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Nathan Whitehorn 861a0b4808 Fix regression introduced in r328806, preventing boot at least on all
PowerPC Apple hardware, and likely all Open Firmware systems.

The loader would allocate memory for its heap at whatever address Open
Firmware gave it, which would in general be the lowest unallocated address,
usually starting a page or two above 0. As the kernel is linked at 1 MB,
and loader insists on running the kernel at its link address, any heap
larger than 1 MB would overlap the kernel, causing loader memory allocations
to corrupt the kernel and vice versa.

Although r328806 made this problem much worse by increasing the heap size
to 8 MB, causing 88% of the loader heap to overlap with the kernel, the
problem has always existed. The old heap size was 1 MB and, unless that
started exactly at zero, which would cause other problems, some number of
pages of the loader heap still overlapped with the kernel.

This patch solves the issue in two ways and cleans up some related code:
- Moves the loader heap inside of the loader. This guarantees that the
  heap will be contiguous with the loader and simplifies the heap
  allocation code at no cost, since the heap lives in BSS.
- Moves the loader, previously at 28 MB and dangerously close to the kernel
  it loads, a bit higher to 44 MB. This has the effect of breaking loader
  on non-embedded PPC machines with < 48 MB of RAM, but we did not support
  those anyway.

The fundamental problem is that the way loader loads ELF files is
incredibly fragile, but that can't be fixed without fundamental
architectural changes.

MFC after:	10 days
2018-02-03 23:49:21 +00:00
bin sh: Refactor job status printing, preparing for -o pipefail and similar 2018-02-02 22:53:58 +00:00
cddl zfsd: Don't spare a vdev that's being replaced 2018-01-30 21:25:43 +00:00
contrib Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to 2018-02-02 22:28:12 +00:00
crypto Add declaration of SSL_get_selected_srtp_profile() for OpenSSL. 2018-01-25 23:38:05 +00:00
etc Support configuring arbitrary limits(1) for any daemon in rc.conf 2018-01-24 14:15:06 +00:00
gnu Recognize mchk_calltrap as a trapframe generator. 2018-01-19 01:36:25 +00:00
include Vendor import of llvm release_60 branch r324090: 2018-02-02 17:07:53 +00:00
kerberos5 various: general adoption of SPDX licensing ID tags. 2017-11-27 15:37:16 +00:00
lib o Let rtld(1) set up psABI user trap handlers prior to executing the 2018-02-03 23:14:11 +00:00
libexec o Let rtld(1) set up psABI user trap handlers prior to executing the 2018-02-03 23:14:11 +00:00
release Change installer default to not install ports tree 2018-01-30 16:34:56 +00:00
rescue Avoid referencing private lib names directly. 2017-11-10 07:53:02 +00:00
sbin Check and report error returns from sbput(3) calls. 2018-02-02 23:26:52 +00:00
secure Merge OpenSSL 1.0.2n. 2017-12-07 18:02:57 +00:00
share pthread: adding missing header to man page 2018-02-03 20:50:46 +00:00
stand Fix regression introduced in r328806, preventing boot at least on all 2018-02-03 23:49:21 +00:00
sys Add new USB ID. 2018-02-03 09:43:32 +00:00
targets Remove a reference to burncd 2017-12-29 23:56:06 +00:00
tests Mark the unused argument to continue_thread() as such. 2018-01-24 17:46:20 +00:00
tools Fix backward conditional. 2018-02-03 21:56:38 +00:00
usr.bin ld.lld.1: miscellaneous style improvements 2018-02-02 21:52:00 +00:00
usr.sbin newsyslog: fix typeo for 'zstd' 2018-02-03 20:53:21 +00:00
.arcconfig callsign isn't required anymore 2016-09-29 06:19:45 +00:00
.arclint arc lint: ignore /tests/ in chmod 2017-12-19 03:38:06 +00:00
.gitattributes .git*: add gitattributes and gitignore 2017-12-25 21:07:54 +00:00
.gitignore .git*: add gitattributes and gitignore 2017-12-25 21:07:54 +00:00
COPYRIGHT Happy New Year 2018 my friends! 2017-12-31 16:48:04 +00:00
LOCKS Explicitly require Security Officer's approval for kernel PRNG bits. 2013-09-17 14:19:05 +00:00
MAINTAINERS Move sys/boot to stand. Fix all references to new location 2017-11-14 23:02:19 +00:00
Makefile Import tzdata 2018c 2018-01-24 06:45:03 +00:00
Makefile.inc1 `make installkernel' should display a completed message if done 2018-01-25 21:36:26 +00:00
Makefile.libcompat X_COMPILER_* may not be defined. 2018-01-24 18:08:37 +00:00
Makefile.sys.inc AUTO_OBJ: For all top-level targets enforce using an OBJDIR. 2017-12-05 21:29:47 +00:00
ObsoleteFiles.inc Remove pcibios forth support. 2018-02-02 15:01:49 +00:00
README Import tzdata 2018c 2018-01-24 06:45:03 +00:00
README.md Document the sys/boot -> stand move in hier.7 and the top-level README. 2017-12-03 20:36:36 +00:00
UPDATING Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to 2018-01-14 00:08:34 +00:00

FreeBSD Source:

This is the top level of the FreeBSD source directory. This file was last revised on: FreeBSD

For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information).

The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7) and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables.

The buildkernel and installkernel targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags.

Building a kernel is a somewhat more involved process. See build(7), config(8), and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information.

Note: If you want to build and install the kernel with the buildkernel and installkernel targets, you might need to build world before. More information is available in the handbook.

The kernel configuration files reside in the sys/<arch>/conf sub-directory. GENERIC is the default configuration used in release builds. NOTES contains entries and documentation for all possible devices, not just those commonly used.

Source Roadmap:

bin				System/user commands.

cddl			Various commands and libraries under the Common Development  
				and Distribution License.

contrib			Packages contributed by 3rd parties.

crypto			Cryptography stuff (see crypto/README).

etc				Template files for /etc.

gnu				Various commands and libraries under the GNU Public License.  
				Please see gnu/COPYING* for more information.

include			System include files.

kerberos5		Kerberos5 (Heimdal) package.

lib				System libraries.

libexec			System daemons.

release			Release building Makefile & associated tools.

rescue			Build system for statically linked /rescue utilities.

sbin			System commands.

secure			Cryptographic libraries and commands.

share			Shared resources.

stand			Boot loader sources.

sys				Kernel sources.

tests			Regression tests which can be run by Kyua.  See tests/README
				for additional information.

tools			Utilities for regression testing and miscellaneous tasks.

usr.bin			User commands.

usr.sbin		System administration commands.

For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see:

https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/current-stable.html