It is above 0x100 (PCI-Express extended register space), so if mmconf
is not enable, we can't access it.
[ hpa: changed the bound from 0x200 to 0x120, which is the tight
bound. ]
Reported-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1261525263-13763-3-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
fix for error that is introduced by
| x86: Use find_e820() instead of hard coded trampoline address
it should end with PAGE_SIZE + PAGE_SIZE
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1261525263-13763-2-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The wrong address was being used to write the SCIR led regs on
remote hubs. Also, there was an inconsistency between how BIOS
and the kernel indexed these regs. Standardize on using the
lower 6 bits of the APIC ID as the index.
This patch fixes the problem of writing to an errant address to
a cpu # >= 64.
Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Jack Steiner <steiner@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@kernel.org
LKML-Reference: <4B3922F9.3060905@sgi.com>
[ v2: fix a number of annoying checkpatch artifacts and whitespace noise ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
As suggested by Vegard Nossum, use KERN_WARNING for error
reporting to make sure kmemcheck reports end up in syslog.
Suggested-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1261990935.4641.7.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andrew Morton reported a strange looking kmemcheck warning:
WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88004fba6c20)
0000000000000000310000000000000000000000000000002413000000c9ffff
u u u u u u u u u u u u u u u u i i i i i i i i u u u u u u u u
[<ffffffff810af3aa>] kmemleak_scan+0x25a/0x540
[<ffffffff810afbcb>] kmemleak_scan_thread+0x5b/0xe0
[<ffffffff8104d0fe>] kthread+0x9e/0xb0
[<ffffffff81003074>] kernel_thread_helper+0x4/0x10
[<ffffffffffffffff>] 0xffffffffffffffff
The above printout is missing register dump completely. The
problem here is that the output comes from syslog which doesn't
show KERN_INFO log-level messages. We didn't see this before
because both of us were testing on 32-bit kernels which use the
_default_ log-level.
Fix that up by explicitly using KERN_DEFAULT log-level for
__show_regs() printks.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1261988819.4641.2.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Recently, some distros have started shipping versions of gcc which
default to -march=i686. This breaks building kernels for pre-i686
machines, even if they have been selected in Kconfig, due to the
generation of CMOV instructions.
There isn't enough benefit to try to preserve the generation of these
instructions even when selected, so simply force -march=i386 for the
decompressor when building a 32-bit kernel.
Reported-and-tested-by: Chris Rankin <rankincj@yahoo.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <219280.97558.qm@web52907.mail.re2.yahoo.com>
The assumption that acpi_table_parse passes the return value
of the hanlder function to the caller proved wrong
recently. The return value of the handler function is
totally ignored. This makes the initialization code for AMD
IOMMU buggy in a way that could cause a kernel panic on
initialization. This patch fixes the issue in the AMD IOMMU
driver.
Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Different version of objdump says its version in different way;
GNU objdump 2.16.1
or
GNU objdump version 2.19.51.0.14-1.fc11 20090722
This patch uses the first argument which starts with a number
as version string.
Changes in v2:
- Remove unneeded increment.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <20091218154012.16960.5113.stgit@dhcp-100-2-132.bos.redhat.com>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
John Blackwood reported:
> on an older Dell PowerEdge 6650 system with 8 cpus (4 are hyper-threaded),
> and 32 bit (x86) kernel, once you change the irq smp_affinity of an irq
> to be less than all cpus in the system, you can never change really the
> irq smp_affinity back to be all cpus in the system (0xff) again,
> even though no error status is returned on the "/bin/echo ff >
> /proc/irq/[n]/smp_affinity" operation.
>
> This is due to that fact that BAD_APICID has the same value as
> all cpus (0xff) on 32bit kernels, and thus the value returned from
> set_desc_affinity() via the cpu_mask_to_apicid_and() function is treated
> as a failure in set_ioapic_affinity_irq_desc(), and no affinity changes
> are made.
set_desc_affinity() is already checking if the incoming cpu mask
intersects with the cpu online mask or not. So there is no need
for the apic op cpu_mask_to_apicid_and() to check again
and return BAD_APICID.
Remove the BAD_APICID return value from cpu_mask_to_apicid_and()
and also fix set_desc_affinity() to return -1 instead of using BAD_APICID
to represent error conditions (as cpu_mask_to_apicid_and() can return
logical or physical apicid values and BAD_APICID is really to represent
bad physical apic id).
Reported-by: John Blackwood <john.blackwood@ccur.com>
Root-caused-by: John Blackwood <john.blackwood@ccur.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1261103386.2535.409.camel@sbs-t61>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* 'cpumask-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
cpumask: rename tsk_cpumask to tsk_cpus_allowed
cpumask: don't recommend set_cpus_allowed hack in Documentation/cpu-hotplug.txt
cpumask: avoid dereferencing struct cpumask
cpumask: convert drivers/idle/i7300_idle.c to cpumask_var_t
cpumask: use modern cpumask style in drivers/scsi/fcoe/fcoe.c
cpumask: avoid deprecated function in mm/slab.c
cpumask: use cpu_online in kernel/perf_event.c
* 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6:
OMAP3: serial - fix bug introduced in
mfd: twl: fix twl4030 rename for remaining driver, board files
USB ehci: replace mach header with plat
omap3: Allow EHCI to be built on OMAP3
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (71 commits)
MIPS: Lasat: Fix botched changes to sysctl code.
RTC: rtc-cmos.c: Fix warning on MIPS
MIPS: Cleanup random differences beween lmo and Linus' kernel.
MIPS: No longer hardwire CONFIG_EMBEDDED to y
MIPS: Fix and enhance built-in kernel command line
MIPS: eXcite: Remove platform.
MIPS: Loongson: Cleanups of serial port support
MIPS: Lemote 2F: Suspend CS5536 MFGPT Timer
MIPS: Excite: move iodev_remove to .devexit.text
MIPS: Lasat: Convert to proc_fops / seq_file
MIPS: Cleanup signal code initialization
MIPS: Modularize COP2 handling
MIPS: Move EARLY_PRINTK to Kconfig.debug
MIPS: Yeeloong 2F: Cleanup reset logic using the new ec_write function
MIPS: Yeeloong 2F: Add LID open event as the wakeup event
MIPS: Yeeloong 2F: Add basic EC operations
MIPS: Move several variables from .bss to .init.data
MIPS: Tracing: Make function graph tracer work with -mmcount-ra-address
MIPS: Tracing: Reserve $12(t0) for mcount-ra-address of gcc 4.5
MIPS: Tracing: Make ftrace for MIPS work without -fno-omit-frame-pointer
...
* 'next-spi' of git://git.secretlab.ca/git/linux-2.6:
spi: spi_txx9.c: use resource_size()
spi: spi_sh_sci.c: use resource_size()
spi: spi_mpc8xxx.c: use resource_size()
spi: spi_bfin5xx.c: use resource_size()
spi: atmel_spi.c: use resource_size()
spi: Add s3c64xx SPI Controller driver
atmel_spi: fix dma addr calculation for len > BUFFER_SIZE
spi_s3c24xx: add FIQ pseudo-DMA support
spi: controller driver for Designware SPI core
spidev: add proper section markers
spidev: use DECLARE_BITMAP instead of declaring the array
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm:
PCMCIA: fix pxa2xx_lubbock modular build error
[ARM] Update mach-types
[ARM] pxa: fix no reference of cpu_is_pxa25x() in devices.c
[ARM] pxa/cm-x300: add PWM backlight support
revert "[ARM] pxa/cm-x300: add PWM backlight support"
ARM: use flush_kernel_dcache_area() for dmabounce
ARM: add size argument to __cpuc_flush_dcache_page
ARM: 5848/1: kill flush_ioremap_region()
ARM: cache-l2x0: make better use of background cache handling
ARM: cache-l2x0: avoid taking spinlock for every iteration
[ARM] Kirkwood: Add LaCie Network Space v2 support
ARM: dove: fix the mm mmu flags of the pj4 procinfo
It says
Warning: objdump version is older than 2.19
Warning: Skipping posttest.
because it used the wrong field from `objdump -v':
akpm:/usr/src/25> /opt/crosstool/gcc-4.0.2-glibc-2.3.6/x86_64-unknown-linux-gnu/bin/x86_64-unknown-linux-gnu-objdump -v
GNU objdump 2.16.1
Copyright 2005 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License. This program has absolutely no warranty.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <200912172326.nBHNQaQl024796@imap1.linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Commit 83ce4009 did the following change
If the TSC is constant and non-stop, also set it reliable.
But, there seems to be few systems that will end up with TSC warp across
sockets, depending on how the cpus come out of reset. Skipping TSC sync
test on such systems may result in time inconsistency later.
So, reenable TSC sync test even on constant and non-stop TSC systems.
Set, sched_clock_stable to 1 by default and reset it in
mark_tsc_unstable, if TSC sync fails.
This change still gives perf benefit mentioned in 83ce4009 for systems
where TSC is reliable.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20091217202702.GA18015@linux-os.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* 'for-linus' of git://gitserver.sunplusct.com/linux-2.6-score:
score: include asm-generic/param.h in asm/delay.h.
score: fixed pfn_valid define.
score: add flush_dcahce_page and PG_dcache_dirty define
Proper Posix O_SYNC handling only made it into 2.6.33, not 2.6.32.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add pseudo-DMA by FIQ to the S3C24XX SPI driver. This allows the driver
to get DMA-like performance where there are either no free DMA channels or
when doing transfers that required both TX and RX data paths.
Since this patch requires the addition of an assembly file to hold the FIQ
code, we rename the module (instead of adding a rename of the .c file to
this patch). We expect most users are loading this via udev and thus
there should be no change to the userland configuration.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* 'for-33' of git://repo.or.cz/linux-kbuild: (29 commits)
net: fix for utsrelease.h moving to generated
gen_init_cpio: fixed fwrite warning
kbuild: fix make clean after mismerge
kbuild: generate modules.builtin
genksyms: properly consider EXPORT_UNUSED_SYMBOL{,_GPL}()
score: add asm/asm-offsets.h wrapper
unifdef: update to upstream revision 1.190
kbuild: specify absolute paths for cscope
kbuild: create include/generated in silentoldconfig
scripts/package: deb-pkg: use fakeroot if available
scripts/package: add KBUILD_PKG_ROOTCMD variable
scripts/package: tar-pkg: use tar --owner=root
Kbuild: clean up marker
net: add net_tstamp.h to headers_install
kbuild: move utsrelease.h to include/generated
kbuild: move autoconf.h to include/generated
drop explicit include of autoconf.h
kbuild: move compile.h to include/generated
kbuild: drop include/asm
kbuild: do not check for include/asm-$ARCH
...
Fixed non-conflicting clean merge of modpost.c as per comments from
Stephen Rothwell (modpost.c had grown an include of linux/autoconf.h
that needed to be changed to generated/autoconf.h)
The loop condition is fragile: we compare an unsigned value to zero, and
then decrement it by something larger than one in the loop. All the
callers should be passing in appropriately aligned buffer lengths, but
it's better to just not rely on it, and have some appropriate defensive
loop limits.
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Not all awk implementations (including the default awk in Ubuntu 9.10)
support POSIX character classes. Since x86-opcode-map.txt is plain
ASCII, we can just use explicit ranges for lower case, alphabetic, and
alphanumeric characters instead.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <adabphy750b.fsf@roland-alpha.cisco.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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>
Currently, MIPS kernels silently overwrite kernel command-line parameters
hardcoded in CONFIG_CMDLINE by the ones received from firmware. Therefore,
using firmware remains the only reliable method to transfer the
command-line parameters, which is not always desirable or convenient, and
the CONFIG_CMDLINE option is thereby effectively rendered useless.
This patch fixes the problem described above and introduces a more flexible
scheme of handling the kernel command line, in a manner identical to what is
currently used for x86. The default behavior, i.e. when CONFIG_CMDLINE_BOOL
is not defined, retains the existing semantics, and firmware command-line
arguments override the hardcoded ones.
[Ralf: I fixed up all the defconfig files so the stay unaffected by this
change.]
Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/689/
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>
This patchs uses a loongson_uart_base variable instead of the
uart_base[] array and adds a new kernel option to avoid to compile
uart_base.c all the time, which will save a little bit of memory for us.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.orghttp://patchwork.linux-mips.org/patch/727/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Before putting the Loongson 2F into wait mode, suspend the MFGPT Timer and
after wake-up resume it. This may save some power.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/706/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The function iodev_remove is used only wrapped by __devexit_p so define
it using __devexit.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/710/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Away with the daemons of ifdef; get ready for future COP2 users.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patchwork: http://patchwork.linux-mips.org/patch/708/
Yeeloong 2F netbook has an KB3310B embedded controller to manage the LID
action. When the LID is closed or opened a SCI interrupt is sent out and
the corresponding event is saved to an EC register for later query.
Allow the LID open interrupt to wake the processor from wait mode if it is
in the suspend mode.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/685/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Several static uninitialized variables are used in the scope of __init
functions but are themselves not marked as __initdata. This patch is to put
those variables to where they belong and to reduce the memory footprint a
little bit.
Also, a couple of lines with spaces instead of tabs were fixed.
Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/698/
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
That thread "MIPS: Add option to pass return address location to
_mcount" from "David Daney <ddaney@caviumnetworks.com>" have added a new
option -mmcount-ra-address to gcc(4.5) for MIPS to transfer the location
of the return address to _mcount.
Benefit from this new feature, function graph tracer on MIPS will be
easier and safer to hijack the return address of the kernel function,
which will save some overhead and make the whole thing more reliable.
In this patch, at first, try to enable the option -mmcount-ra-address in
arch/mips/Makefile with cc-option, if gcc support it, it will be
enabled, otherwise, no side effect.
and then, we need to support this new option of gcc 4.5 and also support
the old gcc versions.
with _mcount in the old gcc versions, it's not easy to get the location
of return address(tracing: add function graph tracer support for MIPS),
so, we do it in a C function: ftrace_get_parent_addr(ftrace.c), but
with -mmcount-ra-address, only several instructions need to get what
we want, so, I put into asm(mcount.S). and also, as the $12(t0) is
used by -mmcount-ra-address for transferring the localtion of return
address to _mcount, we need to save it into the stack and restore it
when enabled dynamic function tracer, 'Cause we have called
"ftrace_call" before "ftrace_graph_caller", which may destroy
$12(t0).
(Thanks to David for providing that -mcount-ra-address and giving the
idea of KBUILD_MCOUNT_RA_ADDRESS, both of them have made the whole
thing more beautiful!)
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/681/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
A new option -mmcount-ra-address for gcc 4.5 have been sent by David
Daney <ddaney@caviumnetworks.com> in the thread "MIPS: Add option to
pass return address location to _mcount", which help to record the
location of the return address(ra) for the function graph tracer of MIPS
to hijack the return address easier and safer. that option used the
$12(t0) register by default, so, we reserve it for it, and use t1,t2,t3
instead of t0,t1,t2.
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/680/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
When remove the -fno-omit-frame-pointer, gcc will not save the frame
pointer for us, we need to save one ourselves.
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/679/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch make function graph tracer work with dynamic function tracer.
To share the source code of dynamic function tracer(MCOUNT_SAVE_REGS),
and avoid restoring the whole saved registers, we need to restore the ra
register from the stack.
(NOTE: This not work with 32bit! need to ensure why!)
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/678/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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>
