Re: Seccomp support for linux-m68k

[Andreas Schwab <schwab@linux-m68k.org>]

On Jul 27 2020, Michael Schmitz wrote:

> Hi Andreas,
>
> On 26/07/20 11:03 PM, Andreas Schwab wrote:
>> On Jul 26 2020, Michael Schmitz wrote:
>>
>>> No particular reason - I had seen testb used in the syscall entry code and
>> Where?  That may be bugs.
>
> Here:
>
> ENTRY(ret_from_signal)
>         movel   %curptr@(TASK_STACK),%a1
>         tstb    %a1@(TINFO_FLAGS+2)
>         jge     1f
>         jbsr    syscall_trace_leave
> 1:      RESTORE_SWITCH_STACK
>         addql   #4,%sp
> ....
>
> and here:
>
> ENTRY(system_call)
>         SAVE_ALL_SYS
>
>         GET_CURRENT(%d1)
>         movel   %d1,%a1
>
>         | save top of frame
>         movel   %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
>
>         | syscall trace?
>         tstb    %a1@(TINFO_FLAGS+2)
>         jmi     do_trace_entry
>         cmpl    #NR_syscalls,%d0
>         jcc     badsys
>

How is that relevant?  That is testing a single bit, of course.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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