As described in the issue #1122, both tst-promise.so and tst-async.so
fail with null pointer execution page fault crash. Both test apps
access '__once_callable' and '__once_call' TLS variables that are part
of C++ library and given it is linked as part of the kernel we must
make sure TLS_DESC relocation logic handles this case correctly.
So this patch changes the logic to handle relocations of ARCH_TLSDESC,
so that the symbols found in the kernel are accessed using correct kernel
block offsets just like PIEs are.
On top of above, this patch also fixes the relocation logic of
R_AARCH64_TLS_TPREL64
that happens in get_init() during early boot to make sure that the TLS
offset for relevant variables (__once_call in this case) is adjusted for
the size of thread_control_block structure. This is essential to make
sure that the __once_proxy function (see assembly below) calling __once_call
variable
using an offset stored in GOT works correctly.
```
__once_proxy:
0x000000004041df50 <+0>: stp x29, x30, [sp, #-16]!
0x000000004041df54 <+4>: mrs x1, tpidr_el0
0x000000004041df58 <+8>: mov x29, sp
0x000000004041df5c <+12>: adrp x0, 0x40098000
0x000000004041df60 <+16>: ldr x0, [x0, #2608] //Accesses
offset of __once_call in GOT which is set by arch_init_reloc_dyn()
0x000000004041df64 <+20>: nop
0x000000004041df68 <+24>: nop
0x000000004041df6c <+28>: ldp x29, x30, [sp], #16
0x000000004041df70 <+32>: ldr x0, [x1, x0]
0x000000004041df74 <+36>: mov x16, x0
0x000000004041df78 <+40>: br x16
```
Fixes #1122
Signed-off-by: Waldemar Kozaczuk <jwkozac...@gmail.com>
---
arch/aarch64/arch-elf.cc | 4 ++--
scripts/test.py | 2 --
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/aarch64/arch-elf.cc b/arch/aarch64/arch-elf.cc
index 39a9b6aa..091517f1 100644
--- a/arch/aarch64/arch-elf.cc
+++ b/arch/aarch64/arch-elf.cc
@@ -29,7 +29,7 @@ bool arch_init_reloc_dyn(struct init_table *t, u32 type, u32
sym,
*static_cast<u64*>(addr) = t->dyn_tabs.lookup(sym)->st_value + addend;
break;
case R_AARCH64_TLS_TPREL64:
- *static_cast<u64*>(addr) = t->dyn_tabs.lookup(sym)->st_value + addend;
+ *static_cast<u64*>(addr) = t->dyn_tabs.lookup(sym)->st_value + addend
+ sizeof(thread_control_block);
break;
default:
return false;
@@ -116,7 +116,7 @@ void object::arch_relocate_tls_desc(u32 sym, void *addr,
Elf64_Sxword addend)
ulong tls_offset;
if (sym) {
auto sm = symbol(sym);
- if (sm.obj->is_executable()) {
+ if (sm.obj->is_executable() || sm.obj->is_core()) {
// If this is an executable (pie or position-dependant one)
// then the variable is located in the reserved slot of the TLS
// right where the kernel TLS lives
diff --git a/scripts/test.py b/scripts/test.py
index 24ae964b..f3856e4e 100755
--- a/scripts/test.py
+++ b/scripts/test.py
@@ -41,8 +41,6 @@ aarch64_disabled_list= [
"java_no_wrapper",
"java-perms",
#Following tests crash with message 'Assertion failed: type ==
ARCH_JUMP_SLOT (core/elf.cc: relocate_pltgot: 789)'
- "tst-async.so",
- "tst-promise.so",
"tst-sigaltstack.so",
#Remaining tests below fail for various different reasons
#Please see comments on the right side for more details
--
2.29.2
--
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