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2016-06-16locking/atomic, arch/mips: Convert to _relaxed atomicsPeter Zijlstra1-20/+22
Generic code will construct {,_acquire,_release} versions by adding the required smp_mb__{before,after}_atomic() calls. XXX if/when MIPS will start using their new SYNCxx instructions they can provide custom __atomic_op_{acquire,release}() macros as per the powerpc example. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-16locking/atomic: Remove linux/atomic.h:atomic_fetch_or()Peter Zijlstra1-2/+0
Since all architectures have this implemented now natively, remove this dead code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-16locking/atomic, arch/mips: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()Peter Zijlstra1-9/+129
Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-11-15Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linusLinus Torvalds1-1/+1
Pull MIPS updates from Ralf Baechle: "These are the highlists of the main MIPS pull request for 4.4: - Add latencytop support - Support appended DTBs - VDSO support and initially use it for gettimeofday. - Drop the .MIPS.abiflags and ELF NOTE sections from vmlinux - Support for the 5KE, an internal test core. - Switch all MIPS platfroms to libata drivers. - Improved support, cleanups for ralink and Lantiq platforms. - Support for the new xilfpga platform. - A number of DTB improvments for BMIPS. - Improved support for CM and CPS. - Minor JZ4740 and BCM47xx enhancements" * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (120 commits) MIPS: idle: add case for CPU_5KE MIPS: Octeon: Support APPENDED_DTB MIPS: vmlinux: create a section for appended DTB MIPS: Clean up compat_siginfo_t MIPS: Fix PAGE_MASK definition MIPS: BMIPS: Enable GZIP ramdisk and timed printks MIPS: Add xilfpga defconfig MIPS: xilfpga: Add mipsfpga platform code MIPS: xilfpga: Add xilfpga device tree files. dt-bindings: MIPS: Document xilfpga bindings and boot style MIPS: Make MIPS_CMDLINE_DTB default MIPS: Make the kernel arguments from dtb available MIPS: Use USE_OF as the guard for appended dtb MIPS: BCM63XX: Use pr_* instead of printk MIPS: Loongson: Cleanup CONFIG_LOONGSON_SUSPEND. MIPS: lantiq: Disable xbar fpi burst mode MIPS: lantiq: Force the crossbar to big endian MIPS: lantiq: Initialize the USB core on boot MIPS: lantiq: Return correct value for fpi clock on ar9 MIPS: ralink: Add missing clock on rt305x ...
2015-10-26MIPS: atomic: Fix comment describing atomic64_add_unless's return value.Ralf Baechle1-1/+1
Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Fixes: f24219b4e90cf70ec4a211b17fbabc725a0ddf3c (cherry picked from commit f0a232cde7be18a207fd057dd79bbac8a0a45dec)
2015-09-23atomic, arch: Audit atomic_{read,set}()Peter Zijlstra1-4/+4
This patch makes sure that atomic_{read,set}() are at least {READ,WRITE}_ONCE(). We already had the 'requirement' that atomic_read() should use ACCESS_ONCE(), and most archs had this, but a few were lacking. All are now converted to use READ_ONCE(). And, by a symmetry and general paranoia argument, upgrade atomic_set() to use WRITE_ONCE(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: james.hogan@imgtec.com Cc: linux-kernel@vger.kernel.org Cc: oleg@redhat.com Cc: will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-27atomic: Provide atomic_{or,xor,and}Peter Zijlstra1-2/+0
Implement atomic logic ops -- atomic_{or,xor,and}. These will replace the atomic_{set,clear}_mask functions that are available on some archs. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-27mips: Provide atomic_{or,xor,and}Peter Zijlstra1-0/+9
Implement atomic logic ops -- atomic_{or,xor,and}. These will replace the atomic_{set,clear}_mask functions that are available on some archs. Acked-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-02-17MIPS: asm: atomic: Update ISA constraints for MIPS R6 supportMarkos Chandras1-6/+6
MIPS R6 changed the opcodes for LL/SC instructions so we need to set the correct ISA level. Cc: Matthew Fortune <Matthew.Fortune@imgtec.com> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2015-02-17MIPS: asm: Rename GCC_OFF12_ASM to GCC_OFF_SMALL_ASMMarkos Chandras1-15/+15
The GCC_OFF12_ASM macro is used for 12-bit immediate constrains but we will also use it for 9-bit constrains on MIPS R6 so we rename it to something more appropriate. Cc: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
2014-11-24MIPS: atomic.h: Reformat to fit in 79 columnsMaciej W. Rozycki1-180/+181
Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8484/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-11-24MIPS: Fix microMIPS LL/SC immediate offsetsMaciej W. Rozycki1-15/+24
In the microMIPS encoding some memory access instructions have their immediate offset reduced to 12 bits only. That does not match the GCC `R' constraint we use in some places to satisfy the requirement, resulting in build failures like this: {standard input}: Assembler messages: {standard input}:720: Error: macro used $at after ".set noat" {standard input}:720: Warning: macro instruction expanded into multiple instructions Fix the problem by defining a macro, `GCC_OFF12_ASM', that expands to the right constraint depending on whether microMIPS or standard MIPS code is produced. Also apply the fix to where `m' is used as in the worst case this change does nothing, e.g. where the pointer was already in a register such as a function argument and no further offset was requested, and in the best case it avoids an extraneous sequence of up to two instructions to load the high 20 bits of the address in the LL/SC loop. This reduces the risk of lock contention that is the higher the more instructions there are in the critical section between LL and SC. Strictly speaking we could just bulk-replace `R' with `ZC' as the latter constraint adjusts automatically depending on the ISA selected. However it was only introduced with GCC 4.9 and we keep supporing older compilers for the standard MIPS configuration, hence the slightly more complicated approach I chose. The choice of a zero-argument function-like rather than an object-like macro was made so that it does not look like a function call taking the C expression used for the constraint as an argument. This is so as not to confuse the reader or formatting checkers like `checkpatch.pl' and follows previous practice. Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com> Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8482/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-10-03locking,arch: Use ACCESS_ONCE() instead of cast to volatile in atomic_read()Pranith Kumar1-2/+2
Use the much more reader friendly ACCESS_ONCE() instead of the cast to volatile. This is purely a stylistic change. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1411482607-20948-1-git-send-email-bobby.prani@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-10locking, mips: Fix atomicsPeter Zijlstra1-3/+3
The patch folding the atomic ops had two silly fails in the _return primitives. Fixes: ef31563e950c ("locking,arch,mips: Fold atomic_ops") Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Hannes Reinecke <hare@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maciej W. Rozycki <macro@codesourcery.com> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Link: http://lkml.kernel.org/r/20140902202126.GA3190@worktop.ger.corp.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-08-14locking,arch,mips: Fold atomic_opsPeter Zijlstra1-370/+187
Many of the atomic op implementations are the same except for one instruction; fold the lot into a few CPP macros and reduce LoC. This also prepares for easy addition of new ops. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maciej W. Rozycki <macro@codesourcery.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Link: http://lkml.kernel.org/r/20140508135852.521548500@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-18arch,mips: Convert smp_mb__*()Peter Zijlstra1-9/+0
MIPS is interesting and has hardware variants that reorder over ll/sc as well as those that do not. Implement the 2 new barrier functions as per the old barriers. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/n/tip-9ph49jbae3hol9v721sbc2g6@git.kernel.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maciej W. Rozycki" <macro@codesourcery.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-03-31MIPS: Fix gigaton of warning building with microMIPS.Ralf Baechle1-20/+20
With binutils 2.24 the attempt to switch with microMIPS mode to MIPS III mode through .set mips3 results in *lots* of warnings like {standard input}: Assembler messages: {standard input}:397: Warning: the 64-bit MIPS architecture does not support the `smartmips' extension during a kernel build. Fixed by using .set arch=r4000 instead. This breaks support for building the kernel with binutils 2.13 which was supported for 32 bit kernels only anyway and 2.14 which was a bad vintage for MIPS anyway. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-11-04MIPS: Random whitespace clean-upsMaciej W. Rozycki1-1/+1
Another whitespace clean-up, this removes tabs from between sentences in some comments. Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6103/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-02-01MIPS: Whitespace cleanup.Ralf Baechle1-2/+2
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>
2012-10-11Improve atomic.h robustnessJoshua Kinard1-35/+29
I've maintained this patch, originally from Thiemo Seufer in 2004, for a really long time, but I think it's time for it to get a look at for possible inclusion. I have had no problems with it across various SGI systems over the years. To quote the post here: http://www.linux-mips.org/archives/linux-mips/2004-12/msg00000.html "the atomic functions use so far memory references for the inline assembler to access the semaphore. This can lead to additional instructions in the ll/sc loop, because newer compilers don't expand the memory reference any more but leave it to the assembler. The appended patch uses registers instead, and makes the ll/sc arguments more explicit. In some cases it will lead also to better register scheduling because the register isn't bound to an output any more." Signed-off-by: Joshua Kinard <kumba@gentoo.org> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/4029/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-03-28Disintegrate asm/system.h for MIPSDavid Howells1-1/+1
Disintegrate asm/system.h for MIPS. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> cc: linux-mips@linux-mips.org
2011-07-26atomic: cleanup asm-generic atomic*.h inclusionArun Sharma1-6/+0
After changing all consumers of atomics to include <linux/atomic.h>, we ran into some compile time errors due to this dependency chain: linux/atomic.h -> asm/atomic.h -> asm-generic/atomic-long.h where atomic-long.h could use funcs defined later in linux/atomic.h without a prototype. This patches moves the code that includes asm-generic/atomic*.h to linux/atomic.h. Archs that need <asm-generic/atomic64.h> need to select CONFIG_GENERIC_ATOMIC64 from now on (some of them used to include it unconditionally). Compile tested on i386 and x86_64 with allnoconfig. Signed-off-by: Arun Sharma <asharma@fb.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26atomic: move atomic_add_unless to generic codeArun Sharma1-5/+5
This is in preparation for more generic atomic primitives based on __atomic_add_unless. Signed-off-by: Arun Sharma <asharma@fb.com> Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26atomic: use <linux/atomic.h>Arun Sharma1-1/+0
This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-29MIPS: Get rid of branches to .subsections.Ralf Baechle1-112/+96
It was a nice optimization - on paper at least. In practice it results in branches that may exceed the maximum legal range for a branch. We can fight that problem with -ffunction-sections but -ffunction-sections again is incompatible with -pg used by the function tracer. By rewriting the loop around all simple LL/SC blocks to C we reduce the amount of inline assembler and at the same time allow GCC to often fill the branch delay slots with something sensible or whatever else clever optimization it may have up in its sleeve. With this optimization gone we also no longer need -ffunction-sections, so drop it. This optimization was originally introduced in 2.6.21, commit 5999eca25c1fd4b9b9aca7833b04d10fe4bc877d (linux-mips.org) rsp. f65e4fa8e0c6022ad58dc88d1b11b12589ed7f9f (kernel.org). Original fix for the issues which caused me to pull this optimization by Paul Gortmaker <paul.gortmaker@windriver.com>. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-10-04MIPS: Use generic atomic64 for 32-bit kernelsDeng-Cheng Zhu1-0/+4
The 64-bit kernel has already had its atomic64 functions. Except for that, we use the generic spinlocked version. The atomic64 types and related functions are needed for the Linux performance counter subsystem. Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com> To: linux-mips@linux-mips.org Cc: a.p.zijlstra@chello.nl Cc: paulus@samba.org Cc: mingo@elte.hu Cc: acme@redhat.com Cc: jamie.iles@picochip.com Patchwork: https://patchwork.linux-mips.org/patch/1361/ Acked-by: David Daney <ddaney@caviumnetworks.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-07-26MIPS: Quit using undefined behavior of ADDU in 64-bit atomic operations.David Daney1-12/+12
For 64-bit, we must use DADDU and DSUBU. Signed-off-by: David Daney <ddaney@caviumnetworks.com> To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/1483/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-05-17atomic_t: Cast to volatile when accessing atomic variablesAnton Blanchard1-2/+2
In preparation for removing volatile from the atomic_t definition, this patch adds a volatile cast to all the atomic read functions. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-27MIPS: New macro smp_mb__before_llsc.David Daney1-8/+8
Replace some instances of smp_llsc_mb() with a new macro smp_mb__before_llsc(). It is used before ll/sc sequences that are documented as needing write barrier semantics. The default implementation of smp_mb__before_llsc() is just smp_llsc_mb(), so there are no changes in semantics. Also simplify definition of smp_mb(), smp_rmb(), and smp_wmb() to be just barrier() in the non-SMP case. Signed-off-by: David Daney <ddaney@caviumnetworks.com> To: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/851/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-09-17MIPS: Allow kernel use of LL/SC to be separate from the presence of LL/SC.David Daney1-20/+20
On some CPUs, it is more efficient to disable and enable interrupts in the kernel rather than use ll/sc for atomic operations. But if we were to set cpu_has_llsc to false, we would break the userspace futex interface (in asm/futex.h). We separate the two concepts, with a new predicate kernel_uses_llsc, that lets us disable the kernel's use of ll/sc while still allowing the futex code to use it. Also there were a couple of cases in bitops.h where we were using ll/sc unconditionally even if cpu_has_llsc were false. Signed-off-by: David Daney <ddaney@caviumnetworks.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-06-11asm-generic: rename atomic.h to atomic-long.hArnd Bergmann1-1/+1
The existing asm-generic/atomic.h only defines the atomic_long type. This renames it to atomic-long.h so we have a place to add a truly generic atomic.h that can be used on all non-SMP systems. Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-01-30MIPS: atomic_*(): Change type of intermediate variables.Ralf Baechle1-26/+26
This shaves of 1912 bytes of an IP27 defconfig kernel and avoids unexpected overflow behaviour in atomic_sub_if_positive. Apply the same changes to the atomic64_* functions for consistency. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-01-06atomic_t: unify all arch definitionsMatthew Wilcox1-4/+1
The atomic_t type cannot currently be used in some header files because it would create an include loop with asm/atomic.h. Move the type definition to linux/types.h to break the loop. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-11MIPS: Move headfiles to new location below arch/mips/includeRalf Baechle1-0/+801
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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