s390x: Implement SAM{24,31,64}

The SAM instructions simply change 2 bits in PSW.MASK to advertise
the current memory mode. While we can't fully guarantee that 31 bit
mode (or even remotely 24 bit mode) actually work correctly, we don't
check whether lpswe modifies these bits, so we shouldn't keep the
guest from executing SAM instructions either.

This patch implements all SAM instrutions with their actual PSW changing
semantics, making more recent Linux kernels boot properly which do issue
a SAM31 call during early boot.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Reviewed-by: Richard Henderson <rth@twiddle.net>

diff --git a/target-s390x/insn-data.def b/target-s390x/insn-data.def
index b42ebb6a1a38a39af52a8fab52700a78d4b85643..4d2feb69770c3c4dd96016ecd1a9c6c55f88e0ce 100644 (file)
--- a/target-s390x/insn-data.def
+++ b/target-s390x/insn-data.def
@@ -744,9 +744,9 @@
 /* SERVICE CALL LOGICAL PROCESSOR (PV hypercall) */
     C(0xb220, SERVC,   RRE,   Z,   r1_o, r2_o, 0, 0, servc, 0)
 /* SET ADDRESSING MODE */
-    /* We only do 64-bit, so accept this as a no-op.
-       Let SAM24 and SAM31 signal illegal instruction.  */
-    C(0x010e, SAM64,   E,     Z,   0, 0, 0, 0, 0, 0)
+    D(0x010c, SAM24,   E,     Z,   0, 0, 0, 0, sam, 0, 0)
+    D(0x010d, SAM31,   E,     Z,   0, 0, 0, 0, sam, 0, 1)
+    D(0x010e, SAM64,   E,     Z,   0, 0, 0, 0, sam, 0, 3)
 /* SET ADDRESS SPACE CONTROL FAST */
     C(0xb279, SACF,    S,     Z,   0, a2, 0, 0, sacf, 0)
 /* SET CLOCK */

diff --git a/target-s390x/translate.c b/target-s390x/translate.c
index 0cb036f667c2d1f9b7c52687c0ec531c159277b9..dbf1993d4653f44bdb772ddc73b163bda732a43a 100644 (file)
--- a/target-s390x/translate.c
+++ b/target-s390x/translate.c
@@ -2925,6 +2925,18 @@ static ExitStatus op_sacf(DisasContext *s, DisasOps *o)
     /* Addressing mode has changed, so end the block.  */
     return EXIT_PC_STALE;
 }
+
+static ExitStatus op_sam(DisasContext *s, DisasOps *o)
+{
+    int sam = s->insn->data;
+    TCGv_i64 tsam = tcg_const_i64(sam);
+
+    /* Overwrite PSW_MASK_64 and PSW_MASK_32 */
+    tcg_gen_deposit_i64(psw_mask, psw_mask, tsam, 31, 2);
+
+    tcg_temp_free_i64(tsam);
+    return EXIT_PC_STALE;
+}
 #endif
 
 static ExitStatus op_sar(DisasContext *s, DisasOps *o)