8300247: Harden C1 xchg on AArch64 and PPC

Co-authored-by: Martin Doerr <mdoerr@openjdk.org> Reviewed-by: aph, rcastanedalo
openjdk · Jan 26, 2023 · 28545dc · 28545dc · openjdk-notifier · Jan 26, 2023
1 parent 3f63381
commit 28545dc
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Showing 3 changed files with 11 additions and 4 deletions.
diff --git a/src/hotspot/cpu/aarch64/c1_LIRAssembler_aarch64.cpp b/src/hotspot/cpu/aarch64/c1_LIRAssembler_aarch64.cpp
@@ -3185,7 +3185,8 @@ void LIR_Assembler::atomic_op(LIR_Code code, LIR_Opr src, LIR_Opr data, LIR_Opr
         __ encode_heap_oop(rscratch2, obj);
         obj = rscratch2;
       }
-      assert_different_registers(obj, addr.base(), tmp, rscratch1, dst);
+      assert_different_registers(obj, addr.base(), tmp, rscratch1);
+      assert_different_registers(dst, addr.base(), tmp, rscratch1);
       __ lea(tmp, addr);
       (_masm->*xchg)(dst, obj, tmp);
       if (is_oop && UseCompressedOops) {

diff --git a/src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cpp b/src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cpp
@@ -3019,8 +3019,13 @@ void LIR_Assembler::atomic_op(LIR_Code code, LIR_Opr src, LIR_Opr data, LIR_Opr
       __ lwarx(Rold, Rptr, MacroAssembler::cmpxchgx_hint_atomic_update());
       __ stwcx_(Rco, Rptr);
     } else {
-      const Register Robj = data->as_register();
-      assert_different_registers(Rptr, Rold, Robj);
+      Register Robj = data->as_register();
+      assert_different_registers(Rptr, Rold, Rtmp);
+      assert_different_registers(Rptr, Robj, Rtmp);
+      if (Robj == Rold) { // May happen with ZGC.
+        __ mr(Rtmp, Robj);
+        Robj = Rtmp;
+      }
       __ ldarx(Rold, Rptr, MacroAssembler::cmpxchgx_hint_atomic_update());
       __ stdcx_(Robj, Rptr);
     }

diff --git a/src/hotspot/cpu/riscv/c1_LIRAssembler_riscv.cpp b/src/hotspot/cpu/riscv/c1_LIRAssembler_riscv.cpp
@@ -1967,7 +1967,8 @@ void LIR_Assembler::atomic_op(LIR_Code code, LIR_Opr src, LIR_Opr data, LIR_Opr
           __ encode_heap_oop(t0, obj);
           obj = t0;
         }
-        assert_different_registers(obj, addr.base(), tmp, dst);
+        assert_different_registers(obj, addr.base(), tmp);
+        assert_different_registers(dst, addr.base(), tmp);
         __ la(tmp, addr);
         (_masm->*xchg)(dst, obj, tmp);
         if (is_oop && UseCompressedOops) {