[PATCH v12 22/26] linux-user: Add LoongArch cpu_loop support

[Song Gao <gaosong@loongson.cn>]

Signed-off-by: Song Gao <gaosong@loongson.cn>
Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 configure                           |  5 ++
 linux-user/loongarch64/cpu_loop.c   | 94 +++++++++++++++++++++++++++++++++++++
 linux-user/loongarch64/target_cpu.h | 34 ++++++++++++++
 3 files changed, 133 insertions(+)
 create mode 100644 linux-user/loongarch64/cpu_loop.c
 create mode 100644 linux-user/loongarch64/target_cpu.h

diff --git a/configure b/configure
index 48c2177..9df99f6 100755
--- a/configure
+++ b/configure
@@ -581,6 +581,8 @@ elif check_define __arm__ ; then
   cpu="arm"
 elif check_define __aarch64__ ; then
   cpu="aarch64"
+elif check_define __loongarch64__ ; then
+  cpu="loongarch64"
 else
   cpu=$(uname -m)
 fi
@@ -612,6 +614,9 @@ case "$cpu" in
   sparc|sun4[cdmuv])
     cpu="sparc"
   ;;
+  loongarch)
+    cpu="loongarch"
+  ;;
   *)
     # This will result in either an error or falling back to TCI later
     ARCH=unknown
diff --git a/linux-user/loongarch64/cpu_loop.c b/linux-user/loongarch64/cpu_loop.c
new file mode 100644
index 0000000..2895472
--- /dev/null
+++ b/linux-user/loongarch64/cpu_loop.c
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * QEMU LoongArch user cpu_loop.
+ *
+ * Copyright (c) 2021 Loongson Technology Corporation Limited
+ */
+
+#include "qemu/osdep.h"
+#include "qemu.h"
+#include "qemu-common.h"
+#include "user-internals.h"
+#include "cpu_loop-common.h"
+#include "signal-common.h"
+
+void cpu_loop(CPULoongArchState *env)
+{
+    CPUState *cs = env_cpu(env);
+    int trapnr, si_code;
+    abi_long ret;
+
+    for (;;) {
+        cpu_exec_start(cs);
+        trapnr = cpu_exec(cs);
+        cpu_exec_end(cs);
+        process_queued_cpu_work(cs);
+
+        switch (trapnr) {
+        case EXCP_INTERRUPT:
+            /* just indicate that signals should be handled asap */
+            break;
+        case EXCP_SYSCALL:
+            env->pc += 4;
+            ret = do_syscall(env, env->gpr[11],
+                             env->gpr[4], env->gpr[5],
+                             env->gpr[6], env->gpr[7],
+                             env->gpr[8], env->gpr[9],
+                             -1, -1);
+            if (ret == -TARGET_ERESTARTSYS) {
+                env->pc -= 4;
+                break;
+            }
+            if (ret == -TARGET_QEMU_ESIGRETURN) {
+                /*
+                 * Returning from a successful sigreturn syscall.
+                 * Avoid clobbering register state.
+                 */
+                break;
+            }
+            env->gpr[4] = ret;
+            break;
+        case EXCP_INE:
+            force_sig_fault(TARGET_SIGILL, 0, env->pc);
+            break;
+        case EXCP_FPE:
+            si_code = TARGET_FPE_FLTUNK;
+            if (GET_FP_CAUSE(env->fcsr0) & FP_INVALID) {
+                si_code = TARGET_FPE_FLTINV;
+            } else if (GET_FP_CAUSE(env->fcsr0) & FP_DIV0) {
+                si_code = TARGET_FPE_FLTDIV;
+            } else if (GET_FP_CAUSE(env->fcsr0) & FP_OVERFLOW) {
+                si_code = TARGET_FPE_FLTOVF;
+            } else if (GET_FP_CAUSE(env->fcsr0) & FP_UNDERFLOW) {
+                si_code = TARGET_FPE_FLTUND;
+            } else if (GET_FP_CAUSE(env->fcsr0) & FP_INEXACT) {
+                si_code = TARGET_FPE_FLTRES;
+            }
+            force_sig_fault(TARGET_SIGFPE, si_code, env->pc);
+            break;
+        case EXCP_DEBUG:
+        case EXCP_BREAK:
+            force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
+            break;
+        case EXCP_ATOMIC:
+            cpu_exec_step_atomic(cs);
+            break;
+        default:
+            EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n",
+                      trapnr);
+            exit(EXIT_FAILURE);
+        }
+        process_pending_signals(env);
+    }
+}
+
+void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
+{
+    int i;
+
+    for (i = 0; i < 32; i++) {
+        env->gpr[i] = regs->regs[i];
+    }
+    env->pc = regs->csr_era;
+
+}
diff --git a/linux-user/loongarch64/target_cpu.h b/linux-user/loongarch64/target_cpu.h
new file mode 100644
index 0000000..a29af66
--- /dev/null
+++ b/linux-user/loongarch64/target_cpu.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * LoongArch specific CPU ABI and functions for linux-user
+ *
+ * Copyright (c) 2021 Loongson Technology Corporation Limited
+ */
+
+#ifndef LOONGARCH_TARGET_CPU_H
+#define LOONGARCH_TARGET_CPU_H
+
+static inline void cpu_clone_regs_child(CPULoongArchState *env,
+                                        target_ulong newsp, unsigned flags)
+{
+    if (newsp) {
+        env->gpr[3] = newsp;
+    }
+    env->gpr[4] = 0;
+}
+
+static inline void cpu_clone_regs_parent(CPULoongArchState *env,
+                                         unsigned flags)
+{
+}
+
+static inline void cpu_set_tls(CPULoongArchState *env, target_ulong newtls)
+{
+    env->gpr[2] = newtls;
+}
+
+static inline abi_ulong get_sp_from_cpustate(CPULoongArchState *state)
+{
+    return state->gpr[3];
+}
+#endif
-- 
1.8.3.1