Commit Graph

47151 Commits

Author SHA1 Message Date
Martin Schwidefsky
52b169c864 [S390] cmm: free pages on hibernate.
The pages allocated by the cmm memory balloon should be freed before
the hibernation image is created. Otherwise the memory reserved by the
balloon gets written to the swap device but there is no content in
these pages that need to be preserved.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:37 +01:00
Martin Schwidefsky
39475179d4 [S390] Improve code generated by atomic operations.
Git commit ea43546750 changed the
definition of atomic_t and atomic64_t for s390 by adding the volatile
modifier to the counter field. This has an unfortunate side effect
with newer versions of the gcc. The typeof operator now picks up the
volatile modifier from the expression. This causes the compiler to
think that it has to store the two temporary variable old_val and
new_val in the __CS_LOOP for the different atomic operations to the
stack as the variables are now volatile. Both stores are superfluous.

The hack to replace typeof(ptr->counter) with int in __CS_LOOP and
and long long in __CSG_LOOP avoids the two stores. A better solution
would be to drop the volatile from the counter field of the atomic_t
and atomic64_t definition. But that is a touchy subject ..

Cc: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:36 +01:00
Christian Borntraeger
779c27820a [S390] dasd: remove dead code
the todclk.h header file is dead code. Remove it.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:34 +01:00
Gerald Schaefer
6c1e3e7943 [S390] Use do_exception() in pagetable walk usercopy functions.
The pagetable walk usercopy functions have used a modified copy of the
do_exception() function for fault handling. This lead to inconsistencies
with recent changes to do_exception(), e.g. performance counters. This
patch changes the pagetable walk usercopy code to call do_exception()
directly, eliminating the redundancy. A new parameter is added to
do_exception() to specify the fault address.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:34 +01:00
Martin Schwidefsky
1ab947de29 [S390] fault handler access flags check.
Simplify the check of the vma->flags in do_exception for the
different fault types.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:34 +01:00
Martin Schwidefsky
50d7280d43 [S390] fault handler performance optimization.
Slim down the do_exception function to handle only the fast path of a
fault and move the exceptional cases into a new function. That slightly
increases the performance of the fault handling.

Build fix for !CONFIG_COMPAT by
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:33 +01:00
Martin Schwidefsky
7ecb344ae8 [S390] Improve notify_page_fault implementation.
notify_page_fault does a preempt_disable/preempt_enable for each
fault generated by a kernel access to user space. If kprobes
is not active that is unnecessary since the interrupts are not
reenabled yet. To play safe repeat the kprobe_running check after
preempt_disable().

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:33 +01:00
Martin Schwidefsky
b11b533427 [S390] Improve address space mode selection.
Introduce user_mode to replace the two variables switch_amode and
s390_noexec. There are three valid combinations of the old values:
  1) switch_amode == 0 && s390_noexec == 0
  2) switch_amode == 1 && s390_noexec == 0
  3) switch_amode == 1 && s390_noexec == 1
They get replaced by
  1) user_mode == HOME_SPACE_MODE
  2) user_mode == PRIMARY_SPACE_MODE
  3) user_mode == SECONDARY_SPACE_MODE
The new kernel parameter user_mode=[primary,secondary,home] lets
you choose the address space mode the user space processes should
use. In addition the CONFIG_S390_SWITCH_AMODE config option
is removed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:33 +01:00
Martin Schwidefsky
61365e132e [S390] Improve address space check.
A data access in access-register mode always is a user mode access,
the code to inspect the access-registers can be removed. The second
change is to use a different test to check for no-execute fault.
The third change is to pass the translation exception identification
as parameter, in theory the trans_exc_code in the lowcore could have
been overwritten by the time the call to check_space from do_no_context
is done.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:33 +01:00
Peter Oberparleiter
454e1fa1eb [S390] cio: split PGID settings and status
Split setting (driver wants feature enabled) and status (feature
setup was successful) for PGID related ccw device features so that
setup errors can be detected. Previously, incorrectly handled setup
errors could in rare cases lead to erratic I/O behavior and
permanently unusuable devices.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:31 +01:00
Hendrik Brueckner
cf87b7439e [S390] s390: clear high-order bits of registers after sam64
When the kernel is IPLed without the CLEAR option and switches
to 64-bit, the high-order half of the registers might contain
random values.  This can cause addressing exceptions and the
kernel enters an interrupt loop.

Initialize the high-order half of the general purpose registers
with zeros after switching to 64-bit mode.

Cc: <stable@kernel.org>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:45:10 +01:00
OGAWA Hirofumi
cbe5c34c8c x86: Compile insn.c and inat.c only for KPROBES
At least, insn.c and inat.c is needed for kprobe for now. So,
this compile those only if KPROBES is enabled.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <878wdg8icq.fsf@devron.myhome.or.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-07 08:31:28 +01:00
Russell King
3d14b5beba Merge branch 'sa1100' into devel 2009-12-06 17:00:33 +00:00
Russell King
ba71e17269 Merge branch 'for-lak' of git://git.linuxtogo.org/home/thesing/collie into sa1100 2009-12-06 16:53:12 +00:00
Dmitry Artamonow
729fae44dd ARM: 5827/1: SA1100: h3100/h3600: emit messages on failed gpio_request
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:58 +00:00
Dmitry Artamonow
a53c876dc1 ARM: 5826/1: SA1100: h3100/h3600: always build htc-egpio driver
Many features of h3100/h3600 (LCD, PCMCIA, Flash write, etc.)
depend on correct functioning of GPIO expander handled by htc-egpio
driver, so force its building in Kconfig.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:58 +00:00
Dmitry Artamonow
ebdb56409d ARM: 5825/1: SA1100: h3600: update defconfig
Update defconfig to current kernel, enable support for iPAQ H3100
and following drivers: gpio-keys, htc-egpio, ide_cs.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:57 +00:00
Dmitry Artamonow
c463eb62ac ARM: 5823/1: SA1100: h3100/h3600: add support for gpio-keys
Add support for "Power" and "Action" (joystick center) buttons -
the only buttons on iPaq h3100/h3600 connected to GPIOs
(other buttons are controlled by microcontroller)
Also remove setting PWER for wakeup on Power button press -
gpio-keys driver will handle it.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:57 +00:00
Dmitry Artamonow
4aa9755580 ARM: 5822/1: SA1100: h3100/h3600: clean up #includes
After a code reorganization and following split, there's some #includes
now unused. Clean them up and sort remaining alphabetticaly where possible.

Compile tested.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:57 +00:00
Dmitry Artamonow
6e23fcb3bd ARM: 5821/1: SA1100: h3100/h3600: revise copyright boilerplates
Correct boilerplates after files split. Also shorten them a bit - use
standart GPL wording (as per http://lkml.org/lkml/2007/5/1/220) and
drop changelog, which only entry about h3800 support and abstracted
EGPIOs is just confusing now, as both of these features are gone.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:56 +00:00
Dmitry Artamonow
86e5e38c46 ARM: 5820/1: SA1100: h3100/h3600: split h3600.c
Split common h3600.c into three separate files: h3100.c, h3600.c and
h3xxx.c (the latter contains common code for h3100/h3600)
Copyright boilerplates and #includes are copied intact and will be
cleaned up later.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:56 +00:00
Dmitry Artamonow
8715b29db2 ARM: 5819/1: SA1100: h3100/h3600: merge h3600.h and h3600_gpio.h into h3xxx.h
Combine both headers into one, rename to h3xxx.h and change all
users accordingly.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:56 +00:00
Dmitry Artamonow
4c88a5c20f ARM: 5818/1: SA1100: h3100/h3600: drop old GPIO definitions
As all existing code was converted to gpiolib, drop no more
used pre-gpiolib (bit-shifted) GPIO definintions.
Supply new gpiolib-friendly definitions for GPIOs which
don't have them yet.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:56 +00:00
Dmitry Artamonow
51834901fa ARM: 5817/1: SA1100: h3100/h3600: configure all unused gpios as inputs
After conversion to gpiolib there's still some GPIOs left, that get
configured in *_mach_init() as outputs (using direct operations
on GPCR/GPDR registers), but otherwise unused. These GPIOs are mainly
sound related and should be configured by corresponding driver once
it is written.

Drop this initialisation and configure all GPIOs as input.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:55 +00:00
Dmitry Artamonow
ca912b17c0 ARM: 5816/1: SA1100: h3600: remove IRQ_GPIO_* definitions
As all the remaining users of these definitions
(in pcmcia/sa1100_h3600 driver) were converted to gpio_to_irq(),
they can be safely removed.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:55 +00:00
Dmitry Artamonow
766f0378a7 ARM: 5815/1: SA1100: h3100/h3600: remove now unused assign_h3600_egpio handlers
As all users of assign_h3600_egpio now converted to gpiolib, we
can safely remove all assign_h3600_egpio handling code and
definitions.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:55 +00:00
Dmitry Artamonow
22f9740552 ARM: 5814/1: SA1100: h3100/h3600: convert all users of assign_h3600_egpio to gpiolib
Use of gpio_request/gpio_free in some callbacks may look ugly, but
corresponding drivers (sa1100_serial and sa1100_fb) don't provide (yet)
init/exit hooks and registering these gpios in *_mach_init is also
not possible, because htc-gpio driver starts a bit later...

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:55 +00:00
Dmitry Artamonow
2eec62d7db ARM: 5813/1: SA1100: h3100/h3600: add htc-egpio driver
It will be used for future conversion of assign_h3600_egpio calls to
gpiolib.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:55 +00:00
Dmitry Artamonow
cf5a87d80a ARM: 5812/1: SA1100: h3100/h3600: separate machine-specific LCD helpers
h3100 and h3600 have different sets of LCD-controlling gpios,
which mapped to the same "abstracted" EGPIO.
As we plan to get rid of those abstracted egpios completely, we
need to separate these helper functions.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:54 +00:00
Dmitry Artamonow
d0e6041efd ARM: 5799/1: SA1100: h3600: stop setting direction for LCD pins
sa1100_fb driver handles this

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:26 +00:00
Dmitry Artamonow
382c14a52d ARM: 5798/1: SA1100: h3600: remove unused cruft from h3600.h
PM_SUSPEND, PM_RESUME and machine_is_h3xxx() are not used anywhere in
kernel (checked with git grep), so it's safe to remove them.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:25 +00:00
Dmitry Artamonow
2a151a0f12 ARM: 5796/1: SA1100: h3600: remove IRDA bits from serial PM callback
IRDA is handled by separate sa1100-ir driver and has
nothing to do with sa1100_serial

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:25 +00:00
Dmitry Artamonow
1e23221e98 ARM: 5797/1: SA1100: h3100/h3600: remove dead links from Kconfig help text
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:25 +00:00
Dmitry Artamonow
e55b20e81d ARM: 5795/1: SA1100: h3100/h3600: mark *_mach_init functions as __init
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:25 +00:00
Russell King
0fb85a5aa0 ARM: iPAQ: no need to set PWER_RTC
The rtc-sa1100 driver takes care of this.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:25 +00:00
Russell King
6e21ee6aa7 ARM: iPAQ: move serial port support functions
No point calling sa1100_register_uart_fns early - these aren't
used until late in the boot sequence.  Also convert to gpiolib
support.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:24 +00:00
Russell King
9c196f0f8d ARM: iPAQ: convert H3100 IrDA to use generic gpio support
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:24 +00:00
Russell King
0831e3e4cf ARM: iPAQ: provide a way to setup platform-controlled GPIOs
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:24 +00:00
Russell King
a5d176a191 ARM: iPAQ: separate IrDA machine specifics
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:24 +00:00
Russell King
898e810ead ARM: h3600: provide each iPAQ machine type with own init function
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:24 +00:00
Russell King
7a5b4e16c8 ARM: sa11x0: convert set_xxx_data() to register_xxx()
Only register devices if we have platform data for those which require
platform data.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-06 16:52:23 +00:00
Jean Delvare
6dfa5ca3c9 i2c-powermac: Include the i2c_adapter in struct pmac_i2c_bus
Include the i2c_adapter in struct pmac_i2c_bus. This avoids memory
fragmentation and allows for several code cleanups.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Michel Daenzer <michel@daenzer.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-12-06 17:06:19 +01:00
Jean Delvare
be2bf0a2df x86, perf probe: Fix warning in test_get_len()
Fix the following warning:

 arch/x86/tools/test_get_len.c: In function "main":
 arch/x86/tools/test_get_len.c:116: warning: unused variable "c"

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-06 12:53:40 +01:00
John Kacur
87fbaf6aea m68k: Remove the BKL from sys_execve
This seems like a copy-and-paste from code that no-longer needs the BKL
Just remove it.

Signed-off-by: John Kacur <jkacur@redhat.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2009-12-06 11:18:26 +01:00
Tim Abbott
7c5fd5619d m68k: Cleanup linker scripts using new linker script macros.
Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Tested-by: Andreas Schwab <schwab@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2009-12-06 11:18:25 +01:00
Tim Abbott
5cdef24b2a m68k: Make thread_info.h usable from assembly.
[Geert] <asm/thread_info_mm.h> pulls in <asm/current.h>, which contains C only.
So the include must be moved inside #ifndef __ASSEMBLY__.

Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2009-12-06 11:18:24 +01:00
Greg Ungerer
f60a557267 m68knommu: define arch_has_single_step() and friends
Towards adding CONFIG_UTRACE support for non-mmu m68k add
arch_has_single_step, and its support functions user_enable_single_step()
and user_disable_single_step().
[Geert] m68k conflict resolution from linux-next

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2009-12-06 11:18:23 +01:00
Shaun Patterson
8055039c2a x86: Fix typo in arch/x86/mm/kmmio.c
Signed-off-by: Shaun Patterson <shaunpatterson@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: pq@iki.fi
LKML-Reference: <1260027694.10074.170.camel@linux-4lgc.site>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-06 09:23:40 +01:00
Frederic Weisbecker
af2d8289f5 x86: Fixup wrong irq frame link in stacktraces
When we enter in irq, two things can happen to preserve the link
to the previous frame pointer:

- If we were in an irq already, we don't switch to the irq stack
  as we are inside. We just need to save the previous frame
  pointer and to link the new one to the previous.

- Otherwise we need another level of indirection. We enter the irq with
  the previous stack. We save the previous bp inside and make bp
  pointing to its saved address. Then we switch to the irq stack and
  push bp another time but to the new stack. This makes two levels to
  dereference instead of one.

In the second case, the current stacktrace code omits the second level
and loses the frame pointer accuracy. The stack that follows will then
be considered as unreliable.

Handling that makes the perf callchain happier.
Before:

43.94%  [k] _raw_read_lock
            |
            --- _read_lock
               |
               |--60.53%-- send_sigio
               |          __kill_fasync
               |          kill_fasync
               |          evdev_pass_event
               |          evdev_event
               |          input_pass_event
               |          input_handle_event
               |          input_event
               |          synaptics_process_byte
               |          psmouse_handle_byte
               |          psmouse_interrupt
               |          serio_interrupt
               |          i8042_interrupt
               |          handle_IRQ_event
               |          handle_edge_irq
               |          handle_irq
               |          __irqentry_text_start
               |          ret_from_intr
               |          |
               |          |--30.43%-- __select
               |          |
               |          |--17.39%-- 0x454f15
               |          |
               |          |--13.04%-- __read
               |          |
               |          |--13.04%-- vread_hpet
               |          |
               |          |--13.04%-- _xcb_lock_io
               |          |
               |           --13.04%-- 0x7f630878ce8

After:

    50.00%  [k] _raw_read_lock
            |
            --- _read_lock
               |
               |--98.97%-- send_sigio
               |          __kill_fasync
               |          kill_fasync
               |          evdev_pass_event
               |          evdev_event
               |          input_pass_event
               |          input_handle_event
               |          input_event
               |          |
               |          |--96.88%-- synaptics_process_byte
               |          |          psmouse_handle_byte
               |          |          psmouse_interrupt
               |          |          serio_interrupt
               |          |          i8042_interrupt
               |          |          handle_IRQ_event
               |          |          handle_edge_irq
               |          |          handle_irq
               |          |          __irqentry_text_start
               |          |          ret_from_intr
               |          |          |
               |          |          |--39.78%-- __const_udelay
               |          |          |          |
               |          |          |          |--91.89%-- ath5k_hw_register_timeout
               |          |          |          |          ath5k_hw_noise_floor_calibration
               |          |          |          |          ath5k_hw_reset
               |          |          |          |          ath5k_reset
               |          |          |          |          ath5k_config
               |          |          |          |          ieee80211_hw_config
               |          |          |          |          |
               |          |          |          |          |--88.24%-- ieee80211_scan_work
               |          |          |          |          |          worker_thread
               |          |          |          |          |          kthread
               |          |          |          |          |          child_rip
               |          |          |          |          |
               |          |          |          |           --11.76%-- ieee80211_scan_completed
               |          |          |          |                     ieee80211_scan_work
               |          |          |          |                     worker_thread
               |          |          |          |                     kthread
               |          |          |          |                     child_rip
               |          |          |          |
               |          |          |           --8.11%-- ath5k_hw_noise_floor_calibration
               |          |          |                     ath5k_hw_reset
               |          |          |                     ath5k_reset
               |          |          |                     ath5k_config

Note: This does not only affect perf events but also x86-64
stacktraces. They were considered as unreliable once we quit
the irq stack frame.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
2009-12-06 08:27:24 +01:00
Frederic Weisbecker
b625b3b3b7 x86: Fixup wrong debug exception frame link in stacktraces
While dumping a stacktrace, the end of the exception stack won't link
the frame pointer to the previous stack.

The interrupted stack will then be considered as unreliable and ignored
by perf, as the frame pointer is unreliable itself.

This happens because we overwrite the frame pointer that links to the
interrupted frame with the address of the exception stack. This is
done in order to reserve space inside.
But rbp has been chosen here only because it is not a scratch register,
so that the address of the exception stack remains in rbp after calling
do_debug(), we can then release the exception stack space without the
need to retrieve its address again.

But we can pick another non-scratch register to do that, so that we
preserve the link to the interrupted stack frame in the stacktraces.

Just randomly choose r12. Every registers are saved just before and
restored just after calling do_debug(). And r12 is not used in the
middle, which makes it a perfect candidate.

Example: perf record -g -a -c 1 -f -e mem:$(tasklist_lock_addr):rw

Before:
    44.18%  [k] _raw_read_lock
            |
            |
            ---  |--6.31%-- waitid
                 |
                 |--4.26%-- writev
                 |
                 |--3.63%-- __select
                 |
                 |--3.15%-- __waitpid
                 |          |
                 |          |--28.57%-- 0x8b52e00000139f
                 |          |
                 |          |--28.57%-- 0x8b52e0000013c6
                 |          |
                 |          |--14.29%-- 0x7fde786dc000
                 |          |
                 |          |--14.29%-- 0x62696c2f7273752f
                 |          |
                 |           --14.29%-- 0x1ea9df800000000
                 |
                 |--3.00%-- __poll

After:

    43.94%  [k] _raw_read_lock
            |
            --- _read_lock
               |
               |--60.53%-- send_sigio
               |          __kill_fasync
               |          kill_fasync
               |          evdev_pass_event
               |          evdev_event
               |          input_pass_event
               |          input_handle_event
               |          input_event
               |          synaptics_process_byte
               |          psmouse_handle_byte
               |          psmouse_interrupt
               |          serio_interrupt
               |          i8042_interrupt
               |          handle_IRQ_event
               |          handle_edge_irq
               |          handle_irq
               |          __irqentry_text_start
               |          ret_from_intr
               |          |
               |          |--30.43%-- __select
               |          |
               |          |--17.39%-- 0x454f15
               |          |
               |          |--13.04%-- __read
               |          |
               |          |--13.04%-- vread_hpet
               |          |
               |          |--13.04%-- _xcb_lock_io
               |          |
               |           --13.04%-- 0x7f630878ce87

Note: it does not only affect perf events but also other stacktraces in
x86-64. They were considered as unreliable once we quit the debug
stack frame.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
2009-12-06 08:27:22 +01:00