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* MIPS: Get rid of branches to .subsections.Ralf Baechle2010-10-291-112/+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>
* MIPS: Use generic atomic64 for 32-bit kernelsDeng-Cheng Zhu2010-10-041-0/+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>
* MIPS: Quit using undefined behavior of ADDU in 64-bit atomic operations.David Daney2010-07-261-12/+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>
* atomic_t: Cast to volatile when accessing atomic variablesAnton Blanchard2010-05-171-2/+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>
* MIPS: New macro smp_mb__before_llsc.David Daney2010-02-271-8/+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>
* MIPS: Allow kernel use of LL/SC to be separate from the presence of LL/SC.David Daney2009-09-171-20/+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>
* asm-generic: rename atomic.h to atomic-long.hArnd Bergmann2009-06-111-1/+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>
* MIPS: atomic_*(): Change type of intermediate variables.Ralf Baechle2009-01-301-26/+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>
* atomic_t: unify all arch definitionsMatthew Wilcox2009-01-061-4/+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>
* MIPS: Move headfiles to new location below arch/mips/includeRalf Baechle2008-10-111-0/+801
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>