Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-22 19:01:37 +00:00
Code Issues Packages Projects Releases Wiki Activity
956421fbb7
linux/arch/c6x/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

138 lines
3.5 KiB
C
Raw Blame History

/*
* Port on Texas Instruments TMS320C6x architecture
*
* Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated
* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
*
* Updated for 2.6.34: Mark Salter <msalter@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _ASM_C6X_PROCESSOR_H
#define _ASM_C6X_PROCESSOR_H
#include <asm/ptrace.h>
#include <asm/page.h>
#include <asm/current.h>
/*
* Default implementation of macro that returns current
* instruction pointer ("program counter").
*/
#define current_text_addr() \
({ \
void *__pc; \
asm("mvc .S2 pce1,%0\n" : "=b"(__pc)); \
__pc; \
})
/*
* User space process size. This is mostly meaningless for NOMMU
* but some C6X processors may have RAM addresses up to 0xFFFFFFFF.
* Since calls like mmap() can return an address or an error, we
* have to allow room for error returns when code does something
* like:
*
* addr = do_mmap(...)
* if ((unsigned long)addr >= TASK_SIZE)
* ... its an error code, not an address ...
*
* Here, we allow for 4096 error codes which means we really can't
* use the last 4K page on systems with RAM extending all the way
* to the end of the 32-bit address space.
*/
#define TASK_SIZE 0xFFFFF000
/*
* This decides where the kernel will search for a free chunk of vm
* space during mmap's. We won't be using it
*/
#define TASK_UNMAPPED_BASE 0
struct thread_struct {
unsigned long long b15_14;
unsigned long long a15_14;
unsigned long long b13_12;
unsigned long long a13_12;
unsigned long long b11_10;
unsigned long long a11_10;
unsigned long long ricl_icl;
unsigned long usp; /* user stack pointer */
unsigned long pc; /* kernel pc */
unsigned long wchan;
};
#define INIT_THREAD \
{ \
.usp = 0, \
.wchan = 0, \
}
#define INIT_MMAP { \
&init_mm, 0, 0, NULL, PAGE_SHARED, VM_READ | VM_WRITE | VM_EXEC, 1, \
NULL, NULL }
#define task_pt_regs(task) \
((struct pt_regs *)(THREAD_START_SP + task_stack_page(task)) - 1)
#define alloc_kernel_stack() __get_free_page(GFP_KERNEL)
#define free_kernel_stack(page) free_page((page))
/* Forward declaration, a strange C thing */
struct task_struct;
extern void start_thread(struct pt_regs *regs, unsigned int pc,
unsigned long usp);
/* Free all resources held by a thread. */
static inline void release_thread(struct task_struct *dead_task)
{
}
#define copy_segments(tsk, mm) do { } while (0)
#define release_segments(mm) do { } while (0)
/*
* saved PC of a blocked thread.
*/
#define thread_saved_pc(tsk) (task_pt_regs(tsk)->pc)
/*
* saved kernel SP and DP of a blocked thread.
*/
#ifdef _BIG_ENDIAN
#define thread_saved_ksp(tsk) \
(*(unsigned long *)&(tsk)->thread.b15_14)
#define thread_saved_dp(tsk) \
(*(((unsigned long *)&(tsk)->thread.b15_14) + 1))
#else
#define thread_saved_ksp(tsk) \
(*(((unsigned long *)&(tsk)->thread.b15_14) + 1))
#define thread_saved_dp(tsk) \
(*(unsigned long *)&(tsk)->thread.b15_14)
#endif
extern unsigned long get_wchan(struct task_struct *p);
#define KSTK_EIP(task) (task_pt_regs(task)->pc)
#define KSTK_ESP(task) (task_pt_regs(task)->sp)
#define cpu_relax() do { } while (0)
#define cpu_relax_lowlatency() cpu_relax()
extern const struct seq_operations cpuinfo_op;
/* Reset the board */
#define HARD_RESET_NOW()
extern unsigned int c6x_core_freq;
extern void (*c6x_restart)(void);
extern void (*c6x_halt)(void);
#endif /* ASM_C6X_PROCESSOR_H */
Reference in New Issue View Git Blame Copy Permalink