Re: [PATCH] ARM: add a private asm/unaligned.h

From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Aaro Koskinen <aaro.koskinen@iki.fi>,
	Petr Cvek <petrcvekcz@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Russell King - ARM Linux <linux@armlinux.org.uk>,
	Andrea Adami <andrea.adami@gmail.com>,
	Romain Izard <romain.izard.pro@gmail.com>,
	Sven Schmidt <4sschmid@informatik.uni-hamburg.de>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] ARM: add a private asm/unaligned.h
Date: Mon, 30 Oct 2017 15:35:38 +0000	[thread overview]
Message-ID: <CAKv+Gu-wOaxV+O5hkDxfvOY7gy5KwnCvvsd6XGTwfnro=dVbcw@mail.gmail.com> (raw)
In-Reply-To: <871slk3b2k.fsf@free-electrons.com>

On 30 October 2017 at 15:33, Gregory CLEMENT
<gregory.clement@free-electrons.com> wrote:
> Hi Ard,
>
>  On lun., oct. 30 2017, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>
>> On 30 October 2017 at 15:09, Gregory CLEMENT
>> <gregory.clement@free-electrons.com> wrote:
>>> Hi Ard,
>>>
>>>  On lun., oct. 30 2017, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>>>
>>>> On 30 October 2017 at 15:05, Gregory CLEMENT
>>>> <gregory.clement@free-electrons.com> wrote:
>>>>> Hi Ard,
>>>>>
>>>>>  On lun., oct. 30 2017, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>>>>>
>>>> ...
>>>>>>
>>>>>> Could you please share the output of 'readelf -S' for those vmlinux
>>>>>> decompressor images?
>>>>>
>>>>> Here it is:
>>>>>
>>>>> In the meantime I also used an arm-linux-gnueabihf- in case it could be
>>>>> related to the toolchain, I had te same issue and here it is the readelf
>>>>> output:
>>>>> arm-linux-gnueabi-readelf -S ../build/vmlinux
>>>>
>>>> Actually, I meant the 'vmlinux' file in arch/arm/boot/compressed, not
>>>> the main one.
>>>
>>> Here it is then:
>>>
>>> arm-linux-gnueabi-readelf -S ../build/arch/arm/boot/compressed/vmlinux
>>> There are 22 section headers, starting at offset 0x4b3e14:
>>>
>>> Section Headers:
>>>   [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
>>>   [ 0]                   NULL            00000000 000000 000000 00      0   0  0
>>>   [ 1] .text             PROGBITS        00000000 010000 005ef8 00  AX  0   0 32
>>>   [ 2] .rodata           PROGBITS        00005ef8 015ef8 000d4c 00   A  0   0  4
>>>   [ 3] .piggydata        PROGBITS        00006c44 016c44 48a33a 00   A  0   0  1
>>>   [ 4] .got.plt          PROGBITS        00490f80 4a0f80 00000c 04  WA  0   0  4
>>>   [ 5] .got              PROGBITS        00490f8c 4a0f8c 000028 00  WA  0   0  4
>>>   [ 6] .pad              PROGBITS        00490fb4 4a0fb4 000004 00  WA  0   0  1
>>>   [ 7] .bss              NOBITS          00490fb8 4a0fb8 00001c 00  WA  0   0  4
>>>   [ 8] .stack            NOBITS          00490fd8 4a0fb8 001000 00  WA  0   0  1
>>>   [ 9] .comment          PROGBITS        00000000 4a0fb8 00001c 01  MS  0   0  1
>>>   [10] .ARM.attributes   ARM_ATTRIBUTES  00000000 4a0fd4 00002d 00      0   0  1
>>>   [11] .debug_line       PROGBITS        00000000 4a1001 00281b 00      0   0  1
>>>   [12] .debug_info       PROGBITS        00000000 4a381c 0066cb 00      0   0  1
>>>   [13] .debug_abbrev     PROGBITS        00000000 4a9ee7 0013ea 00      0   0  1
>>>   [14] .debug_aranges    PROGBITS        00000000 4ab2d8 0001a8 00      0   0  8
>>>   [15] .debug_str        PROGBITS        00000000 4ab480 0019b4 01  MS  0   0  1
>>>   [16] .debug_ranges     PROGBITS        00000000 4ace38 000640 00      0   0  8
>>>   [17] .debug_frame      PROGBITS        00000000 4ad478 001010 00      0   0  4
>>>   [18] .debug_loc        PROGBITS        00000000 4ae488 003643 00      0   0  1
>>>   [19] .symtab           SYMTAB          00000000 4b1acc 0015b0 10     20 225  4
>>>   [20] .strtab           STRTAB          00000000 4b307c 000cc5 00      0   0  1
>>>   [21] .shstrtab         STRTAB          00000000 4b3d41 0000d2 00      0   0  1
>>> Key to Flags:
>>>   W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
>>>   L (link order), O (extra OS processing required), G (group), T (TLS),
>>>   C (compressed), x (unknown), o (OS specific), E (exclude),
>>>   y (purecode), p (processor specific)
>>>
>>
>> And this is from the build the build that generated the linker assert?
>
> Humm no, actually it was with the wrong branch. If I have the patch
> "ARM: verify size of zImage" then arch/arm/boot/compressed/vmlinux is
> not generated.
>
> But if I remove this patch then I can generate this file and so:
> arm-linux-gnueabi-readelf -S ../build/arch/arm/boot/compressed/vmlinux
> There are 22 section headers, starting at offset 0x4b402c:
>
> Section Headers:
>   [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
>   [ 0]                   NULL            00000000 000000 000000 00      0   0  0
>   [ 1] .text             PROGBITS        00000000 010000 005ef8 00  AX  0   0 32
>   [ 2] .rodata           PROGBITS        00005ef8 015ef8 000d4c 00   A  0   0  4
>   [ 3] .piggydata        PROGBITS        00006c44 016c44 48a552 00   A  0   0  1
>   [ 4] .got.plt          PROGBITS        00491198 4a1198 00000c 04  WA  0   0  4
>   [ 5] .got              PROGBITS        004911a4 4a11a4 000028 00  WA  0   0  4
>   [ 6] .pad              PROGBITS        004911cc 4a11cc 000004 00  WA  0   0  1
>   [ 7] .bss              NOBITS          004911d0 4a11d0 00001c 00  WA  0   0  4
>   [ 8] .stack            NOBITS          004911f0 4a11d0 001000 00  WA  0   0  1
>   [ 9] .comment          PROGBITS        00000000 4a11d0 00001c 01  MS  0   0  1
>   [10] .ARM.attributes   ARM_ATTRIBUTES  00000000 4a11ec 00002d 00      0   0  1
>   [11] .debug_line       PROGBITS        00000000 4a1219 00281b 00      0   0  1
>   [12] .debug_info       PROGBITS        00000000 4a3a34 0066cb 00      0   0  1
>   [13] .debug_abbrev     PROGBITS        00000000 4aa0ff 0013ea 00      0   0  1
>   [14] .debug_aranges    PROGBITS        00000000 4ab4f0 0001a8 00      0   0  8
>   [15] .debug_str        PROGBITS        00000000 4ab698 0019b4 01  MS  0   0  1
>   [16] .debug_ranges     PROGBITS        00000000 4ad050 000640 00      0   0  8
>   [17] .debug_frame      PROGBITS        00000000 4ad690 001010 00      0   0  4
>   [18] .debug_loc        PROGBITS        00000000 4ae6a0 003643 00      0   0  1
>   [19] .symtab           SYMTAB          00000000 4b1ce4 0015b0 10     20 225  4
>   [20] .strtab           STRTAB          00000000 4b3294 000cc5 00      0   0  1
>   [21] .shstrtab         STRTAB          00000000 4b3f59 0000d2 00      0   0  1
>
>>
>> Could you check the value of _edata in the output of 'nm vmlinux'
>> please?
> With this kernel:
>
> arm-linux-gnueabi-nm  ../build/arch/arm/boot/compressed/vmlinux | grep _edata
> 004911d0 D _edata
>

Well, that is disappointing. This means the ASSERT() does not work
reliably, and we're back to using a bunch of shell scripts to check
whether _edata appears at the end of the image.

Which version of binutils are you using?