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linux/arch/m32r/include/asm/processor.h
Davidlohr Bueso 3a6bfbc91d arch, locking: Ciao arch_mutex_cpu_relax() 
The arch_mutex_cpu_relax() function, introduced by 34b133f, is
hacky and ugly. It was added a few years ago to address the fact
that common cpu_relax() calls include yielding on s390, and thus
impact the optimistic spinning functionality of mutexes. Nowadays
we use this function well beyond mutexes: rwsem, qrwlock, mcs and
lockref. Since the macro that defines the call is in the mutex header,
any users must include mutex.h and the naming is misleading as well.

This patch (i) renames the call to cpu_relax_lowlatency  ("relax, but
only if you can do it with very low latency") and (ii) defines it in
each arch's asm/processor.h local header, just like for regular cpu_relax
functions. On all archs, except s390, cpu_relax_lowlatency is simply cpu_relax,
and thus we can take it out of mutex.h. While this can seem redundant,
I believe it is a good choice as it allows us to move out arch specific
logic from generic locking primitives and enables future(?) archs to
transparently define it, similarly to System Z.

Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bharat Bhushan <r65777@freescale.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Joseph Myers <joseph@codesourcery.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Stratos Karafotis <stratosk@semaphore.gr>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: adi-buildroot-devel@lists.sourceforge.net
Cc: linux390@de.ibm.com
Cc: linux-alpha@vger.kernel.org
Cc: linux-am33-list@redhat.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-cris-kernel@axis.com
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux@lists.openrisc.net
Cc: linux-m32r-ja@ml.linux-m32r.org
Cc: linux-m32r@ml.linux-m32r.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-metag@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1404079773.2619.4.camel@buesod1.americas.hpqcorp.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-17 12:32:47 +02:00

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#ifndef _ASM_M32R_PROCESSOR_H
#define _ASM_M32R_PROCESSOR_H
/*
* include/asm-m32r/processor.h
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 Linus Torvalds
* Copyright (C) 2001 Hiroyuki Kondo, Hirokazu Takata, and Hitoshi Yamamoto
* Copyright (C) 2004 Hirokazu Takata <takata at linux-m32r.org>
*/
#include <linux/kernel.h>
#include <asm/cache.h>
#include <asm/ptrace.h> /* pt_regs */
/*
* Default implementation of macro that returns current
* instruction pointer ("program counter").
*/
#define current_text_addr() ({ __label__ _l; _l: &&_l; })
/*
* CPU type and hardware bug flags. Kept separately for each CPU.
* Members of this structure are referenced in head.S, so think twice
* before touching them. [mj]
*/
struct cpuinfo_m32r {
unsigned long pgtable_cache_sz;
unsigned long cpu_clock;
unsigned long bus_clock;
unsigned long timer_divide;
unsigned long loops_per_jiffy;
};
/*
* capabilities of CPUs
*/
extern struct cpuinfo_m32r boot_cpu_data;
#ifdef CONFIG_SMP
extern struct cpuinfo_m32r cpu_data[];
#define current_cpu_data cpu_data[smp_processor_id()]
#else
#define cpu_data (&boot_cpu_data)
#define current_cpu_data boot_cpu_data
#endif
/*
* User space process size: 2GB (default).
*/
#ifdef CONFIG_MMU
#define TASK_SIZE (0x80000000UL)
#else
#define TASK_SIZE (0x00400000UL)
#endif
#ifdef __KERNEL__
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX STACK_TOP
#endif
/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE PAGE_ALIGN(TASK_SIZE / 3)
typedef struct {
unsigned long seg;
} mm_segment_t;
#define MAX_TRAPS 10
struct debug_trap {
int nr_trap;
unsigned long addr[MAX_TRAPS];
unsigned long insn[MAX_TRAPS];
};
struct thread_struct {
unsigned long address;
unsigned long trap_no; /* Trap number */
unsigned long error_code; /* Error code of trap */
unsigned long lr; /* saved pc */
unsigned long sp; /* user stack pointer */
struct debug_trap debug_trap;
};
#define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack)
#define INIT_THREAD { \
.sp = INIT_SP, \
}
/*
* Do necessary setup to start up a newly executed thread.
*/
/* User process Backup PSW */
#define USERPS_BPSW (M32R_PSW_BSM|M32R_PSW_BIE|M32R_PSW_BPM)
#define start_thread(regs, new_pc, new_spu) \
do { \
regs->psw = (regs->psw | USERPS_BPSW) & 0x0000FFFFUL; \
regs->bpc = new_pc; \
regs->spu = new_spu; \
} while (0)
/* Forward declaration, a strange C thing */
struct task_struct;
struct mm_struct;
/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
/* Copy and release all segment info associated with a VM */
extern void copy_segments(struct task_struct *p, struct mm_struct * mm);
extern void release_segments(struct mm_struct * mm);
extern unsigned long thread_saved_pc(struct task_struct *);
/* Copy and release all segment info associated with a VM */
#define copy_segments(p, mm) do { } while (0)
#define release_segments(mm) do { } while (0)
unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(tsk) ((tsk)->thread.lr)
#define KSTK_ESP(tsk) ((tsk)->thread.sp)
#define cpu_relax() barrier()
#define cpu_relax_lowlatency() cpu_relax()
#endif /* _ASM_M32R_PROCESSOR_H */
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