This is the mail archive of the
mailing list for the binutils project.
Re: AARCH64 text start address: why so low?
- From: Matt Thomas <matt at 3am-software dot com>
- To: Andrew Pinski <pinskia at gmail dot com>
- Cc: binutils <binutils at sourceware dot org>
- Date: Mon, 20 Jan 2014 22:33:01 -0800
- Subject: Re: AARCH64 text start address: why so low?
- Authentication-results: sourceware.org; auth=none
- References: <209F1186-6425-4EB3-9DDE-7B7DCEAA8CE4 at 3am-software dot com> <CA+=Sn1kZ+qefjbUFWbMQBjzXG4=+rMeugawxpmtTrTkz9pUucA at mail dot gmail dot com> <CA+=Sn1n4pdVNYt1uPywRM+dYQ9By6PqPMd-ZDKnu5dmQcvs=Pw at mail dot gmail dot com>
On Jan 20, 2014, at 7:51 PM, Andrew Pinski <firstname.lastname@example.org> wrote:
> On Mon, Jan 20, 2014 at 7:50 PM, Andrew Pinski <email@example.com> wrote:
>> On Mon, Jan 20, 2014 at 7:46 PM, Matt Thomas <firstname.lastname@example.org> wrote:
>>> As I was looking at the aarch64 text start address for Linux, I
>>> wondered why it defaulted to 4MB (well within the first 4GB) instead
>>> of (like alpha, mips64 elf, sparc64, hppa64, etc.) defaulting to a
>>> starting address at or above 4GB.
>> Because that is the default one for all elf files. x86_64 is the
>> same as aarch64 here.
>>> Given there is a minimum of 39 address bits (512GB) of address space,
>>> skipping first 4 GB shouldn't be a problem.
>> I think it matters due to how the different code models work. The
>> default code model is small which means fit in the lower 4 GB. This
>> is just like x86_64's code models.
> And just like MIPS64 msym32 code model which we had this same
> discussion as we are having now for changing MIPS64 default load
> address too.
I primarily thought -msym32 was for kernels, not userland. I did wonder
about a -msym32 equivalent for aarch64.