target-arm: add support for v8 VMULL.P64 instruction

Add support for the VMULL.P64 polynomial 64x64 to 128 bit multiplication
instruction in the A32/T32 instruction sets; this is part of the v8
Crypto Extensions.

To do this we have to move the neon_pmull_64_{lo,hi} helpers from
helper-a64.c into neon_helper.c so they can be used by the AArch32
translator.

Inspired-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1401386724-26529-4-git-send-email-peter.maydell@linaro.org

linux-user/elfload.c

@@ -468,6 +468,7 @@ static uint32_t get_elf_hwcap2(void)
     uint32_t hwcaps = 0;
 
     GET_FEATURE(ARM_FEATURE_V8_AES, ARM_HWCAP2_ARM_AES);
+    GET_FEATURE(ARM_FEATURE_V8_PMULL, ARM_HWCAP2_ARM_PMULL);
     GET_FEATURE(ARM_FEATURE_V8_SHA1, ARM_HWCAP2_ARM_SHA1);
     GET_FEATURE(ARM_FEATURE_V8_SHA256, ARM_HWCAP2_ARM_SHA2);
     GET_FEATURE(ARM_FEATURE_CRC, ARM_HWCAP2_ARM_CRC32);

target-arm/cpu.c

@@ -319,6 +319,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
         set_feature(env, ARM_FEATURE_V8_AES);
         set_feature(env, ARM_FEATURE_V8_SHA1);
         set_feature(env, ARM_FEATURE_V8_SHA256);
+        set_feature(env, ARM_FEATURE_V8_PMULL);
     }
     if (arm_feature(env, ARM_FEATURE_V7)) {
         set_feature(env, ARM_FEATURE_VAPA);

target-arm/cpu.h

@@ -637,6 +637,7 @@ enum arm_features {
     ARM_FEATURE_EL3, /* has EL3 Secure monitor support */
     ARM_FEATURE_V8_SHA1, /* implements SHA1 part of v8 Crypto Extensions */
     ARM_FEATURE_V8_SHA256, /* implements SHA256 part of v8 Crypto Extensions */
+    ARM_FEATURE_V8_PMULL, /* implements PMULL part of v8 Crypto Extensions */
 };
 
 static inline int arm_feature(CPUARMState *env, int feature)

target-arm/helper-a64.c

@@ -186,36 +186,6 @@ uint64_t HELPER(simd_tbl)(CPUARMState *env, uint64_t result, uint64_t indices,
     return result;
 }
 
-/* Helper function for 64 bit polynomial multiply case:
- * perform PolynomialMult(op1, op2) and return either the top or
- * bottom half of the 128 bit result.
- */
-uint64_t HELPER(neon_pmull_64_lo)(uint64_t op1, uint64_t op2)
-{
-    int bitnum;
-    uint64_t res = 0;
-
-    for (bitnum = 0; bitnum < 64; bitnum++) {
-        if (op1 & (1ULL << bitnum)) {
-            res ^= op2 << bitnum;
-        }
-    }
-    return res;
-}
-uint64_t HELPER(neon_pmull_64_hi)(uint64_t op1, uint64_t op2)
-{
-    int bitnum;
-    uint64_t res = 0;
-
-    /* bit 0 of op1 can't influence the high 64 bits at all */
-    for (bitnum = 1; bitnum < 64; bitnum++) {
-        if (op1 & (1ULL << bitnum)) {
-            res ^= op2 >> (64 - bitnum);
-        }
-    }
-    return res;
-}
-
 /* 64bit/double versions of the neon float compare functions */
 uint64_t HELPER(neon_ceq_f64)(float64 a, float64 b, void *fpstp)
 {

target-arm/helper-a64.h

@@ -28,8 +28,6 @@ DEF_HELPER_3(vfp_cmpes_a64, i64, f32, f32, ptr)
 DEF_HELPER_3(vfp_cmpd_a64, i64, f64, f64, ptr)
 DEF_HELPER_3(vfp_cmped_a64, i64, f64, f64, ptr)
 DEF_HELPER_FLAGS_5(simd_tbl, TCG_CALL_NO_RWG_SE, i64, env, i64, i64, i32, i32)
-DEF_HELPER_FLAGS_2(neon_pmull_64_lo, TCG_CALL_NO_RWG_SE, i64, i64, i64)
-DEF_HELPER_FLAGS_2(neon_pmull_64_hi, TCG_CALL_NO_RWG_SE, i64, i64, i64)
 DEF_HELPER_FLAGS_3(vfp_mulxs, TCG_CALL_NO_RWG, f32, f32, f32, ptr)
 DEF_HELPER_FLAGS_3(vfp_mulxd, TCG_CALL_NO_RWG, f64, f64, f64, ptr)
 DEF_HELPER_FLAGS_3(neon_ceq_f64, TCG_CALL_NO_RWG, i64, i64, i64, ptr)

target-arm/helper.h

@@ -525,6 +525,9 @@ 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)
 DEF_HELPER_2(dc_zva, void, env, i64)
 
+DEF_HELPER_FLAGS_2(neon_pmull_64_lo, TCG_CALL_NO_RWG_SE, i64, i64, i64)
+DEF_HELPER_FLAGS_2(neon_pmull_64_hi, TCG_CALL_NO_RWG_SE, i64, i64, i64)
+
 #ifdef TARGET_AARCH64
 #include "helper-a64.h"
 #endif

target-arm/neon_helper.c

@@ -2211,3 +2211,33 @@ void HELPER(neon_zip16)(CPUARMState *env, uint32_t rd, uint32_t rm)
     env->vfp.regs[rm] = make_float64(m0);
     env->vfp.regs[rd] = make_float64(d0);
 }
+
+/* Helper function for 64 bit polynomial multiply case:
+ * perform PolynomialMult(op1, op2) and return either the top or
+ * bottom half of the 128 bit result.
+ */
+uint64_t HELPER(neon_pmull_64_lo)(uint64_t op1, uint64_t op2)
+{
+    int bitnum;
+    uint64_t res = 0;
+
+    for (bitnum = 0; bitnum < 64; bitnum++) {
+        if (op1 & (1ULL << bitnum)) {
+            res ^= op2 << bitnum;
+        }
+    }
+    return res;
+}
+uint64_t HELPER(neon_pmull_64_hi)(uint64_t op1, uint64_t op2)
+{
+    int bitnum;
+    uint64_t res = 0;
+
+    /* bit 0 of op1 can't influence the high 64 bits at all */
+    for (bitnum = 1; bitnum < 64; bitnum++) {
+        if (op1 & (1ULL << bitnum)) {
+            res ^= op2 >> (64 - bitnum);
+        }
+    }
+    return res;
+}

target-arm/translate.c

@@ -5977,7 +5977,7 @@ static int disas_neon_data_insn(CPUARMState * env, DisasContext *s, uint32_t ins
                     {0, 0, 0, 9}, /* VQDMLSL */
                     {0, 0, 0, 0}, /* Integer VMULL */
                     {0, 0, 0, 1}, /* VQDMULL */
-                    {0, 0, 0, 15}, /* Polynomial VMULL */
+                    {0, 0, 0, 0xa}, /* Polynomial VMULL */
                     {0, 0, 0, 7}, /* Reserved: always UNDEF */
                 };
 
@@ -5996,6 +5996,30 @@ static int disas_neon_data_insn(CPUARMState * env, DisasContext *s, uint32_t ins
                     return 1;
                 }
 
+                /* Handle VMULL.P64 (Polynomial 64x64 to 128 bit multiply)
+                 * outside the loop below as it only performs a single pass.
+                 */
+                if (op == 14 && size == 2) {
+                    TCGv_i64 tcg_rn, tcg_rm, tcg_rd;
+
+                    if (!arm_feature(env, ARM_FEATURE_V8_PMULL)) {
+                        return 1;
+                    }
+                    tcg_rn = tcg_temp_new_i64();
+                    tcg_rm = tcg_temp_new_i64();
+                    tcg_rd = tcg_temp_new_i64();
+                    neon_load_reg64(tcg_rn, rn);
+                    neon_load_reg64(tcg_rm, rm);
+                    gen_helper_neon_pmull_64_lo(tcg_rd, tcg_rn, tcg_rm);
+                    neon_store_reg64(tcg_rd, rd);
+                    gen_helper_neon_pmull_64_hi(tcg_rd, tcg_rn, tcg_rm);
+                    neon_store_reg64(tcg_rd, rd + 1);
+                    tcg_temp_free_i64(tcg_rn);
+                    tcg_temp_free_i64(tcg_rm);
+                    tcg_temp_free_i64(tcg_rd);
+                    return 0;
+                }
+
                 /* Avoid overlapping operands.  Wide source operands are
                    always aligned so will never overlap with wide
                    destinations in problematic ways.  */