[syslinux] Only 2.5G of RAM available when syslinux64.efi boots 32-bit linux 686-pae

[Ady]

> Hello,
> 
> I'm booting linux-3.16-686-pae kernel (32-bit) via syslinux.efi 64-bit version.
> After boot linux sees only 2.5G of RAM while system has 32G installed.
> 
> If I boot the same kernel with GRUB64 efi instead of syslinux 
> then amount of RAM available to linux is 32G.
> 
> Is this a bug or I'm missing something?
> 
> syslinux.cfg:
> 
> label live-686-pae
>         menu label Linux (686-pae)
>         menu default
>         linux /live/vmlinuz
>         initrd /live/initrd.img
>         append boot=live config persistence username=user live-config.utc=no acpi_osi=Linux live-config.noautologin
> 
> 
> Current git: e0be4d87135
> 
> Regards,
> Andrey
 
 
It saddens (me) to see no reply to this email thread at all, especially 
from developers.

C'mon; really? Not even a comment asking to post the _complete_ content 
of the syslinux.cfg file?

No suggestion about kernel options such as 'mem=', 'vmalloc=' or any 
other / similar?

No question about the building environment (nasm, gnu-efi, gcc, 
binutils, mtools...)?

No chance that someone could suggest that updating the gnu-efi 
submodule _might_ _perhaps_ affect the result?

I cannot believe that there is not even one developer that could think 
(and post here) about the potential idea that some code in EFISTUB (or 
whatever is related to EFI in the Linux kernel) needs to be also 
incorporated in Syslinux. Really? There is not one person that could 
think that some development in the EFISTUB code (or similar) during the 
last year-and-a-half / two years might need to be ported to the 
Syslinux code too?

And what about fallback booting methods (a matter that has been 
mentioned here more than once, but it is not clear how much has been 
really done to completely support older kernels)? We have seen problems 
with kernels built with or without certain options in the past. There 
is really not even one subscriber to this Syslinux Mailing List that 
could suggest in this email thread that there might still be some issue 
regarding kernel building options when the kernel is booted by 
Syslinux?

Let's also not forget that Syslinux seems to be "more respectful" than 
GRUB2 when booting (u)efi images. Could this be a factor in how much 
RAM is seen after successfully booting the kernel?

I do not know the reason for the different behavior between 
syslinux.efi X64 and GRUB2.efi X64 when booting this 32-bit pae kernel, 
nor the answers to these questions, but I am at least trying.

Regards,
Ady.
 
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