linux/arch/powerpc/include/asm/system.h
Nick Piggin 957ab07b44 powerpc: Optimise smp_rmb
After commit 598056d5af ("[POWERPC] Fix
rmb to order cacheable vs. noncacheable"), rmb() becomes a sync
instruction, which is needed to order cacheable vs noncacheable loads.
However smp_rmb() is #defined to rmb(), and smp_rmb() can be an
lwsync.

This restores smp_rmb() performance by using lwsync there and updates
the comments.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-11-19 16:04:57 +11:00

551 lines
14 KiB
C

/*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
*/
#ifndef _ASM_POWERPC_SYSTEM_H
#define _ASM_POWERPC_SYSTEM_H
#include <linux/kernel.h>
#include <linux/irqflags.h>
#include <asm/hw_irq.h>
/*
* Memory barrier.
* The sync instruction guarantees that all memory accesses initiated
* by this processor have been performed (with respect to all other
* mechanisms that access memory). The eieio instruction is a barrier
* providing an ordering (separately) for (a) cacheable stores and (b)
* loads and stores to non-cacheable memory (e.g. I/O devices).
*
* mb() prevents loads and stores being reordered across this point.
* rmb() prevents loads being reordered across this point.
* wmb() prevents stores being reordered across this point.
* read_barrier_depends() prevents data-dependent loads being reordered
* across this point (nop on PPC).
*
* *mb() variants without smp_ prefix must order all types of memory
* operations with one another. sync is the only instruction sufficient
* to do this.
*
* For the smp_ barriers, ordering is for cacheable memory operations
* only. We have to use the sync instruction for smp_mb(), since lwsync
* doesn't order loads with respect to previous stores. Lwsync can be
* used for smp_rmb() and smp_wmb().
*
* However, on CPUs that don't support lwsync, lwsync actually maps to a
* heavy-weight sync, so smp_wmb() can be a lighter-weight eieio.
*/
#define mb() __asm__ __volatile__ ("sync" : : : "memory")
#define rmb() __asm__ __volatile__ ("sync" : : : "memory")
#define wmb() __asm__ __volatile__ ("sync" : : : "memory")
#define read_barrier_depends() do { } while(0)
#define set_mb(var, value) do { var = value; mb(); } while (0)
#ifdef __KERNEL__
#define AT_VECTOR_SIZE_ARCH 6 /* entries in ARCH_DLINFO */
#ifdef CONFIG_SMP
#ifdef __SUBARCH_HAS_LWSYNC
# define SMPWMB LWSYNC
#else
# define SMPWMB eieio
#endif
#define smp_mb() mb()
#define smp_rmb() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory")
#define smp_wmb() __asm__ __volatile__ (stringify_in_c(SMPWMB) : : :"memory")
#define smp_read_barrier_depends() read_barrier_depends()
#else
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#define smp_read_barrier_depends() do { } while(0)
#endif /* CONFIG_SMP */
/*
* This is a barrier which prevents following instructions from being
* started until the value of the argument x is known. For example, if
* x is a variable loaded from memory, this prevents following
* instructions from being executed until the load has been performed.
*/
#define data_barrier(x) \
asm volatile("twi 0,%0,0; isync" : : "r" (x) : "memory");
struct task_struct;
struct pt_regs;
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
extern int (*__debugger)(struct pt_regs *regs);
extern int (*__debugger_ipi)(struct pt_regs *regs);
extern int (*__debugger_bpt)(struct pt_regs *regs);
extern int (*__debugger_sstep)(struct pt_regs *regs);
extern int (*__debugger_iabr_match)(struct pt_regs *regs);
extern int (*__debugger_dabr_match)(struct pt_regs *regs);
extern int (*__debugger_fault_handler)(struct pt_regs *regs);
#define DEBUGGER_BOILERPLATE(__NAME) \
static inline int __NAME(struct pt_regs *regs) \
{ \
if (unlikely(__ ## __NAME)) \
return __ ## __NAME(regs); \
return 0; \
}
DEBUGGER_BOILERPLATE(debugger)
DEBUGGER_BOILERPLATE(debugger_ipi)
DEBUGGER_BOILERPLATE(debugger_bpt)
DEBUGGER_BOILERPLATE(debugger_sstep)
DEBUGGER_BOILERPLATE(debugger_iabr_match)
DEBUGGER_BOILERPLATE(debugger_dabr_match)
DEBUGGER_BOILERPLATE(debugger_fault_handler)
#else
static inline int debugger(struct pt_regs *regs) { return 0; }
static inline int debugger_ipi(struct pt_regs *regs) { return 0; }
static inline int debugger_bpt(struct pt_regs *regs) { return 0; }
static inline int debugger_sstep(struct pt_regs *regs) { return 0; }
static inline int debugger_iabr_match(struct pt_regs *regs) { return 0; }
static inline int debugger_dabr_match(struct pt_regs *regs) { return 0; }
static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }
#endif
extern int set_dabr(unsigned long dabr);
extern void do_dabr(struct pt_regs *regs, unsigned long address,
unsigned long error_code);
extern void print_backtrace(unsigned long *);
extern void show_regs(struct pt_regs * regs);
extern void flush_instruction_cache(void);
extern void hard_reset_now(void);
extern void poweroff_now(void);
#ifdef CONFIG_6xx
extern long _get_L2CR(void);
extern long _get_L3CR(void);
extern void _set_L2CR(unsigned long);
extern void _set_L3CR(unsigned long);
#else
#define _get_L2CR() 0L
#define _get_L3CR() 0L
#define _set_L2CR(val) do { } while(0)
#define _set_L3CR(val) do { } while(0)
#endif
extern void via_cuda_init(void);
extern void read_rtc_time(void);
extern void pmac_find_display(void);
extern void giveup_fpu(struct task_struct *);
extern void disable_kernel_fp(void);
extern void enable_kernel_fp(void);
extern void flush_fp_to_thread(struct task_struct *);
extern void enable_kernel_altivec(void);
extern void giveup_altivec(struct task_struct *);
extern void load_up_altivec(struct task_struct *);
extern int emulate_altivec(struct pt_regs *);
extern void __giveup_vsx(struct task_struct *);
extern void giveup_vsx(struct task_struct *);
extern void enable_kernel_spe(void);
extern void giveup_spe(struct task_struct *);
extern void load_up_spe(struct task_struct *);
extern int fix_alignment(struct pt_regs *);
extern void cvt_fd(float *from, double *to, struct thread_struct *thread);
extern void cvt_df(double *from, float *to, struct thread_struct *thread);
#ifndef CONFIG_SMP
extern void discard_lazy_cpu_state(void);
#else
static inline void discard_lazy_cpu_state(void)
{
}
#endif
#ifdef CONFIG_ALTIVEC
extern void flush_altivec_to_thread(struct task_struct *);
#else
static inline void flush_altivec_to_thread(struct task_struct *t)
{
}
#endif
#ifdef CONFIG_VSX
extern void flush_vsx_to_thread(struct task_struct *);
#else
static inline void flush_vsx_to_thread(struct task_struct *t)
{
}
#endif
#ifdef CONFIG_SPE
extern void flush_spe_to_thread(struct task_struct *);
#else
static inline void flush_spe_to_thread(struct task_struct *t)
{
}
#endif
extern int call_rtas(const char *, int, int, unsigned long *, ...);
extern void cacheable_memzero(void *p, unsigned int nb);
extern void *cacheable_memcpy(void *, const void *, unsigned int);
extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long);
extern void bad_page_fault(struct pt_regs *, unsigned long, int);
extern int die(const char *, struct pt_regs *, long);
extern void _exception(int, struct pt_regs *, int, unsigned long);
extern void _nmask_and_or_msr(unsigned long nmask, unsigned long or_val);
#ifdef CONFIG_BOOKE_WDT
extern u32 booke_wdt_enabled;
extern u32 booke_wdt_period;
#endif /* CONFIG_BOOKE_WDT */
struct device_node;
extern void note_scsi_host(struct device_node *, void *);
extern struct task_struct *__switch_to(struct task_struct *,
struct task_struct *);
#define switch_to(prev, next, last) ((last) = __switch_to((prev), (next)))
struct thread_struct;
extern struct task_struct *_switch(struct thread_struct *prev,
struct thread_struct *next);
extern unsigned int rtas_data;
extern int mem_init_done; /* set on boot once kmalloc can be called */
extern int init_bootmem_done; /* set on !NUMA once bootmem is available */
extern unsigned long memory_limit;
extern unsigned long klimit;
extern void *alloc_maybe_bootmem(size_t size, gfp_t mask);
extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);
extern int powersave_nap; /* set if nap mode can be used in idle loop */
/*
* Atomic exchange
*
* Changes the memory location '*ptr' to be val and returns
* the previous value stored there.
*/
static __always_inline unsigned long
__xchg_u32(volatile void *p, unsigned long val)
{
unsigned long prev;
__asm__ __volatile__(
LWSYNC_ON_SMP
"1: lwarx %0,0,%2 \n"
PPC405_ERR77(0,%2)
" stwcx. %3,0,%2 \n\
bne- 1b"
ISYNC_ON_SMP
: "=&r" (prev), "+m" (*(volatile unsigned int *)p)
: "r" (p), "r" (val)
: "cc", "memory");
return prev;
}
/*
* Atomic exchange
*
* Changes the memory location '*ptr' to be val and returns
* the previous value stored there.
*/
static __always_inline unsigned long
__xchg_u32_local(volatile void *p, unsigned long val)
{
unsigned long prev;
__asm__ __volatile__(
"1: lwarx %0,0,%2 \n"
PPC405_ERR77(0,%2)
" stwcx. %3,0,%2 \n\
bne- 1b"
: "=&r" (prev), "+m" (*(volatile unsigned int *)p)
: "r" (p), "r" (val)
: "cc", "memory");
return prev;
}
#ifdef CONFIG_PPC64
static __always_inline unsigned long
__xchg_u64(volatile void *p, unsigned long val)
{
unsigned long prev;
__asm__ __volatile__(
LWSYNC_ON_SMP
"1: ldarx %0,0,%2 \n"
PPC405_ERR77(0,%2)
" stdcx. %3,0,%2 \n\
bne- 1b"
ISYNC_ON_SMP
: "=&r" (prev), "+m" (*(volatile unsigned long *)p)
: "r" (p), "r" (val)
: "cc", "memory");
return prev;
}
static __always_inline unsigned long
__xchg_u64_local(volatile void *p, unsigned long val)
{
unsigned long prev;
__asm__ __volatile__(
"1: ldarx %0,0,%2 \n"
PPC405_ERR77(0,%2)
" stdcx. %3,0,%2 \n\
bne- 1b"
: "=&r" (prev), "+m" (*(volatile unsigned long *)p)
: "r" (p), "r" (val)
: "cc", "memory");
return prev;
}
#endif
/*
* This function doesn't exist, so you'll get a linker error
* if something tries to do an invalid xchg().
*/
extern void __xchg_called_with_bad_pointer(void);
static __always_inline unsigned long
__xchg(volatile void *ptr, unsigned long x, unsigned int size)
{
switch (size) {
case 4:
return __xchg_u32(ptr, x);
#ifdef CONFIG_PPC64
case 8:
return __xchg_u64(ptr, x);
#endif
}
__xchg_called_with_bad_pointer();
return x;
}
static __always_inline unsigned long
__xchg_local(volatile void *ptr, unsigned long x, unsigned int size)
{
switch (size) {
case 4:
return __xchg_u32_local(ptr, x);
#ifdef CONFIG_PPC64
case 8:
return __xchg_u64_local(ptr, x);
#endif
}
__xchg_called_with_bad_pointer();
return x;
}
#define xchg(ptr,x) \
({ \
__typeof__(*(ptr)) _x_ = (x); \
(__typeof__(*(ptr))) __xchg((ptr), (unsigned long)_x_, sizeof(*(ptr))); \
})
#define xchg_local(ptr,x) \
({ \
__typeof__(*(ptr)) _x_ = (x); \
(__typeof__(*(ptr))) __xchg_local((ptr), \
(unsigned long)_x_, sizeof(*(ptr))); \
})
/*
* Compare and exchange - if *p == old, set it to new,
* and return the old value of *p.
*/
#define __HAVE_ARCH_CMPXCHG 1
static __always_inline unsigned long
__cmpxchg_u32(volatile unsigned int *p, unsigned long old, unsigned long new)
{
unsigned int prev;
__asm__ __volatile__ (
LWSYNC_ON_SMP
"1: lwarx %0,0,%2 # __cmpxchg_u32\n\
cmpw 0,%0,%3\n\
bne- 2f\n"
PPC405_ERR77(0,%2)
" stwcx. %4,0,%2\n\
bne- 1b"
ISYNC_ON_SMP
"\n\
2:"
: "=&r" (prev), "+m" (*p)
: "r" (p), "r" (old), "r" (new)
: "cc", "memory");
return prev;
}
static __always_inline unsigned long
__cmpxchg_u32_local(volatile unsigned int *p, unsigned long old,
unsigned long new)
{
unsigned int prev;
__asm__ __volatile__ (
"1: lwarx %0,0,%2 # __cmpxchg_u32\n\
cmpw 0,%0,%3\n\
bne- 2f\n"
PPC405_ERR77(0,%2)
" stwcx. %4,0,%2\n\
bne- 1b"
"\n\
2:"
: "=&r" (prev), "+m" (*p)
: "r" (p), "r" (old), "r" (new)
: "cc", "memory");
return prev;
}
#ifdef CONFIG_PPC64
static __always_inline unsigned long
__cmpxchg_u64(volatile unsigned long *p, unsigned long old, unsigned long new)
{
unsigned long prev;
__asm__ __volatile__ (
LWSYNC_ON_SMP
"1: ldarx %0,0,%2 # __cmpxchg_u64\n\
cmpd 0,%0,%3\n\
bne- 2f\n\
stdcx. %4,0,%2\n\
bne- 1b"
ISYNC_ON_SMP
"\n\
2:"
: "=&r" (prev), "+m" (*p)
: "r" (p), "r" (old), "r" (new)
: "cc", "memory");
return prev;
}
static __always_inline unsigned long
__cmpxchg_u64_local(volatile unsigned long *p, unsigned long old,
unsigned long new)
{
unsigned long prev;
__asm__ __volatile__ (
"1: ldarx %0,0,%2 # __cmpxchg_u64\n\
cmpd 0,%0,%3\n\
bne- 2f\n\
stdcx. %4,0,%2\n\
bne- 1b"
"\n\
2:"
: "=&r" (prev), "+m" (*p)
: "r" (p), "r" (old), "r" (new)
: "cc", "memory");
return prev;
}
#endif
/* This function doesn't exist, so you'll get a linker error
if something tries to do an invalid cmpxchg(). */
extern void __cmpxchg_called_with_bad_pointer(void);
static __always_inline unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new,
unsigned int size)
{
switch (size) {
case 4:
return __cmpxchg_u32(ptr, old, new);
#ifdef CONFIG_PPC64
case 8:
return __cmpxchg_u64(ptr, old, new);
#endif
}
__cmpxchg_called_with_bad_pointer();
return old;
}
static __always_inline unsigned long
__cmpxchg_local(volatile void *ptr, unsigned long old, unsigned long new,
unsigned int size)
{
switch (size) {
case 4:
return __cmpxchg_u32_local(ptr, old, new);
#ifdef CONFIG_PPC64
case 8:
return __cmpxchg_u64_local(ptr, old, new);
#endif
}
__cmpxchg_called_with_bad_pointer();
return old;
}
#define cmpxchg(ptr, o, n) \
({ \
__typeof__(*(ptr)) _o_ = (o); \
__typeof__(*(ptr)) _n_ = (n); \
(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
(unsigned long)_n_, sizeof(*(ptr))); \
})
#define cmpxchg_local(ptr, o, n) \
({ \
__typeof__(*(ptr)) _o_ = (o); \
__typeof__(*(ptr)) _n_ = (n); \
(__typeof__(*(ptr))) __cmpxchg_local((ptr), (unsigned long)_o_, \
(unsigned long)_n_, sizeof(*(ptr))); \
})
#ifdef CONFIG_PPC64
/*
* We handle most unaligned accesses in hardware. On the other hand
* unaligned DMA can be very expensive on some ppc64 IO chips (it does
* powers of 2 writes until it reaches sufficient alignment).
*
* Based on this we disable the IP header alignment in network drivers.
* We also modify NET_SKB_PAD to be a cacheline in size, thus maintaining
* cacheline alignment of buffers.
*/
#define NET_IP_ALIGN 0
#define NET_SKB_PAD L1_CACHE_BYTES
#define cmpxchg64(ptr, o, n) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
cmpxchg((ptr), (o), (n)); \
})
#define cmpxchg64_local(ptr, o, n) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
cmpxchg_local((ptr), (o), (n)); \
})
#else
#include <asm-generic/cmpxchg-local.h>
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
#endif
#define arch_align_stack(x) (x)
/* Used in very early kernel initialization. */
extern unsigned long reloc_offset(void);
extern unsigned long add_reloc_offset(unsigned long);
extern void reloc_got2(unsigned long);
#define PTRRELOC(x) ((typeof(x)) add_reloc_offset((unsigned long)(x)))
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
extern void account_system_vtime(struct task_struct *);
#endif
extern struct dentry *powerpc_debugfs_root;
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_SYSTEM_H */