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This patch re-organises the way the zImage wrapper code is entered, to
allow more flexibility on platforms with unusual entry conditions.
After this patch, a platform .o file has two options:
1) It can define a _zimage_start, in which case the platform code gets
control from the very beginning of execution. In this case the
platform code is responsible for relocating the zImage if necessary,
clearing the BSS, performing any platform specific initialization, and
finally calling start() to load and enter the kernel.
2) It can define platform_init(). In this case the generic crt0.S
handles initial entry, and calls platform_init() before calling
start(). The signature of platform_init() is changed, however, to
take up to 5 parameters (in r3..r7) as they come from the platform's
initial loader, instead of a fixed set of parameters based on OF's
usage.
When using the generic crt0.S, the platform .o can optionally
supply a custom stack to use, using the BSS_STACK() macro. If this
is not supplied, the crt0.S will assume that the loader has
supplied a usable stack.
In either case, the platform code communicates information to the
generic code (specifically, a PROM pointer for OF systems, and/or an
initrd image address supplied by the bootloader) via a global
structure "loader_info".
In addition the wrapper script is rearranged to ensure that the
platform .o is always linked first. This means that platforms where
the zImage entry point is at a fixed address or offset, rather than
being encoded in the binary header can be supported using option (1).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This patch rewrites prep_kernel() in the zImage wrapper code to be
clearer and more flexible. Notable changes:
- Handling of the initrd image from prep_kernel() has moved
into a new prep_initrd() function.
- The address of the initrd image is now added as device tree
properties, as the kernel expects.
- We only copy a packaged initrd image to a new location if it
is in danger of being clobbered when the kernel moves to its final
location, instead of always.
- By default we decompress the kernel directly to address 0,
instead of requiring it to relocate itself. Platforms (such as OF)
where doing this could clobber still-live firmware data structures can
override the vmlinux_alloc hook to provide an alternate place to
decompress the kernel.
- We no longer pass lots of information between functions in
global variables.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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At present, arch/powerpc/boot/main.c includes a gunzip() function
which is a convenient wrapper around zlib. However, it doesn't
conveniently allow decompressing part of an image to one location,
then the remainder to a different address.
This patch adds a new set of more flexible convenience wrappers around
zlib, moving them to their own file, gunzip_util.c, in the process.
These wrappers allow decompressing sections of the compressed image to
different locations. In addition, they transparently handle
uncompressed data, avoiding special case code to handle uncompressed
vmlinux images.
The patch also converts main.c to use the new wrappers, using the new
flexibility to avoid decompressing the vmlinux's ELF header twice as
we did previously. That in turn means we avoid extending our
allocations for the vmlinux to allow space for the extra copy of the
ELF header.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This makes 2 changes to clean up the flat device tree handling
logic in the zImage wrapper.
First, there were two callbacks from the dt_ops structure used for
producing a final flat tree to pass to the kerne: dt_ops.ft_pack()
which packed the flat tree (possibly a no-op) and dt_ops.ft_addr()
which retreived the address of the final blob. Since they were only
ever called together, this patch combines the two into a single new
callback, dt_ops.finalize(). This new callback does whatever
platform-dependent things are necessary to produce a final flat device
tree blob, and returns the blob's addres.
Second, the current logic calls the kernel with a flat device tree if
one is build into the zImage wrapper, otherwise it boots the kernel
with a PROM pointer, expecting the kernel to copy the OF device tree
itself. This approach precludes the possibility of the platform
wrapper code building a flat device tree from whatever
platform-specific information firmware provides. Thus, this patch
takes the more sensible approach of invoking the kernel with a flat
tree if the dt_ops.finalize callback provides one (by whatever means).
So, the dt_ops.finalize callback can be NULL, or can be a function
which returns NULL. In either case, the zImage wrapper logic assumes
that this is a platform with OF and invokes the kernel accordingly.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This patch makes the handling of the initrd (or initramfs) in the
zImage wrapper a little easier to follow. Instead of passing the
initrd addresses out from prep_kernel() via the cryptic a1 and a2
parameters, use the global struct add_range, 'initrd'. prep_kernel()
already passes information through the 'vmlinux' addr_range struct, so
this seems like a reasonable extension.
Some comments also clarify the logic with prep_kernel(): we use an
initrd included in the zImage if present, otherwise we use an initrd
passed in by the bootloader in the a1 and a2 parameters (yaboot, at
least, uses this mechanism to pass an initrd).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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More reorganization of the bootwrapper:
- Add dtb section to zImage
- ft_init now called by platform_init
- Pack a flat dt before calling kernel
- Remove size parameter from free
- printf only calls console_ops.write it its not NULL
- Some cleanup
Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This abstracts the operations used in the bootwrapper, and defines
the operations needed for the bootwrapper to run on an OF platform.
The operations have been divided up into platform ops (platform_ops),
firmware ops (fw_ops), device tree ops (dt_ops), and console ops
(console_ops).
The proper operations will be hooked up at runtime to provide the
functionality that you need.
Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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zImage will set /chosen/bootargs (if it is otherwise empty) with the
contents of a buffer in the section "__builtin_cmdline". This permits
tools to edit zImage binaries to set the command-line eventually
processed by vmlinux.
--
Signed-off-by: Michal Ostrowski <mostrows@watson.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Do not check for offset, it is always set.
Signed-off-by: Olaf Hering <olh@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This adds code to build zImage.coff and/or zImage.initrd.coff when
CONFIG_PPC32 and CONFIG_PPC_PMAC are defined. It also restructures
the OF client code and adds some workarounds for OF quirks on the
older machines.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This also extends the code to handle 32-bit ELF vmlinux files as well
as 64-bit ones. This is sufficient for booting on new-world 32-bit
powermacs (i.e. all recent machines).
Signed-off-by: Paul Mackerras <paulus@samba.org>
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