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bsd-user: Add RISC-V CPU execution loop and syscall handling

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Implemented the RISC-V CPU execution loop, including handling various
exceptions and system calls. The loop continuously executes CPU
instructions,processes exceptions, and handles system calls by invoking
FreeBSD syscall handlers.

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>
Co-authored-by: Kyle Evans <kevans@FreeBSD.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240916155119.14610-3-itachis@FreeBSD.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Mark Corbin 2024-09-17 01:51:04 +10:00 committed by Alistair Francis
parent 9d49b1c9ed
commit 92c15617e1
1 changed files with 94 additions and 0 deletions
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94
bsd-user/riscv/target_arch_cpu.h
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@ -37,4 +37,98 @@ static inline void target_cpu_init(CPURISCVState *env,
env->pc = regs->sepc;
}
static inline void target_cpu_loop(CPURISCVState *env)
{
CPUState *cs = env_cpu(env);
int trapnr;
abi_long ret;
unsigned int syscall_num;
int32_t signo, code;
for (;;) {
cpu_exec_start(cs);
trapnr = cpu_exec(cs);
cpu_exec_end(cs);
process_queued_cpu_work(cs);
signo = 0;
switch (trapnr) {
case EXCP_INTERRUPT:
/* just indicate that signals should be handled asap */
break;
case EXCP_ATOMIC:
cpu_exec_step_atomic(cs);
break;
case RISCV_EXCP_U_ECALL:
syscall_num = env->gpr[xT0];
env->pc += TARGET_INSN_SIZE;
/* Compare to cpu_fetch_syscall_args() in riscv/riscv/trap.c */
if (TARGET_FREEBSD_NR___syscall == syscall_num ||
TARGET_FREEBSD_NR_syscall == syscall_num) {
ret = do_freebsd_syscall(env,
env->gpr[xA0],
env->gpr[xA1],
env->gpr[xA2],
env->gpr[xA3],
env->gpr[xA4],
env->gpr[xA5],
env->gpr[xA6],
env->gpr[xA7],
0);
} else {
ret = do_freebsd_syscall(env,
syscall_num,
env->gpr[xA0],
env->gpr[xA1],
env->gpr[xA2],
env->gpr[xA3],
env->gpr[xA4],
env->gpr[xA5],
env->gpr[xA6],
env->gpr[xA7]
);
}
/*
* Compare to cpu_set_syscall_retval() in
* riscv/riscv/vm_machdep.c
*/
if (ret >= 0) {
env->gpr[xA0] = ret;
env->gpr[xT0] = 0;
} else if (ret == -TARGET_ERESTART) {
env->pc -= TARGET_INSN_SIZE;
} else if (ret != -TARGET_EJUSTRETURN) {
env->gpr[xA0] = -ret;
env->gpr[xT0] = 1;
}
break;
case RISCV_EXCP_ILLEGAL_INST:
signo = TARGET_SIGILL;
code = TARGET_ILL_ILLOPC;
break;
case RISCV_EXCP_BREAKPOINT:
signo = TARGET_SIGTRAP;
code = TARGET_TRAP_BRKPT;
break;
case EXCP_DEBUG:
signo = TARGET_SIGTRAP;
code = TARGET_TRAP_BRKPT;
break;
default:
fprintf(stderr, "qemu: unhandled CPU exception "
"0x%x - aborting\n", trapnr);
cpu_dump_state(cs, stderr, 0);
abort();
}
if (signo) {
force_sig_fault(signo, code, env->pc);
}
process_pending_signals(env);
}
}
#endif /* TARGET_ARCH_CPU_H */