[PULL 29/34] target/arm: Add support for DC CVAP & DC CVADP ins

[Peter Maydell]

From: Beata Michalska <address@hidden>

ARMv8.2 introduced support for Data Cache Clean instructions
to PoP (point-of-persistence) - DC CVAP and PoDP (point-of-deep-persistence)
- DV CVADP. Both specify conceptual points in a memory system where all writes
that are to reach them are considered persistent.
The support provided considers both to be actually the same so there is no
distinction between the two. If none is available (there is no backing store
for given memory) both will result in Data Cache Clean up to the point of
coherency. Otherwise sync for the specified range shall be performed.

Signed-off-by: Beata Michalska <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
Message-id: address@hidden
Signed-off-by: Peter Maydell <address@hidden>
---
 target/arm/cpu.h     | 10 ++++++++
 linux-user/elfload.c |  2 ++
 target/arm/cpu64.c   |  1 +
 target/arm/helper.c  | 56 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 69 insertions(+)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index cebb3511a51..4106e4ae590 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -3618,6 +3618,16 @@ static inline bool isar_feature_aa64_frint(const 
ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, FRINTTS) != 0;
 }
 
+static inline bool isar_feature_aa64_dcpop(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, DPB) != 0;
+}
+
+static inline bool isar_feature_aa64_dcpodp(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, DPB) >= 2;
+}
+
 static inline bool isar_feature_aa64_fp16(const ARMISARegisters *id)
 {
     /* We always set the AdvSIMD and FP fields identically wrt FP16.  */
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index f6693e57609..07b16cc0f47 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -656,6 +656,7 @@ static uint32_t get_elf_hwcap(void)
     GET_FEATURE_ID(aa64_jscvt, ARM_HWCAP_A64_JSCVT);
     GET_FEATURE_ID(aa64_sb, ARM_HWCAP_A64_SB);
     GET_FEATURE_ID(aa64_condm_4, ARM_HWCAP_A64_FLAGM);
+    GET_FEATURE_ID(aa64_dcpop, ARM_HWCAP_A64_DCPOP);
 
     return hwcaps;
 }
@@ -665,6 +666,7 @@ static uint32_t get_elf_hwcap2(void)
     ARMCPU *cpu = ARM_CPU(thread_cpu);
     uint32_t hwcaps = 0;
 
+    GET_FEATURE_ID(aa64_dcpodp, ARM_HWCAP2_A64_DCPODP);
     GET_FEATURE_ID(aa64_condm_5, ARM_HWCAP2_A64_FLAGM2);
     GET_FEATURE_ID(aa64_frint, ARM_HWCAP2_A64_FRINT);
 
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index a39d6fcea34..61fd0ade29a 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -646,6 +646,7 @@ static void aarch64_max_initfn(Object *obj)
         cpu->isar.id_aa64isar0 = t;
 
         t = cpu->isar.id_aa64isar1;
+        t = FIELD_DP64(t, ID_AA64ISAR1, DPB, 2);
         t = FIELD_DP64(t, ID_AA64ISAR1, JSCVT, 1);
         t = FIELD_DP64(t, ID_AA64ISAR1, FCMA, 1);
         t = FIELD_DP64(t, ID_AA64ISAR1, APA, 1); /* PAuth, architected only */
diff --git a/target/arm/helper.c b/target/arm/helper.c
index a4f7b61b4e1..3a93844a3bc 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -5974,6 +5974,52 @@ static const ARMCPRegInfo rndr_reginfo[] = {
       .access = PL0_R, .readfn = rndr_readfn },
     REGINFO_SENTINEL
 };
+
+#ifndef CONFIG_USER_ONLY
+static void dccvap_writefn(CPUARMState *env, const ARMCPRegInfo *opaque,
+                          uint64_t value)
+{
+    ARMCPU *cpu = env_archcpu(env);
+    /* CTR_EL0 System register -> DminLine, bits [19:16] */
+    uint64_t dline_size = 4 << ((cpu->ctr >> 16) & 0xF);
+    uint64_t vaddr_in = (uint64_t) value;
+    uint64_t vaddr = vaddr_in & ~(dline_size - 1);
+    void *haddr;
+    int mem_idx = cpu_mmu_index(env, false);
+
+    /* This won't be crossing page boundaries */
+    haddr = probe_read(env, vaddr, dline_size, mem_idx, GETPC());
+    if (haddr) {
+
+        ram_addr_t offset;
+        MemoryRegion *mr;
+
+        /* RCU lock is already being held */
+        mr = memory_region_from_host(haddr, &offset);
+
+        if (mr) {
+            memory_region_do_writeback(mr, offset, dline_size);
+        }
+    }
+}
+
+static const ARMCPRegInfo dcpop_reg[] = {
+    { .name = "DC_CVAP", .state = ARM_CP_STATE_AA64,
+      .opc0 = 1, .opc1 = 3, .crn = 7, .crm = 12, .opc2 = 1,
+      .access = PL0_W, .type = ARM_CP_NO_RAW | ARM_CP_SUPPRESS_TB_END,
+      .accessfn = aa64_cacheop_access, .writefn = dccvap_writefn },
+    REGINFO_SENTINEL
+};
+
+static const ARMCPRegInfo dcpodp_reg[] = {
+    { .name = "DC_CVADP", .state = ARM_CP_STATE_AA64,
+      .opc0 = 1, .opc1 = 3, .crn = 7, .crm = 13, .opc2 = 1,
+      .access = PL0_W, .type = ARM_CP_NO_RAW | ARM_CP_SUPPRESS_TB_END,
+      .accessfn = aa64_cacheop_access, .writefn = dccvap_writefn },
+    REGINFO_SENTINEL
+};
+#endif /*CONFIG_USER_ONLY*/
+
 #endif
 
 static CPAccessResult access_predinv(CPUARMState *env, const ARMCPRegInfo *ri,
@@ -7046,6 +7092,16 @@ void register_cp_regs_for_features(ARMCPU *cpu)
     if (cpu_isar_feature(aa64_rndr, cpu)) {
         define_arm_cp_regs(cpu, rndr_reginfo);
     }
+#ifndef CONFIG_USER_ONLY
+    /* Data Cache clean instructions up to PoP */
+    if (cpu_isar_feature(aa64_dcpop, cpu)) {
+        define_one_arm_cp_reg(cpu, dcpop_reg);
+
+        if (cpu_isar_feature(aa64_dcpodp, cpu)) {
+            define_one_arm_cp_reg(cpu, dcpodp_reg);
+        }
+    }
+#endif /*CONFIG_USER_ONLY*/
 #endif
 
     /*
-- 
2.20.1