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2020-05-22mips: Add udelay lpj numbers adjustmentSerge Semin
Loops-per-jiffies is a special number which represents a number of noop-loop cycles per CPU-scheduler quantum - jiffies. As you understand aside from CPU-specific implementation it depends on the CPU frequency. So when a platform has the CPU frequency fixed, we have no problem and the current udelay interface will work just fine. But as soon as CPU-freq driver is enabled and the cores frequency changes, we'll end up with distorted udelay's. In order to fix this we have to accordinly adjust the per-CPU udelay_val (the same as the global loops_per_jiffy) number. This can be done in the CPU-freq transition event handler. We subscribe to that event in the MIPS arch time-inititalization method. Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-14MIPS: Convert update_persistent_clock() to update_persistent_clock64()Baolin Wang
Since struct timespec is not y2038 safe on 32bit machines, this patch converts update_persistent_clock() to update_persistent_clock64() using struct timespec64. The rtc_mips_set_time() and rtc_mips_set_mmss() interfaces were using 'unsigned long' type that is not y2038 safe on 32bit machines, moreover there is only one platform implementing rtc_mips_set_time() and two platforms implementing rtc_mips_set_mmss(), so we can just make them each implement update_persistent_clock64() directly, to get that helper out of the common mips code by removing rtc_mips_set_time() and rtc_mips_set_mmss() interfaces. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Huacai Chen <chenhc@lemote.com> Cc: Paul Burton <paul.burton@mips.com> Cc: linux-mips@linux-mips.org Signed-off-by: James Hogan <jhogan@kernel.org>
2017-08-29MIPS: Remove plat_timer_setup()Paul Burton
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>
2017-03-28KVM: MIPS: Implement VZ supportJames Hogan
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
2016-12-11MIPS: Return -ENODEV from weak implementation of rtc_mips_set_timeLuuk Paulussen
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>
2014-05-24MIPS: MT: Remove SMTC supportRalf Baechle
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>
2013-09-17MIPS: Optimize current_cpu_type() for better code.Ralf Baechle
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/
2013-09-03MIPS: R4k clock source initialization bug fixMaciej W. Rozycki
This is a fix for a bug introduced with commit 447cdf2628b59aa513a42785450b348dced26d8a, 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/
2013-02-01MIPS: Whitespace cleanup.Ralf Baechle
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>
2011-10-31mips: migrate core kernel file from module.h --> export.hPaul Gortmaker
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>
2011-03-31Fix common misspellingsLucas De Marchi
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2009-11-13mips: Use generic mult/shift factor calculation for clocksThomas Gleixner
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>
2008-04-28[MIPS] unexport null_perf_irq() and make it staticDmitri Vorobiev
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[MIPS] unexport rtc_mips_set_time()Dmitri Vorobiev
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>
2008-04-01[MIPS] Fix the installation condition of MIPS clocksourceYoichi Yuasa
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29[MIPS] time: remove unused mips_timer_state()Yoichi Yuasa
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-07[MIPS] Assume R4000/R4400 newer than 3.0 don't have the mfc0 count bugThomas Bogendoerfer
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>
2007-12-14[MIPS] time: Delete weak definition of plat_time_init() due to gcc bug.Ralf Baechle
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>
2007-11-26[MIPS] Only build r4k clocksource for systems that work ok with it.Ralf Baechle
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[MIPS] Handle R4000/R4400 mfc0 from count register.Ralf Baechle
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.
2007-11-02[MIPS] time: Code cleanupsAtsushi Nemoto
* 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[MIPS] time: Remove now unused local_timer_interrupt.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-29[MIPS] time: Cause platform definitions of plat_timer_setup to cause error.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-22[MIPS] time: Fix calculation in clockevent_set_clock()Atsushi Nemoto
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-19[MIPS] time: Helpers to compute clocksource/event shift and mult values.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-19[MIPS] time: Delete dead code.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-18[MIPS] time: Move R4000 clockevent device code to separate configurable fileRalf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-18[MIPS] time: Delete dead cycles_per_jiffy, mips_timer_ack and null_timer_ackRalf Baechle
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>
2007-10-17[MIPS] Probe for usability of cp0 compare interrupt.Ralf Baechle
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>
2007-10-16[MIPS] Increase cp0 compare clockevent min_delta_ns from 0x30 to 0x300.Ralf Baechle
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>
2007-10-11[MIPS] Fix "no space between function name and open parenthesis" warnings.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11[MIPS] Dyntick support for SMTC:Ralf Baechle
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[MIPS] Implement clockevents for R4000-style cp0 count/compare interruptRalf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11[MIPS] Consolidate all variants of MIPS cp0 timer interrupt handlers.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11[MIPS] Switch from to_tm to rtc_time_to_tmRalf Baechle
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[MIPS] Deforest the function pointer jungle in the time code.Ralf Baechle
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[MIPS] Use generic NTP code for all MIPS platformsRalf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-09-14[MIPS] Add #include <linux/profile.h> to arch/mips/kernel/time.cYoichi Yuasa
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>
2007-06-20[MIPS] Don't drag a platform specific header into generic arch code.Ralf Baechle
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>
2007-06-14[MIPS] Separate performance counter interruptsChris Dearman
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>
2007-05-11[MIPS] clocksource: use CLOCKSOURCE_MASK() macroFranck Bui-Huu
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-02-16[PATCH] clocksource: fixup is_continous changes on MIPSThomas Gleixner
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>
2007-02-11[PATCH] Consolidate default sched_clock()Alexey Dobriyan
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>
2007-01-08[MIPS] PNX8550: Fix system timer supportVitaly Wool
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>
2006-11-30[MIPS] mips HPT cleanup: make clocksource_mips publicAtsushi Nemoto
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[MIPS] mips hpt cleanup: get rid of mips_hpt_initAtsushi Nemoto
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>
2006-10-31[MIPS] Fixup migration to GENERIC_TIMEAtsushi Nemoto
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>
2006-10-08[MIPS] Complete fixes after removal of pt_regs argument to int handlers.Ralf Baechle
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-10-05IRQ: Maintain regs pointer globally rather than passing to IRQ handlersDavid Howells
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)