Commit dc1ce18b authored by Richard Henderson's avatar Richard Henderson Committed by Laurent Vivier
Browse files

linux-user: Split out do_syscall1 



There was supposed to be a single point of return for do_syscall
so that tracing works properly.  However, there are a few bugs
in that area.  It is significantly simpler to simply split out
an inner function to enforce this.

Reviewed-by: default avatarPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: default avatarLaurent Vivier <laurent@vivier.eu>
Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Message-Id: <20180818190118.12911-3-richard.henderson@linaro.org>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
parent 8a85e5dd

linux-user/syscall.c

+48 −29
Original line number Diff line number Diff line
@@ -8092,10 +8092,12 @@ static int host_to_target_cpu_mask(const unsigned long *host_mask, 
    return 0;

}



/* do_syscall() should always have a single exit point at the end so

   that actions, such as logging of syscall results, can be performed.

   All errnos that do_syscall() returns must be -TARGET_<errcode>. */

abi_long do_syscall(void *cpu_env, int num, abi_long arg1,

/* This is an internal helper for do_syscall so that it is easier

 * to have a single return point, so that actions, such as logging

 * of syscall results, can be performed.

 * All errnos that do_syscall() returns must be -TARGET_<errcode>.

 */

static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,

                            abi_long arg2, abi_long arg3, abi_long arg4,

                            abi_long arg5, abi_long arg6, abi_long arg7,

                            abi_long arg8)
@@ -8113,25 +8115,6 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
#endif

    void *p;



#if defined(DEBUG_ERESTARTSYS)

    /* Debug-only code for exercising the syscall-restart code paths

     * in the per-architecture cpu main loops: restart every syscall

     * the guest makes once before letting it through.

     */

    {

        static int flag;



        flag = !flag;

        if (flag) {

            return -TARGET_ERESTARTSYS;

        }

    }

#endif



    trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);

    if(do_strace)

        print_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);



    switch(num) {

    case TARGET_NR_exit:

        /* In old applications this may be used to implement _exit(2).
@@ -12942,11 +12925,47 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
        break;

    }

fail:

    if(do_strace)

        print_syscall_ret(num, ret);

    trace_guest_user_syscall_ret(cpu, num, ret);

    return ret;

efault:

    ret = -TARGET_EFAULT;

    goto fail;

}



abi_long do_syscall(void *cpu_env, int num, abi_long arg1,

                    abi_long arg2, abi_long arg3, abi_long arg4,

                    abi_long arg5, abi_long arg6, abi_long arg7,

                    abi_long arg8)

{

    CPUState *cpu = ENV_GET_CPU(cpu_env);

    abi_long ret;



#ifdef DEBUG_ERESTARTSYS

    /* Debug-only code for exercising the syscall-restart code paths

     * in the per-architecture cpu main loops: restart every syscall

     * the guest makes once before letting it through.

     */

    {

        static bool flag;

        flag = !flag;

        if (flag) {

            return -TARGET_ERESTARTSYS;

        }

    }

#endif



    trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4,

                             arg5, arg6, arg7, arg8);



    if (unlikely(do_strace)) {

        print_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);

        ret = do_syscall1(cpu_env, num, arg1, arg2, arg3, arg4,

                          arg5, arg6, arg7, arg8);

        print_syscall_ret(num, ret);

    } else {

        ret = do_syscall1(cpu_env, num, arg1, arg2, arg3, arg4,

                          arg5, arg6, arg7, arg8);

    }



    trace_guest_user_syscall_ret(cpu, num, ret);

    return ret;

}