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linux/include/asm-arm/system.h
Nick Piggin 4866cde064 [PATCH] sched: cleanup context switch locking 
Instead of requiring architecture code to interact with the scheduler's
locking implementation, provide a couple of defines that can be used by the
architecture to request runqueue unlocked context switches, and ask for
interrupts to be enabled over the context switch.

Also replaces the "switch_lock" used by these architectures with an oncpu
flag (note, not a potentially slow bitflag).  This eliminates one bus
locked memory operation when context switching, and simplifies the
task_running function.

Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:43 -07:00

372 lines
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#ifndef __ASM_ARM_SYSTEM_H
#define __ASM_ARM_SYSTEM_H
#ifdef __KERNEL__
#include <linux/config.h>
#define CPU_ARCH_UNKNOWN 0
#define CPU_ARCH_ARMv3 1
#define CPU_ARCH_ARMv4 2
#define CPU_ARCH_ARMv4T 3
#define CPU_ARCH_ARMv5 4
#define CPU_ARCH_ARMv5T 5
#define CPU_ARCH_ARMv5TE 6
#define CPU_ARCH_ARMv5TEJ 7
#define CPU_ARCH_ARMv6 8
/*
* CR1 bits (CP#15 CR1)
*/
#define CR_M (1 << 0) /* MMU enable */
#define CR_A (1 << 1) /* Alignment abort enable */
#define CR_C (1 << 2) /* Dcache enable */
#define CR_W (1 << 3) /* Write buffer enable */
#define CR_P (1 << 4) /* 32-bit exception handler */
#define CR_D (1 << 5) /* 32-bit data address range */
#define CR_L (1 << 6) /* Implementation defined */
#define CR_B (1 << 7) /* Big endian */
#define CR_S (1 << 8) /* System MMU protection */
#define CR_R (1 << 9) /* ROM MMU protection */
#define CR_F (1 << 10) /* Implementation defined */
#define CR_Z (1 << 11) /* Implementation defined */
#define CR_I (1 << 12) /* Icache enable */
#define CR_V (1 << 13) /* Vectors relocated to 0xffff0000 */
#define CR_RR (1 << 14) /* Round Robin cache replacement */
#define CR_L4 (1 << 15) /* LDR pc can set T bit */
#define CR_DT (1 << 16)
#define CR_IT (1 << 18)
#define CR_ST (1 << 19)
#define CR_FI (1 << 21) /* Fast interrupt (lower latency mode) */
#define CR_U (1 << 22) /* Unaligned access operation */
#define CR_XP (1 << 23) /* Extended page tables */
#define CR_VE (1 << 24) /* Vectored interrupts */
#define CPUID_ID 0
#define CPUID_CACHETYPE 1
#define CPUID_TCM 2
#define CPUID_TLBTYPE 3
#define read_cpuid(reg) \
({ \
unsigned int __val; \
asm("mrc p15, 0, %0, c0, c0, " __stringify(reg) \
: "=r" (__val) \
: \
: "cc"); \
__val; \
})
/*
* This is used to ensure the compiler did actually allocate the register we
* asked it for some inline assembly sequences. Apparently we can't trust
* the compiler from one version to another so a bit of paranoia won't hurt.
* This string is meant to be concatenated with the inline asm string and
* will cause compilation to stop on mismatch.
* (for details, see gcc PR 15089)
*/
#define __asmeq(x, y) ".ifnc " x "," y " ; .err ; .endif\n\t"
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
struct thread_info;
struct task_struct;
/* information about the system we're running on */
extern unsigned int system_rev;
extern unsigned int system_serial_low;
extern unsigned int system_serial_high;
extern unsigned int mem_fclk_21285;
struct pt_regs;
void die(const char *msg, struct pt_regs *regs, int err)
__attribute__((noreturn));
void die_if_kernel(const char *str, struct pt_regs *regs, int err);
void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
struct pt_regs *),
int sig, const char *name);
#include <asm/proc-fns.h>
#define xchg(ptr,x) \
((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
#define tas(ptr) (xchg((ptr),1))
extern asmlinkage void __backtrace(void);
extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
extern void show_pte(struct mm_struct *mm, unsigned long addr);
extern void __show_regs(struct pt_regs *);
extern int cpu_architecture(void);
extern void cpu_init(void);
#define set_cr(x) \
__asm__ __volatile__( \
"mcr p15, 0, %0, c1, c0, 0 @ set CR" \
: : "r" (x) : "cc")
#define get_cr() \
({ \
unsigned int __val; \
__asm__ __volatile__( \
"mrc p15, 0, %0, c1, c0, 0 @ get CR" \
: "=r" (__val) : : "cc"); \
__val; \
})
extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
extern unsigned long cr_alignment; /* defined in entry-armv.S */
#define UDBG_UNDEFINED (1 << 0)
#define UDBG_SYSCALL (1 << 1)
#define UDBG_BADABORT (1 << 2)
#define UDBG_SEGV (1 << 3)
#define UDBG_BUS (1 << 4)
extern unsigned int user_debug;
#if __LINUX_ARM_ARCH__ >= 4
#define vectors_high() (cr_alignment & CR_V)
#else
#define vectors_high() (0)
#endif
#define mb() __asm__ __volatile__ ("" : : : "memory")
#define rmb() mb()
#define wmb() mb()
#define read_barrier_depends() do { } while(0)
#define set_mb(var, value) do { var = value; mb(); } while (0)
#define set_wmb(var, value) do { var = value; wmb(); } while (0)
#define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
/*
* switch_mm() may do a full cache flush over the context switch,
* so enable interrupts over the context switch to avoid high
* latency.
*/
#define __ARCH_WANT_INTERRUPTS_ON_CTXSW
/*
* switch_to(prev, next) should switch from task `prev' to `next'
* `prev' will never be the same as `next'. schedule() itself
* contains the memory barrier to tell GCC not to cache `current'.
*/
extern struct task_struct *__switch_to(struct task_struct *, struct thread_info *, struct thread_info *);
#define switch_to(prev,next,last) \
do { \
last = __switch_to(prev,prev->thread_info,next->thread_info); \
} while (0)
/*
* CPU interrupt mask handling.
*/
#if __LINUX_ARM_ARCH__ >= 6
#define local_irq_save(x) \
({ \
__asm__ __volatile__( \
"mrs %0, cpsr @ local_irq_save\n" \
"cpsid i" \
: "=r" (x) : : "memory", "cc"); \
})
#define local_irq_enable() __asm__("cpsie i @ __sti" : : : "memory", "cc")
#define local_irq_disable() __asm__("cpsid i @ __cli" : : : "memory", "cc")
#define local_fiq_enable() __asm__("cpsie f @ __stf" : : : "memory", "cc")
#define local_fiq_disable() __asm__("cpsid f @ __clf" : : : "memory", "cc")
#else
/*
* Save the current interrupt enable state & disable IRQs
*/
#define local_irq_save(x) \
({ \
unsigned long temp; \
(void) (&temp == &x); \
__asm__ __volatile__( \
"mrs %0, cpsr @ local_irq_save\n" \
" orr %1, %0, #128\n" \
" msr cpsr_c, %1" \
: "=r" (x), "=r" (temp) \
: \
: "memory", "cc"); \
})
/*
* Enable IRQs
*/
#define local_irq_enable() \
({ \
unsigned long temp; \
__asm__ __volatile__( \
"mrs %0, cpsr @ local_irq_enable\n" \
" bic %0, %0, #128\n" \
" msr cpsr_c, %0" \
: "=r" (temp) \
: \
: "memory", "cc"); \
})
/*
* Disable IRQs
*/
#define local_irq_disable() \
({ \
unsigned long temp; \
__asm__ __volatile__( \
"mrs %0, cpsr @ local_irq_disable\n" \
" orr %0, %0, #128\n" \
" msr cpsr_c, %0" \
: "=r" (temp) \
: \
: "memory", "cc"); \
})
/*
* Enable FIQs
*/
#define local_fiq_enable() \
({ \
unsigned long temp; \
__asm__ __volatile__( \
"mrs %0, cpsr @ stf\n" \
" bic %0, %0, #64\n" \
" msr cpsr_c, %0" \
: "=r" (temp) \
: \
: "memory", "cc"); \
})
/*
* Disable FIQs
*/
#define local_fiq_disable() \
({ \
unsigned long temp; \
__asm__ __volatile__( \
"mrs %0, cpsr @ clf\n" \
" orr %0, %0, #64\n" \
" msr cpsr_c, %0" \
: "=r" (temp) \
: \
: "memory", "cc"); \
})
#endif
/*
* Save the current interrupt enable state.
*/
#define local_save_flags(x) \
({ \
__asm__ __volatile__( \
"mrs %0, cpsr @ local_save_flags" \
: "=r" (x) : : "memory", "cc"); \
})
/*
* restore saved IRQ & FIQ state
*/
#define local_irq_restore(x) \
__asm__ __volatile__( \
"msr cpsr_c, %0 @ local_irq_restore\n" \
: \
: "r" (x) \
: "memory", "cc")
#define irqs_disabled() \
({ \
unsigned long flags; \
local_save_flags(flags); \
(int)(flags & PSR_I_BIT); \
})
#ifdef CONFIG_SMP
#error SMP not supported
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#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)
#if defined(CONFIG_CPU_SA1100) || defined(CONFIG_CPU_SA110)
/*
* On the StrongARM, "swp" is terminally broken since it bypasses the
* cache totally. This means that the cache becomes inconsistent, and,
* since we use normal loads/stores as well, this is really bad.
* Typically, this causes oopsen in filp_close, but could have other,
* more disasterous effects. There are two work-arounds:
* 1. Disable interrupts and emulate the atomic swap
* 2. Clean the cache, perform atomic swap, flush the cache
*
* We choose (1) since its the "easiest" to achieve here and is not
* dependent on the processor type.
*/
#define swp_is_buggy
#endif
static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
{
extern void __bad_xchg(volatile void *, int);
unsigned long ret;
#ifdef swp_is_buggy
unsigned long flags;
#endif
switch (size) {
#ifdef swp_is_buggy
case 1:
local_irq_save(flags);
ret = *(volatile unsigned char *)ptr;
*(volatile unsigned char *)ptr = x;
local_irq_restore(flags);
break;
case 4:
local_irq_save(flags);
ret = *(volatile unsigned long *)ptr;
*(volatile unsigned long *)ptr = x;
local_irq_restore(flags);
break;
#else
case 1: __asm__ __volatile__ ("swpb %0, %1, [%2]"
: "=&r" (ret)
: "r" (x), "r" (ptr)
: "memory", "cc");
break;
case 4: __asm__ __volatile__ ("swp %0, %1, [%2]"
: "=&r" (ret)
: "r" (x), "r" (ptr)
: "memory", "cc");
break;
#endif
default: __bad_xchg(ptr, size), ret = 0;
}
return ret;
}
#endif /* CONFIG_SMP */
#endif /* __ASSEMBLY__ */
#define arch_align_stack(x) (x)
#endif /* __KERNEL__ */
#endif
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