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Sergey Senozhatsky 04b8eb7a4c symbol lookup: introduce dereference_symbol_descriptor()
dereference_symbol_descriptor() invokes appropriate ARCH specific
function descriptor dereference callbacks:
- dereference_kernel_function_descriptor() if the pointer is a
  kernel symbol;

- dereference_module_function_descriptor() if the pointer is a
  module symbol.

This is the last step needed to make '%pS/%ps' smart enough to
handle function descriptor dereference on affected ARCHs and
to retire '%pF/%pf'.

To refresh it:
  Some architectures (ia64, ppc64, parisc64) use an indirect pointer
  for C function pointers - the function pointer points to a function
  descriptor and we need to dereference it to get the actual function
  pointer.

  Function descriptors live in .opd elf section and all affected
  ARCHs (ia64, ppc64, parisc64) handle it properly for kernel and
  modules. So we, technically, can decide if the dereference is
  needed by simply looking at the pointer: if it belongs to .opd
  section then we need to dereference it.

  The kernel and modules have their own .opd sections, obviously,
  that's why we need to split dereference_function_descriptor()
  and use separate kernel and module dereference arch callbacks.

Link: http://lkml.kernel.org/r/20171206043649.GB15885@jagdpanzerIV
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: James Bottomley <jejb@parisc-linux.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-ia64@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tested-by: Tony Luck <tony.luck@intel.com> #ia64
Tested-by: Santosh Sivaraj <santosh@fossix.org> #powerpc
Tested-by: Helge Deller <deller@gmx.de> #parisc64
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-01-09 10:45:38 +01:00
Documentation symbol lookup: introduce dereference_symbol_descriptor() 2018-01-09 10:45:38 +01:00
arch parisc64: Add .opd based function descriptor dereference 2018-01-09 10:45:38 +01:00
block Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 12:08:18 -08:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2017-11-15 18:21:04 -08:00
drivers fbdev changes for v4.15: 2017-11-20 21:50:24 -10:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs Lots of good bugfixes, including: 2017-11-18 11:22:04 -08:00
include symbol lookup: introduce dereference_symbol_descriptor() 2018-01-09 10:45:38 +01:00
init EXPERT Kconfig menu: fix broken EXPERT menu 2017-11-17 16:10:05 -08:00
ipc Merge branch 'akpm' (patches from Andrew) 2017-11-17 16:56:17 -08:00
kernel symbol lookup: introduce dereference_symbol_descriptor() 2018-01-09 10:45:38 +01:00
lib symbol lookup: introduce dereference_symbol_descriptor() 2018-01-09 10:45:38 +01:00
mm mm: add infrastructure for get_user_pages_fast() benchmarking 2017-11-17 16:10:04 -08:00
net Lots of good bugfixes, including: 2017-11-18 11:22:04 -08:00
samples media updates for v4.15-rc1 2017-11-15 20:30:12 -08:00
scripts Kbuild misc updates for v4.15 2017-11-17 17:51:33 -08:00
security ima: do not update security.ima if appraisal status is not INTEGRITY_PASS 2017-11-20 08:23:10 +11:00
sound sound updates for 4.15-rc1 2017-11-14 18:01:46 -08:00
tools platform-drivers-x86 for v4.15-1 2017-11-18 10:26:57 -08:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt Merge branch 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-11-17 11:54:55 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild misc updates for v4.15 2017-11-17 17:51:33 -08:00
.mailmap Add Jason Gunthorpe as co-maintainer of the RDMA stack 2017-11-17 09:36:18 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS MAINTAINERS: fix jfs tree location 2017-11-20 12:13:28 -06:00
Makefile Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.