[PATCH v4 20/36] bsd-user/arm/target_arch_cpu.h: Implement system call dispatch

[Warner Losh <imp@bsdimp.com>]

Implement the system call dispatch. This implements all three kinds of
system call: direct and the two indirect variants. It handles all the
special cases for thumb as well.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Kyle Evans <kevans@FreeBSD.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/arm/target_arch_cpu.h | 94 ++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)

diff --git a/bsd-user/arm/target_arch_cpu.h b/bsd-user/arm/target_arch_cpu.h
index 905a5ffaff..c675419c30 100644
--- a/bsd-user/arm/target_arch_cpu.h
+++ b/bsd-user/arm/target_arch_cpu.h
@@ -40,6 +40,7 @@ static inline void target_cpu_loop(CPUARMState *env)
 {
     int trapnr;
     target_siginfo_t info;
+    unsigned int n;
     CPUState *cs = env_cpu(env);
 
     for (;;) {
@@ -62,6 +63,99 @@ static inline void target_cpu_loop(CPUARMState *env)
                 /* TODO: What about instruction emulation? */
             }
             break;
+        case EXCP_SWI:
+        case EXCP_BKPT:
+            {
+                /*
+                 * system call
+                 * See arm/arm/trap.c cpu_fetch_syscall_args()
+                 */
+                if (trapnr == EXCP_BKPT) {
+                    if (env->thumb) {
+                        env->regs[15] += 2;
+                    } else {
+                        env->regs[15] += 4;
+                    }
+                }
+                n = env->regs[7];
+                if (bsd_type == target_freebsd) {
+                    int ret;
+                    abi_ulong params = get_sp_from_cpustate(env);
+                    int32_t syscall_nr = n;
+                    int32_t arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8;
+
+                    /* See arm/arm/trap.c cpu_fetch_syscall_args() */
+                    if (syscall_nr == TARGET_FREEBSD_NR_syscall) {
+                        syscall_nr = env->regs[0];
+                        arg1 = env->regs[1];
+                        arg2 = env->regs[2];
+                        arg3 = env->regs[3];
+                        get_user_s32(arg4, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg5, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg6, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg7, params);
+                        arg8 = 0;
+                    } else if (syscall_nr == TARGET_FREEBSD_NR___syscall) {
+                        syscall_nr = env->regs[0];
+                        arg1 = env->regs[2];
+                        arg2 = env->regs[3];
+                        get_user_s32(arg3, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg4, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg5, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg6, params);
+                        arg7 = 0;
+                        arg8 = 0;
+                    } else {
+                        arg1 = env->regs[0];
+                        arg2 = env->regs[1];
+                        arg3 = env->regs[2];
+                        arg4 = env->regs[3];
+                        get_user_s32(arg5, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg6, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg7, params);
+                        params += sizeof(int32_t);
+                        get_user_s32(arg8, params);
+                    }
+                    ret = do_freebsd_syscall(env, syscall_nr, arg1, arg2, arg3,
+                            arg4, arg5, arg6, arg7, arg8);
+                    /*
+                     * Compare to arm/arm/vm_machdep.c
+                     * cpu_set_syscall_retval()
+                     */
+                    if (-TARGET_EJUSTRETURN == ret) {
+                        /*
+                         * Returning from a successful sigreturn syscall.
+                         * Avoid clobbering register state.
+                         */
+                        break;
+                    }
+                    if (-TARGET_ERESTART == ret) {
+                        env->regs[15] -= env->thumb ? 2 : 4;
+                        break;
+                    }
+                    if ((unsigned int)ret >= (unsigned int)(-515)) {
+                        ret = -ret;
+                        cpsr_write(env, CPSR_C, CPSR_C, CPSRWriteByInstr);
+                        env->regs[0] = ret;
+                    } else {
+                        cpsr_write(env, 0, CPSR_C, CPSRWriteByInstr);
+                        env->regs[0] = ret; /* XXX need to handle lseek()? */
+                        /* env->regs[1] = 0; */
+                    }
+                } else {
+                    fprintf(stderr, "qemu: bsd_type (= %d) syscall "
+                            "not supported\n", bsd_type);
+                }
+            }
+            break;
         case EXCP_INTERRUPT:
             /* just indicate that signals should be handled asap */
             break;
-- 
2.33.0