Re: Seccomp support for linux-m68k

Michael Schmitz
2020-07-26T21:02:18Z

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

....

plus when saving the FPU context on resume (the comment there suggests
FPUs keep 8 bits of status that must be tested, so that should be OK).

Cheers,

Michael

>
> Andreas.
>