Re: Debugging Epiphany/Midori (webkit-gtk based) on earmv6hf (RPI 2)

[Rhialto]

On Thu 08 Oct 2015 at 17:59:22 +, Stephan wrote:
> IMHO it would be valid to pass the value of sp as the first argument
> (mov r0, sp). However, the way how r0 is computed looks quite
> obfuscated to me:
> 
>0x4621402c : mov r3, sp=> ?
>0x46214030 : lsr r7, r3, #3   => ?
>0x46214034 : lsl r4, r7, #3   => ?
...
>0x46214040 : mov r0, r4  => ?

I don't really know any ARM assembly but it seems that the value from sp
is shifted right 3 bits and then left again. In effect clearing the low
3 bits, or aligning to 8. Which by itself is a very sensible thing to do
for an allocator.

Unfortunately (since it rounds down) it can have the effect of
allocating the memory lower than sp, which is bound to fail at some
point. Probably the value should also go back into sp.

There is also an alloca in libc: cvs/src/lib/libc/arch/arm/gen/alloca.S.
It uses a similar shifting trick but it uses it to round up the
allocation size to multiples of 8, and it does end up with the same
value in r0 and sp.

-Olaf.
-- 
___ Olaf 'Rhialto' Seibert  -- The Doctor: No, 'eureka' is Greek for
\X/ rhialto/at/xs4all.nl-- 'this bath is too hot.'


pgpFCM8YmMK22.pgp
Description: PGP signature

Automated report: NetBSD-current/i386 build failure

[NetBSD Test Fixture]

This is an automatically generated notice of a NetBSD-current/i386
build failure.

The failure occurred on babylon5.NetBSD.org, a NetBSD/amd64 host,
using sources from CVS date 2015.10.11.01.01.45.

An extract from the build.sh output follows:

--- dependall-lua ---

/tmp/bracket/build/2015.10.11.01.01.45-i386/src/sys/../external/mit/lua/dist/src/lobject.c:
 In function 'luaO_tostring':

/tmp/bracket/build/2015.10.11.01.01.45-i386/src/sys/../external/mit/lua/dist/src/lobject.c:373:42:
 error: macro "lua_integer2str" requires 3 arguments, but only 2 given
   len = lua_integer2str(buff, ivalue(obj));
  ^

/tmp/bracket/build/2015.10.11.01.01.45-i386/src/sys/../external/mit/lua/dist/src/lobject.c:373:9:
 error: 'lua_integer2str' undeclared (first use in this function)
   len = lua_integer2str(buff, ivalue(obj));
 ^

/tmp/bracket/build/2015.10.11.01.01.45-i386/src/sys/../external/mit/lua/dist/src/lobject.c:373:9:
 note: each undeclared identifier is reported only once for each function it 
appears in
*** [lobject.o] Error code 1
nbmake[8]: stopped in 
/tmp/bracket/build/2015.10.11.01.01.45-i386/src/sys/modules/lua
1 error

The following commits were made between the last successful build and
the failed build:

2015.10.11.00.58.24 dholland src/share/misc/acronyms.comp,v 1.151
2015.10.11.01.01.45 christos src/external/mit/lua/dist/src/lobject.c,v 1.6
2015.10.11.01.01.45 christos src/external/mit/lua/dist/src/lstrlib.c,v 1.10
2015.10.11.01.01.45 christos src/external/mit/lua/dist/src/luac.c,v 1.5
2015.10.11.01.01.45 christos src/external/mit/lua/dist/src/luaconf.h,v 1.15

Log files can be found at:


http://releng.NetBSD.org/b5reports/i386/commits-2015.10.html#2015.10.11.01.01.45

daily CVS update output

[NetBSD source update]

Updating src tree:
P src/distrib/sets/lists/base/mi
P src/doc/3RDPARTY
P src/doc/CHANGES
P src/etc/mtree/Makefile
U src/etc/mtree/NetBSD.dist.dtrace
P src/lib/libc/time/Makefile
P src/lib/libc/time/NEWS
P src/lib/libc/time/localtime.c
P src/lib/libc/time/private.h
P src/lib/libc/time/strftime.c
P src/lib/libc/time/strptime.c
P src/lib/libc/time/tz-art.htm
P src/lib/libc/time/tz-link.htm
P src/lib/libc/time/tzfile.5
P src/lib/libc/time/zic.c
P src/share/man/man5/rc.conf.5
P src/sys/arch/arm/allwinner/awin_debe.c
P src/sys/arch/x86/x86/intr.c
P src/tools/compat/fgetln.c
P src/usr.bin/tail/forward.c

Updating xsrc tree:


Killing core files:


Updating tar files:
src/top-level: collecting... replacing... done
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src/x11: collecting...pax: Unable to access src/x11 (No such file or directory)
pax: WARNING! These file names were not selected:
src/x11
 done
src: collecting... replacing... done
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xsrc/xfree: collecting...pax: Unable to access xsrc/xfree (No such file or 
directory)
pax: WARNING! These file names were not selected:
xsrc/xfree
 done
xsrc: collecting... replacing... done

Running the SUP scanner:
SUP Scan for current starting at Sat Oct 10 04:13:14 2015
SUP Scan for current completed at Sat Oct 10 04:15:51 2015
SUP Scan for mirror starting at Sat Oct 10 04:15:51 2015
SUP Scan for mirror completed at Sat Oct 10 04:24:13 2015



Updating release-5 src tree (netbsd-5):

Updating release-5 xsrc tree (netbsd-5):


Updating release-5 tar files:
src/top-level: collecting... replacing... done
src/bin: collecting... replacing... done
src/common: collecting... replacing... done
src/compat: collecting... replacing... done
src/crypto: collecting... replacing... done
src/dist: collecting... replacing... done
src/distrib: collecting... replacing... done
src/doc: collecting... replacing... done
src/etc: collecting... replacing... done
src/external: collecting... replacing... done
src/games: collecting... replacing... done
src/gnu: collecting... replacing... done
src/include: collecting... replacing... done
src/lib: collecting... replacing... done
src/libexec: collecting... replacing... done
src/regress: collecting... replacing... done
src/rescue: collecting... replacing... done
src/sbin: collecting... replacing... done
src/share: collecting... replacing... done
src/sys: collecting... replacing... done
src/tests: collecting... replacing... done
src/tools: collecting... replacing... done
src/usr.bin: collecting... replacing... done
src/usr.sbin: collecting... replacing... done
src/config: collecting... replacing... done
src/x11: collecting... replacing... done
src: collecting... replacing... done
xsrc/top-level: collecting... replacing... done
xsrc/local: collecting... replacing... done
xsrc/xfree: collecting... replacing... done
xsrc/external: collecting... replacing... done
xsrc: collecting... replacing... done

Running the SUP scanner:
SUP Scan for release-5 starting at Sat Oct 10 05:48:41 2015
SUP Scan for release-5 completed at Sat Oct 10 05:48:48 2015



Updating release-6 src tree (netbsd-6):

Updating release-6 xsrc tree (netbsd-6):


Updating release-6 tar files:
src/top-level: collecting... replacing... done
src/bin: collecting... replacing... done
src/common: collecting... replacing... done
src/compat: collecting... replacing... done
src/crypto: collecting... replacing... done
src/dist: collecting... replacing... done
src/distrib: collecting... replacing... done
src/doc: collecting... replacing... done
src/etc: collecting... replacing... done
src/external: collecting... replacing... done
src/extsrc: collecting... replacing... done
src/games: collecting... replacing... done
src/gnu: collecting... replacing... done
src/include: collecting... replacing... done
src/lib: collecting... replacing... done
src/libexec: