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[Qemu-arm] [PATCH 7/7] target/arm: Implement TT instruction
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From: |
Peter Maydell |
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Subject: |
[Qemu-arm] [PATCH 7/7] target/arm: Implement TT instruction |
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Date: |
Fri, 1 Dec 2017 18:44:39 +0000 |
Implement the TT instruction which queries the security
state and access permissions of a memory location.
Signed-off-by: Peter Maydell <address@hidden>
---
target/arm/helper.h | 2 +
target/arm/helper.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++++
target/arm/translate.c | 29 ++++++++++++-
3 files changed, 138 insertions(+), 1 deletion(-)
diff --git a/target/arm/helper.h b/target/arm/helper.h
index 439d228..066729e 100644
--- a/target/arm/helper.h
+++ b/target/arm/helper.h
@@ -66,6 +66,8 @@ DEF_HELPER_2(v7m_mrs, i32, env, i32)
DEF_HELPER_2(v7m_bxns, void, env, i32)
DEF_HELPER_2(v7m_blxns, void, env, i32)
+DEF_HELPER_3(v7m_tt, i32, env, i32, i32)
+
DEF_HELPER_4(access_check_cp_reg, void, env, ptr, i32, i32)
DEF_HELPER_3(set_cp_reg, void, env, ptr, i32)
DEF_HELPER_2(get_cp_reg, i32, env, ptr)
diff --git a/target/arm/helper.c b/target/arm/helper.c
index be8d797..5368ad8 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -5947,6 +5947,28 @@ void HELPER(v7m_blxns)(CPUARMState *env, uint32_t dest)
g_assert_not_reached();
}
+uint32_t HELPER(v7m_tt)(CPUARMState *env, uint32_t addr, uint32_t op)
+{
+ /* The TT instructions can be used by unprivileged code, but in
+ * user-only emulation we don't have the MPU.
+ * Luckily since we know we are NonSecure unprivileged (and that in
+ * turn means that the A flag wasn't specified), all the bits in the
+ * register must be zero:
+ * IREGION: 0 because IRVALID is 0
+ * IRVALID: 0 because NS
+ * S: 0 because NS
+ * NSRW: 0 because NS
+ * NSR: 0 because NS
+ * RW: 0 because unpriv and A flag not set
+ * R: 0 because unpriv and A flag not set
+ * SRVALID: 0 because NS
+ * MRVALID: 0 because unpriv and A flag not set
+ * SREGION: 0 becaus SRVALID is 0
+ * MREGION: 0 because MRVALID is 0
+ */
+ return 0;
+}
+
void switch_mode(CPUARMState *env, int mode)
{
ARMCPU *cpu = arm_env_get_cpu(env);
@@ -10143,6 +10165,92 @@ void HELPER(v7m_msr)(CPUARMState *env, uint32_t
maskreg, uint32_t val)
}
}
+uint32_t HELPER(v7m_tt)(CPUARMState *env, uint32_t addr, uint32_t op)
+{
+ /* Implement the TT instruction. op is bits [7:6] of the insn. */
+ bool forceunpriv = op & 1;
+ bool alt = op & 2;
+ V8M_SAttributes sattrs = {};
+ uint32_t tt_resp;
+ bool r, rw, nsr, nsrw, mrvalid;
+ int prot;
+ MemTxAttrs attrs = {};
+ hwaddr phys_addr;
+ uint32_t fsr;
+ ARMMMUIdx mmu_idx;
+ uint32_t mregion;
+ bool targetpriv;
+ bool targetsec = env->v7m.secure;
+
+ /* Work out what the security state and privilege level we're
+ * interested in is...
+ */
+ if (alt) {
+ targetsec = !targetsec;
+ }
+
+ if (forceunpriv) {
+ targetpriv = false;
+ } else {
+ targetpriv = arm_v7m_is_handler_mode(env) ||
+ !(env->v7m.control[targetsec] & R_V7M_CONTROL_NPRIV_MASK);
+ }
+
+ /* ...and then figure out which MMU index this is */
+ mmu_idx = arm_v7m_mmu_idx_for_secstate_and_priv(env, targetsec,
targetpriv);
+
+ /* We know that the MPU and SAU don't care about the access type
+ * for our purposes beyond that we don't want to claim to be
+ * an insn fetch, so we arbitrarily call this a read.
+ */
+
+ /* MPU region info only available for privileged or if
+ * inspecting the other MPU state.
+ */
+ if (arm_current_el(env) != 0 || alt) {
+ /* We can ignore the return value as prot is always set */
+ pmsav8_mpu_lookup(env, addr, MMU_DATA_LOAD, mmu_idx,
+ &phys_addr, &attrs, &prot, &fsr, &mregion);
+ if (mregion == -1) {
+ mrvalid = false;
+ mregion = 0;
+ } else {
+ mrvalid = true;
+ }
+ r = prot & PAGE_READ;
+ rw = prot & PAGE_WRITE;
+ } else {
+ r = false;
+ rw = false;
+ mrvalid = false;
+ mregion = 0;
+ }
+
+ if (env->v7m.secure) {
+ v8m_security_lookup(env, addr, MMU_DATA_LOAD, mmu_idx, &sattrs);
+ nsr = sattrs.ns && r;
+ nsrw = sattrs.ns && rw;
+ } else {
+ sattrs.ns = true;
+ nsr = false;
+ nsrw = false;
+ }
+
+ tt_resp = (sattrs.iregion << 24) |
+ (sattrs.irvalid << 23) |
+ ((!sattrs.ns) << 22) |
+ (nsrw << 21) |
+ (nsr << 20) |
+ (rw << 19) |
+ (r << 18) |
+ (sattrs.srvalid << 17) |
+ (mrvalid << 16) |
+ (sattrs.sregion << 8) |
+ mregion;
+
+ return tt_resp;
+}
+
#endif
void HELPER(dc_zva)(CPUARMState *env, uint64_t vaddr_in)
diff --git a/target/arm/translate.c b/target/arm/translate.c
index 6df4d90..002055b 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -9810,7 +9810,7 @@ static int disas_thumb2_insn(DisasContext *s, uint32_t
insn)
if (insn & (1 << 22)) {
/* 0b1110_100x_x1xx_xxxx_xxxx_xxxx_xxxx_xxxx
* - load/store doubleword, load/store exclusive, ldacq/strel,
- * table branch.
+ * table branch, TT.
*/
if (insn == 0xe97fe97f && arm_dc_feature(s, ARM_FEATURE_M) &&
arm_dc_feature(s, ARM_FEATURE_V8)) {
@@ -9887,8 +9887,35 @@ static int disas_thumb2_insn(DisasContext *s, uint32_t
insn)
} else if ((insn & (1 << 23)) == 0) {
/* 0b1110_1000_010x_xxxx_xxxx_xxxx_xxxx_xxxx
* - load/store exclusive word
+ * - TT (v8M only)
*/
if (rs == 15) {
+ if (!(insn & (1 << 20)) &&
+ arm_dc_feature(s, ARM_FEATURE_M) &&
+ arm_dc_feature(s, ARM_FEATURE_V8)) {
+ /* 0b1110_1000_0100_xxxx_1111_xxxx_xxxx_xxxx
+ * - TT (v8M only)
+ */
+ bool alt = insn & (1 << 7);
+ TCGv_i32 addr, op, ttresp;
+
+ if ((insn & 0x3f) || rd == 13 || rd == 15 || rn == 15)
{
+ /* we UNDEF for these UNPREDICTABLE cases */
+ goto illegal_op;
+ }
+
+ if (alt && !s->v8m_secure) {
+ goto illegal_op;
+ }
+
+ addr = load_reg(s, rn);
+ op = tcg_const_i32(extract32(insn, 6, 2));
+ ttresp = tcg_temp_new_i32();
+ gen_helper_v7m_tt(ttresp, cpu_env, addr, op);
+ tcg_temp_free_i32(addr);
+ tcg_temp_free_i32(op);
+ store_reg(s, rd, ttresp);
+ }
goto illegal_op;
}
addr = tcg_temp_local_new_i32();
--
2.7.4