target-tilegx: Handle atomic instructions

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>

1 files changed, 166 insertions, 0 deletions

diff --git a/linux-user/main.c b/linux-user/main.c
index 4b579c9..782037d 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3436,6 +3436,148 @@ static void gen_sigill_reg(CPUTLGState *env)
     queue_signal(env, info.si_signo, &info);
 }
 
+static void set_regval(CPUTLGState *env, uint8_t reg, uint64_t val)
+{
+    if (unlikely(reg >= TILEGX_R_COUNT)) {
+        switch (reg) {
+        case TILEGX_R_SN:
+        case TILEGX_R_ZERO:
+            return;
+        case TILEGX_R_IDN0:
+        case TILEGX_R_IDN1:
+        case TILEGX_R_UDN0:
+        case TILEGX_R_UDN1:
+        case TILEGX_R_UDN2:
+        case TILEGX_R_UDN3:
+            gen_sigill_reg(env);
+            return;
+        default:
+            g_assert_not_reached();
+        }
+    }
+    env->regs[reg] = val;
+}
+
+/*
+ * Compare the 8-byte contents of the CmpValue SPR with the 8-byte value in
+ * memory at the address held in the first source register. If the values are
+ * not equal, then no memory operation is performed. If the values are equal,
+ * the 8-byte quantity from the second source register is written into memory
+ * at the address held in the first source register. In either case, the result
+ * of the instruction is the value read from memory. The compare and write to
+ * memory are atomic and thus can be used for synchronization purposes. This
+ * instruction only operates for addresses aligned to a 8-byte boundary.
+ * Unaligned memory access causes an Unaligned Data Reference interrupt.
+ *
+ * Functional Description (64-bit)
+ *       uint64_t memVal = memoryReadDoubleWord (rf[SrcA]);
+ *       rf[Dest] = memVal;
+ *       if (memVal == SPR[CmpValueSPR])
+ *           memoryWriteDoubleWord (rf[SrcA], rf[SrcB]);
+ *
+ * Functional Description (32-bit)
+ *       uint64_t memVal = signExtend32 (memoryReadWord (rf[SrcA]));
+ *       rf[Dest] = memVal;
+ *       if (memVal == signExtend32 (SPR[CmpValueSPR]))
+ *           memoryWriteWord (rf[SrcA], rf[SrcB]);
+ *
+ *
+ * This function also processes exch and exch4 which need not process SPR.
+ */
+static void do_exch(CPUTLGState *env, bool quad, bool cmp)
+{
+    target_ulong addr;
+    target_long val, sprval;
+
+    start_exclusive();
+
+    addr = env->atomic_srca;
+    if (quad ? get_user_s64(val, addr) : get_user_s32(val, addr)) {
+        goto sigsegv_maperr;
+    }
+
+    if (cmp) {
+        if (quad) {
+            sprval = env->spregs[TILEGX_SPR_CMPEXCH];
+        } else {
+            sprval = sextract64(env->spregs[TILEGX_SPR_CMPEXCH], 0, 32);
+        }
+    }
+
+    if (!cmp || val == sprval) {
+        target_long valb = env->atomic_srcb;
+        if (quad ? put_user_u64(valb, addr) : put_user_u32(valb, addr)) {
+            goto sigsegv_maperr;
+        }
+    }
+
+    set_regval(env, env->atomic_dstr, val);
+    end_exclusive();
+    return;
+
+ sigsegv_maperr:
+    end_exclusive();
+    gen_sigsegv_maperr(env, addr);
+}
+
+static void do_fetch(CPUTLGState *env, int trapnr, bool quad)
+{
+    int8_t write = 1;
+    target_ulong addr;
+    target_long val, valb;
+
+    start_exclusive();
+
+    addr = env->atomic_srca;
+    valb = env->atomic_srcb;
+    if (quad ? get_user_s64(val, addr) : get_user_s32(val, addr)) {
+        goto sigsegv_maperr;
+    }
+
+    switch (trapnr) {
+    case TILEGX_EXCP_OPCODE_FETCHADD:
+    case TILEGX_EXCP_OPCODE_FETCHADD4:
+        valb += val;
+        break;
+    case TILEGX_EXCP_OPCODE_FETCHADDGEZ:
+        valb += val;
+        if (valb < 0) {
+            write = 0;
+        }
+        break;
+    case TILEGX_EXCP_OPCODE_FETCHADDGEZ4:
+        valb += val;
+        if ((int32_t)valb < 0) {
+            write = 0;
+        }
+        break;
+    case TILEGX_EXCP_OPCODE_FETCHAND:
+    case TILEGX_EXCP_OPCODE_FETCHAND4:
+        valb &= val;
+        break;
+    case TILEGX_EXCP_OPCODE_FETCHOR:
+    case TILEGX_EXCP_OPCODE_FETCHOR4:
+        valb |= val;
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    if (write) {
+        if (quad ? put_user_u64(valb, addr) : put_user_u32(valb, addr)) {
+            goto sigsegv_maperr;
+        }
+    }
+
+    set_regval(env, env->atomic_dstr, val);
+    end_exclusive();
+    return;
+
+ sigsegv_maperr:
+    end_exclusive();
+    gen_sigsegv_maperr(env, addr);
+}
+
 void cpu_loop(CPUTLGState *env)
 {
     CPUState *cs = CPU(tilegx_env_get_cpu(env));
@@ -3456,6 +3598,30 @@ void cpu_loop(CPUTLGState *env)
                                                       ? - env->regs[TILEGX_R_RE]
                                                       : 0;
             break;
+        case TILEGX_EXCP_OPCODE_EXCH:
+            do_exch(env, true, false);
+            break;
+        case TILEGX_EXCP_OPCODE_EXCH4:
+            do_exch(env, false, false);
+            break;
+        case TILEGX_EXCP_OPCODE_CMPEXCH:
+            do_exch(env, true, true);
+            break;
+        case TILEGX_EXCP_OPCODE_CMPEXCH4:
+            do_exch(env, false, true);
+            break;
+        case TILEGX_EXCP_OPCODE_FETCHADD:
+        case TILEGX_EXCP_OPCODE_FETCHADDGEZ:
+        case TILEGX_EXCP_OPCODE_FETCHAND:
+        case TILEGX_EXCP_OPCODE_FETCHOR:
+            do_fetch(env, trapnr, true);
+            break;
+        case TILEGX_EXCP_OPCODE_FETCHADD4:
+        case TILEGX_EXCP_OPCODE_FETCHADDGEZ4:
+        case TILEGX_EXCP_OPCODE_FETCHAND4:
+        case TILEGX_EXCP_OPCODE_FETCHOR4:
+            do_fetch(env, trapnr, false);
+            break;
         case TILEGX_EXCP_REG_IDN_ACCESS:
         case TILEGX_EXCP_REG_UDN_ACCESS:
             gen_sigill_reg(env);