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>
Add CONFIG_VIRTUALIZATION to the MIPS architecture and include the
the virtio code there. Used to enable the virtio drivers under QEMU.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2002/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch adds initial support for various Atheros SoCs based on the
MIPS 24Kc core. The following models are supported at the moment:
- AR7130
- AR7141
- AR7161
- AR9130
- AR9132
- AR7240
- AR7241
- AR7242
The current patch contains minimal support only, but the resulting
kernel can boot into user-space with using of an initramfs image on
various boards which are using these SoCs. Support for more built-in
devices and individual boards will be implemented in further patches.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1947/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
In order not to be left behind, we add jump label support for MIPS.
Tested on 64-bit big endian (Octeon), and 32-bit little endian
(malta/qemu).
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>
Patchwork: https://patchwork.linux-mips.org/patch/1923/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch adds a generic solution to support multiple machines based on
a given SoC within a single kernel image. It is implemented already for
several other architectures but MIPS has no generic support for that yet.
[Ralf: This competes with DT but DT is a much more complex solution and this
code has been used by OpenWRT for a long time so for now DT is a bad reason
to stop the merge but longer term this should be migrated to DT.]
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: kaloz@openwrt.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1814/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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>
For huge page support with base page size of 16K or 32K, we have to
increase the MAX_ORDER so that huge pages can be allocated.
[Ralf: I don't think a user should have to configure obscure constants like
this but for the time being this will have to suffice.]
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1685/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Recent changes to CONFIG_GENERIC_HARDIRQS have caused us to start getting:
warning: (SMP && SYS_SUPPORTS_SMP) selects IRQ_PER_CPU which has unmet direct dependencies (HAVE_GENERIC_HARDIRQS)
Rearranging our Kconfig quiets the message.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Patchwork: https://patchwork.linux-mips.org/patch/1757/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Selects HAVE_C_RECORDMCOUNT to use the C version of the recordmcount
intead of the old Perl Version of recordmcount.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
LKML-Reference: <bb99009a9ac79d3f55a8c8bf1c8bd2bc0e1f160e.1288176026.git.wuzhangjin@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch provides the skeleton of the HW perf event support. To enable
this feature, we can not choose the SMTC kernel; Oprofile should be
disabled; kernel performance events be selected. Then we can enable it in
Kernel type menu.
Oprofile for MIPS platforms initializes irq at arch init time. Currently
we do not change this logic to allow PMU reservation.
If a platform has EIC, we can use the irq base and perf counter irq offset
defines for the interrupt controller in specific init_hw_perf_events().
Based on this skeleton patch, the 3 different kinds of MIPS PMU, namely,
mipsxx/loongson2/rm9000, can be supported by adding corresponding lower
level C files at the bottom. The suggested names of these files are
perf_event_mipsxx.c/perf_event_loongson2.c/perf_event_rm9000.c. So, for
example, we can do this by adding "#include perf_event_mipsxx.c" at the
bottom of perf_event.c.
In addition, PMUs with 64bit counters are also considered in this patch.
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: linux-mips@linux-mips.org
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: jamie.iles@picochip.com
Cc: ddaney@caviumnetworks.com
Cc: matt@console-pimps.org
Patchwork: https://patchwork.linux-mips.org/patch/1688/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Software events are required as part of the measurable stuff by the
Linux performance counter subsystem. Here is the list of events added by
this patch:
PERF_COUNT_SW_PAGE_FAULTS
PERF_COUNT_SW_PAGE_FAULTS_MIN
PERF_COUNT_SW_PAGE_FAULTS_MAJ
PERF_COUNT_SW_ALIGNMENT_FAULTS
PERF_COUNT_SW_EMULATION_FAULTS
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: linux-mips@linux-mips.org
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: jamie.iles@picochip.com
Acked-by: David Daney <ddaney@caviumnetworks.com>
Reviewed-by: Matt Fleming <matt@console-pimps.org>
Patchwork: https://patchwork.linux-mips.org/patch/1686/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Use asm-generic/dma-mapping-common.h to handle all DMA mapping operations
and establish a default get_dma_ops() that forwards all operations to the
existing code.
Augment dev_archdata to carry a pointer to the struct dma_map_ops, allowing
DMA operations to be overridden on a per device basis. Currently this is
never filled in, so the default dma_map_ops are used. A follow-on patch
sets this for Octeon PCI devices.
Also initialize the dma_debug system as it is now used if it is configured.
Includes fixes by Kevin Cernekee <cernekee@gmail.com>.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Patchwork: http://patchwork.linux-mips.org/patch/1637/
Patchwork: http://patchwork.linux-mips.org/patch/1678/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Give us a nice place to allocate coherent DMA memory for 32-bit devices.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Patchwork: http://patchwork.linux-mips.org/patch/1635/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* '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
* 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6:
mtd/m25p80: add support to parse the partitions by OF node
of/irq: of_irq.c needs to include linux/irq.h
of/mips: Cleanup some include directives/files.
of/mips: Add device tree support to MIPS
of/flattree: Eliminate need to provide early_init_dt_scan_chosen_arch
of/device: Rework to use common platform_device_alloc() for allocating devices
of/xsysace: Fix OF probing on little-endian systems
of: use __be32 types for big-endian device tree data
of/irq: remove references to NO_IRQ in drivers/of/platform.c
of/promtree: add package-to-path support to pdt
of/promtree: add of_pdt namespace to pdt code
of/promtree: no longer call prom_ functions directly; use an ops structure
of/promtree: make drivers/of/pdt.c no longer sparc-only
sparc: break out some PROM device-tree building code out into drivers/of
of/sparc: convert various prom_* functions to use phandle
sparc: stop exporting openprom.h header
powerpc, of_serial: Endianness issues setting up the serial ports
of: MTD: Fix OF probing on little-endian systems
of: GPIO: Fix OF probing on little-endian systems
Add the ability to enable CONFIG_OF on the MIPS architecture.
Signed-off-by: Dezhong Diao <dediao@cisco.com>
[grant.likely@secretlab.ca: cleared out obsolete hooks,
removed ARCH_HAS_DEVTREE_MEM,
remove __init tags from header file,
removed debugfs support hunk]
[ddaney@linux-mips.org: backed out over aggressive trimming of hooks]
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* 'upstream' of git://git.linux-mips.org/pub/scm/upstream-linus:
MIPS: Enable ISA_DMA_API config to fix build failure
MIPS: 32-bit: Fix build failure in asm/fcntl.h
MIPS: Remove all generated vmlinuz* files on "make clean"
MIPS: do_sigaltstack() expects userland pointers
MIPS: Fix error values in case of bad_stack
MIPS: Sanitize restart logics
MIPS: secure_computing, syscall audit: syscall number should in r2, not r0.
MIPS: Don't block signals if we'd failed to setup a sigframe
Add ISA_DMA_API config item and select it when GENERIC_ISA_DMA enabled.
This fixes build failure on allmodconfig like following:
CC sound/isa/es18xx.o
sound/isa/es18xx.c: In function 'snd_es18xx_playback1_prepare':
sound/isa/es18xx.c:501:9: error: implicit declaration of function 'snd_dma_program'
sound/isa/es18xx.c: In function 'snd_es18xx_playback_pointer':
sound/isa/es18xx.c:818:3: error: implicit declaration of function 'snd_dma_pointer'
make[3]: *** [sound/isa/es18xx.o] Error 1
make[2]: *** [sound/isa/es18xx.o] Error 2
make[1]: *** [sub-make] Error 2
make: *** [all] Error 2
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1717/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The patch below updates broken web addresses in the arch directory.
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Finn Thain <fthain@telegraphics.com.au>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Reviewed-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* '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 47916be4e2 ("Merge branch
'powerpc.cherry-picks' into timers/clocksource")
A 'select EXPORT_UASM' in Kconfig will cause the uasm to be exported
for use in modules. When it is exported, all the uasm data and code
cease to be __init and __initdata.
Also daddiu_bug cannot be __cpuinitdata if uasm is exported. The
cleanest thing is to just make it normal data.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
To: wim@iguana.be
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1500/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Remove the CONFIG_SOC_AU1X00 Kconfig symbol since its job can also be done
by MACH_ALCHEMY, now renamed to MIPS_ALCHEMY.
Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
To: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/1461/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
B43_pci_bridge is needed to use the b43 driver with brcm47xx. Activate it
by default if PCI is available.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1510/
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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>
As documented in the Loongson 2F User Manual [2, 3], the old Loongson2F
series (2F01 / 2F02) have the NOP & JUMP issues which requires workarounds
in the kernel and binutils. This issue has been rectified in Loongson 2F
series 2F03 so no workarounds needed.
Now that the workarounds [1] adding the the -mfix-loongson2f-nop and
-mfix-loongson2f-jump options have been comitted to the binutils the CVS
repository), we can add the workarounds in the kernel.
The workarounds have no significant side effect on the system but may
decrease performance so we control them through a a new
CPU_LOONGSON2F_WORKAROUNDS config option allowing the users to only enable
it as necessary.
[1] "Fixups of Loongson2F" patch for binutils(actually for gas)
http://sourceware.org/ml/binutils/2009-11/msg00387.html
[2] Chapter 15 of "Loongson2F User Manual"(Chinese Version)
http://www.loongson.cn/uploadfile/file/200808211
[3] English Version of the above chapter 15
http://groups.google.com.hk/group/loongson-dev/msg/e0d2e220958f10a6?dmode=source
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: http://patchwork.linux-mips.org/patch/1105/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
According to include/asm/sibyte/swarm.h both systems provide a
platform device for the ide controler. Until now the IDE subsystem was
used which is deprecated by now. The same structure can be used with the
PATA driver.
Signed-off-by: Sebastian Andrzej Siewior <sebatian@breakpoint.cc>
Cc: tbm@cyrius.com
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/1127/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
I believe these changes are needed on Alchemy SoCs in order to
use iomem above 4G with the usual platform_device machinery:
- Set CONFIG_ARCH_PHYS_ADDR_T_64BIT to make resource_size_t 64-bit.
- Increase IOMEM_RESOURCE_END so that platforms can register resources.
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/814/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The compressed kernel support on loongson family machines is stable now,
so, remove the debug information via using SYS_SUPPORTS_ZBOOT instead of
SYS_SUPPORTS_ZBOOT_UART16550. This may reduce the image size and speedup
the booting.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: yanh@lemote.com
Cc: huhb@lemote.com
Cc: zhangfx@lemote.com
Patchwork: http://patchwork.linux-mips.org/patch/824/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
In order to achieve correct synchronization semantics, the Octeon port
had defined CONFIG_WEAK_REORDERING_BEYOND_LLSC. This resulted in code
that looks like:
sync
ll ...
.
.
.
sc ...
.
.
sync
The second SYNC was redundant, but harmless.
Octeon has a SYNCW instruction that acts as a write-memory-barrier
(due to an erratum in some parts two SYNCW are used). It is much
faster than SYNC because it imposes ordering on the writes, but
doesn't otherwise stall the execution pipeline. On Octeon, SYNC
stalls execution until all preceeding writes are committed to the
coherent memory system.
Using:
syncw;syncw
ll
.
.
.
sc
.
.
Has identical semantics to the first sequence, but is much faster.
The SYNCW orders the writes, and the SC will not complete successfully
until the write is committed to the coherent memory system. So at the
end all preceeding writes have been committed. Since Octeon does not
do speculative reads, this functions as a full barrier.
The patch removes CONFIG_WEAK_REORDERING_BEYOND_LLSC, and substitutes
SYNCW for SYNC in write-memory-barriers.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/850/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The necessary changes to the x86 Kconfig and boot/compressed to allow the
use of this new compression method.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Patchwork: http://patchwork.linux-mips.org/patch/857/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
There's no reason for MIPS to select EMBEDDED. In fact, EMBEDDED makes
MIPS more awkward to deal with because it makes it different to the
majority of architectures for no good reason.
[Ralf: Historically disabling EMBEDDED had hid essential options for many
MIPS platforms such as serial console and forced crap like VGA support
or power managment enabled for platforms where those don't make any sense.
The name of the option is also _very_ missleading so many users don't
select it even where is was required for a functioning kernel.]
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/663/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The platform has never been fully merged
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Koeller <thomas.koeller@baslerweb.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mtd@lists.infradead.org
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
The implementation of function graph tracer for MIPS is a little
different from X86.
in MIPS, gcc(with -pg) only transfer the caller's return address(at) and
the _mcount's return address(ra) to us.
For the kernel part without -mlong-calls:
move at, ra
jal _mcount
For the module part with -mlong-calls:
lui v1, hi16bit_of_mcount
addiu v1, v1, low16bit_of_mcount
move at, ra
jal _mcount
Without -mlong-calls,
if the function is a leaf, it will not save the return address(ra):
ffffffff80101298 <au1k_wait>:
ffffffff80101298: 67bdfff0 daddiu sp,sp,-16
ffffffff8010129c: ffbe0008 sd s8,8(sp)
ffffffff801012a0: 03a0f02d move s8,sp
ffffffff801012a4: 03e0082d move at,ra
ffffffff801012a8: 0c042930 jal ffffffff8010a4c0 <_mcount>
ffffffff801012ac: 00020021 nop
so, we can hijack it directly in _mcount, but if the function is non-leaf, the
return address is saved in the stack.
ffffffff80133030 <copy_process>:
ffffffff80133030: 67bdff50 daddiu sp,sp,-176
ffffffff80133034: ffbe00a0 sd s8,160(sp)
ffffffff80133038: 03a0f02d move s8,sp
ffffffff8013303c: ffbf00a8 sd ra,168(sp)
ffffffff80133040: ffb70098 sd s7,152(sp)
ffffffff80133044: ffb60090 sd s6,144(sp)
ffffffff80133048: ffb50088 sd s5,136(sp)
ffffffff8013304c: ffb40080 sd s4,128(sp)
ffffffff80133050: ffb30078 sd s3,120(sp)
ffffffff80133054: ffb20070 sd s2,112(sp)
ffffffff80133058: ffb10068 sd s1,104(sp)
ffffffff8013305c: ffb00060 sd s0,96(sp)
ffffffff80133060: 03e0082d move at,ra
ffffffff80133064: 0c042930 jal ffffffff8010a4c0 <_mcount>
ffffffff80133068: 00020021 nop
but we can not get the exact stack address(which saved ra) directly in
_mcount, we need to search the content of at register in the stack space
or search the "s{d,w} ra, offset(sp)" instruction in the text. 'Cause we
can not prove there is only a match in the stack space, so, we search
the text instead.
as we can see, if the first instruction above "move at, ra" is not a
store instruction, there should be a leaf function, so we hijack the at
register directly via putting &return_to_handler into it, otherwise, we
search the "s{d,w} ra, offset(sp)" instruction to get the stack offset,
and then the stack address. we use the above copy_process() as an
example, we at last find "ffbf00a8", 0xa8 is the stack offset, we plus
it with s8(fp), that is the stack address, we hijack the content via
writing the &return_to_handler in.
If with -mlong-calls, since there are two more instructions above "move
at, ra", so, we can move the pointer to the position above "lui v1,
hi16bit_of_mcount".
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: zhangfx@lemote.com
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/677/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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 -v4 version, the implementation of this support is basically the same as
X86 version does: _mcount is implemented as an empty function and ftrace_caller
is implemented as a real tracing function respectively.
But in this version, to support module tracing with the help of
-mlong-calls in arch/mips/Makefile:
MODFLAGS += -mlong-calls.
The stuff becomes a little more complex. We need to cope with two
different type of calling to _mcount.
For the kernel part, the calling to _mcount(result of "objdump -hdr
vmlinux"). is like this:
108: 03e0082d move at,ra
10c: 0c000000 jal 0 <fpcsr_pending>
10c: R_MIPS_26 _mcount
10c: R_MIPS_NONE *ABS*
10c: R_MIPS_NONE *ABS*
110: 00020021 nop
For the module with -mlong-calls, it looks like this:
c: 3c030000 lui v1,0x0
c: R_MIPS_HI16 _mcount
c: R_MIPS_NONE *ABS*
c: R_MIPS_NONE *ABS*
10: 64630000 daddiu v1,v1,0
10: R_MIPS_LO16 _mcount
10: R_MIPS_NONE *ABS*
10: R_MIPS_NONE *ABS*
14: 03e0082d move at,ra
18: 0060f809 jalr v1
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, but in the module version, we need to choose
one of the two to match. Herein, I choose the first one with
"R_MIPS_HI16 _mcount".
and In the kernel verion, without module tracing support, we just need
to replace "jal _mcount" by "jal ftrace_caller" to do real tracing, and
filter the tracing of some kernel functions via replacing it by a nop
instruction.
but as we have described before, the instruction "jal ftrace_caller" only left
32bit length for the address of ftrace_caller, it will fail when calling from
the module space. so, herein, we must replace something else.
the basic idea is loading the address of ftrace_caller to v1 via changing these
two instructions:
lui v1,0x0
addiu v1,v1,0
If we want to enable the tracing, we need to replace the above instructions to:
lui v1, HI_16BIT_ftrace_caller
addiu v1, v1, LOW_16BIT_ftrace_caller
If we want to stop the tracing of the indicated kernel functions, we
just need to replace the "jalr v1" to a nop instruction. but we need to
replace two instructions and encode the above two instructions
oursevles.
Is there a simpler solution? Yes! Here it is, in this version, we put _mcount
and ftrace_caller together, which means the address of _mcount and
ftrace_caller is the same:
_mcount:
ftrace_caller:
j ftrace_stub
nop
...(do real tracing here)...
ftrace_stub:
jr ra
move ra, at
By default, the kernel functions call _mcount, and then jump to ftrace_stub and
return. and when we want to do real tracing, we just need to remove that "j
ftrace_stub", and it will run through the two "nop" instructions and then do
the real tracing job.
what about filtering job? we just need to do this:
lui v1, hi_16bit_of_mcount <--> b 1f (0x10000004)
addiu v1, v1, low_16bit_of_mcount
move at, ra
jalr v1
nop
1f: (rec->ip + 12)
In linux-mips64, there will be some local symbols, whose name are
prefixed by $L, which need to be filtered. thanks goes to Steven for
writing the mips64-specific function_regex.
In a conclusion, with RISC, things becomes easier with such a "stupid"
trick, RISC is something like K.I.S.S, and also, there are lots of
"simple" tricks in the whole ftrace support, thanks goes to Steven and
the other folks for providing such a wonderful tracing framework!
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: zhangfx@lemote.com
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/675/
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
