1 files changed, 221 insertions, 0 deletions
diff --git a/target/arm/translate-m-nocp.c b/target/arm/translate-m-nocp.c
new file mode 100644
index 0000000000..d47eb8e153
--- /dev/null
+++ b/target/arm/translate-m-nocp.c
@@ -0,0 +1,221 @@
+/*
+ *  ARM translation: M-profile NOCP special-case instructions
+ *
+ *  Copyright (c) 2020 Linaro, Ltd.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "tcg/tcg-op.h"
+#include "translate.h"
+#include "translate-a32.h"
+
+#include "decode-m-nocp.c.inc"
+
+/*
+ * Decode VLLDM and VLSTM are nonstandard because:
+ *  * if there is no FPU then these insns must NOP in
+ *    Secure state and UNDEF in Nonsecure state
+ *  * if there is an FPU then these insns do not have
+ *    the usual behaviour that vfp_access_check() provides of
+ *    being controlled by CPACR/NSACR enable bits or the
+ *    lazy-stacking logic.
+ */
+static bool trans_VLLDM_VLSTM(DisasContext *s, arg_VLLDM_VLSTM *a)
+{
+    TCGv_i32 fptr;
+
+    if (!arm_dc_feature(s, ARM_FEATURE_M) ||
+        !arm_dc_feature(s, ARM_FEATURE_V8)) {
+        return false;
+    }
+
+    if (a->op) {
+        /*
+         * T2 encoding ({D0-D31} reglist): v8.1M and up. We choose not
+         * to take the IMPDEF option to make memory accesses to the stack
+         * slots that correspond to the D16-D31 registers (discarding
+         * read data and writing UNKNOWN values), so for us the T2
+         * encoding behaves identically to the T1 encoding.
+         */
+        if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
+            return false;
+        }
+    } else {
+        /*
+         * T1 encoding ({D0-D15} reglist); undef if we have 32 Dregs.
+         * This is currently architecturally impossible, but we add the
+         * check to stay in line with the pseudocode. Note that we must
+         * emit code for the UNDEF so it takes precedence over the NOCP.
+         */
+        if (dc_isar_feature(aa32_simd_r32, s)) {
+            unallocated_encoding(s);
+            return true;
+        }
+    }
+
+    /*
+     * If not secure, UNDEF. We must emit code for this
+     * rather than returning false so that this takes
+     * precedence over the m-nocp.decode NOCP fallback.
+     */
+    if (!s->v8m_secure) {
+        unallocated_encoding(s);
+        return true;
+    }
+    /* If no fpu, NOP. */
+    if (!dc_isar_feature(aa32_vfp, s)) {
+        return true;
+    }
+
+    fptr = load_reg(s, a->rn);
+    if (a->l) {
+        gen_helper_v7m_vlldm(cpu_env, fptr);
+    } else {
+        gen_helper_v7m_vlstm(cpu_env, fptr);
+    }
+    tcg_temp_free_i32(fptr);
+
+    /* End the TB, because we have updated FP control bits */
+    s->base.is_jmp = DISAS_UPDATE_EXIT;
+    return true;
+}
+
+static bool trans_VSCCLRM(DisasContext *s, arg_VSCCLRM *a)
+{
+    int btmreg, topreg;
+    TCGv_i64 zero;
+    TCGv_i32 aspen, sfpa;
+
+    if (!dc_isar_feature(aa32_m_sec_state, s)) {
+        /* Before v8.1M, fall through in decode to NOCP check */
+        return false;
+    }
+
+    /* Explicitly UNDEF because this takes precedence over NOCP */
+    if (!arm_dc_feature(s, ARM_FEATURE_M_MAIN) || !s->v8m_secure) {
+        unallocated_encoding(s);
+        return true;
+    }
+
+    if (!dc_isar_feature(aa32_vfp_simd, s)) {
+        /* NOP if we have neither FP nor MVE */
+        return true;
+    }
+
+    /*
+     * If FPCCR.ASPEN != 0 && CONTROL_S.SFPA == 0 then there is no
+     * active floating point context so we must NOP (without doing
+     * any lazy state preservation or the NOCP check).
+     */
+    aspen = load_cpu_field(v7m.fpccr[M_REG_S]);
+    sfpa = load_cpu_field(v7m.control[M_REG_S]);
+    tcg_gen_andi_i32(aspen, aspen, R_V7M_FPCCR_ASPEN_MASK);
+    tcg_gen_xori_i32(aspen, aspen, R_V7M_FPCCR_ASPEN_MASK);
+    tcg_gen_andi_i32(sfpa, sfpa, R_V7M_CONTROL_SFPA_MASK);
+    tcg_gen_or_i32(sfpa, sfpa, aspen);
+    arm_gen_condlabel(s);
+    tcg_gen_brcondi_i32(TCG_COND_EQ, sfpa, 0, s->condlabel);
+
+    if (s->fp_excp_el != 0) {
+        gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
+                           syn_uncategorized(), s->fp_excp_el);
+        return true;
+    }
+
+    topreg = a->vd + a->imm - 1;
+    btmreg = a->vd;
+
+    /* Convert to Sreg numbers if the insn specified in Dregs */
+    if (a->size == 3) {
+        topreg = topreg * 2 + 1;
+        btmreg *= 2;
+    }
+
+    if (topreg > 63 || (topreg > 31 && !(topreg & 1))) {
+        /* UNPREDICTABLE: we choose to undef */
+        unallocated_encoding(s);
+        return true;
+    }
+
+    /* Silently ignore requests to clear D16-D31 if they don't exist */
+    if (topreg > 31 && !dc_isar_feature(aa32_simd_r32, s)) {
+        topreg = 31;
+    }
+
+    if (!vfp_access_check(s)) {
+        return true;
+    }
+
+    /* Zero the Sregs from btmreg to topreg inclusive. */
+    zero = tcg_const_i64(0);
+    if (btmreg & 1) {
+        write_neon_element64(zero, btmreg >> 1, 1, MO_32);
+        btmreg++;
+    }
+    for (; btmreg + 1 <= topreg; btmreg += 2) {
+        write_neon_element64(zero, btmreg >> 1, 0, MO_64);
+    }
+    if (btmreg == topreg) {
+        write_neon_element64(zero, btmreg >> 1, 0, MO_32);
+        btmreg++;
+    }
+    assert(btmreg == topreg + 1);
+    /* TODO: when MVE is implemented, zero VPR here */
+    return true;
+}
+
+static bool trans_NOCP(DisasContext *s, arg_nocp *a)
+{
+    /*
+     * Handle M-profile early check for disabled coprocessor:
+     * all we need to do here is emit the NOCP exception if
+     * the coprocessor is disabled. Otherwise we return false
+     * and the real VFP/etc decode will handle the insn.
+     */
+    assert(arm_dc_feature(s, ARM_FEATURE_M));
+
+    if (a->cp == 11) {
+        a->cp = 10;
+    }
+    if (arm_dc_feature(s, ARM_FEATURE_V8_1M) &&
+        (a->cp == 8 || a->cp == 9 || a->cp == 14 || a->cp == 15)) {
+        /* in v8.1M cp 8, 9, 14, 15 also are governed by the cp10 enable */
+        a->cp = 10;
+    }
+
+    if (a->cp != 10) {
+        gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
+                           syn_uncategorized(), default_exception_el(s));
+        return true;
+    }
+
+    if (s->fp_excp_el != 0) {
+        gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
+                           syn_uncategorized(), s->fp_excp_el);
+        return true;
+    }
+
+    return false;
+}
+
+static bool trans_NOCP_8_1(DisasContext *s, arg_nocp *a)
+{
+    /* This range needs a coprocessor check for v8.1M and later only */
+    if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
+        return false;
+    }
+    return trans_NOCP(s, a);
+}