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2015-05-13arch: Remove __ARCH_HAVE_CMPXCHGThomas Gleixner1-2/+0
We removed the only user of this define in the rtmutex code. Get rid of it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
2015-04-01MIPS: Fall back to generic implementation of cmpxchg64 on 32-bit platformsDeng-Cheng Zhu1-5/+6
This is in preparation of adding HAVE_VIRT_CPU_ACCOUNTING_GEN support in the next patch. Without having cmpxchg64 to use the generic implementation, kernel linking will complain: kernel/built-in.o: In function `cputime_adjust': cputime.c:(.text+0x33748): undefined reference to `__cmpxchg_called_with_bad_pointer' cputime.c:(.text+0x33810): undefined reference to `__cmpxchg_called_with_bad_pointer' Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com> Cc: linux-mips@linux-mips.org Cc: macro@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9474/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-02-17MIPS: asm: cmpxchg: Update ISA constraints for MIPS R6 supportMarkos Chandras1-5/+5
MIPS R6 changed the opcodes for LL/SC instructions so we need to set the correct ISA. 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 Chandras1-12/+12
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: Fix microMIPS LL/SC immediate offsetsMaciej W. Rozycki1-12/+15
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>
2014-03-31MIPS: Fix gigaton of warning building with microMIPS.Ralf Baechle1-10/+10
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>
2013-02-01MIPS: Whitespace cleanup.Ralf Baechle1-3/+3
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>
2012-07-19MIPS: cmpxchg.h: Add missing includeAaro Koskinen1-0/+1
Fix the following build breakage in v3.4-rc1: CC kernel/irq_work.o In file included from include/linux/irq_work.h:4:0, from kernel/irq_work.c:10: include/linux/llist.h: In function 'llist_del_all': include/linux/llist.h:178:2: error: implicit declaration of function 'BUILD_BUG_ON' [-Werror=implicit-function-declaration] Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/3568/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-03-28Disintegrate asm/system.h for MIPSDavid Howells1-0/+124
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
2010-10-29MIPS: Get rid of branches to .subsections.Ralf Baechle1-5/+2
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>
2010-04-30MIPS: cmpxchg.h: Fix excessive indentation.Ralf Baechle1-1/+1
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-02-27MIPS: New macro smp_mb__before_llsc.David Daney1-5/+5
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 Daney1-2/+2
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>
2008-10-11MIPS: Move headfiles to new location below arch/mips/includeRalf Baechle1-0/+124
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>