Re: [Qemu-devel] arm return

[Davide Ferraretto <femudevelopment@gmail.com>]

I'm in "arm user space" with "sigle step mode". I want write "exit\n" in 
linux shell (no QEMU monitor) when emulate code arrives to "return 0"

On 06/01/12 14:23, Max Filippov wrote:
> On Fri, Jun 1, 2012 at 3:57 PM, Davide Ferraretto
> <femudevelopment@gmail.com>  wrote:
>> I tried to insert " printf("exit\n"); ", but qemu dosen't write to monitor.
> printf should not write to monitor (if you mean QEMU monitor), it
> should go to stdout.
> I don't have ARM compiler set up ATM, but x86_64 with the following
> patch does what I describe:
>
> $ git diff
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 20d2a74..ccb71dc 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -5052,6 +5052,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>
>       switch(num) {
>       case TARGET_NR_exit:
> +        fprintf(stderr, "TARGET_NR_exit\n");
>   #ifdef CONFIG_USE_NPTL
>         /* In old applications this may be used to implement _exit(2).
>            However in threaded applictions it is used for thread termination,
> @@ -6833,6 +6834,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
>   #ifdef __NR_exit_group
>           /* new thread calls */
>       case TARGET_NR_exit_group:
> +        fprintf(stderr, "TARGET_NR_exit_group\n");
>   #ifdef TARGET_GPROF
>           _mcleanup();
>   #endif
>
> $ cat a.c
> #include<stdio.h>
> int main()
> {
>      printf("Hello, world\n");
>      return 0;
> }
>
> $ gcc -static a.c -o a
> $ qemu-all/root/bin/qemu-x86_64 ./a
> Hello, world
> TARGET_NR_exit_group
>
>> On 06/01/12 13:43, Max Filippov wrote:
>>> On Fri, Jun 1, 2012 at 3:16 PM, Davide Ferraretto
>>> <femudevelopment@gmail.com>    wrote:
>>>> In arm user mode, where does qemu exit? Where is last qemu's instruction?
>>>>
>>>> I.E.
>>>> int main (){return 0;}
>>>> in what file does qemu run "return 0"??
>>> Simulated code reaches the point where libc calls 'exit' or 'exit_group'
>>> syscall
>>> and then QEMU goes to the do_syscall in the linux-user/syscall.c to
>>> terminate
>>> the process.
>>>