target/arm: Add PAuth helpers

The cryptographic internals are stubbed out for now,
but the enable and trap bits are checked.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20190108223129.5570-6-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 186 insertions, 0 deletions

diff --git a/target/arm/pauth_helper.c b/target/arm/pauth_helper.c
new file mode 100644
index 0000000000..902f68a24c
--- /dev/null
+++ b/target/arm/pauth_helper.c
@@ -0,0 +1,186 @@
+/*
+ * ARM v8.3-PAuth Operations
+ *
+ * Copyright (c) 2019 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 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 "cpu.h"
+#include "internals.h"
+#include "exec/exec-all.h"
+#include "exec/cpu_ldst.h"
+#include "exec/helper-proto.h"
+#include "tcg/tcg-gvec-desc.h"
+
+
+static uint64_t pauth_computepac(uint64_t data, uint64_t modifier,
+                                 ARMPACKey key)
+{
+    g_assert_not_reached(); /* FIXME */
+}
+
+static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,
+                             ARMPACKey *key, bool data)
+{
+    g_assert_not_reached(); /* FIXME */
+}
+
+static uint64_t pauth_auth(CPUARMState *env, uint64_t ptr, uint64_t modifier,
+                           ARMPACKey *key, bool data, int keynumber)
+{
+    g_assert_not_reached(); /* FIXME */
+}
+
+static uint64_t pauth_strip(CPUARMState *env, uint64_t ptr, bool data)
+{
+    g_assert_not_reached(); /* FIXME */
+}
+
+static void QEMU_NORETURN pauth_trap(CPUARMState *env, int target_el,
+                                     uintptr_t ra)
+{
+    raise_exception_ra(env, EXCP_UDEF, syn_pactrap(), target_el, ra);
+}
+
+static void pauth_check_trap(CPUARMState *env, int el, uintptr_t ra)
+{
+    if (el < 2 && arm_feature(env, ARM_FEATURE_EL2)) {
+        uint64_t hcr = arm_hcr_el2_eff(env);
+        bool trap = !(hcr & HCR_API);
+        /* FIXME: ARMv8.1-VHE: trap only applies to EL1&0 regime.  */
+        /* FIXME: ARMv8.3-NV: HCR_NV trap takes precedence for ERETA[AB].  */
+        if (trap) {
+            pauth_trap(env, 2, ra);
+        }
+    }
+    if (el < 3 && arm_feature(env, ARM_FEATURE_EL3)) {
+        if (!(env->cp15.scr_el3 & SCR_API)) {
+            pauth_trap(env, 3, ra);
+        }
+    }
+}
+
+static bool pauth_key_enabled(CPUARMState *env, int el, uint32_t bit)
+{
+    uint32_t sctlr;
+    if (el == 0) {
+        /* FIXME: ARMv8.1-VHE S2 translation regime.  */
+        sctlr = env->cp15.sctlr_el[1];
+    } else {
+        sctlr = env->cp15.sctlr_el[el];
+    }
+    return (sctlr & bit) != 0;
+}
+
+uint64_t HELPER(pacia)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    int el = arm_current_el(env);
+    if (!pauth_key_enabled(env, el, SCTLR_EnIA)) {
+        return x;
+    }
+    pauth_check_trap(env, el, GETPC());
+    return pauth_addpac(env, x, y, &env->apia_key, false);
+}
+
+uint64_t HELPER(pacib)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    int el = arm_current_el(env);
+    if (!pauth_key_enabled(env, el, SCTLR_EnIB)) {
+        return x;
+    }
+    pauth_check_trap(env, el, GETPC());
+    return pauth_addpac(env, x, y, &env->apib_key, false);
+}
+
+uint64_t HELPER(pacda)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    int el = arm_current_el(env);
+    if (!pauth_key_enabled(env, el, SCTLR_EnDA)) {
+        return x;
+    }
+    pauth_check_trap(env, el, GETPC());
+    return pauth_addpac(env, x, y, &env->apda_key, true);
+}
+
+uint64_t HELPER(pacdb)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    int el = arm_current_el(env);
+    if (!pauth_key_enabled(env, el, SCTLR_EnDB)) {
+        return x;
+    }
+    pauth_check_trap(env, el, GETPC());
+    return pauth_addpac(env, x, y, &env->apdb_key, true);
+}
+
+uint64_t HELPER(pacga)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    uint64_t pac;
+
+    pauth_check_trap(env, arm_current_el(env), GETPC());
+    pac = pauth_computepac(x, y, env->apga_key);
+
+    return pac & 0xffffffff00000000ull;
+}
+
+uint64_t HELPER(autia)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    int el = arm_current_el(env);
+    if (!pauth_key_enabled(env, el, SCTLR_EnIA)) {
+        return x;
+    }
+    pauth_check_trap(env, el, GETPC());
+    return pauth_auth(env, x, y, &env->apia_key, false, 0);
+}
+
+uint64_t HELPER(autib)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    int el = arm_current_el(env);
+    if (!pauth_key_enabled(env, el, SCTLR_EnIB)) {
+        return x;
+    }
+    pauth_check_trap(env, el, GETPC());
+    return pauth_auth(env, x, y, &env->apib_key, false, 1);
+}
+
+uint64_t HELPER(autda)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    int el = arm_current_el(env);
+    if (!pauth_key_enabled(env, el, SCTLR_EnDA)) {
+        return x;
+    }
+    pauth_check_trap(env, el, GETPC());
+    return pauth_auth(env, x, y, &env->apda_key, true, 0);
+}
+
+uint64_t HELPER(autdb)(CPUARMState *env, uint64_t x, uint64_t y)
+{
+    int el = arm_current_el(env);
+    if (!pauth_key_enabled(env, el, SCTLR_EnDB)) {
+        return x;
+    }
+    pauth_check_trap(env, el, GETPC());
+    return pauth_auth(env, x, y, &env->apdb_key, true, 1);
+}
+
+uint64_t HELPER(xpaci)(CPUARMState *env, uint64_t a)
+{
+    return pauth_strip(env, a, false);
+}
+
+uint64_t HELPER(xpacd)(CPUARMState *env, uint64_t a)
+{
+    return pauth_strip(env, a, true);
+}