Commit graph

101 commits

Author SHA1 Message Date
Linus Torvalds
b0c79f49c3 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:

 - Introduce the ORC unwinder, which can be enabled via
   CONFIG_ORC_UNWINDER=y.

   The ORC unwinder is a lightweight, Linux kernel specific debuginfo
   implementation, which aims to be DWARF done right for unwinding.
   Objtool is used to generate the ORC unwinder tables during build, so
   the data format is flexible and kernel internal: there's no
   dependency on debuginfo created by an external toolchain.

   The ORC unwinder is almost two orders of magnitude faster than the
   (out of tree) DWARF unwinder - which is important for perf call graph
   profiling. It is also significantly simpler and is coded defensively:
   there has not been a single ORC related kernel crash so far, even
   with early versions. (knock on wood!)

   But the main advantage is that enabling the ORC unwinder allows
   CONFIG_FRAME_POINTERS to be turned off - which speeds up the kernel
   measurably:

   With frame pointers disabled, GCC does not have to add frame pointer
   instrumentation code to every function in the kernel. The kernel's
   .text size decreases by about 3.2%, resulting in better cache
   utilization and fewer instructions executed, resulting in a broad
   kernel-wide speedup. Average speedup of system calls should be
   roughly in the 1-3% range - measurements by Mel Gorman [1] have shown
   a speedup of 5-10% for some function execution intense workloads.

   The main cost of the unwinder is that the unwinder data has to be
   stored in RAM: the memory cost is 2-4MB of RAM, depending on kernel
   config - which is a modest cost on modern x86 systems.

   Given how young the ORC unwinder code is it's not enabled by default
   - but given the performance advantages the plan is to eventually make
   it the default unwinder on x86.

   See Documentation/x86/orc-unwinder.txt for more details.

 - Remove lguest support: its intended role was that of a temporary
   proof of concept for virtualization, plus its removal will enable the
   reduction (removal) of the paravirt API as well, so Rusty agreed to
   its removal. (Juergen Gross)

 - Clean up and fix FSGS related functionality (Andy Lutomirski)

 - Clean up IO access APIs (Andy Shevchenko)

 - Enhance the symbol namespace (Jiri Slaby)

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
  objtool: Handle GCC stack pointer adjustment bug
  x86/entry/64: Use ENTRY() instead of ALIGN+GLOBAL for stub32_clone()
  x86/fpu/math-emu: Add ENDPROC to functions
  x86/boot/64: Extract efi_pe_entry() from startup_64()
  x86/boot/32: Extract efi_pe_entry() from startup_32()
  x86/lguest: Remove lguest support
  x86/paravirt/xen: Remove xen_patch()
  objtool: Fix objtool fallthrough detection with function padding
  x86/xen/64: Fix the reported SS and CS in SYSCALL
  objtool: Track DRAP separately from callee-saved registers
  objtool: Fix validate_branch() return codes
  x86: Clarify/fix no-op barriers for text_poke_bp()
  x86/switch_to/64: Rewrite FS/GS switching yet again to fix AMD CPUs
  selftests/x86/fsgsbase: Test selectors 1, 2, and 3
  x86/fsgsbase/64: Report FSBASE and GSBASE correctly in core dumps
  x86/fsgsbase/64: Fully initialize FS and GS state in start_thread_common
  x86/asm: Fix UNWIND_HINT_REGS macro for older binutils
  x86/asm/32: Fix regs_get_register() on segment registers
  x86/xen/64: Rearrange the SYSCALL entries
  x86/asm/32: Remove a bunch of '& 0xffff' from pt_regs segment reads
  ...
2017-09-04 09:52:57 -07:00
Cao jin
312a3d0918 kbuild: trivial cleanups on the comments
This is a bunch of trivial fixes and cleanups.

Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-08-10 00:58:20 +09:00
Josh Poimboeuf
ee9f8fce99 x86/unwind: Add the ORC unwinder
Add the new ORC unwinder which is enabled by CONFIG_ORC_UNWINDER=y.
It plugs into the existing x86 unwinder framework.

It relies on objtool to generate the needed .orc_unwind and
.orc_unwind_ip sections.

For more details on why ORC is used instead of DWARF, see
Documentation/x86/orc-unwinder.txt - but the short version is
that it's a simplified, fundamentally more robust debugninfo
data structure, which also allows up to two orders of magnitude
faster lookups than the DWARF unwinder - which matters to
profiling workloads like perf.

Thanks to Andy Lutomirski for the performance improvement ideas:
splitting the ORC unwind table into two parallel arrays and creating a
fast lookup table to search a subset of the unwind table.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/0a6cbfb40f8da99b7a45a1a8302dc6aef16ec812.1500938583.git.jpoimboe@redhat.com
[ Extended the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-26 13:18:20 +02:00
Josh Poimboeuf
867ac9d737 objtool: Fix gcov check for older versions of GCC
Objtool tries to silence 'unreachable instruction' warnings when it
detects gcov is enabled, because gcov produces a lot of unreachable
instructions and they don't really matter.

However, the 0-day bot is still reporting some unreachable instruction
warnings with CONFIG_GCOV_KERNEL=y on GCC 4.6.4.

As it turns out, objtool's gcov detection doesn't work with older
versions of GCC because they don't create a bunch of symbols with the
'gcov.' prefix like newer versions of GCC do.

Move the gcov check out of objtool and instead just create a new
'--no-unreachable' flag which can be passed in by the kernel Makefile
when CONFIG_GCOV_KERNEL is defined.

Also rename the 'nofp' variable to 'no_fp' for consistency with the new
'no_unreachable' variable.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 9cfffb1168 ("objtool: Skip all "unreachable instruction" warnings for gcov kernels")
Link: http://lkml.kernel.org/r/c243dc78eb2ffdabb6e927844dea39b6033cd395.1500939244.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-25 11:12:45 +02:00
Nicholas Piggin
9a6cfca4f4 kbuild: thin archives use P option to ar
The P option makes ar do full path name matching and can prevent ar
from discarding files with duplicate names in some cases of creating
thin archives from thin archives. The sh architecture in particular
loses some object files from its kernel/cpu/sh*/ directories without
this option.

This could be a bug in binutils ar, but the P option should not cause
any negative effects so it is safe to use to work around this with.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-06-30 09:03:03 +09:00
Jiri Slaby
e8a3118e1f objtool: make it visible in make V=1 output
It is currently impossible to see what is going on with objtool when
building, so call echo-cmd to see the actions:
  gcc -Wp,-MD,arch/x86/entry/.entry_64.o.d  -nostdinc -isystem ...
  ./tools/objtool/objtool check "arch/x86/entry/entry_64.o";

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Michal Marek <mmarek@suse.com>
Cc: linux-kbuild@vger.kernel.org
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-05-03 13:39:37 +09:00
Vinícius Tinti
433db3e260 kbuild: Add support to generate LLVM assembly files
Add rules to kbuild in order to generate LLVM assembly files with the .ll
extension when using clang.

  # from c code
  make CC=clang kernel/pid.ll

Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-04-25 08:13:52 +09:00
Ard Biesheuvel
56067812d5 kbuild: modversions: add infrastructure for emitting relative CRCs
This add the kbuild infrastructure that will allow architectures to emit
vmlinux symbol CRCs as 32-bit offsets to another location in the kernel
where the actual value is stored. This works around problems with CRCs
being mistaken for relocatable symbols on kernels that self relocate at
runtime (i.e., powerpc with CONFIG_RELOCATABLE=y)

For the kbuild side of things, this comes down to the following:

 - introducing a Kconfig symbol MODULE_REL_CRCS

 - adding a -R switch to genksyms to instruct it to emit the CRC symbols
   as references into the .rodata section

 - making modpost distinguish such references from absolute CRC symbols
   by the section index (SHN_ABS)

 - making kallsyms disregard non-absolute symbols with a __crc_ prefix

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-03 08:28:25 -08:00
Linus Torvalds
41e0e24b45 Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild updates from Michal Marek:

 - prototypes for x86 asm-exported symbols (Adam Borowski) and a warning
   about missing CRCs (Nick Piggin)

 - asm-exports fix for LTO (Nicolas Pitre)

 - thin archives improvements (Nick Piggin)

 - linker script fix for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION (Nick
   Piggin)

 - genksyms support for __builtin_va_list keyword

 - misc minor fixes

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  x86/kbuild: enable modversions for symbols exported from asm
  kbuild: fix scripts/adjust_autoksyms.sh* for the no modules case
  scripts/kallsyms: remove last remnants of --page-offset option
  make use of make variable CURDIR instead of calling pwd
  kbuild: cmd_export_list: tighten the sed script
  kbuild: minor improvement for thin archives build
  kbuild: modpost warn if export version crc is missing
  kbuild: keep data tables through dead code elimination
  kbuild: improve linker compatibility with lib-ksyms.o build
  genksyms: Regenerate parser
  kbuild/genksyms: handle va_list type
  kbuild: thin archives for multi-y targets
  kbuild: kallsyms allow 3-pass generation if symbols size has changed
2016-12-17 16:24:13 -08:00
Nicolas Pitre
76bee23411 kbuild: cmd_export_list: tighten the sed script
When LTO is used, some ___ksymtab_string sections are seen by this sed
script, creating lines containing a single ) such as:

EXPORT(foo)
)
)
EXPORT(bar)

Let's make it so the + character is also required for any line to be
printed.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-12-11 11:51:43 +01:00
Nicholas Piggin
9da2f584b5 kbuild: improve linker compatibility with lib-ksyms.o build
lib-ksyms.o is created by linking an empty input file with a linker
script containing the interesting bits. Currently the empty input file
is an archive containing nothing, however this causes the gold linker
to segfault.

I have opened a bug against gold

  https://sourceware.org/bugzilla/show_bug.cgi?id=20767

However this can be worked around by assembling an empty file to link
with instead. The resulting lib-ksyms.o is slightly larger (seemingly
due to empty .text, .data, .bss setions added), but final linked
output should not be changed.

Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-11-29 15:58:57 +01:00
Nicholas Piggin
fe026a851b kbuild: thin archives for multi-y targets
THIN_ARCHIVES builds archives for built-in.o targets, have it build
multi-y targets as archives as well.

This saves another ~15% of the size of intermediate artifacts in the
build tree. After this patch, the linker is only used in final link,
and special cases like vdsos.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-11-29 15:53:19 +01:00
Nicholas Piggin
cc6acc11ca kbuild: be more careful about matching preprocessed asm ___EXPORT_SYMBOL
The CRC code for asm exports grabs the preprocessed asm, finds the
___EXPORT_SYMBOL and turns those into EXPORT_SYMBOL in a C program
that can be preprocessed and parsed to create the CRC signatures from
the type.

The existing regex matching and replacement is too strict, and doesn't
deal well with whitespace among other things. The line
" EXPORT_SYMBOL(sym)" in a .S file would not match due to initial
whitespace, for example, which resulted in x86's ___preempt_schedule
failing to get CRCs.

Reported-by: Philip Müller <philm@manjaro.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-11-09 22:29:53 +01:00
Nicholas Piggin
4efca4ed05 kbuild: modversions for EXPORT_SYMBOL() for asm
Allow architectures to create asm/asm-prototypes.h file that
provides C prototypes for exported asm functions, which enables
proper CRC versions to be generated for them.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-11-01 16:20:17 +01:00
Nicholas Piggin
989cea5c14 kbuild: prevent lib-ksyms.o rebuilds
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reported-by: Russell King <rmk+kernel@armlinux.org.uk>
Tested-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-10-22 21:49:30 +02:00
Stephen Rothwell
a5967db9af kbuild: allow architectures to use thin archives instead of ld -r
ld -r is an incremental link used to create built-in.o files in build
subdirectories. It produces relocatable object files containing all
its input files, and these are are then pulled together and relocated
in the final link. Aside from the bloat, this constrains the final
link relocations, which has bitten large powerpc builds with
unresolvable relocations in the final link.

Alan Modra has recommended the kernel use thin archives for linking.
This is an alternative and means that the linker has more information
available to it when it links the kernel.

This patch enables a config option architectures can select, which
causes all built-in.o files to be built as thin archives. built-in.o
files in subdirectories do not get symbol table or index attached,
which improves speed and size. The final link pass creates a
built-in.o archive in the root output directory which includes the
symbol table and index. The linker then uses takes this file to link.

The --whole-archive linker option is required, because the linker now
has visibility to every individual object file, and it will otherwise
just completely avoid including those without external references
(consider a file with EXPORT_SYMBOL or initcall or hardware exceptions
as its only entry points). The traditional built works "by luck" as
built-in.o files are large enough that they're going to get external
references. However this optimisation is unpredictable for the kernel
(due to above external references), ineffective at culling unused, and
costly because the .o files have to be searched for references.
Superior alternatives for link-time culling should be used instead.

Build characteristics for inclink vs thinarc, on a small powerpc64le
pseries VM with a modest .config:

                                  inclink       thinarc
sizes
vmlinux                        15 618 680    15 625 028
sum of all built-in.o          56 091 808     1 054 334
sum excluding root built-in.o                   151 430

find -name built-in.o | xargs rm ; time make vmlinux
real                              22.772s       21.143s
user                              13.280s       13.430s
sys                                4.310s        2.750s

- Final kernel pulled in only about 6K more, which shows how
  ineffective the object file culling is.
- Build performance looks improved due to less pagecache activity.
  On IO constrained systems it could be a bigger win.
- Build size saving is significant.

Side note, the toochain understands archives, so there's some tricks,
$ ar t built-in.o          # list all files you linked with
$ size built-in.o          # and their sizes
$ objdump -d built-in.o    # disassembly (unrelocated) with filenames

Implementation by sfr, minor tweaks by npiggin.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-09-09 10:31:19 +02:00
Al Viro
7f2084fa55 [kbuild] handle exports in lib-y objects reliably
Collect the symbols exported by anything that goes into lib.a and
add an empty object (lib-exports.o) with explicit undefs for each
of those to obj-y.

That allows to relax the rules regarding the use of exports in
lib-* objects - right now an object with export can be in lib-*
only if we are guaranteed that there always will be users in
built-in parts of the tree, otherwise it needs to be in obj-*.
As the result, we have an unholy mix of lib- and obj- in lib/Makefile
and (especially) in arch/*/lib/Makefile.  Moreover, a change in
generic part of the kernel can lead to mysteriously missing exports
on some configs.  With this change we don't have to worry about
that anymore.

One side effect is that built-in.o now pulls everything with exports
from the corresponding lib.a (if such exists).  That's exactly what
we want for linking vmlinux and fortunately it's almost the only thing
built-in.o is used in.  arch/ia64/hp/sim/boot/bootloader is the only
exception and it's easy to get rid of now - just turn everything in
arch/ia64/lib into lib-* and don't bother with arch/ia64/lib/built-in.o
anymore.

[AV: stylistic fix from Michal folded in]

Acked-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-08-07 23:46:30 -04:00
Emese Revfy
2440387431 Shared library support
Infrastructure for building independent shared library targets.

Based on work created by the PaX Team.

Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-06-07 22:57:10 +02:00
Masahiro Yamada
e0f41e52dd kbuild: rename cmd_as_s_S to cmd_cpp_s_S
This command just preprocesses .S files into .s files, so cmd_cpp_s_S
seems more suitable.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-04-20 10:49:09 +02:00
Masahiro Yamada
23d4384870 kbuild: rename cmd_cc_i_c to cmd_cpp_i_c
This command just preprocesses .c files into .i files, so cmd_cpp_i_c
seems more suitable.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-04-20 10:48:19 +02:00
Nicolas Pitre
e4aca45950 kbuild: de-duplicate fixdep usage
The generation and postprocessing of automatic dependency rules is
duplicated in rule_cc_o_c, rule_as_o_S and if_changed_dep. Since
this is not a trivial one-liner action, it is now abstracted under
cmd_and_fixdep to simplify things and make future changes in this area
easier.

In the rule_cc_o_c and rule_as_o_S cases that means the order of some
commands has been altered, namely fixdep and related file manipulations
are executed earlier, but they didn't depend on those commands that now
execute later.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
2016-03-29 16:30:56 -04:00
Nicolas Pitre
9895c03d48 kbuild: record needed exported symbols for modules
Kernel modules are partially linked object files with some undefined
symbols that are expected to be matched with EXPORT_SYMBOL() entries
from elsewhere.

Each .tmp_versions/*.mod file currently contains two line of text
separated by a newline character. The first line has the actual module
file name while the second line has a list of object files constituting
that module. Those files are parsed by modpost (scripts/mod/sumversion.c),
scripts/Makefile.modpost, scripts/Makefile.modsign, etc.  Only the
modpost utility cares about the second line while the others retrieve
only the first line.

Therefore we can add a third line to record the list of undefined symbols
aka required EXPORT_SYMBOL() entries for each module into that file
without breaking anything. Like for the second line, symbols are separated
by a blank and the list is terminated with a newline character.

To avoid needless build overhead, the undefined symbols extraction is
performed only when CONFIG_TRIM_UNUSED_KSYMS is selected.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
2016-03-29 13:30:54 -04:00
Josh Poimboeuf
3b27a0c85d objtool: Detect and warn if libelf is missing and don't break the build
With CONFIG_STACK_VALIDATION enabled, if the host system doesn't have
a development version of libelf installed, the build fails with errors
like:

  elf.h:22:18: fatal error: gelf.h: No such file or directory compilation terminated.

Instead of failing to build, instead just print a warning and disable
stack validation.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-next@vger.kernel.org
Cc: linux@roeck-us.net
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/8c27fe00face60f42e888ddb3142c97e45223165.1457026550.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-05 09:20:44 +01:00
Josh Poimboeuf
b9ab5ebb14 objtool: Add CONFIG_STACK_VALIDATION option
Add a CONFIG_STACK_VALIDATION option which will run "objtool check" for
each .o file to ensure the validity of its stack metadata.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/92baab69a6bf9bc7043af0bfca9fb964a1d45546.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-29 08:35:13 +01:00
Michal Marek
cf4f21938e kbuild: Allow to specify composite modules with modname-m
This allows to write

  drm-$(CONFIG_AGP) += drm_agpsupport.o

without having to handle CONFIG_AGP=y vs. CONFIG_AGP=m. Only support
this syntax for modules, since built-in code depending on something
modular cannot work and init/Makefile actually relies on the current
semantics. There are a few drivers which adapted to the current
semantics out of necessity; these are fixed to also work when the
respective subsystem is modular.

Acked-by: Peter Chen <peter.chen@freescale.com> [chipidea]
Signed-off-by: Michal Marek <mmarek@suse.com>
2015-11-25 11:23:25 +01:00
Heiko Carstens
c0a80c0c27 ftrace: allow architectures to specify ftrace compile options
If the kernel is compiled with function tracer support the -pg compile option
is passed to gcc to generate extra code into the prologue of each function.

This patch replaces the "open-coded" -pg compile flag with a CC_FLAGS_FTRACE
makefile variable which architectures can override if a different option
should be used for code generation.

Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-01-29 09:19:19 +01:00
Masahiro Yamada
a4954fd772 kbuild: remove obj-n and lib-n handling
Kconfig never defines CONFIG_* as 'n'.
Now obj-n is only used in firmware/Makefile and it can be
replaced with obj-.  No makefile uses lib-n.

Let's rip off obj-n and lib-n.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Peter Foley <pefoley2@pefoley.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-10-02 13:55:02 +02:00
Masahiro Yamada
c8589d1e9e kbuild: handle multi-objs dependency appropriately
The comment in scripts/Makefile.build says as follows:

  We would rather have a list of rules like
        foo.o: $(foo-objs)
  but that's not so easy, so we rather make all composite objects depend
  on the set of all their parts

This commit makes it possible!

For example, assume a Makefile like this

  obj-m = foo.o bar.o
  foo-objs := foo1.o foo2.o
  bar-objs := bar1.o bar2.o

Without this patch, foo.o depends on all of
foo1.o foo2.o bar1.o bar2.o.
It looks funny that foo.o is regenerated when bar1.c is updated.

Now we can handle the dependency of foo.o and bar.o separately.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-08-19 10:26:19 +02:00
Masahiro Yamada
38385f8f01 kbuild: trivial - remove trailing spaces
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-04-30 17:34:32 +02:00
Masahiro Yamada
a86fe35373 kbuild: move extra gcc checks to scripts/Makefile.extrawarn
W=... provides extra gcc checks.

Having such code in scripts/Makefile.build results in the same flags
being added to KBUILD_CFLAGS multiple times becuase
scripts/Makefile.build is invoked every time Kbuild descends into
the subdirectories.

Since the top Makefile is already too cluttered, this commit moves
all of extra gcc check stuff to a new file scripts/Makefile.extrawarn,
which is included from the top Makefile.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
CC: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-04-16 23:28:41 +02:00
Jan-Simon Möller
3d3d6b8474 kbuild: LLVMLinux: Adapt warnings for compilation with clang
When compiling kernel with clang, disable warnings which are too noisy, and
add the clang flag catch-undefined-behavior.

Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Mark Charlebois <mcharleb@gmail.com>
Cc: PaX Team <pageexec@freemail.hu>
2014-04-09 13:44:34 -07:00
Andi Kleen
1e64ff42ea Kbuild, lto: Disable LTO for asm-offsets.c
The asm-offset.c technique to fish data out of the assembler file
does not work with LTO. Just disable for the asm-offset.c build.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391846481-31491-11-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-02-13 20:25:03 -08:00
James Hogan
d70f82acf3 genksyms: pass symbol-prefix instead of arch
Pass symbol-prefix to genksyms instead of arch, so that the decision
what symbol prefix to use is kept in one place.

Basically genksyms used to take a -a $ARCH argument and it used that to
determine whether to add an underscore symbol prefix. It's now changed
to take a -s $SYMBOL_PREFIX argument so that the caller decides whether
a symbol prefix is required. The build system then uses
CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX to determine whether to pass the
argument.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-03-20 11:27:27 +10:30
David Howells
4520c6a49a X.509: Add simple ASN.1 grammar compiler
Add a simple ASN.1 grammar compiler.  This produces a bytecode output that can
be fed to a decoder to inform the decoder how to interpret the ASN.1 stream it
is trying to parse.

Action functions can be specified in the grammar by interpolating:

	({ foo })

after a type, for example:

	SubjectPublicKeyInfo ::= SEQUENCE {
		algorithm		AlgorithmIdentifier,
		subjectPublicKey	BIT STRING ({ do_key_data })
		}

The decoder is expected to call these after matching this type and parsing the
contents if it is a constructed type.

The grammar compiler does not currently support the SET type (though it does
support SET OF) as I can't see a good way of tracking which members have been
encountered yet without using up extra stack space.

Currently, the grammar compiler will fail if more than 256 bytes of bytecode
would be produced or more than 256 actions have been specified as it uses
8-bit jump values and action indices to keep space usage down.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-10-08 13:50:19 +10:30
Kirill A. Shutemov
f858ee8b8c kbuild: disable -Wmissing-field-initializers for W=1
-Wmissing-field-initializers is too noisy to be useful on W=1. Let's
move it to W=2.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2012-01-26 11:07:26 +01:00
Arnaud Lacombe
49c57d254e scripts/Makefile.build: do not reference EXTRA_CFLAGS as CFLAGS replacement
Usage of these flags has been deprecated for nearly 4 years by:

    commit f77bf01425
    Author: Sam Ravnborg <sam@neptun.(none)>
    Date:   Mon Oct 15 22:25:06 2007 +0200

        kbuild: introduce ccflags-y, asflags-y and ldflags-y

Moreover, these flags (at least EXTRA_CFLAGS) have been documented for
command line use. By default, gmake(1) do not override command line
setting, so this is likely to result in build failure or unexpected
behavior.

Do not advertise for its usage.

Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-08-31 16:41:39 +02:00
Linus Torvalds
2bb732cdb4 Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
  kbuild: make KBUILD_NOCMDDEP=1 handle empty built-in.o
  scripts/kallsyms.c: fix potential segfault
  scripts/gen_initramfs_list.sh: Convert to a /bin/sh script
  kbuild: Fix GNU make v3.80 compatibility
  kbuild: Fix passing -Wno-* options to gcc 4.4+
  kbuild: move scripts/basic/docproc.c to scripts/docproc.c
  kbuild: Fix Makefile.asm-generic for um
  kbuild: Allow to combine multiple W= levels
  kbuild: Disable -Wunused-but-set-variable for gcc 4.6.0
  Fix handling of backlash character in LINUX_COMPILE_BY name
  kbuild: asm-generic support
  kbuild: implement several W= levels
  kbuild: Fix build with binutils <= 2.19
  initramfs: Use KBUILD_BUILD_TIMESTAMP for generated entries
  kbuild: Allow to override LINUX_COMPILE_BY and LINUX_COMPILE_HOST macros
  kbuild: Drop unused LINUX_COMPILE_TIME and LINUX_COMPILE_DOMAIN macros
  kbuild: Use the deterministic mode of ar
  kbuild: Call gzip with -n
  kbuild: move KALLSYMS_EXTRA_PASS from Kconfig to Makefile
  Kconfig: improve KALLSYMS_ALL documentation

Fix up trivial conflict in Makefile
2011-05-24 13:31:37 -07:00
Michal Marek
d6971822c2 ftrace/kbuild: Add recordmcount files to force full build
Modifications to recordmcount must be performed on all object
files to stay consistent with what the kernel code may expect.
Add the recordmcount files to the main dependencies to make sure
any change to them causes a full recompile.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Link: http://lkml.kernel.org/r/20110517133646.GP13293@sepie.suse.cz
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-05-19 07:58:28 -04:00
Steven Rostedt
85356f8022 kbuild/recordmcount: Add RECORDMCOUNT_WARN to warn about mcount callers
When mcount is called in a section that ftrace will not modify it into
a nop, we want to warn about this. But not warn about this always. Now
if the user builds the kernel with the option RECORDMCOUNT_WARN=1 then
the build will warn about mcount callers that are ignored and will just
waste execution time.

Acked-by: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Link: http://lkml.kernel.org/r/20110421023738.714956282@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-05-16 14:45:03 -04:00
Michal Marek
a6de553da0 kbuild: Allow to combine multiple W= levels
Add support for make W=12, make W=123 and so on, to enable warnings from
multiple W= levels. Normally, make W=<level> does not include warnings
from the previous level.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>
2011-05-02 17:37:10 +02:00
Dave Jones
af0e5d565d kbuild: Disable -Wunused-but-set-variable for gcc 4.6.0
Disable the new -Wunused-but-set-variable that was added in gcc 4.6.0
It produces more false positives than useful warnings.

This can still be enabled using W=1

Signed-off-by: Dave Jones <davej@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Tested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-04-29 16:58:14 +02:00
Sam Ravnborg
28bc20dcca kbuild: implement several W= levels
Building a kernel with "make W=1" produces far too much noise to be
useful.

Divide the warning options in three groups:

    W=1 - warnings that may be relevant and does not occur too often
    W=2 - warnings that occur quite often but may still be relevant
    W=3 - the more obscure warnings, can most likely be ignored

When building the whole kernel, those levels produce:

W=1 - 4859 warnings
W=2 - 1394 warnings
W=3 - 86666 warnings

respectively. Warnings have been counted with Geert's script at

http://www.kernel.org/pub/linux/kernel/people/geert/linux-log/linux-log-summary.pl

Many warnings occur from .h files so fixing one file may have a nice
effect on the total number of warnings.

With these changes I am actually tempted to try W=1 now and then.
Previously there was just too much noise.

Borislav:

- make the W= levels exclusive
- move very noisy and making little sense for the kernel warnings to W=3
- drop -Woverlength-strings due to useless warning message
- copy explanatory text for the different warning levels to 'make help'
- recount warnings per level

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Borislav Petkov <bp@alien8.de>
Cc: Dave Jones <davej@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-04-28 17:59:07 +02:00
Michal Marek
40df759e2b kbuild: Fix build with binutils <= 2.19
The D option of ar is only available in newer versions.

Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-04-20 15:39:22 +02:00
Michal Marek
09ff9fecc0 kbuild: Use the deterministic mode of ar
Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-04-18 14:24:45 +02:00
Borislav Petkov
4a5838ad9d kbuild: Add extra gcc checks
Add a 'W=1' Makefile switch which adds additional checking per build
object.

The idea behind this option is targeted at developers who, in the
process of writing their code, want to do the occasional

make W=1 [target.o]

and let gcc do more extensive code checking for them. Then, they
could eyeball the output for valid gcc warnings about various
bugs/discrepancies which are not reported during the normal build
process.

For more background information and a use case, read through this
thread: http://marc.info/?l=kernel-janitors&m=129802065918147&w=2

Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2011-03-09 15:35:35 +01:00
Wu Zhangjin
45677454dd ftrace: Speed up recordmcount
cmd_record_mcount is used to locate the _mcount symbols in the object
files, only the files compiled with -pg has the _mcount symbol, so, it
is only needed for such files, but the current cmd_record_mcount is used
for all of the object files, so, we need to fix it and speed it up.

Since -pg may be removed by the method used in kernel/trace/Makefile:

ORIG_CFLAGS := $(KBUILD_CFLAGS)
KBUILD_CFLAGS = $(subst -pg,,$(ORIG_CFLAGS))

Or may be removed by the method used in arch/x86/kernel/Makefile:

CFLAGS_REMOVE_file.o = -pg

So, we must check the last variable stores the compiling flags, that is
c_flags(Please refer to cmd_cc_o_c and rule_cc_o_c defined in
scripts/Makefile.build) and since the CFLAGS_REMOVE_file.o is already
filtered in _c_flags(Please refer to scripts/Makefile.lib) and _c_flags
has less symbols, therefore, we only need to check _c_flags.

---------------
Changes from v1:

  o Don't touch Makefile for CONFIG_FTRACE_MCOUNT_RECORD is enough
  o Use _c_flags intead of KBUILD_CFLAGS to cover CONFIG_REMOVE_file.o = -pg
  (feedback from Steven Rostedt <rostedt@goodmis.org>)

Acked-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
LKML-Reference: <3dc8cddf022eb7024f9f2cf857529a15bee8999a.1288196498.git.wuzhangjin@gmail.com>

[ changed if [ .. == .. ] to if [ .. = .. ] to handle dash environments ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-11-18 17:16:05 -05:00
Linus Torvalds
b5153163ed Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (278 commits)
  arm: remove machine_desc.io_pg_offst and .phys_io
  arm: use addruart macro to establish debug mappings
  arm: return both physical and virtual addresses from addruart
  arm/debug: consolidate addruart macros for CONFIG_DEBUG_ICEDCC
  ARM: make struct machine_desc definition coherent with its comment
  eukrea_mbimxsd-baseboard: Pass the correct GPIO to gpio_free
  cpuimx27: fix compile when ULPI is selected
  mach-pcm037_eet: fix compile errors
  Fixing ethernet driver compilation error for i.MX31 ADS board
  cpuimx51: update board support
  mx5: add cpuimx51sd module and its baseboard
  iomux-mx51: fix GPIO_1_xx 's IOMUX configuration
  imx-esdhc: update devices registration
  mx51: add resources for SD/MMC on i.MX51
  iomux-mx51: fix SD1 and SD2's iomux configuration
  clock-mx51: rename CLOCK1 to CLOCK_CCGR for better readability
  clock-mx51: factorize clk_set_parent and clk_get_rate
  eukrea_mbimxsd: add support for DVI displays
  cpuimx25 & cpuimx35: fix OTG port registration in host mode
  i.MX31 and i.MX35 : fix errate TLSbo65953 and ENGcm09472
  ...
2010-10-21 16:42:32 -07:00
Steven Rostedt
d7b4d6de57 ftrace: Remove recursion between recordmcount and scripts/mod/empty
When DYNAMIC_FTRACE is enabled and we use the C version of recordmcount,
all objects are run through the recordmcount program to create a
separate section that stores all the callers of mcount.

The build process has a special file: scripts/mod/empty.o. This is
built from empty.c which is literally an empty file (except for a
single comment). This file is used to find information about the target
elf format, like endianness and word size.

The problem comes up when we need to build recordmcount. The
build process requires that empty.o is built first. The build rules
for empty.o will try to execute recordmcount on the empty.o file.
We get an error that recordmcount does not exist.

To avoid this recursion, the build file will skip running recordmcount
if the file that it is building is script/mod/empty.o.

[ extra comment Suggested-by: Sam Ravnborg <sam@ravnborg.org> ]

Reported-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Ingo Molnar <mingo@elte.hu>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-18 17:08:10 -04:00
Steven Rostedt
85caa993d7 ftrace: Use objtree for C version of recordmcount
The C version of recordmcount is compiled to a binary, which will
end up located in the objtree. If the kernel is built with O=path,
the srctree will not include the binary recordmcount caller.

Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-15 12:09:25 -04:00
Steven Rostedt
72441cb1fd ftrace/x86: Add support for C version of recordmcount
This patch adds the support for the C version of recordmcount and
compile times show ~ 12% improvement.

After verifying this works, other archs can add:

 HAVE_C_MCOUNT_RECORD

in its Kconfig and it will use the C version of recordmcount
instead of the perl version.

Cc: <linux-arch@vger.kernel.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Cc: John Reiser <jreiser@bitwagon.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-14 16:52:41 -04:00