[Qemu-devel] [PULL 38/45] target-arm: Add support for AArch32 ARMv8 CRC32 instructions

[Peter Maydell]

From: Will Newton <address@hidden>

Add support for AArch32 CRC32 and CRC32C instructions added in ARMv8
and add a CPU feature flag to enable these instructions.

The CRC32-C implementation used is the built-in qemu implementation
and The CRC-32 implementation is from zlib. This requires adding zlib
to LIBS to ensure it is linked for the linux-user binary.

Signed-off-by: Will Newton <address@hidden>
Reviewed-by: Peter Maydell <address@hidden>
Message-id: address@hidden
Signed-off-by: Peter Maydell <address@hidden>
---
 configure              |  2 +-
 target-arm/cpu.c       |  1 +
 target-arm/cpu.h       |  1 +
 target-arm/helper.c    | 39 +++++++++++++++++++++++++++++++++++
 target-arm/helper.h    |  3 +++
 target-arm/translate.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index 423f435..030da86 100755
--- a/configure
+++ b/configure
@@ -1657,7 +1657,7 @@ EOF
             "Make sure to have the zlib libs and headers installed."
     fi
 fi
-libs_softmmu="$libs_softmmu -lz"
+LIBS="$LIBS -lz"
 
 ##########################################
 # libseccomp check
diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index 7384e17..1ce8a9b 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -924,6 +924,7 @@ static void arm_any_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_THUMB2EE);
     set_feature(&cpu->env, ARM_FEATURE_ARM_DIV);
     set_feature(&cpu->env, ARM_FEATURE_V7MP);
+    set_feature(&cpu->env, ARM_FEATURE_CRC);
 #ifdef TARGET_AARCH64
     set_feature(&cpu->env, ARM_FEATURE_AARCH64);
 #endif
diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index afc46b2..49fef3f 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -626,6 +626,7 @@ enum arm_features {
     ARM_FEATURE_AARCH64, /* supports 64 bit mode */
     ARM_FEATURE_V8_AES, /* implements AES part of v8 Crypto Extensions */
     ARM_FEATURE_CBAR, /* has cp15 CBAR */
+    ARM_FEATURE_CRC, /* ARMv8 CRC instructions */
 };
 
 static inline int arm_feature(CPUARMState *env, int feature)
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 5621952..90f85f1 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -5,6 +5,8 @@
 #include "sysemu/arch_init.h"
 #include "sysemu/sysemu.h"
 #include "qemu/bitops.h"
+#include "qemu/crc32c.h"
+#include <zlib.h> /* For crc32 */
 
 #ifndef CONFIG_USER_ONLY
 static inline int get_phys_addr(CPUARMState *env, uint32_t address,
@@ -4703,3 +4705,40 @@ int arm_rmode_to_sf(int rmode)
     }
     return rmode;
 }
+
+static void crc_init_buffer(uint8_t *buf, uint32_t val, uint32_t bytes)
+{
+    memset(buf, 0, 4);
+
+    if (bytes == 1) {
+        buf[0] = val & 0xff;
+    } else if (bytes == 2) {
+        buf[0] = val & 0xff;
+        buf[1] = (val >> 8) & 0xff;
+    } else {
+        buf[0] = val & 0xff;
+        buf[1] = (val >> 8) & 0xff;
+        buf[2] = (val >> 16) & 0xff;
+        buf[3] = (val >> 24) & 0xff;
+    }
+}
+
+uint32_t HELPER(crc32)(uint32_t acc, uint32_t val, uint32_t bytes)
+{
+    uint8_t buf[4];
+
+    crc_init_buffer(buf, val, bytes);
+
+    /* zlib crc32 converts the accumulator and output to one's complement.  */
+    return crc32(acc ^ 0xffffffff, buf, bytes) ^ 0xffffffff;
+}
+
+uint32_t HELPER(crc32c)(uint32_t acc, uint32_t val, uint32_t bytes)
+{
+    uint8_t buf[4];
+
+    crc_init_buffer(buf, val, bytes);
+
+    /* Linux crc32c converts the output to one's complement.  */
+    return crc32c(acc, buf, bytes) ^ 0xffffffff;
+}
diff --git a/target-arm/helper.h b/target-arm/helper.h
index 4a063c1..276f3a9 100644
--- a/target-arm/helper.h
+++ b/target-arm/helper.h
@@ -499,6 +499,9 @@ DEF_HELPER_3(neon_qzip32, void, env, i32, i32)
 DEF_HELPER_4(crypto_aese, void, env, i32, i32, i32)
 DEF_HELPER_4(crypto_aesmc, void, env, i32, i32, i32)
 
+DEF_HELPER_FLAGS_3(crc32, TCG_CALL_NO_RWG_SE, i32, i32, i32, i32)
+DEF_HELPER_FLAGS_3(crc32c, TCG_CALL_NO_RWG_SE, i32, i32, i32, i32)
+
 #ifdef TARGET_AARCH64
 #include "helper-a64.h"
 #endif
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 6ccf0ba..253d2a1 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -7561,6 +7561,36 @@ static void disas_arm_insn(CPUARMState * env, 
DisasContext *s)
             store_reg(s, 14, tmp2);
             gen_bx(s, tmp);
             break;
+        case 0x4:
+        {
+            /* crc32/crc32c */
+            uint32_t c = extract32(insn, 8, 4);
+
+            /* Check this CPU supports ARMv8 CRC instructions.
+             * op1 == 3 is UNPREDICTABLE but handle as UNDEFINED.
+             * Bits 8, 10 and 11 should be zero.
+             */
+            if (!arm_feature(env, ARM_FEATURE_CRC) || op1 == 0x3 ||
+                (c & 0xd) != 0) {
+                goto illegal_op;
+            }
+
+            rn = extract32(insn, 16, 4);
+            rd = extract32(insn, 12, 4);
+
+            tmp = load_reg(s, rn);
+            tmp2 = load_reg(s, rm);
+            tmp3 = tcg_const_i32(1 << op1);
+            if (c & 0x2) {
+                gen_helper_crc32c(tmp, tmp, tmp2, tmp3);
+            } else {
+                gen_helper_crc32(tmp, tmp, tmp2, tmp3);
+            }
+            tcg_temp_free_i32(tmp2);
+            tcg_temp_free_i32(tmp3);
+            store_reg(s, rd, tmp);
+            break;
+        }
         case 0x5: /* saturating add/subtract */
             ARCH(5TE);
             rd = (insn >> 12) & 0xf;
@@ -9145,6 +9175,32 @@ static int disas_thumb2_insn(CPUARMState *env, 
DisasContext *s, uint16_t insn_hw
                 case 0x18: /* clz */
                     gen_helper_clz(tmp, tmp);
                     break;
+                case 0x20:
+                case 0x21:
+                case 0x22:
+                case 0x28:
+                case 0x29:
+                case 0x2a:
+                {
+                    /* crc32/crc32c */
+                    uint32_t sz = op & 0x3;
+                    uint32_t c = op & 0x8;
+
+                    if (!arm_feature(env, ARM_FEATURE_CRC)) {
+                        goto illegal_op;
+                    }
+
+                    tmp2 = load_reg(s, rm);
+                    tmp3 = tcg_const_i32(1 << sz);
+                    if (c) {
+                        gen_helper_crc32c(tmp, tmp, tmp2, tmp3);
+                    } else {
+                        gen_helper_crc32(tmp, tmp, tmp2, tmp3);
+                    }
+                    tcg_temp_free_i32(tmp2);
+                    tcg_temp_free_i32(tmp3);
+                    break;
+                }
                 default:
                     goto illegal_op;
                 }
-- 
1.9.0