From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: your mail
Date: Tue, 21 Apr 2015 16:06:02 +0200 [thread overview]
Message-ID: <CAKv+Gu_KsgBau8f8ZmUpBZmD4chmRsD2126LcN5qeNEwcJH+oQ@mail.gmail.com> (raw)
In-Reply-To: <20150421135552.GX12732@n2100.arm.linux.org.uk>
On 21 April 2015 at 15:55, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Tue, Apr 21, 2015 at 02:18:03PM +0100, Dave P Martin wrote:
>> On Tue, Apr 21, 2015 at 01:50:50PM +0100, Russell King - ARM Linux wrote:
>> > On Tue, Apr 21, 2015 at 12:24:20PM +0100, Russell King - ARM Linux wrote:
>> > > We should probably create a badr macro to complement the adr pseudo-op
>> > > which incorporates the BSYM thing so make this clearer - and a comment
>> > > before it. This is really the case where BSYM should be used.
>> >
>> > Something like this. Note that I've also removed the BSYM() usage in
>> > the KVM code.
>>
>> Nice. Wrapping this around adr will make the assembler check that it's
>> not a cross-section reference too.
>
> While looking at this, I've become very upset with our toolchain's
> abilities. This is with stock binutils 2.22-2.25, and Ard's suggestion
> for using blx:
>
> 00000000 <secondary_startup_arm>:
> 0: fafffffe blx 4 <secondary_startup>
>
> 00000004 <secondary_startup>:
> 4: f7ff fffe bl 0 <__hyp_stub_install_secondary>
> 8: f3ef 8900 mrs r9, CPSR
> c: f089 091a eor.w r9, r9, #26
> 10: f019 0f1f tst.w r9, #31
>
> That's fine, but now if we look at the .head.text section (I also added
> an ENTRY(start) to try and solve this):
>
> 00000000 <stext>:
> 0: ffff faff ; <UNDEFINED> instruction: 0xfffffaff
>
> 00000004 <start>:
> 4: fffef7ff .word 0xfffef7ff
> 8: f3ef 8900 mrs r9, CPSR
> c: 091af089 .word 0x091af089
> 10: f019 0f1f tst.w r9, #31
> 14: 091ff029 .word 0x091ff029
> 18: 09d3f049 .word 0x09d3f049
> 1c: f049 0920 orr.w r9, r9, #32
> 20: f449d109 .word 0xf449d109
> 24: f20f7980 .word 0xf20f7980
> 28: 0e13 lsrs r3, r2, #24
> 2a: f399 .short 0xf399
> 2c: 8f00 ldrh r0, [r0, #56] ; 0x38
> 2e: f38e .short 0xf38e
> 30: f3de8e30 .word 0xf3de8e30
> 34: 8f00 .short 0x8f00
> 36: f389 8100 msr CPSR_c, r9
>
> readelf for this shows for section 5:
>
> Section Headers:
> [Nr] Name Type Addr Off Size ES Flg Lk Inf Al
> [ 5] .head.text PROGBITS 00000000 000290 000254 00 AX 0 0 4
> ...
> Num: Value Size Type Bind Vis Ndx Name
> 4: 00000000 0 SECTION LOCAL DEFAULT 5
> 5: 00000000 0 NOTYPE LOCAL DEFAULT 5 $a
> 6: 00000004 0 NOTYPE LOCAL DEFAULT 5 $t
> 7: 0000002e 0 NOTYPE LOCAL DEFAULT 5 $d
> 8: 00000036 0 NOTYPE LOCAL DEFAULT 5 $t
> ...
> 65: 00000000 4 FUNC GLOBAL DEFAULT 5 stext
> 66: 00000005 122 FUNC GLOBAL DEFAULT 5 start
>
> One has to wonder about the toolchain when the stupid $[adt] hack seems
> to be going soooo wrong.
>
> I think I'm going to stop working on this until we have a toolchain
> which behaves sensibly... when you can't get the damned thing to
> disassemble for confirmation purposes, its best to leave the damned
> code alone.
>
It indeed seems to be objdump that is failing, but the code itself
looks fine to me. For the record, binutils v2.23.52 works fine
next prev parent reply other threads:[~2015-04-21 14:06 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-21 10:18 No subject Ard Biesheuvel
2015-04-21 10:46 ` your mail Dave P Martin
2015-04-21 10:50 ` Ard Biesheuvel
2015-04-21 11:10 ` Dave P Martin
2015-04-21 11:15 ` Ard Biesheuvel
2015-04-21 11:24 ` Russell King - ARM Linux
2015-04-21 12:50 ` Russell King - ARM Linux
2015-04-21 13:10 ` Ard Biesheuvel
2015-04-21 13:21 ` Dave P Martin
2015-04-21 13:28 ` Ard Biesheuvel
2015-04-21 15:51 ` Dave Martin
2015-04-21 14:05 ` Russell King - ARM Linux
2015-04-21 13:18 ` Dave P Martin
2015-04-21 13:55 ` Russell King - ARM Linux
2015-04-21 14:06 ` Ard Biesheuvel [this message]
2015-04-21 17:03 ` Dave Martin
[not found] <20191026192359.27687-1-frank-w@public-files.de>
2019-10-26 19:30 ` Greg Kroah-Hartman
-- strict thread matches above, loose matches on Subject: below --
2017-06-04 11:59 No subject Yury Norov
2017-06-14 20:16 ` your mail Yury Norov
2014-10-28 14:13 No subject Mark Rutland
2014-10-28 14:19 ` your mail Mark Rutland
2012-06-21 18:26 No subject Paul Walmsley
2012-06-22 8:56 ` your mail Tony Lindgren
2011-12-02 16:01 No subject Will Deacon
2011-12-02 16:11 ` your mail Will Deacon
2011-05-13 19:35 No subject Vadim Bendebury
2011-05-14 3:32 ` your mail Jean-Christophe PLAGNIOL-VILLARD
2010-06-07 17:58 No subject Dave Hylands
2010-06-07 22:10 ` your mail Jamie Lokier
2010-06-07 22:44 ` Dave Hylands
2010-05-18 10:38 No subject Marek Szyprowski
2010-05-19 2:24 ` your mail Ben Dooks
[not found] <1250258343-14203-1-git-send-email-thierry.reding@avionic-design.de>
2009-10-02 14:53 ` Thierry Reding
2010-01-02 12:06 ` Russell King - ARM Linux
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