[PATCH v2 0/4] kallsyms: remove special handling for CONFIG_ARM

On 3 Feb 2016, Ard Biesheuvel wrote:

This series applies on top of today's -next, and addresses an issue
with the new kallsyms code that is queued there, that enables base
relative kallsyms tables for all architectures (except IA-64)

Two issues have surfaced on ARM with the new kallsyms code:
a) CONFIG_HAVE_TCM creates a virtual region that is too far away for the
   relative kallsyms code to reach it;
b) CONFIG_XIP_KERNEL=y kernel symbols are not filtered against PAGE_OFFSET,
  as is the case for kernels that execute from RAM, resulting in symbols
  that are out of range.

Since the way kallsyms deals with XIP kernels on ARM leaves some room for
 improvement regardless of the base relative changes, this series proposes
 a fix that allows the special case to be removed from the kallsyms
 handling entirely.

Changes since v1:
- new patch #4 (optional, RFC)
- added Nico's ack to #1 - #3
- use PROVIDE() for vector_fiq_offset since vector_fiq itself is not
 always
  defined
- put __stubs_start/_end inside the section definition so that the
 value of the
  start symbol equals the start of the section after alignment
 (fixes an issue
  on XIP spotted by Chris)

Patch #1 moves the .stubs and .vectors section back into the kernel
VMA, while preserving the guaranteed virtual offset of 4 KB. This
results in all symbols that kallsyms sees to be in a reasonable interval.

Patch #2 removes the special case for CONFIG_ARM && !CONFIG_XIP_KERNEL
in the invocation of scripts/kallsyms

Patch #3 removes the now unused --page-offset command line argument
handling from scripts/kallsyms.c

Patch #4 is included as an RFC, it removes the magic constant 0x1000
which is the offset between the start of the .vectors section and the
start of the .stubs section.

For patches 1,2,3:

Tested with ARCH_R7S72100 with CONFIG_XIP_KERNEL=y


Acked-by: Chris Brandt <chris.brandt@renesas.com>