[Valgrind-developers] [PATCH] amd64: Kludgey 64-bit version of iret implementation from i386.

[Daniel L. <dle...@gm...>]

https://bugs.kde.org/show_bug.cgi?id=400538

See also: https://bugs.kde.org/show_bug.cgi?id=253657
Signed-off-by: Daniel Lehman <dle...@gm...>
---
 VEX/priv/guest_amd64_toIR.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/VEX/priv/guest_amd64_toIR.c b/VEX/priv/guest_amd64_toIR.c
index 7a20d4523..68fc88924 100644
--- a/VEX/priv/guest_amd64_toIR.c
+++ b/VEX/priv/guest_amd64_toIR.c
@@ -21052,6 +21052,41 @@ Long dis_ESC_NONE (
       }
       goto decode_failure;
 
+   case 0xCF: /* IRET */
+      /* Note, this is an extremely kludgey and limited implementation of iret
+         based on the extremely kludgey and limited implementation of iret for x86
+            popq %RIP; popl %CS; popq %RFLAGS; popq %RSP; popl %SS
+         %CS and %SS are ignored */
+      if (sz != 8) goto decode_failure;
+
+      t1 = newTemp(Ity_I64); /* RSP */
+      t2 = newTemp(Ity_I64); /* new RIP */
+      /* t3 = newTemp(Ity_I32);  new CS */
+      t4 = newTemp(Ity_I64); /* new RFLAGS */
+      t5 = newTemp(Ity_I64); /* new RSP */
+      /* t6 = newTemp(Ity_I32);  new SS */
+
+      assign(t1, getIReg64(R_RSP));
+      assign(t2, loadLE(Ity_I64, binop(Iop_Add64,mkexpr(t1),mkU64(0))));
+      /* assign(t3, loadLE(Ity_I32, binop(Iop_Add64,mkexpr(t1),mkU64(8)))); */
+      assign(t4, loadLE(Ity_I64, binop(Iop_Add64,mkexpr(t1),mkU64(16))));
+      assign(t5, loadLE(Ity_I64, binop(Iop_Add64,mkexpr(t1),mkU64(24))));
+      /* assign(t6, loadLE(Ity_I32, binop(Iop_Add64,mkexpr(t1),mkU64(32)))); */
+
+      /* set %RFLAGS */
+      stmt( IRStmt_Put( OFFB_CC_OP,   mkU64(AMD64G_CC_OP_COPY) ));
+      stmt( IRStmt_Put( OFFB_CC_DEP1, mkexpr(t4) ));
+      stmt( IRStmt_Put( OFFB_CC_DEP2, mkU64(0) ));
+      stmt( IRStmt_Put( OFFB_CC_NDEP, mkU64(0) ));
+
+      /* set new stack */
+      putIReg64(R_RSP, mkexpr(t5));
+
+      /* goto new RIP value */
+      jmp_treg(dres, Ijk_Ret, t2);
+      DIP("iret (very kludgey)\n");
+      return delta;
+
    case 0xD0: { /* Grp2 1,Eb */
       Bool decode_OK = True;
       if (haveF2orF3(pfx)) goto decode_failure;
-- 
2.17.1