Commit Graph

65 Commits

Author SHA1 Message Date
Paul Burton
7d630e83fc MIPS: Remove plat_timer_setup()
The plat_timer_setup() function is entirely unused - nothing calls it,
and no platforms provide it. Perhaps our dummy implementation was once
useful as an aid in forward porting platforms, but its time has long
since passed so let's remove the dead code.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17175/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-08-29 15:21:55 +02:00
James Hogan
c992a4f6a9 KVM: MIPS: Implement VZ support
Add the main support for the MIPS Virtualization ASE (A.K.A. VZ) to MIPS
KVM. The bulk of this work is in vz.c, with various new state and
definitions elsewhere.

Enough is implemented to be able to run on a minimal VZ core. Further
patches will fill out support for guest features which are optional or
can be disabled.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:54 +01:00
Luuk Paulussen
edb6fa1a64 MIPS: Return -ENODEV from weak implementation of rtc_mips_set_time
The sync_cmos_clock function in kernel/time/ntp.c first tries to update
the internal clock of the cpu by calling the "update_persistent_clock64"
architecture specific function.  If this returns -ENODEV, it then tries
to update an external RTC using "rtc_set_ntp_time".

On the mips architecture, the weak implementation of the underlying
function would return 0 if it wasn't overridden.  This meant that the
sync_cmos_clock function would never try to update an external RTC
(if both CONFIG_GENERIC_CMOS_UPDATE and CONFIG_RTC_SYSTOHC are
configured)

Returning -ENODEV instead, means that an external RTC will be tried.

Signed-off-by: Luuk Paulussen <luuk.paulussen@alliedtelesis.co.nz>
Reviewed-by: Richard Laing <richard.laing@alliedtelesis.co.nz>
Reviewed-by: Scott Parlane <scott.parlane@alliedtelesis.co.nz>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14649/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-12-11 11:19:04 +01:00
Ralf Baechle
b633648c5a MIPS: MT: Remove SMTC support
Nobody is maintaining SMTC anymore and there also seems to be no userbase.
Which is a pity - the SMTC technology primarily developed by Kevin D.
Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT
ASE's power and elegance.

Based on Markos Chandras <Markos.Chandras@imgtec.com> patch
https://patchwork.linux-mips.org/patch/6719/ which while very similar did
no longer apply cleanly when I tried to merge it plus some additional
post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to
merge once upon a time.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-05-24 00:07:01 +02:00
Ralf Baechle
69f24d1784 MIPS: Optimize current_cpu_type() for better code.
o Move current_cpu_type() to a separate header file
 o #ifdefing on supported CPU types lets modern GCC know that certain
   code in callers may be discarded ideally turning current_cpu_type() into
   a function returning a constant.
 o Use current_cpu_type() rather than direct access to struct cpuinfo_mips.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5833/
2013-09-17 18:50:53 +02:00
Maciej W. Rozycki
afddce0cc9 MIPS: R4k clock source initialization bug fix
This is a fix for a bug introduced with commit
447cdf2628, submitted as archived here:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=20080312235002.c717dde3.yoichi_yuasa%40tripeaks.co.jp
regrettably with no further explanation.

The issue is with the CP0 Count register read erratum present on R4000 and
some R4400 processors.  If this erratum is present, then a read from this
register that happens around the time it reaches the value stored in the
CP0 Compare register causes a CP0 timer interrupt that is supposed to
happen when the values in the two registers match to be missed.  The
implication for the chips affected is the CP0 timer can be used either as
a source of a timer interrupt (a clock event) or as a source of a
high-resolution counter (a clock source), but not both at a time.

The erratum does not affect timer interrupt operation itself, because in
this case the CP0 Count register is only read while the timer interrupt
has already been raised, while high-resolution counter references happen
at random times.

Additionally some systems apparently have issues with the timer interrupt
line being routed externally and not following the usual CP0 Count/Compare
semantics.  In this case we don't want to use the R4k clock event.

We've meant to address the erratum and the timer interrupt routing issue
in time_init, however the commit referred to above broke our solution.
What we currently have is we enable the R4k clock source if the R4k clock
event initialization has succeeded (the timer is present and has no timer
interrupt routing issue) or there is no CP0 Count register read erratum.
Which gives the following boolean matrix:

clock event | count erratum => clock source
------------+---------------+--------------
     0      |       0       |      1 (OK)
     0      |       1       |      0 (bug!) -> no interference, could use
     1      |       0       |      1 (OK)
     1      |       1       |      1 (bug!) -> can't use, interference

What we want instead is to enable the R4k clock source if there is no CP0
Count register read erratum (obviously) or the R4k clock event
initialization has *failed* -- because in the latter case we won't be
using the timer interrupt anyway, so we don't care about any interference
CP0 Count reads might cause with the interrupt.  This corresponds to the
following boolean matrix:

clock event | count erratum => clock source
------------+---------------+--------------
     0      |       0       |      1
     0      |       1       |      1
     1      |       0       |      1
     1      |       1       |      0

This is implemented here, effectively reverting the problematic commit,
and a short explanation is given next to code modified so that the
rationale is known to future readers and confusion is prevented from
happening here again.

It is worth noting that mips_clockevent_init returns 0 upon success while
cpu_has_mfc0_count_bug returns 0 upon failure.  This is because the former
function returns an error code while the latter returns a boolean value.
To signify the difference I have therefore chosen to compare the result of
the former call explicitly against 0.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5799/
2013-09-03 14:44:02 +02:00
Ralf Baechle
7034228792 MIPS: Whitespace cleanup.
Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-02-01 10:00:22 +01:00
Paul Gortmaker
73bc256d47 mips: migrate core kernel file from module.h --> export.h
These files are not modules, but were including module.h only for
EXPORT_SYMBOL and/or THIS_MODULE.  Now that we have the lightweight
export.h, use it in these kinds of cases.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:56 -04:00
Lucas De Marchi
25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Thomas Gleixner
e3a4fab0c0 mips: Use generic mult/shift factor calculation for clocks
Replace the MIPS functions of mult/shift factor calculation for clock
events and clock sources with inline functions which call the generic
functions. The minimum guaranteed conversion range is set to 4 seconds
which corresponds to the current MIPS implementation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Cc: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20091111134229.807255074@linutronix.de>
2009-11-13 20:46:24 +01:00
Dmitri Vorobiev
46684734dd [MIPS] unexport null_perf_irq() and make it static
This patch unexports the null_perf_irq() symbol, and simultaneously
makes this function static.

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:31 +01:00
Dmitri Vorobiev
c5b0680aa1 [MIPS] unexport rtc_mips_set_time()
No users for the rtc_mips_set_time() routine exist outside of the
core kernel code. Therefore, EXPORT_SYMBOL(rtc_mips_set_time) is
useless, and this patch removes it.

Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-28 17:14:30 +01:00
Yoichi Yuasa
447cdf2628 [MIPS] Fix the installation condition of MIPS clocksource
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-04-01 15:46:33 +01:00
Yoichi Yuasa
c9662341f8 [MIPS] time: remove unused mips_timer_state()
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:15:00 +00:00
Thomas Bogendoerfer
ce202cbb9e [MIPS] Assume R4000/R4400 newer than 3.0 don't have the mfc0 count bug
This seems as reasonable assumption and gets some SNI machines to work
which currently must rely on the cp0 counter as clocksource.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-07 15:32:03 +00:00
Ralf Baechle
4037500ebc [MIPS] time: Delete weak definition of plat_time_init() due to gcc bug.
Frank Rowand <frank.rowand@am.sony.com> reports:

> In linux-2.6.24-rc4 the Toshiba RBTX4927 hangs on boot.
>
> The cause is that plat_time_init() from arch/mips/tx4927/common/
> tx4927_setup.c does not override the __weak plat_time_init() from
> arch/mips/kernel/time.c.  This is due to a compiler bug in gcc 4.1.1.  The
> bug is reported to not exist in earlier versions of gcc, and to be fixed in
> 4.1.2.  The problem is that the __weak plat_time_init() is empty and thus
> gets optimized out of existence (thus the linker is never given the option
> to replace the __weak function).

[ He meant the call to plat_time_init() from time_init() gets optimized away ]

> For more info on the gcc bug see
>
>    http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
>
> The attached patch is one workaround.  Another possible workaround

[ His patch adds -fno-unit-at-a-time for time.c ]

> would be to change the __weak plat_time_init() to be a non-empty
> function.

The __weak definition of plat_time_init was only ever meant to be a
migration helper to keep platforms that don't have a plat_time_init
compiling.  A few greps says that all platforms now supply their own
plat_time_init() so the weak definition is no longer needed.  So I
instead delete it.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-12-14 17:34:30 +00:00
Ralf Baechle
940f6b48a1 [MIPS] Only build r4k clocksource for systems that work ok with it.
In particular as-is it's not suited for multicore and mutiprocessors
systems where there is on guarantee that the counter are synchronized
or running from the same clock at all.  This broke Sibyte and probably
others since the "[MIPS] Handle R4000/R4400 mfc0 from count register."
commit.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-11-26 17:26:14 +00:00
Ralf Baechle
5aa85c9fc4 [MIPS] Handle R4000/R4400 mfc0 from count register.
The R4000 and R4400 have an errata where if the cp0 count register is read
in the exact moment when it matches the compare register no interrupt will
be generated.

This bug may be triggered if the cp0 count register is being used as
clocksource and the compare interrupt as clockevent.  So a simple
workaround is to avoid using the compare for both facilities on the
affected CPUs.

This is different from the workaround suggested in the old errata documents;
at some opportunity probably the official version should be implemented
and tested.  Another thing to find out is which processor versions
exactly are affected.  I only have errata documents upto R4400 V3.0
available so for the moment the code treats all R4000 and R4400 as broken.

This is potencially a problem for some machines that have no other decent
clocksource available; this workaround will cause them to fall back to
another clocksource, worst case the "jiffies" source.
2007-11-26 17:26:14 +00:00
Atsushi Nemoto
d9eec1a5d6 [MIPS] time: Code cleanups
* Do not include unnecessary headers.
* Do not mention time.README.
* Do not mention mips_timer_ack.
* Make clocksource_mips static.  It is now dedicated to c0_timer.
* Initialize clocksource_mips.read statically.
* Remove null_hpt_read.
* Remove an argument of plat_timer_setup.  It is just a placeholder.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-11-02 16:13:46 +00:00
Ralf Baechle
1d0a909cfc [MIPS] time: Remove now unused local_timer_interrupt.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-11-02 16:13:46 +00:00
Ralf Baechle
656db5061d [MIPS] time: Cause platform definitions of plat_timer_setup to cause error.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-29 19:35:34 +00:00
Atsushi Nemoto
508a775a3c [MIPS] time: Fix calculation in clockevent_set_clock()
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22 22:09:00 +01:00
Ralf Baechle
93c846f904 [MIPS] time: Helpers to compute clocksource/event shift and mult values.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-19 18:15:57 +01:00
Ralf Baechle
9c9ad7917b [MIPS] time: Delete dead code.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-19 18:15:57 +01:00
Ralf Baechle
42f77542f4 [MIPS] time: Move R4000 clockevent device code to separate configurable file
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-18 18:11:47 +01:00
Ralf Baechle
2cfa7660db [MIPS] time: Delete dead cycles_per_jiffy, mips_timer_ack and null_timer_ack
cycles_per_jiffy was only ever getting assigned and the function pointer
not being called anymore and mips_timer_ack had gotten similarly stale.  I
leave the remaining assignments unfixed as a lighthouse pointing platform
maintainers to what needs a rewrite.  These changes make null_timer_ack()
unreferenced, so delete that too.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-18 18:11:47 +01:00
Ralf Baechle
b0d4056dd6 [MIPS] Probe for usability of cp0 compare interrupt.
Some processors offer the option of using the interrupt on which
normally the count / compare interrupt would be signaled as a normal
interupt pin.  Previously this required some ugly hackery for each
system which is much easier done by a quick and simple probe.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-17 18:28:47 +01:00
Ralf Baechle
8bb00d83d8 [MIPS] Increase cp0 compare clockevent min_delta_ns from 0x30 to 0x300.
Extremly low values are of dubious usefulness anyway but in this case
they actually were killing Qemu which simply wasn't able to complete
mips_next_event() within 0x30 100MHz cycles even on fast hosts.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-16 18:23:50 +01:00
Ralf Baechle
49a89efbbb [MIPS] Fix "no space between function name and open parenthesis" warnings.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:46:15 +01:00
Ralf Baechle
ea5804015c [MIPS] Dyntick support for SMTC:
The kernel currently only supports broadcasting of the timer interrupt
from a single timer, not multicasting into two multicast groups of
processors.  So the implemented mechanism for SMTC works by broadcasting
the cp0 compare interrupt on VPE 0 and ignoring it on any additional VPEs.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:46:09 +01:00
Ralf Baechle
7bcf7717b6 [MIPS] Implement clockevents for R4000-style cp0 count/compare interrupt
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:46:09 +01:00
Ralf Baechle
91a2fcc886 [MIPS] Consolidate all variants of MIPS cp0 timer interrupt handlers.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:46:09 +01:00
Ralf Baechle
90b02340dc [MIPS] Switch from to_tm to rtc_time_to_tm
This replaces the MIPS-specific to_tm function with the generic
rtc_time_to_tm function.  The big difference between the two functions is
that rtc_time_to_tm uses epoch 70 while to_tm uses 1970, so the result of
rtc_time_to_tm needs to be fixed up.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:46:09 +01:00
Ralf Baechle
4b550488f8 [MIPS] Deforest the function pointer jungle in the time code.
Hard to follow who is pointing what to where and why so it's simply getting
in the way of the time code renovation.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:46:08 +01:00
Ralf Baechle
f5ff0a2802 [MIPS] Use generic NTP code for all MIPS platforms
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:46:08 +01:00
Yoichi Yuasa
b1043cc7d9 [MIPS] Add #include <linux/profile.h> to arch/mips/kernel/time.c
It refer to CPU_PROFILING.

arch/mips/kernel/time.c: In function 'local_timer_interrupt':
arch/mips/kernel/time.c:142: error: implicit declaration of function 'profile_tick'
arch/mips/kernel/time.c:142: error: 'CPU_PROFILING' undeclared (first use in this function)
arch/mips/kernel/time.c:142: error: (Each undeclared identifier is reported only once
arch/mips/kernel/time.c:142: error: for each function it appears in.)

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-09-14 19:08:42 +01:00
Ralf Baechle
3b1d4ed535 [MIPS] Don't drag a platform specific header into generic arch code.
For some platforms it's definitions may conflict.  So that's the one-liner.
The rest is 10 square kilometers of collateral damage fixup this include
used to paper over.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-06-20 22:27:10 +01:00
Chris Dearman
ffe9ee4709 [MIPS] Separate performance counter interrupts
Support for performance counter overflow interrupt that is on a separate
interrupt from the timer.

Signed-off-by: Chris Dearman <chris@mips.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-06-14 18:25:15 +01:00
Franck Bui-Huu
55d0b4e3f6 [MIPS] clocksource: use CLOCKSOURCE_MASK() macro
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-05-11 14:28:31 +01:00
Thomas Gleixner
877fe38029 [PATCH] clocksource: fixup is_continous changes on MIPS
Fixup the is_contionous replacement by a flag field.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 08:13:57 -08:00
Alexey Dobriyan
b035b6de24 [PATCH] Consolidate default sched_clock()
Use attribute(weak).

Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:28 -08:00
Vitaly Wool
2dbda7dcec [MIPS] PNX8550: Fix system timer support
the patch inlined below restores proper time accounting for PNX8550-based
boards. It also gets rid of #ifdef in the generic code which becomes
unnecessary then.

It's functionally identical to the previous patch with the same name but
it has minor comments from Atsushi and Sergei taken into account.

Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-01-08 21:41:04 +00:00
Atsushi Nemoto
005985609f [MIPS] mips HPT cleanup: make clocksource_mips public
Make clocksource_mips public and get rid of mips_hpt_read,
mips_hpt_mask.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-11-30 01:14:49 +00:00
Atsushi Nemoto
c87b6ebaea [MIPS] mips hpt cleanup: get rid of mips_hpt_init
Currently nobody outside time.c require mips_hpt_init().  Remove it
and call c0_hpt_timer_init() directly if R4k counter was used for
timer interrupt.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-11-30 01:14:46 +00:00
Atsushi Nemoto
16b7b2ac01 [MIPS] Fixup migration to GENERIC_TIME
Since we already moved to GENERIC_TIME, we should implement alternatives
of old do_gettimeoffset routines to get sub-jiffies resolution from
gettimeofday().  This patch includes:

 * MIPS clocksource support (based on works by Manish Lachwani).
 * remove unused gettimeoffset routines and related codes.
 * remove unised 64bit do_div64_32().
 * simplify mips_hpt_init. (no argument needed, __init tag)
 * simplify c0_hpt_timer_init. (no need to write to c0_count)
 * remove some hpt_init routines.
 * mips_hpt_mask variable to specify bitmask of hpt value.
 * convert jmr3927_do_gettimeoffset to jmr3927_hpt_read.
 * convert ip27_do_gettimeoffset to ip27_hpt_read.
 * convert bcm1480_do_gettimeoffset to bcm1480_hpt_read.
 * simplify sb1250 hpt functions. (no need to subtract and shift)
    
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-10-31 20:13:23 +00:00
Ralf Baechle
937a801576 [MIPS] Complete fixes after removal of pt_regs argument to int handlers.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-10-08 02:38:28 +01:00
David Howells
7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00
Ralf Baechle
8db0201026 [MIPS] Fix wreckage after removal of tickadj; convert to GENERIC_TIME.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-10-03 17:59:18 +01:00
Atsushi Nemoto
8ef386092d [PATCH] kill wall_jiffies
With 2.6.18-rc4-mm2, now wall_jiffies will always be the same as jiffies.
So we can kill wall_jiffies completely.

This is just a cleanup and logically should not change any real behavior
except for one thing: RTC updating code in (old) ppc and xtensa use a
condition "jiffies - wall_jiffies == 1".  This condition is never met so I
suppose it is just a bug.  I just remove that condition only instead of
kill the whole "if" block.

[heiko.carstens@de.ibm.com: s390 build fix and cleanup]
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:27 -07:00
Atsushi Nemoto
3171a0305d [PATCH] simplify update_times (avoid jiffies/jiffies_64 aliasing problem)
Pass ticks to do_timer() and update_times(), and adjust x86_64 and s390
timer interrupt handler with this change.

Currently update_times() calculates ticks by "jiffies - wall_jiffies", but
callers of do_timer() should know how many ticks to update.  Passing ticks
get rid of this redundant calculation.  Also there are another redundancy
pointed out by Martin Schwidefsky.

This cleanup make a barrier added by
5aee405c66 needless.  So this patch removes
it.

As a bonus, this cleanup make wall_jiffies can be removed easily, since now
wall_jiffies is always synced with jiffies.  (This patch does not really
remove wall_jiffies.  It would be another cleanup patch)

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:15 -07:00