On 03/24/2016 08:08 PM, Sergey Kubushyn wrote:
On Thu, 24 Mar 2016, Marek Vasut wrote:
On 03/24/2016 07:43 PM, Sergey Kubushyn wrote:
On Thu, 24 Mar 2016, Sergey Kubushyn wrote:
On Thu, 24 Mar 2016, Marek Vasut wrote:
On 03/24/2016 12:54 AM, Sergey Kubushyn wrote:
On Thu, 24 Mar 2016, Marek Vasut wrote: >> On 03/24/2016 12:47 AM, Sergey Kubushyn wrote: >> On Thu, 24 Mar 2016, Marek Vasut wrote: >>>>>> On 03/24/2016 12:08 AM, Tom Rini wrote: >>>> On Wed, Mar 23, 2016 at 04:02:07PM -0700, Sergey Kubushyn
wrote:
>>>>> On Wed, 23 Mar 2016, Tom Rini wrote: >>>>>>>>>>>> On Wed, Mar 23, 2016 at 06:08:45PM +0100,
Albert ARIBAUD > > > > > > > wrote:
>>>>>>> Hello Tom, >>>>>>>>>>>>>>> On Wed, 23 Mar 2016 09:22:38 -0400,
Tom Rini > > > > > > > > trini@konsulko.com
>>>>>>> wrote: >>>>>>>> On Wed, Mar 23, 2016 at 01:53:35PM +0100, Albert
ARIBAUD > > > > > > > > > wrote:
>>>>>>>>> Hello Marek, >>>>>>>>>>>>>>>>>>> On Sun, 20 Mar 2016 17:15:34
+0100, Marek Vasut > > > > > > > > > > marex@denx.de
>>>>>>>>> wrote: >>>>>>>>>> This patch decouples U-Boot binary from the > >>>>>>>>> toolchain on >>>>>>>>>> systems where >>>>>>>>>> private libgcc is available. Instead of
pulling in > > > > > > > > > > > functions
>>>>>>>>>> provided >>>>>>>>>> by the libgcc from the toolchain, U-Boot will
use > > > > > > > > > > > it's own set
>>>>>>>>>> of libgcc >>>>>>>>>> functions. These functions are usually
imported from > > > > > > > > > > > Linux
>>>>>>>>>> kernel, which >>>>>>>>>> also uses it's own libgcc functions instead of
the > > > > > > > > > > > ones
>>>>>>>>>> provided by the >>>>>>>>>> toolchain. >>>>>>>>>>>>>>>>>>>>> This patch solves a
rather common problem. The > > > > > > > > > > > toolchain can
>>>>>>>>>> usually >>>>>>>>>> generate code for many variants of target > > >>>>>>>> architecture and >>>>>>>>>> often even >>>>>>>>>> different endianness. The libgcc on the other
hand > > > > > > > > > > > is usually
>>>>>>>>>> compiled >>>>>>>>>> for one particular configuration and the
functions > > > > > > > > > > > provided by
>>>>>>>>>> it may >>>>>>>>>> or may not be suited for use in U-Boot. This
can > > > > > > > > > > > manifest in
>>>>>>>>>> two ways, >>>>>>>>>> either the U-Boot fails to compile altogether
and > > > > > > > > > > > linker will
>>>>>>>>>> complain >>>>>>>>>> or, in the much worse case, the resulting
U-Boot > > > > > > > > > > > will build,
>>>>>>>>>> but will >>>>>>>>>> misbehave in very subtle and hard to debug ways. >>>>>>>>>>>>>>>>>>> I don't think using private
libgcc by default is a > > > > > > > > > > good idea.
>>>>>>>>>>>>>>>>>>> U-Boot's private libgcc is
not a feature of U-Boot, > > > > > > > > > > but a fix
>>>>>>>>> for some >>>>>>>>> cases where a target cannot properly link with
the > > > > > > > > > > libgcc
>>>>>>>>> provided by >>>>>>>>> the (specific release of the) GCC toolchain in
use. > > > > > > > > > > Using
>>>>>>>>> private libgcc >>>>>>>>> to other cases than these does not fix or
improve > > > > > > > > > > anything; those
>>>>>>>>> other cases were working and did not require any
fix > > > > > > > > > > in this
>>>>>>>>> respect. >>>>>>>>>>>>>>>>> This isn't true, exactly. If
using clang for example > > > > > > > > > everyone
>>>>>>>> needs to >>>>>>>> enable this code. We're also using -fno-builtin > >>>>>>> -ffreestanding >>>>>>>> which >>>>>>>> should limit the amount of interference from the > >>>>>>> toolchain. And >>>>>>>> we get >>>>>>>> that. >>>>>>>>>>>>>>> You mean clang does not produce
self-sustained binaries?
>>>>>>>>>>>>> clang does not provide "libgcc", so
there's no -lgcc > > > > > > > providing
>>>>>> all of >>>>>> the functions that are (today) in: >>>>>> _ashldi3.S _ashrdi3.S _divsi3.S _lshrdi3.S _modsi3.S >>>>>> _udivsi3.S >>>>>> _umodsi3.S div0.S _uldivmod.S >>>>>> which aside from __modsi3 and __umodsi3 are all
__aeabi_xxx
>>>>>>>>>>> There is also _udivmoddi4 pulled from libgcc
for 64-bit > > > > > > division
>>>>> since we >>>>> switched to 64-bit all around ARM. It comes from clock >>>>> calculations for >>>>> video, e.g. from drivers/video/ipu_common.c for i.MX6. >>>>>>>>> Well, this is an example of why we both don't
want libgcc ever > > > > > nor
>>>> do we >>>> want to overly expand what we do offer. In this case
isn't it > > > > > an
>>>> example of something that should be using lldiv/do_div/etc? >>>>>>> I haven't seen the _udivmoddi4 emitted in my tests.
Linux's libgcc > > > > copy
>>> also doesn't implement the function. Which toolchain do you
use > > > > and
>>> which target did you compile? >>>>> I'm using my own armv7hl-linux-gnueabi toolchain built
for hard > > > float.
>> Linux >> arm libgcc does have arch/arm/lib/div64.S file that provides >> __do_div64() >> function that is used by do_div() from include/asm/div64.h for >> 32-bit >> ARM >> platform. Sure, arm64 has neither div64.h nor div64.S. We _DO_
have
>> div64.h >> (that is totally different from what Linux provides) but no
div64.S > > > in
>> arch/arm/lib. >>> In that case, we should just import div64.S from Linux on
arm32 and be
> done with it ? Since we now have all the necessary macros thanks
to > > the
> first four patches in this series, that should be trivial. >>> What do you think? I can bake a patch real quick, so you can
test it ?
> Sure I'll test it, no problems. Just bake the patch :)
Done, give it a go please.
OK, it didn't work, _udivmoddi4.o is still being pulled from libgcc. I'm analyzing it right now, will come up with more later today.
OK, it requires a CONFIG_USE_PRIVATE_LIBGCC defined to use private libgcc, my bad -- thought it would be automatic. Having that defined makes build fail complaining about assembly syntax in div64.S:
=== Cut === arch/arm/lib/div64.S: Assembler messages: arch/arm/lib/div64.S:185: Error: bad instruction `arm( orr r2,r2,r1,lsl ip)' arch/arm/lib/div64.S:186: Error: bad instruction `thumb( lsl r1,r1,ip)' arch/arm/lib/div64.S:187: Error: bad instruction `thumb( orr r2,r2,r1)' scripts/Makefile.build:316: recipe for target 'arch/arm/lib/div64.o' failed make[1]: *** [arch/arm/lib/div64.o] Error 1 Makefile:1214: recipe for target 'arch/arm/lib' failed make: *** [arch/arm/lib] Error 2 === Cut ===
Probably something is missing in div64.h? The Linux one is totally different. Digging in right now...
Are you building the stuff with all of these 5+1 patches ?
Nope. Aren't those already in U-Boot master? I pulled the latest master and thought those were there. If not would you please send me those 5 patches so I wouldn't have to hunt them through archives?
I'll send you all six off-list.
Best regards, Marek Vasut