[07/99] target/arm: Implement v8M VLLDM and VLSTM

Message ID 20180723201748.25573-8-mdroth@linux.vnet.ibm.com
State New
Headers show
Series
  • Untitled series #13438
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Commit Message

Michael Roth July 23, 2018, 8:16 p.m.
From: Peter Maydell <peter.maydell@linaro.org>


For v8M the instructions VLLDM and VLSTM support lazy saving
and restoring of the secure floating-point registers. Even
if the floating point extension is not implemented, these
instructions must act as NOPs in Secure state, so they can
be used as part of the secure-to-nonsecure call sequence.

Fixes: https://bugs.launchpad.net/qemu/+bug/1768295
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Message-id: 20180503105730.5958-1-peter.maydell@linaro.org
(cherry picked from commit b1e5336a9899016c53d59eba53ebf6abcc21995c)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

---
 target/arm/translate.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

-- 
2.17.1

Patch

diff --git a/target/arm/translate.c b/target/arm/translate.c
index db1ce6510a..64b9bf33af 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -10783,8 +10783,23 @@  static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
         /* Coprocessor.  */
         if (arm_dc_feature(s, ARM_FEATURE_M)) {
             /* We don't currently implement M profile FP support,
-             * so this entire space should give a NOCP fault.
+             * so this entire space should give a NOCP fault, with
+             * the exception of the v8M VLLDM and VLSTM insns, which
+             * must be NOPs in Secure state and UNDEF in Nonsecure state.
              */
+            if (arm_dc_feature(s, ARM_FEATURE_V8) &&
+                (insn & 0xffa00f00) == 0xec200a00) {
+                /* 0b1110_1100_0x1x_xxxx_xxxx_1010_xxxx_xxxx
+                 *  - VLLDM, VLSTM
+                 * We choose to UNDEF if the RAZ bits are non-zero.
+                 */
+                if (!s->v8m_secure || (insn & 0x0040f0ff)) {
+                    goto illegal_op;
+                }
+                /* Just NOP since FP support is not implemented */
+                break;
+            }
+            /* All other insns: NOCP */
             gen_exception_insn(s, 4, EXCP_NOCP, syn_uncategorized(),
                                default_exception_el(s));
             break;