init: support longer command lines

The Linux kernel supports command lines up to 2048 bytes on x86,
see COMMAND_LINE_SIZE in asm/setup.h.

If any androidboot.xxxx arguments were past the 1024 byte limit
here, they were lost.

Change-Id: I6247c511a7de04109490fffa0125801d274a5501
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
mkbootimg: support longer kernel command lines

We can't simply increase the value of BOOT_ARGS_SIZE since that
would break past binary compatibility; the offset of 'id' would
change. This can cause serious problems with incremental OTA updates.

Instead, define a supplemental field which stores command line
information beyond the first 512 bytes. A value of 1024 was chosen
to keep the total size of struct boot_img_hdr under the smallest
page size of 2048 bytes.

Even if the extra_cmdline field is used, the original cmdline
field is still always NULL-terminated to avoid issues with older
bootloaders that haven't been updated.

Change-Id: I887e6f1db351a5b71a61e3a03363cf8856123d74
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Merge "init: support longer command lines"
Merge "mkbootimg: support longer kernel command lines"
Merge branch 'master' of https://android.googlesource.com/platform/system/core