git.zerfleddert.de Git - ms2-kexec/blob - README

   1 Android kexec port
   2 By Matthew Veety, et al.
   3
   4 Contents:
   5         Synopsis
   6         Cross-compiling on Gentoo and other Linuxes How-to
   7         Troubleshooting
   8
   9 ================================================================================
  10
  11 Synopsis:
  12
  13 This is the kmod from the project trying to unlock the Milestone. It is still
  14 localized to that phone, but, with modification, I got working on the Droid X
  15 and a few others. Currently, this is a work in progress and is not recommended
  16 for mission critical situations.
  17
  18 To compile:
  19 Place your kernel sources into kernel/ and build the kernel
  20 in that directory. Then run make (or gmake on freebsd) to build
  21 the kernel module. I highly recommend actually doing the build on
  22 the phone you desire to run the kmod on. I use a gentoo stage3
  23 chroot environment on my Droid X to do the building.
  24
  25 Targets:
  26 Droid X
  27
  28 In-progress Targets:
  29 Droid 2
  30 Nexus S
  31
  32 Future Targets:
  33 Droid 2 Global
  34 Droid Bionic
  35
  36 ================================================================================
  37
  38 Cross-compiling on Gentoo and other Linuxes How-to:
  39
  40     To set this up you need a cross-compiler. A cross-compiler allows your to
  41 make binaries for something other than your platform. If you've ever built Android
  42 then you've used one. There are two methods to do this; the first method is using
  43 Android's cross-compiler to build. There are tools to set this up and it seems
  44 to be very easy to use, but I've never got that method to work. The method I use
  45 uses a nice tool that is in portage (I'm a gentoo user) called cross dev.
  46
  47         ~note from palmercurling~
  48         To set up a cross-compiler in Debian or a Debian fork (Ubuntu, Mint, others)
  49         follow the steps at http://www.scratchbox.org/
  50
  51 Your first step should be setting up a stage3 chroot. The Gentoo handbook outlines
  52 how to do this, and the process is pretty simple. It only needs to be very
  53 minimal and doesn't need X or any other sort of graphical environment.
  54 I install mine to /opt because I have a nice 300 GB hard drive mounted there to
  55 hold all of my Android things.
  56
  57 So after you're chrooted into your cross environment install crossdev by running:
  58 # emerge -avp crossdev      # This is to see dependencies
  59 # emerge -av crossdev        # This makes sure you want to go through with it
  60
  61 After crossdev gets done emerging run:
  62 # emerge --sync
  63 to get the latest version of the portage tree. If rsync is blocked choose the http
  64 method outlined in the Gentoo Handbook.
  65
  66 crossdev has pretty simple options that can be seen by invoking:
  67 $ crossdev
  68 or
  69 # crossdev
  70
  71 The option you'll be interested in is --target. This allows your to build the specified
  72 gcc, libc, and binutils. --target takes its option as ARCH-VENDOR-OS-LIBC. For
  73 possible choices invoke:
  74 $ crossdev -t help
  75 $ crossdev --target help
  76 # crossdev -t help
  77 or
  78 # crossdev --target help
  79
  80 Now because Adnroid is Linux and initx requires glibc your tuple for --target
  81 will look something like ARCH-VENDOR-linux-glibc. Also because Android
  82 kexec only supports ARM right now you're going to want either arm or armeb
  83 for ARCH. That is phone dependent. The Droid X seems to run fine with either,
  84 but the Nexus One really doesn't like using arm without compiling the kernel with
  85 softfloat in the vendor.
  86
  87 TIPS: This doesn't work on Gentoo/FreeBSD yet. No idea why either. Cross
  88 works fine on normal *BSD though. Crossdev is also crazy useful for
  89 compiling Windows apps. crossdev + wine = windows development bliss.
  90
  91 ================================================================================
  92
  93 TROUBLESHOOTING:
  94
  95 1. I'm getting segmentation faults!
  96     Check your cross setup. The common cause for me is adding in softfloat when I
  97     didn't need it. Don't feel bad, it's a common issue.
  98 2. kexec won't load into the kernel!
  99     The cross setup needs to be the same configuration as the one that compiles your
 100     kernel. Check your CHOST after running make menuconfig in your kernel.
 101 3. I'm getting errors on compile!
 102     Read them and fix them, if it's my fault send me a fix for it.
 103 4. How do I actually use this?
 104      You'll need to write a wrapper to make the system call. I did that so inexperienced
 105      users won't damage their phone. kexec is pretty well documented, and you can look
 106      at the i686 sources for a really well done reference, plus the man pages have it pretty
 107      well documented.
 108 5. This file looks funny in my emacs window!
 109    I know, I didn't format it to 80 cols just to be a dick to you :P. Actually, I use
 110    TextEdit.app (it's a GNUstep app because I'm a GNUstep user) which doesn't easily
 111    understand the concepts of "wrap the damn line at 80."