bsd-user: Implement RISC-V CPU initialization and main loop

Added the initial implementation for RISC-V CPU initialization and main
loop. This includes setting up the general-purpose registers and
program counter based on the provided target architecture definitions.

Signed-off-by: Mark Corbin <mark@dibsco.co.uk>
Signed-off-by: Ajeet Singh <itachis@FreeBSD.org>
Co-authored-by: Jessica Clarke <jrtc27@jrtc27.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240916155119.14610-2-itachis@FreeBSD.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

bsd-user/riscv/target_arch_cpu.h

@@ -0,0 +1,40 @@
+/*
+ *  RISC-V CPU init and loop
+ *
+ *  Copyright (c) 2019 Mark Corbin
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TARGET_ARCH_CPU_H
+#define TARGET_ARCH_CPU_H
+
+#include "target_arch.h"
+#include "signal-common.h"
+
+#define TARGET_DEFAULT_CPU_MODEL "max"
+
+static inline void target_cpu_init(CPURISCVState *env,
+        struct target_pt_regs *regs)
+{
+    int i;
+
+    for (i = 1; i < 32; i++) {
+        env->gpr[i] = regs->regs[i];
+    }
+
+    env->pc = regs->sepc;
+}
+
+#endif /* TARGET_ARCH_CPU_H */