Lawrence Gold napisał(a):
> On Nov 28, 2005, at 2:29 AM, Adam D. Moss wrote:
>
>> Julian is using a processor (implied by -march=prescott) which supports
>> the NX bit. SELinux (or a kernel reconfig, or Linux 2.6.8+ by default)
>> may very well be configured to enable no-execute on process data pages,
>> which is a nice security move but would cause a fault as soon as a
>> process jumps to dynamically generated code in a data/heap area,
>> as I would guess dynarec cores and many other JITs do.
>>
>> I think that execute-protection can be lowered by mmapping the
>> appropriate area with PROT_EXEC, or using mprotect, though I've
>> never had the hardware to try.
>
>
> Good idea. I'd forgotten about the NX bit.
>
> Julian: Look for HAVE_MPROTECT in the makefile. I don't think this has
> ever been tested, so you'll be a guinea pig. :-)
>
> Thanks.
>
>
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I have enabled HAVE_MPROTECT, now the backtrace is different:
(gdb) bt
#0 0x08501f04 in drc_cache_reset (drc=0x0) at src/x86drc.c:114
#1 0x0835ac3e in ppcdrc603_reset (param=0xab12c60)
at src/cpu/powerpc/ppcdrc.c:1135
#2 0x080ac3fd in cpunum_reset (cpunum=0, param=0xab12c60,
irqack=0x80aa616 <cpu_0_irq_callback>) at src/cpuintrf.c:1460
#3 0x080a68c2 in cpu_pre_run () at src/cpuexec.c:410
#4 0x080a694b in cpu_run () at src/cpuexec.c:462
#5 0x080fb6b1 in run_machine_core () at src/mame.c:598
#6 0x080fb550 in run_machine () at src/mame.c:529
#7 0x080fb268 in run_game (game=2968) at src/mame.c:361
#8 0x09ed0aec in main (argc=2, argv=0xbfa6ec74) at src/unix/main.c:104
(gdb)
The othe with HAVE_MPROTECT disabled:
(gdb) bt
#0 0x08502056 in drc_execute (drc=0xd47e908) at src/x86drc.c:156
#1 0x0835ac66 in ppcdrc603_execute (cycles=833333)
at src/cpu/powerpc/ppcdrc.c:1155
#2 0x080ac343 in cpunum_execute (cpunum=0, cycles=833333)
at src/cpuintrf.c:1444
#3 0x080a74b8 in cpu_timeslice () at src/cpuexec.c:1042
#4 0x080a6951 in cpu_run () at src/cpuexec.c:477
#5 0x080fb671 in run_machine_core () at src/mame.c:598
#6 0x080fb510 in run_machine () at src/mame.c:529
#7 0x080fb228 in run_game (game=2968) at src/mame.c:361
#8 0x09ed0a76 in main (argc=2, argv=0xbfe6ad84) at src/unix/main.c:104
(gdb)
Maybe we're getting somewhere? Moreover, a selinux and kernel update
have arrived. I'll check them as soon as livna releases updated kernel
modules. Greets.
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