rename open_issues.mdwn to service_solahart_jakarta_selatan__082122541663.mdwn

1 files changed, 0 insertions, 267 deletions

diff --git a/open_issues/arm_port.mdwn b/open_issues/arm_port.mdwn
deleted file mode 100644
index 26e0b770..00000000
--- a/open_issues/arm_port.mdwn
+++ /dev/null
@@ -1,267 +0,0 @@
-[[!meta copyright="Copyright © 2012, 2013, 2014 Free Software Foundation,
-Inc."]]
-
-[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
-id="license" text="Permission is granted to copy, distribute and/or modify this
-document under the terms of the GNU Free Documentation License, Version 1.2 or
-any later version published by the Free Software Foundation; with no Invariant
-Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
-is included in the section entitled [[GNU Free Documentation
-License|/fdl]]."]]"""]]
-
-Several people have expressed interested in a port of GNU/Hurd for the ARM
-architecture.
-
-
-# IRC, freenode, #hurd, 2012-07-28
-
-    <mcsim> Has anyone heard about porting hurd and gnu/mach to arm
-      architecture?
-    <braunr> mcsim: i think so
-    <braunr> mcsim: why are you asking ?
-    <mcsim> I found an article where author stated that he has ported hurd to
-      arm, but I have never met this information before.
-    <mcsim> He wrote ethernet driver and managed to use ping command
-    <mcsim> author's name is Sartakov Vasily
-    <braunr> well that's possible, a long time ago
-    <braunr> and it was probably not complete enough to be merged upstream
-    <braunr> like many other attempts at many other things
-    <mcsim> Not so long. Article is dated by June 2011.
-    <braunr> do you have a link ?
-    <mcsim> Yes, but it is in Russian.
-    <braunr> oh
-    <braunr> well i don't remember him sharing that with us
-    <antrik> mcsim: he did some work on porting Mach, but AIUI never got it
-      nearly finished
-    <antrik> nowadays he does L4 stuff
-    <antrik> was also at FOSDEM
-
-
-## IRC, freenode, #hurd, 2012-10-09
-
-    <mcsim> bootinfdsds: There was an unfinished port to arm, if you're
-      interested.
-    <tschwinge> mcsim: Has that ever been published?
-    <mcsim> tschwinge: I don't think so. But I have an email of that person and
-      I think that this could be discussed with him.
-
-
-## IRC, freenode, #hurd, 2012-10-10
-
-    <tschwinge> mcsim: If you have a contact to the ARM porter, could you
-      please ask him to post what he has?
-    <antrik> tschwinge: we all have the "contact" -- let me remind you that he
-      posted his questions to the list...
-
-
-## IRC, freenode, #hurd, 2012-10-17
-
-    <mcsim> tschwinge: Hello. The person who I wrote regarding arm port of
-      gnumach still hasn't answered. And I don't think that he is going to
-      answer.
-
-
-# IRC, freenode, #hurd, 2012-11-15
-
-    <matty3269> Well, I have a big interest in the ARM architecture, I worked
-      at ARM for a bit too, and I've written my own little OS that runs on
-      qemu. Is there an interest in getting hurd running on ARM?
-    <braunr> matty3269: not really currently
-    <braunr> but if that's what you want to do, sure
-    <tschwinge> matty3269: Well, interest -- sure!, but we don't really have
-      people savvy in low-level kernel implementation on ARM.  I do know some
-      bits about it, but more about the instruction set than about its memory
-      architecture, for example.
-    <tschwinge> matty3269: But if you're feeling adventurous, by all means work
-      on it, and we'll try to help as we can.
-    <tschwinge> matty3269: There has been one previous attempt for an ARM port,
-      but that person never published his code, and apparently moved to a
-      different project.
-    <tschwinge> matty3269: I can help with toolchains (GCC, etc.) things for
-      ARM, if there's need.
-    <matty3269> tschwinge: That sounds great, thanks! Where would you recommend
-      I start (at the moment I've got Mach checked out and am trying to get it
-      compiled for i386)
-    <matty3269> I'm guessing that the Mach micro-kernel is all that would need
-      to be ported or are there arch-dependant bits of code in the server
-      processes?
-    <tschwinge> matty3269:
-      http://www.gnu.org/software/hurd/faq/system_port.html has some
-      information.  Mach is the biggest part, yes.  Then some bits in glibc and
-      libpthread, and even less in the Hurd libraries and servers.
-    <tschwinge> matty3269: Basically, you'd need equivalents for the i386 (and
-      similar) directories, yep.
-    <tschwinge> Though, you may be able to avoid some cruft in there.
-    <tschwinge> Does building for x86 have any issues?
-    <tschwinge> matty3269: How is generally your understanding of the Hurd on
-      Mach system architecture, and on microkernel-based systems generally, and
-      on Mach in particular?
-    <matty3269> tschwinge: yes, it seems to be progressing... I've got mig
-      installed and it's just compiling now
-    <matty3269> hmm, not too great if I'm honest, I've done mostly monolithic
-      kernel development so having such low-level processes, such as
-      scheduling, done in user-space seems a little strinage
-    <tschwinge> Ah, yes, MIG will need a little bit of porting, too.  I can
-      help with that, but that's not a priority -- first you have to get Mach
-      to boot at all; MIG will only be needed once you need to deal with RPCs,
-      so user-land/kernel interaction, basically.  Before, you can hack around
-      it.
-    <matty3269> tschwinge: I have been running a GNU/Hurd system for a while
-      now though
-    <tschwinge> I'm happy to tell you that the schedules is still in the
-      kernel.  ;-)
-    <tschwinge> OK, good, so you know about the basic ideas.
-    <braunr> matty3269: there has to be machine specific stuff in user space
-    <braunr> for initial thread contexts for example
-    <matty3269> tschwinge: Ok, just got gnumach built
-    <braunr> but there isn't much and you can easily base your work from the
-      x86 implementation
-    <tschwinge> Yes.  Mach itself is the more difficult one.
-    <matty3269> braunr: Yeah, looking around at things, it doesn't seem that
-      there will be too much work involoved in the user-space stuff
-    <tschwinge> braunr: Do you know off-hand whether there are some old Mach
-      research papers describing architecture ports?
-    <tschwinge> I know there are some describing the memory system (obviously),
-      and I/O system -- which may help matty3269 to understand the general
-      design/structure.
-    <tschwinge> We might want to identify some documents, and make a list.
-    <braunr> all mach related documentation i have is available here:
-      ftp://ftp.sceen.net/mach/
-    <braunr> (also through http://)
-    <tschwinge> matty3269: Oh, definitely I'd suggest the Mach 3 Kernel
-      Principles book.  That gives a good description of the Mach architecture.
-    <matty3269> Great, that's my weekends reading then!
-    <braunr> you don't need all that for a port
-    <matty3269> Is it possible to run the gnumach binary standalone with qemu?
-    <braunr> you won't go far with it
-    <braunr> you really need at least one program
-    <braunr> but sure, for a port development, it can easily be done
-    <braunr> i'd suggest writing a basic static application for your tests once
-      you reach an advanced state
-    <braunr> the critical parts of a port are memory and interrupts
-    <braunr> and memory can be particularly difficult to implement correctly
-    <tschwinge> matty3269: I once used QEMU's
-      virtual-FAT-filesystem-from-a-directory-on-the-host, and configured GRUB
-      to boot from that one, so it was easy to quickly reboot for kernel
-      development.
-    <braunr> but the good news is that almost every bsd system still uses a
-      similar interface
-    <tschwinge> matty3269: And, you may want to become familiar with QEMU's
-      built-in gdbserver, and how to connect to and use that.
-    <braunr> so, for example, you could base your work from the netbsd/arm pmap
-      module
-    <tschwinge> matty3269: I think that's better than starting on real
-      hardware.
-    <braunr> tschwinge: you can use -kernel with a multiboot binary now
-
-[[hurd/running/qemu#multiboot]].
-
-    <braunr> tschwinge: and even creating iso images is so fast it's not any
-      slower
-
-    <braunr> ah, the gnumach executable is a correct elf image
-    <matty3269> Is there particular reason that mach is linked at 0xc0100000?
-    <matty3269> or is that where it is expected to be in VM>
-    <tschwinge> That's my understanding.
-    <braunr> kernels commmonly sti at high addresses
-    <braunr> that's the "standard" 3G/1G split for user/kernel space
-    <matty3269> I think Linux sits at a similar VA for 32-bit
-    <braunr> no
-    <matty3269> Oh, I thought it did, I know it does on ARM, the kernel is
-      mapped to 0xc000000 
-    <braunr> i don't know arm, but are you sure about this number ?
-    <braunr> seems to lack a 0
-    <matty3269> Ah, yes sorry
-    <matty3269> so 0xC0000000
-    <braunr> 0xc0100000 is just 1 MiB above it
-    <braunr> the .text section of linux on x86 actually starts at c1000000
-      (above 16 MiB, certainly to preserve as much dma-able memory since modern
-      machines now have a lot more)
-    <matty3269> so with gnumach, does the boot-up sequence use PIC until VM is
-      active and the kernel mapped to the linking address?
-    <braunr> no
-    <braunr> actually i'm not certain of the details
-    <braunr> but there is no PIC
-    <braunr> either special sections are linked at physical addresses
-    <braunr> or it relies on the fact that all executable code uses near jumps
-    <braunr> and uses offsets when accessing data
-    <braunr> (which is why the kernel text is at 3 GiB + 1 MiB, and not 3 GiB)
-    <matty3269> hmm,
-    <braunr> but you shouldn't worry about that i suppose, as the protocol
-      between the boot loader and an arm kernel will certainly not be the saem
-    <braunr> same*
-    <matty3269> indeed, ARM is tricky because memory maps are vastly differnt
-      on every platform
-
-
-## IRC, freenode, #hurd, 2012-11-21
-
-    <matty3269> Well, I have a ARM gnumach kernel compiled. It just doesn't
-      run! :)
-    <braunr> matty3269: good luck :)
-
-
-# IRC, freenode, #hurd, 2013-01-30
-
-    <slpz> Hi, i've read there's an ongoing effort to port GNU Mach to ARM. How
-      is it going?
-    <braunr> not sure where you read that
-    <braunr> but i'm pretty sure it's not started if it exists
-    <slpz> braunr: http://www.gnu.org/software/hurd/open_issues/arm_port.html
-    <braunr> i confirm what i said
-    <slpz> braunr: OK, thanks. I'm interested on it, and didn't want to
-      duplicate efforts.
-    <braunr> little addition: it may have started, but we don't know about it
-
-
-# IRC, freenode, #hurd, 2013-09-18
-
-    <Hooligan0> as i understand ; on startup, vm_resident.c functions configure
-      the whole available memory ; but at this point the system does not split
-      space for kernel and space for future apps
-    <Hooligan0> when pages are tagged to be used by userspace ?
-    <braunr> Hooligan0: at page fault time
-    <braunr> the split is completely virtual, vm_resident deals with physical
-      memory only
-    <Hooligan0> braunr: do you think it's possible to change (at least)
-      pmap_steal_memory to mark somes pages as kernel-reserved ?
-    <braunr> why do you want to reserve memory ?
-    <braunr> and which memory ?
-    <Hooligan0> braunr: first because on my mmu i have two entry points ; so i
-      want to set kernel pages into a dedicated space that never change on
-      context switch (for best cache performance)
-    <Hooligan0> braunr: and second, because i want to use larger pages into
-      kernel (1MB) to reduce mmu work
-    <braunr> vm_resident isn't well suited for large pages :(
-    <braunr> i don't see the effect of context switch on kernel pages
-    <Hooligan0> at many times, context switch flush caches
-    <braunr> ah you want something like global pages on x86 ?
-    <Hooligan0> yes, something like
-    <braunr> how is it done on arm ?
-    <Hooligan0> virtual memory is split into two parts depending on msb bits
-    <Hooligan0> for example 3G/1G
-    <Hooligan0> MMU will use two pages tables depending on vaddr (hi-side or
-      low-side)
-    <braunr> hi is kernel, low is user ?
-    <Hooligan0> so, for the moment i've put mach at 0xC0000000 -> 0xFFFFFFFF  ;
-      and want to use 0x00000000 -> 0xBFFFFFFF for userspace
-    <Hooligan0> yes
-    <braunr> ok, that's what is done for x86 too
-    <Hooligan0> 1MB pages for kernel ; and 4kB (or 64kB) pages for apps
-    <braunr> i suggest you give up the large page stuff
-    <braunr> well, you can use them for the direct physical mapping, but for
-      kernel objects, it's a waste
-    <braunr> or you can rewrite vm_resident to use something like a buddy
-      allocator but it's additional work
-    <Hooligan0> for the moment it's waste ; but with some littles changes this
-      allow only one level of allocation mapping ;  -i think- it's better for
-      performances
-    <braunr> Hooligan0: it is, but not worth it
-    <Hooligan0> will you allow changes into vm_resident if i update i386 too ?
-    <braunr> Hooligan0: sure, as long as these are relevant and don't introduce
-      regressions
-    <Hooligan0> ok
-    <braunr> Hooligan0: i suggest you look at x15, since you may want to use it
-      as a template for your own changes
-    <braunr> as it was done for the slab allocator for example
-    <braunr> e.g. x15 already uses a buddy allocator for physical memory