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Davidlohr Bueso
3a6bfbc91d
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 <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Anton Blanchard <[email protected]>
Cc: Aurelien Jacquiot <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Bharat Bhushan <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Chen Liqin <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: David Howells <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Deepthi Dharwar <[email protected]>
Cc: Dominik Dingel <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Guan Xuetao <[email protected]>
Cc: Haavard Skinnemoen <[email protected]>
Cc: Hans-Christian Egtvedt <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Hirokazu Takata <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Cc: James E.J. Bottomley <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Jonas Bonn <[email protected]>
Cc: Joseph Myers <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Koichi Yasutake <[email protected]>
Cc: Lennox Wu <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Michael Neuling <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Mikael Starvik <[email protected]>
Cc: Nicolas Pitre <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Qais Yousef <[email protected]>
Cc: Qiaowei Ren <[email protected]>
Cc: Rafael Wysocki <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Richard Kuo <[email protected]>
Cc: Russell King <[email protected]>
Cc: Steven Miao <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Stratos Karafotis <[email protected]>
Cc: Tim Chen <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Vasily Kulikov <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Wolfram Sang <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
159 lines
3.4 KiB
C
159 lines
3.4 KiB
C
/*
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* Copyright 2004-2009 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*/
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#ifndef __ASM_BFIN_PROCESSOR_H
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#define __ASM_BFIN_PROCESSOR_H
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/*
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* Default implementation of macro that returns current
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* instruction pointer ("program counter").
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*/
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#define current_text_addr() ({ __label__ _l; _l: &&_l;})
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#include <asm/ptrace.h>
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#include <mach/blackfin.h>
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static inline unsigned long rdusp(void)
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{
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unsigned long usp;
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__asm__ __volatile__("%0 = usp;\n\t":"=da"(usp));
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return usp;
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}
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static inline void wrusp(unsigned long usp)
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{
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__asm__ __volatile__("usp = %0;\n\t"::"da"(usp));
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}
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static inline unsigned long __get_SP(void)
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{
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unsigned long sp;
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__asm__ __volatile__("%0 = sp;\n\t" : "=da"(sp));
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return sp;
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}
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/*
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* User space process size: 1st byte beyond user address space.
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* Fairly meaningless on nommu. Parts of user programs can be scattered
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* in a lot of places, so just disable this by setting it to 0xFFFFFFFF.
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*/
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#define TASK_SIZE 0xFFFFFFFF
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#ifdef __KERNEL__
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#define STACK_TOP TASK_SIZE
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#endif
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#define TASK_UNMAPPED_BASE 0
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struct thread_struct {
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unsigned long ksp; /* kernel stack pointer */
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unsigned long usp; /* user stack pointer */
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unsigned short seqstat; /* saved status register */
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unsigned long esp0; /* points to SR of stack frame pt_regs */
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unsigned long pc; /* instruction pointer */
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void * debuggerinfo;
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};
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#define INIT_THREAD { \
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sizeof(init_stack) + (unsigned long) init_stack, 0, \
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PS_S, 0, 0 \
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}
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extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
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unsigned long new_sp);
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/* Forward declaration, a strange C thing */
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struct task_struct;
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/* Free all resources held by a thread. */
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static inline void release_thread(struct task_struct *dead_task)
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{
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}
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/*
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* Free current thread data structures etc..
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*/
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static inline void exit_thread(void)
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{
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}
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/*
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* Return saved PC of a blocked thread.
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*/
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#define thread_saved_pc(tsk) (tsk->thread.pc)
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unsigned long get_wchan(struct task_struct *p);
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#define KSTK_EIP(tsk) \
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({ \
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unsigned long eip = 0; \
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if ((tsk)->thread.esp0 > PAGE_SIZE && \
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MAP_NR((tsk)->thread.esp0) < max_mapnr) \
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eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
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eip; })
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#define KSTK_ESP(tsk) ((tsk) == current ? rdusp() : (tsk)->thread.usp)
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#define cpu_relax() smp_mb()
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#define cpu_relax_lowlatency() cpu_relax()
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/* Get the Silicon Revision of the chip */
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static inline uint32_t __pure bfin_revid(void)
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{
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/* Always use CHIPID, to work around ANOMALY_05000234 */
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uint32_t revid = (bfin_read_CHIPID() & CHIPID_VERSION) >> 28;
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#ifdef _BOOTROM_GET_DXE_ADDRESS_TWI
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/*
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* ANOMALY_05000364
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* Incorrect Revision Number in DSPID Register
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*/
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if (ANOMALY_05000364 &&
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bfin_read16(_BOOTROM_GET_DXE_ADDRESS_TWI) == 0x2796)
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revid = 1;
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#endif
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return revid;
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}
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static inline uint16_t __pure bfin_cpuid(void)
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{
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return (bfin_read_CHIPID() & CHIPID_FAMILY) >> 12;
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}
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static inline uint32_t __pure bfin_dspid(void)
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{
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return bfin_read_DSPID();
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}
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#define blackfin_core_id() (bfin_dspid() & 0xff)
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static inline uint32_t __pure bfin_compiled_revid(void)
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{
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#if defined(CONFIG_BF_REV_0_0)
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return 0;
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#elif defined(CONFIG_BF_REV_0_1)
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return 1;
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#elif defined(CONFIG_BF_REV_0_2)
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return 2;
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#elif defined(CONFIG_BF_REV_0_3)
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return 3;
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#elif defined(CONFIG_BF_REV_0_4)
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return 4;
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#elif defined(CONFIG_BF_REV_0_5)
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return 5;
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#elif defined(CONFIG_BF_REV_0_6)
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return 6;
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#elif defined(CONFIG_BF_REV_ANY)
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return 0xffff;
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#else
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return -1;
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#endif
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}
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#endif
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