Tags 695547 +patch
Thanks
On 05/07/16 23:37, Steve McIntyre wrote:
So Peter and I were talking a little earlier on #debian-arm,
Specifically we were talking about the arm tag/flag stuff. I haven't
looked into the powerpc issue. Freepascal has a chunk of platform/cpu
specific assembler code that is used for mixed pascal/c programs to
initialise both the freepascal runtime library and libc. The powerpc
linux version of this file is located at rtl/linux/powerpc/cprt0.as . It
would not surprise me if it was something to do with this init code.
It would be good to try and get a backtrace ("access violation"
generally means that the freepascal runtime library trapped a segfault
and turned it into an exception).
The remainder of this mail is about the arm tag/flag stuff.
and he
was making good progress on fixing stuff. He may have stuff all done
shortly, I guess... :-)
I think i've fixed the arm tag/flag stuff. With the small patch attached
I get the following.
root@odroidu2:/# readelf --file-header /usr/bin/fpc
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: ARM
Version: 0x1
Entry point address: 0x100ec
Start of program headers: 52 (bytes into file)
Start of section headers: 410616 (bytes into file)
Flags: 0x5000400, Version5 EABI, hard-float ABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 4
Size of section headers: 40 (bytes)
Number of section headers: 8
Section header string table index: 7
root@odroidu2:/#
root@odroidu2:/# readelf -a /usr/bin/fpc
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class: ELF32
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: ARM
Version: 0x1
Entry point address: 0x100ec
Start of program headers: 52 (bytes into file)
Start of section headers: 410616 (bytes into file)
Flags: 0x5000400, Version5 EABI, hard-float ABI
Size of this header: 52 (bytes)
Size of program headers: 32 (bytes)
Number of program headers: 4
Size of section headers: 40 (bytes)
Number of section headers: 8
Section header string table index: 7
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .note.ABI-tag NOTE 000100c0 0000c0 000020 00 A 0 0 16
[ 2] .text PROGBITS 000100e0 0000e0 0501a4 00 AX 0 0 4
[ 3] .rodata PROGBITS 00060288 050288 010828 00 A 0 0 8
[ 4] .data PROGBITS 00081000 061000 003395 00 WA 0 0 8
[ 5] .bss NOBITS 00084398 064395 00237c 00 WA 0 0 4
[ 6] .ARM.attributes ARM_ATTRIBUTES 00000000 064395 000021 00 0 0 1
[ 7] .shstrtab STRTAB 00000000 0643b6 000042 00 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
There are no section groups in this file.
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x000000 0x00010000 0x00010000 0x60ab0 0x60ab0 R E 0x10000
LOAD 0x061000 0x00081000 0x00081000 0x03395 0x05714 RW 0x10000
NOTE 0x0000c0 0x000100c0 0x000100c0 0x00020 0x00020 R 0x10
GNU_STACK 0x000000 0x00000000 0x00000000 0x00000 0x00000 RW 0x10
Section to Segment mapping:
Segment Sections...
00 .note.ABI-tag .text .rodata
01 .data .bss
02 .note.ABI-tag
03
There is no dynamic section in this file.
There are no relocations in this file.
There are no unwind sections in this file.
No version information found in this file.
Displaying notes found at file offset 0x000000c0 with length 0x00000020:
Owner Data size Description
GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
OS: Linux, ABI: 2.0.0
Attribute Section: aeabi
File Attributes
Tag_CPU_name: "7-A"
Tag_CPU_arch: v7
Tag_CPU_arch_profile: Application
Tag_ARM_ISA_use: Yes
Tag_THUMB_ISA_use: Thumb-2
Tag_FP_arch: VFPv3-D16
Tag_ABI_VFP_args: VFP registers
root@odroidu2:/#
Which looks good to me, does it look ok to others here?
Some extracts from IRC for future reference.
<plugwash> does anyone know where I can find a decoder for
.eabi_attribute statements ?
<--snip-->
* plugwash is trying to decipher the output of gcc -S but is struggling
to find a list anywhere of what the numbers mean
<Sledge> ok...
<--snip-->
<Sledge> plugwash: I just tend to use readelf -A
<plugwash> what i'm trying to figure out is what I need to make fpc put
in it's assembler files so the binaries come out tagged correctly
<Sledge> ack
<Sledge> I'm looking myself again, I added this stuff in binutils after all
<Sledge> but it's been a while
<Sledge> waiting on downloads ...
<--snip-->
<Sledge> plugwash: look at 3bfcb6528e6fb6a324b2e119f50f72a0674a1402 in
git://sourceware.org/git/binutils-gdb.git for inspiration, maybe
* Sicelo009N (~sicelo@137.158.22.65) has joined #debian-arm
<Sledge> (unfortunately that's a few changes pushed together)
<plugwash> looks like the numbers are in elfcpp/arm.h in the binutils source
<Sledge> yup
<plugwash> one thing that is puzzling me, how do tags relate to flags?
<Sledge> tags are in the attributes section, and are basically a list
<Sledge> flags are specifically added in the ELF header to make them
easier to work with
<Sledge> (not sure if that's what you're asking)
<plugwash> more what I was meaning is where do flags come from?
<Sledge> ah, ok
<plugwash> does the compiler have to set them explicitly? (and if so
how?) does the linker turn tags into flags? something else?
<vagrantc> when one flag loves another flag...
<Sledge> vagrantc: :-)
<Sledge> plugwash: the compiler will set tags on various objects as it runs
<Sledge> the linker will check for the union of the tags and flags set
and set flags appropriately on the output objects
<Sledge> elf32_arm_post_process_headers() is important here
<plugwash> right, so If I set the tags correctly binutils should set the
flags correctly?
<plugwash> ok, it seems .o files have meaninful tags but not meaninful flags
* TiN (~t...@00018ff4.user.oftc.net) has joined #debian-arm
<plugwash> ok, just tested it looks like tags in the assembler file
remain as tags in the .o file and are then converted to flags by the linker.
<Sledge> yup
<plugwash> i'm guessing the critical tag is Tag_ABI_VFP_args correct?
<plugwash> looks like it, removing that tag results in a change of flags
<Sledge> yeah
<Sledge> (sorry, just changed rooms here)
* Sicelo009N has quit (Read error: Connection reset by peer)
<plugwash> ok, now to try and insert that into freepascal
* Sicelo009N (~sicelo@137.158.22.65) has joined #debian-arm
<plugwash> i've just make a change to fpc which I hope will fix this,
now for a testbuild
<Sledge> woo
<plugwash> btw one thing i've noticed about this issue is it only seems
to affect "pure" pascal binaries, binaries that link against libc seem
to pick up the tags from somewhere
<plugwash> I gtg
<Sledge> right
<Sledge> the things linking with libc will probably end up getting the
right flags automatically by merging with the libc flags
diff -Nru fpc-3.0.0+dfsg/debian/changelog fpc-3.0.0+dfsg/debian/changelog
--- fpc-3.0.0+dfsg/debian/changelog 2016-06-02 19:43:38.000000000 +0000
+++ fpc-3.0.0+dfsg/debian/changelog 2016-07-05 13:14:03.000000000 +0000
@@ -1,3 +1,9 @@
+fpc (3.0.0+dfsg-7) unstable; urgency=medium
+
+ * Add elf tag to mark hardfp binaries as such. (Closes: 695547)
+
+ -- Peter Michael Green <plugw...@debian.org> Tue, 05 Jul 2016 13:11:56 +0000
+
fpc (3.0.0+dfsg-6) unstable; urgency=medium
* Fix FTBFS due to wrong logic for latex files, we only need to ship
diff -Nru fpc-3.0.0+dfsg/debian/patches/armhf-tags.patch
fpc-3.0.0+dfsg/debian/patches/armhf-tags.patch
--- fpc-3.0.0+dfsg/debian/patches/armhf-tags.patch 1970-01-01
00:00:00.000000000 +0000
+++ fpc-3.0.0+dfsg/debian/patches/armhf-tags.patch 2016-07-05
21:28:40.000000000 +0000
@@ -0,0 +1,16 @@
+Description: Add tags to make armhf binaries come out correctly.
+ Add elf tag to mark hardfp binaries as such. (Closes: 695547)
+Author: Peter Michael Green <plugw...@debian.org>
+Bug-Debian: https://bugs.debian.org/695547
+
+--- fpc-3.0.0+dfsg.orig/fpcsrc/compiler/arm/agarmgas.pas
++++ fpc-3.0.0+dfsg/fpcsrc/compiler/arm/agarmgas.pas
+@@ -135,6 +135,8 @@ unit agarmgas;
+ inherited WriteExtraHeader;
+ if TArmInstrWriter(InstrWriter).unified_syntax then
+ AsmWriteLn(#9'.syntax unified');
++ if target_info.abi = abi_eabihf then
++ AsmWriteLn(#9'.eabi_attribute 28, 1 @Tag_ABI_VFP_args');
+ end;
+
+ {****************************************************************************}
diff -Nru fpc-3.0.0+dfsg/debian/patches/series
fpc-3.0.0+dfsg/debian/patches/series
--- fpc-3.0.0+dfsg/debian/patches/series 2016-06-01 19:45:01.000000000
+0000
+++ fpc-3.0.0+dfsg/debian/patches/series 2016-07-05 21:27:47.000000000
+0000
@@ -33,3 +33,4 @@
Fixed-i386-case-jump-table-when-PIC-with-GOT-and-an-.patch
Fixed-calling-of-external-procs-for-i386-non-darwin-.patch
arm_UMULL_support_fix.patch
+armhf-tags.patch
