0x.+ \(PLTRELSZ\) \s+.+ \(bytes\)
+ 0x.+ \(PLTREL\) \s+RELA
+ 0x.+ \(JMPREL\) \s+0x.+
+ 0x.+ \(BIND_NOW\) \s+
+ 0x.+ \(FLAGS_1\) \s+ Flags: NOW
+ 0x.+ \(NULL\) \s+ 0x0
+
+Relocation section '\.rela\.plt' at offset .+ contains 1 entry:
+ Offset Info Type Sym\. Value Sym\. Name \+ Addend
+.+ .+ R_AARCH64_TLSDESC 0
--
2.21.0
