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2012-05-25microblaze: Do not select GENERIC_GPIO by defaultLars-Peter Clausen
The microblaze architecture does not provide a native GPIO API implementation nor requires GPIOLIB, but still selects GENERIC_GPIO by default. As a result the following build error occurs, if GPIOLIB is not selected: include/asm-generic/gpio.h: In function 'gpio_get_value_cansleep': include/asm-generic/gpio.h:218: error: implicit declaration of function '__gpio_get_value' include/asm-generic/gpio.h: In function 'gpio_set_value_cansleep': include/asm-generic/gpio.h:224: error: implicit declaration of function '__gpio_set_value' This patch addresses the issue by not selecting GENERIC_GPIO by default. This causes the GPIO API to be stubbed out if no implementation is provided. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Cc: stable@vger.kernel.org Tested-by: Michal Simek <monstr@monstr.eu>
2012-03-27Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblazeLinus Torvalds
Pull arch/microblaze fixes from Michal Simek * 'next' of git://git.monstr.eu/linux-2.6-microblaze: microblaze: Handle TLB skip size dynamically microblaze: Introduce TLB skip size microblaze: Improve TLB calculation for small systems microblaze: Extend space for compiled-in FDT to 32kB microblaze: Clear all MSR flags on the first kernel instruction microblaze: Use node name instead of compatible string microblaze: Fix mapin_ram function microblaze: Highmem support microblaze: Use active regions microblaze: Show more detailed information about memory microblaze: Introduce fixmap microblaze: mm: Fix lowmem max memory size limits microblaze: mm: Use ZONE_DMA instead of ZONE_NORMAL microblaze: trivial: Fix typo fault in timer.c microblaze: Use vsprintf extention %pf with builtin_return_address microblaze: Add PVR version string for MB 8.20.b and 8.30.a microblaze: Fix makefile to work with latest toolchain microblaze: Fix typo in early_printk.c
2012-03-23microblaze: Improve TLB calculation for small systemsMichal Simek
Systems with small amount of memory need to be handled differently. Linux can't allocate the whole 32MB with two TLBs because then there is no MMU protection. Signed-off-by: Michal Simek <monstr@monstr.eu>
2012-03-23microblaze: Highmem supportMichal Simek
The first highmem implementation. Signed-off-by: Michal Simek <monstr@monstr.eu>
2012-03-23microblaze: Use active regionsMichal Simek
Register lowmem active regions. Signed-off-by: Michal Simek <monstr@monstr.eu>
2012-03-23microblaze: mm: Use ZONE_DMA instead of ZONE_NORMALMichal Simek
We should use ZONE_DMA because all address space is dma-able. Signed-off-by: Michal Simek <monstr@monstr.eu>
2012-02-16irq_domain/microblaze: Convert microblaze to use irq_domainsGrant Likely
This patch converts Microblaze to use the irq_domain remapper and get away from hard coding the offset between hwirq number and the linux irq number space. This also paves the way for multiple interrupt controllers. v2: Don't enable SPARSE_IRQ and keep NR_IRQS set to 33 Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Michal Simek <monstr@monstr.eu> Cc: Rob Herring <rob.herring@calxeda.com> Cc: John Williams <john.williams@petalogix.com> Cc: John Linn <john.linn@xilinx.com>
2012-01-20microblaze: generic atomic64 supportDaniel Borkmann
This tiny patch adds generic atomic64 support for the Microblaze architecture. The patch is against the latest linux-2.6-microblaze tree. It also fixes the kernel build for microblaze: Error log: CC kernel/trace/trace_clock.o kernel/trace/trace_clock.c:117: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'trace_counter' kernel/trace/trace_clock.c: In function 'trace_clock_counter': kernel/trace/trace_clock.c:126: error: implicit declaration of function 'atomic64_add_return' kernel/trace/trace_clock.c:126: error: 'trace_counter' undeclared (first use in this function) kernel/trace/trace_clock.c:126: error: (Each undeclared identifier is reported only once kernel/trace/trace_clock.c:126: error: for each function it appears in.) make[2]: *** [kernel/trace/trace_clock.o] Error 1 make[1]: *** [kernel/trace] Error 2 make: *** [kernel] Error 2 Signed-off-by: Ariane Keller <ariane.keller@tik.ee.ethz.ch> Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch> Signed-off-by: Michal Simek <monstr@monstr.eu>
2012-01-11cpu: Register a generic CPU device on architectures that currently do notBen Hutchings
frv, h8300, m68k, microblaze, openrisc, score, um and xtensa currently do not register a CPU device. Add the config option GENERIC_CPU_DEVICES which causes a generic CPU device to be registered for each present CPU, and make all these architectures select it. Richard Weinberger <richard@nod.at> covered UML and suggested using per_cpu. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-28microblaze: switch to GENERIC_PCI_IOMAPMichael S. Tsirkin
microblaze copied pci_iomap from generic code, probably to avoid pulling the rest of iomap.c in. Since that's in a separate file now, we can reuse the common implementation. The only difference is handling of nocache flag, that turns out to be done correctly by the generic code since arch/microblaze/include/asm/io.h defines ioremap_nocache same as ioremap. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2011-05-26arch: remove CONFIG_GENERIC_FIND_{NEXT_BIT,BIT_LE,LAST_BIT}Akinobu Mita
By the previous style change, CONFIG_GENERIC_FIND_NEXT_BIT, CONFIG_GENERIC_FIND_BIT_LE, and CONFIG_GENERIC_FIND_LAST_BIT are not used to test for existence of find bitops anymore. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Greg Ungerer <gerg@uclinux.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-13usb: Fix Kconfig unmet dependencies for Microblaze EHCIMichal Simek
Disable USB_ARCH_HAS_EHCI in arch Kconfig and enable it in usb Kconfig Warning log: warning: (MICROBLAZE) selects USB_ARCH_HAS_EHCI which has unmet direct dependencies (USB_SUPPORT) Signed-off-by: Michal Simek <monstr@monstr.eu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-30genirq: Remove the now obsolete config options and select statementsThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-29microblaze: Use generic show_interrupts()Thomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-23bitops: introduce CONFIG_GENERIC_FIND_BIT_LEAkinobu Mita
This introduces CONFIG_GENERIC_FIND_BIT_LE to tell whether to use generic implementation of find_*_bit_le() in lib/find_next_bit.c or not. For now we select CONFIG_GENERIC_FIND_BIT_LE for all architectures which enable CONFIG_GENERIC_FIND_NEXT_BIT. But m68knommu wants to define own faster find_next_zero_bit_le() and continues using generic find_next_{,zero_}bit(). (CONFIG_GENERIC_FIND_NEXT_BIT and !CONFIG_GENERIC_FIND_BIT_LE) Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-15microblaze: Do not copy reset vectors/manual reset vector setupMichal Simek
Reset vector can be setup by bootloader and kernel doens't need to touch it. If you require to setup reset vector, please use CONFIG_MANUAL_RESET_VECTOR throught menuconfig. It is not possible to setup address 0x0 as reset address because make no sense to set it up at all. Signed-off-by: Michal Simek <monstr@monstr.eu> Signed-off-by: John Williams <john.williams@petalogix.com>
2011-03-09microblaze: Fix typo in KconfigTobias Klauser
s/Exectuable/Executable/ Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
2011-03-09microblaze: Select GENERIC_HARDIRQS_NO_DEPRECATEDThomas Gleixner
All irq_chips converted. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-21microblaze: Use generic irq KconfigThomas Gleixner
No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michal Simek <monstr@monstr.eu>
2011-01-21genirq: Remove __do_IRQThomas Gleixner
All architectures are finally converted. Remove the cruft. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Mike Frysinger <vapier@gentoo.org> Cc: David Howells <dhowells@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Michal Simek <monstr@monstr.eu> Acked-by: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Chen Liqin <liqin.chen@sunplusct.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Jeff Dike <jdike@addtoit.com>
2010-12-29of/flattree: Add Kconfig for EARLY_FLATTREEStephen Neuendorffer
The device tree code is now in two pieces: some which can be used generically on any platform which selects CONFIG_OF_FLATTREE, and some early which is used at boot time on only a few architectures. This patch segregates the early code so that only those architectures which care about it need compile it. This also means that some of the requirements in the early code (such as a cmd_line variable) that most architectures (e.g. X86) don't provide can be ignored. Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com> [grant.likely@secretlab.ca: remove extra blank line addition] [grant.likely@secretlab.ca: fixed incorrect #ifdef CONFIG_EARLY_FLATTREE check] [grant.likely@secretlab.ca: Made OF_EARLY_FLATTREE select instead of depend on OF_FLATTREE] Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-10-28Merge branch 'kconfig' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 * 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6: (38 commits) kbuild: convert `arch/tile' to the kconfig mainmenu upgrade README: cite nconfig Revert "kconfig: Temporarily disable dependency warnings" kconfig: Use PATH_MAX instead of 128 for path buffer sizes. kconfig: Fix realloc usage() kconfig: Propagate const kconfig: Don't go out from read config loop when you read new symbol kconfig: fix menuconfig on debian lenny kbuild: migrate all arch to the kconfig mainmenu upgrade kconfig: expand file names kconfig: use the file's name of sourced file kconfig: constify file name kconfig: don't emit warning upon rootmenu's prompt redefinition kconfig: replace KERNELVERSION usage by the mainmenu's prompt kconfig: delay gconf window initialization kconfig: expand by default the rootmenu's prompt kconfig: add a symbol string expansion helper kconfig: regen parser kconfig: implement the `mainmenu' directive kconfig: allow PACKAGE to be defined on the compiler's command-line ... Fix up trivial conflict in arch/mn10300/Kconfig
2010-10-21microblaze: Add seccomp supportMichal Simek
Add seccomp support. Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-10-12Merge branch 'kbuild/rc-fixes' into kbuild/kconfigMichal Marek
We need to revert the temporary hack in 71ebc01, hence the merge.
2010-09-19kbuild: migrate all arch to the kconfig mainmenu upgradeArnaud Lacombe
Signed-off-by: Arnaud Lacombe <lacombar@gmail.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Michal Marek <mmarek@suse.cz>
2010-08-06Merge branch 'timers-timekeeping-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-timekeeping-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: um: Fix read_persistent_clock fallout kgdb: Do not access xtime directly powerpc: Clean up obsolete code relating to decrementer and timebase powerpc: Rework VDSO gettimeofday to prevent time going backwards clocksource: Add __clocksource_updatefreq_hz/khz methods x86: Convert common clocksources to use clocksource_register_hz/khz timekeeping: Make xtime and wall_to_monotonic static hrtimer: Cleanup direct access to wall_to_monotonic um: Convert to use read_persistent_clock timkeeping: Fix update_vsyscall to provide wall_to_monotonic offset powerpc: Cleanup xtime usage powerpc: Simplify update_vsyscall time: Kill off CONFIG_GENERIC_TIME time: Implement timespec_add x86: Fix vtime/file timestamp inconsistencies Trivial conflicts in Documentation/feature-removal-schedule.txt Much less trivial conflicts in arch/powerpc/kernel/time.c resolved as per Thomas' earlier merge commit 47916be4e28c ("Merge branch 'powerpc.cherry-picks' into timers/clocksource")
2010-08-05Merge branch 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6Linus Torvalds
* 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6: (63 commits) of/platform: Register of_platform_drivers with an "of:" prefix of/address: Clean up function declarations of/spi: call of_register_spi_devices() from spi core code of: Provide default of_node_to_nid() implementation. of/device: Make of_device_make_bus_id() usable by other code. of/irq: Fix endian issues in parsing interrupt specifiers of: Fix phandle endian issues of/flattree: fix of_flat_dt_is_compatible() to match the full compatible string of: remove of_default_bus_ids of: make of_find_device_by_node generic microblaze: remove references to of_device and to_of_device sparc: remove references to of_device and to_of_device powerpc: remove references to of_device and to_of_device of/device: Replace of_device with platform_device in includes and core code of/device: Protect against binding of_platform_drivers to non-OF devices of: remove asm/of_device.h of: remove asm/of_platform.h of/platform: remove all of_bus_type and of_platform_bus_type references of: Merge of_platform_bus_type with platform_bus_type drivercore/of: Add OF style matching to platform bus ... Fix up trivial conflicts in arch/microblaze/kernel/Makefile due to just some obj-y removals by the devicetree branch, while the microblaze updates added a new file.
2010-08-04microblaze: Add KGDB supportMichal Simek
Kgdb uses brki r16, 0x18 instruction to call low level _debug_exception function which save current state to pt_regs and call microblaze_kgdb_break function. _debug_exception should be called only from the kernel space. User space calling is not supported because user application debugging uses different handling. pt_regs_to_gdb_regs loads additional special registers which can't be changed * Enable KGDB in Kconfig * Remove ancient not-tested KGDB support * Remove ancient _debug_exception code from entry.S Only MMU KGDB support is supported. Signed-off-by: Michal Simek <monstr@monstr.eu> CC: Jason Wessel <jason.wessel@windriver.com> CC: John Williams <john.williams@petalogix.com> CC: Edgar E. Iglesias <edgar.iglesias@petalogix.com> CC: linux-kernel@vger.kernel.org Acked-by: Jason Wessel <jason.wessel@windriver.com>
2010-08-04microblaze: Allow PAGE_SIZE configurationSteven J. Magnani
Allow developer to configure memory page size at compile time. Larger pages can improve performance on some workloads. Based on PowerPC code. Signed-off-by: Steven J. Magnani <steve@digidescorp.com> Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-07-27time: Kill off CONFIG_GENERIC_TIMEJohn Stultz
Now that all arches have been converted over to use generic time via clocksources or arch_gettimeoffset(), we can remove the GENERIC_TIME config option and simplify the generic code. Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1279068988-21864-4-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-07-24Merge commit 'v2.6.35-rc6' into devicetree/nextGrant Likely
Conflicts: arch/sparc/kernel/prom_64.c
2010-07-14lmb: rename to memblockYinghai Lu
via following scripts FILES=$(find * -type f | grep -vE 'oprofile|[^K]config') sed -i \ -e 's/lmb/memblock/g' \ -e 's/LMB/MEMBLOCK/g' \ $FILES for N in $(find . -name lmb.[ch]); do M=$(echo $N | sed 's/lmb/memblock/g') mv $N $M done and remove some wrong change like lmbench and dlmb etc. also move memblock.c from lib/ to mm/ Suggested-by: Ingo Molnar <mingo@elte.hu> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-07-05proc: unify PROC_DEVICETREE configAndres Salomon
Microblaze and PPC both use PROC_DEVICETREE, and OLPC will as well.. put the Kconfig option into fs/ rather than in arch/*/Kconfig. Signed-off-by: Andres Salomon <dilinger@queued.net> [grant.likely@secretlab.ca: changed depends to PROC_FS && !SPARC] [grant.likely@secretlab.ca: moved to drivers/of/Kconfig] Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-05of: Put all CONFIG_OF dependencies into a Kconfig menu blockGrant Likely
All of the options in drivers/of/Kconfig depend on CONFIG_OF. Putting all of them inside a menu block simplifies the dependency statements. It also creates a logical group for adding user selectable OF options. This patch also changes (PPC_OF || MICROBLAZE) statements to (!SPARC) so that those options are available to other architectures (and in fact the !SPARC conditions should probably be re-evalutated since the code is more generic now) This patch also moves the definition of CONFIG_DTC from arch/* to drivers/of/Kconfig Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-05of: remove architecture CONFIG_OF definitionsStephen Rothwell
now that CONFIG_OF is defined globally Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Michal Simek <monstr@monstr.eu> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-07-05microblaze: turn CONFIG_OF into a selectStephen Rothwell
so that we can make CONFIG_OF global and remove it from the architecture Kconfig files later. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Michal Simek <monstr@monstr.eu> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-04-01microblaze: Kconfig Fix - pciMichal Simek
I forget to remove pci Kconfig option. Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-03-11microblaze: Add consistent codeMichal Simek
Remove ancient Kconfig option for consistent code. MMU uses cache inhibit pages. noMMU uses UNCACHE SHADOW feature where is used double ram size. For example: Physical ram is 256MB and cache are setup to cover the same size. But if you setup in HW that size is 512MB and cache covers 256MB than you can use adresses from 256-512MB without caches and correspond with 0-256MB with cache. That's why I am using dcache base/high addresses to find out uncache area. Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-03-11microblaze: Remove ancient Kconfig option for consistent mappingMichal Simek
We don't use CONSISTENT option from Kconfig that's why I am removing them. Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-03-11microblaze: Add support for Xilinx PCI host bridgeMichal Simek
This patch is based on powerpc patch 64f16502475ddf663169369fffff6da9b10ea9fb We did some cleanups and removed powerpc parts. There is one new debug early listing function too. Exclude function is only in Debug options. We tested in on custom board. Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-03-11microblaze: Enable PCI, missing filesMichal Simek
There are two parts of changes. The first is just enable PCI in Makefiles and in Kconfig. The second is the rest of missing files. I didn't want to add it with previous patch because that patch is too big. Current Microblaze toolchain has problem with weak symbols that's why is necessary to apply this changes to be possible to compile pci support. Xilinx knows about this problem. Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-03-11microblaze: Support DMAMichal Simek
Add DMA support for Microblaze. There are some part of this new feature: 1. Basic DMA support 2. Enable DMA debug option 3. Setup notifier Ad 1. dma-mapping come from powerpc and x86 version and it is based on generic dma-mapping-common.h Ad 2. DMA support debug features which is used in generic file. For more information please look at Documentation/DMA-API.txt Ad 3. notifier is very important to setup dma_ops. Without this part for example ll_temac driver failed because there are no setup dma operations. Signed-off-by: Michal Simek <monstr@monstr.eu>
2010-01-28Merge commit 'v2.6.33-rc5' into secretlab/test-devicetreeGrant Likely
2010-01-18microblaze: Add missing double apostrophe in KconfigMichal Simek
Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-12-14microblaze: Enable DTC compilationMichal Simek
For simpleImage format we need to compile DTC. There is still possibility to compile only Linux kernel without DTB compiled-in. Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-12-14microblaze: Core oprofile configs and hooksJohn Williams
Microblaze uses timer interrupt mode. Microblaze don't have any performance counter that's why we use just simple implementation. Signed-off-by: John Williams <john.williams@petalogix.com> Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-12-14microblaze: ftrace: add function graph supportMichal Simek
For more information look at Documentation/trace folder. Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-12-14microblaze: ftrace: Add dynamic trace supportMichal Simek
With dynamic function tracer, by default, _mcount is defined as an "empty" function, it returns directly without any more action. When enabling it in user-space, it will jump to a real tracing function(ftrace_caller), and do the real job for us. Differ from the static function tracer, dynamic function tracer provides two functions ftrace_make_call()/ftrace_make_nop() to enable/disable the tracing of some indicated kernel functions(set_ftrace_filter). In the kernel version, there is only one "_mcount" string for every kernel function, so, we just need to match this one in mcount_regex of scripts/recordmcount.pl. For more information please look at code and Documentation/trace folder. Steven ACK that scripts/recordmcount.pl part. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-12-14microblaze: ftrace: enable HAVE_FUNCTION_TRACE_MCOUNT_TESTMichal Simek
Implement MCOUNT_TEST in asm code - it is faster than use generic code Signed-off-by: Michal Simek <monstr@monstr.eu>
2009-12-14microblaze: ftrace: add static function tracerMichal Simek
If -pg of gcc is enabled with CONFIG_FUNCTION_TRACER=y. a calling to _mcount will be inserted into each kernel function. so, there is a possibility to trace the kernel functions in _mcount. This patch add the specific _mcount support for static function tracing. by default, ftrace_trace_function is initialized as ftrace_stub(an empty function), so, the default _mcount will introduce very little overhead. after enabling ftrace in user-space, it will jump to a real tracing function and do static function tracing for us. Commit message from Wu Zhangjin <wuzhangjin@gmail.com> Signed-off-by: Michal Simek <monstr@monstr.eu>