[PULL 05/23] linux-user: Add LoongArch cpu_loop support

[Richard Henderson <richard.henderson@linaro.org>]

From: 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>
Message-Id: <20220624031049.1716097-6-gaosong@loongson.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/loongarch64/target_cpu.h | 34 ++++++++++
 linux-user/loongarch64/cpu_loop.c   | 96 +++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 linux-user/loongarch64/target_cpu.h
 create mode 100644 linux-user/loongarch64/cpu_loop.c

diff --git a/linux-user/loongarch64/target_cpu.h b/linux-user/loongarch64/target_cpu.h
new file mode 100644
index 0000000000..a29af66156
--- /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
diff --git a/linux-user/loongarch64/cpu_loop.c b/linux-user/loongarch64/cpu_loop.c
new file mode 100644
index 0000000000..894fdd111a
--- /dev/null
+++ b/linux-user/loongarch64/cpu_loop.c
@@ -0,0 +1,96 @@
+/* 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 "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 EXCCODE_SYS:
+            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 == -QEMU_ERESTARTSYS) {
+                env->pc -= 4;
+                break;
+            }
+            if (ret == -QEMU_ESIGRETURN) {
+                /*
+                 * Returning from a successful sigreturn syscall.
+                 * Avoid clobbering register state.
+                 */
+                break;
+            }
+            env->gpr[4] = ret;
+            break;
+        case EXCCODE_INE:
+            force_sig_fault(TARGET_SIGILL, 0, env->pc);
+            break;
+        case EXCCODE_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 EXCCODE_BRK:
+            force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
+            break;
+        case EXCCODE_BCE:
+            force_sig_fault(TARGET_SIGSYS, TARGET_SI_KERNEL, 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;
+
+}
-- 
2.34.1