From: Sergey Fedorov <serge.f...@gmail.com>
Ensure direct jump patching in AArch64 is atomic by using
atomic_read()/atomic_set() for code patching.
Signed-off-by: Sergey Fedorov <serge.f...@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedo...@linaro.org>
---
Changes in v2:
* Use tcg_debug_assert() instead of assert()
tcg/aarch64/tcg-target.inc.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/tcg/aarch64/tcg-target.inc.c b/tcg/aarch64/tcg-target.inc.c
index 0ed10a974121..29839765b828 100644
--- a/tcg/aarch64/tcg-target.inc.c
+++ b/tcg/aarch64/tcg-target.inc.c
@@ -73,6 +73,18 @@ static inline void reloc_pc26(tcg_insn_unit *code_ptr,
tcg_insn_unit *target)
*code_ptr = deposit32(*code_ptr, 0, 26, offset);
}
+static inline void reloc_pc26_atomic(tcg_insn_unit *code_ptr,
+ tcg_insn_unit *target)
+{
+ ptrdiff_t offset = target - code_ptr;
+ tcg_insn_unit insn;
+ tcg_debug_assert(offset == sextract64(offset, 0, 26));
+ /* read instruction, mask away previous PC_REL26 parameter contents,
+ set the proper offset, then write back the instruction. */
+ insn = atomic_read(code_ptr);
+ atomic_set(code_ptr, deposit32(insn, 0, 26, offset));
+}
+
static inline void reloc_pc19(tcg_insn_unit *code_ptr, tcg_insn_unit *target)
{
ptrdiff_t offset = target - code_ptr;
@@ -835,7 +847,7 @@ void aarch64_tb_set_jmp_target(uintptr_t jmp_addr,
uintptr_t addr)
tcg_insn_unit *code_ptr = (tcg_insn_unit *)jmp_addr;
tcg_insn_unit *target = (tcg_insn_unit *)addr;
- reloc_pc26(code_ptr, target);
+ reloc_pc26_atomic(code_ptr, target);
flush_icache_range(jmp_addr, jmp_addr + 4);
}
--
2.8.1
