parisc: boot: Nuke some sparse warnings in decompressor

Signed-off-by: Helge Deller <deller@gmx.de>

parisc: Fix unaligned-access crash in bootloader

Kernel v5.14 has various changes to optimize unaligned memory accesses,
e.g. commit 0652035a5794 ("asm-generic: unaligned: remove byteshift helpers").

Those changes triggered an unalignment-exception and thus crashed the
bootloader on parisc because the unaligned "output_len" variable now suddenly
was read word-wise while it was read byte-wise in the past.

Fix this issue by declaring the external output_len variable as char which then
forces the compiler to generate byte-accesses.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: John David Anglin <dave.anglin@bell.net>
Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102162
Fixes: 8c031ba63f8f ("parisc: Unbreak bootloader due to gcc-7 optimizations")
Fixes: 0652035a5794 ("asm-generic: unaligned: remove byteshift helpers")
Cc: <stable@vger.kernel.org> # v5.14+

parisc: PA-Linux requires at least 32 MB RAM

Even a 32-bit kernel requires at least 27 MB to decompress itself, so
halt the system with a message if the system has less memory than 32 MB.

Signed-off-by: Helge Deller <deller@gmx.de>

parisc: Include compressed vmlinux file in vmlinuz boot kernel

Change the parisc vmlinuz boot code to include and process the real
compressed vmlinux.gz ELF file instead of a compressed memory dump.
This brings parisc in sync on how it's done on x86_64.

The benefit of this change is that, e.g. for debugging purposes, one can
then extract the vmlinux file out of the vmlinuz which was booted which
wasn't possible before. This can be archieved with the existing
scripts/extract-vmlinux script, which just needs a small tweak to prefer
to extract a compressed file before trying the existing given binary.

The downside of this approach is that due to the extra round of
decompression/ELF processing we need more physical memory installed to
be able to boot a kernel.

Signed-off-by: Helge Deller <deller@gmx.de>

parisc: Fix indenting in puts()

Static analysis tools complain that we intended to have curly braces
around this indent block. In this case this assumption is wrong, so fix
the indenting.

Fixes: 2f3c7b8137ef ("parisc: Add core code for self-extracting kernel")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v4.14+

parisc: Unbreak bootloader due to gcc-7 optimizations

gcc-7 optimizes the byte-wise accesses of get_unaligned_le32() into
word-wise accesses if the 32-bit integer output_len is declared as
external. This panics then the bootloader since we don't have the
unaligned access fault trap handler installed during boot time.

Avoid this optimization by declaring output_len as byte-aligned and thus
unbreak the bootloader code.

Additionally, compile the boot code optimized for size.

Signed-off-by: Helge Deller <deller@gmx.de>

parisc: Add core code for self-extracting kernel

Signed-off-by: Helge Deller <deller@gmx.de>