system.h

/*
 * Copyright IBM Corp. 1999, 2009
 *
 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#ifndef __ASM_SYSTEM_H
#define __ASM_SYSTEM_H

#include <linux/kernel.h>
#include <linux/errno.h>
#include <asm/types.h>
#include <asm/ptrace.h>
#include <asm/setup.h>
#include <asm/processor.h>
#include <asm/lowcore.h>
#include <asm/cmpxchg.h>

#ifdef __KERNEL__

struct task_struct;

extern struct task_struct *__switch_to(void *, void *);
extern void update_per_regs(struct task_struct *task);

static inline void save_fp_regs(s390_fp_regs *fpregs)
{
	asm volatile(
		"	std	0,%O0+8(%R0)\n"
		"	std	2,%O0+24(%R0)\n"
		"	std	4,%O0+40(%R0)\n"
		"	std	6,%O0+56(%R0)"
		: "=Q" (*fpregs) : "Q" (*fpregs));
	if (!MACHINE_HAS_IEEE)
		return;
	asm volatile(
		"	stfpc	%0\n"
		"	std	1,%O0+16(%R0)\n"
		"	std	3,%O0+32(%R0)\n"
		"	std	5,%O0+48(%R0)\n"
		"	std	7,%O0+64(%R0)\n"
		"	std	8,%O0+72(%R0)\n"
		"	std	9,%O0+80(%R0)\n"
		"	std	10,%O0+88(%R0)\n"
		"	std	11,%O0+96(%R0)\n"
		"	std	12,%O0+104(%R0)\n"
		"	std	13,%O0+112(%R0)\n"
		"	std	14,%O0+120(%R0)\n"
		"	std	15,%O0+128(%R0)\n"
		: "=Q" (*fpregs) : "Q" (*fpregs));
}

static inline void restore_fp_regs(s390_fp_regs *fpregs)
{
	asm volatile(
		"	ld	0,%O0+8(%R0)\n"
		"	ld	2,%O0+24(%R0)\n"
		"	ld	4,%O0+40(%R0)\n"
		"	ld	6,%O0+56(%R0)"
		: : "Q" (*fpregs));
	if (!MACHINE_HAS_IEEE)
		return;
	asm volatile(
		"	lfpc	%0\n"
		"	ld	1,%O0+16(%R0)\n"
		"	ld	3,%O0+32(%R0)\n"
		"	ld	5,%O0+48(%R0)\n"
		"	ld	7,%O0+64(%R0)\n"
		"	ld	8,%O0+72(%R0)\n"
		"	ld	9,%O0+80(%R0)\n"
		"	ld	10,%O0+88(%R0)\n"
		"	ld	11,%O0+96(%R0)\n"
		"	ld	12,%O0+104(%R0)\n"
		"	ld	13,%O0+112(%R0)\n"
		"	ld	14,%O0+120(%R0)\n"
		"	ld	15,%O0+128(%R0)\n"
		: : "Q" (*fpregs));
}

static inline void save_access_regs(unsigned int *acrs)
{
	asm volatile("stam 0,15,%0" : "=Q" (*acrs));
}

static inline void restore_access_regs(unsigned int *acrs)
{
	asm volatile("lam 0,15,%0" : : "Q" (*acrs));
}

#define switch_to(prev,next,last) do {					\
	if (prev->mm) {							\
		save_fp_regs(&prev->thread.fp_regs);			\
		save_access_regs(&prev->thread.acrs[0]);		\
	}								\
	if (next->mm) {							\
		restore_fp_regs(&next->thread.fp_regs);			\
		restore_access_regs(&next->thread.acrs[0]);		\
		update_per_regs(next);					\
	}								\
	prev = __switch_to(prev,next);					\
} while (0)

extern void account_vtime(struct task_struct *, struct task_struct *);
extern void account_tick_vtime(struct task_struct *);

#ifdef CONFIG_PFAULT
extern int pfault_init(void);
extern void pfault_fini(void);
#else /* CONFIG_PFAULT */
#define pfault_init()		({-1;})
#define pfault_fini()		do { } while (0)
#endif /* CONFIG_PFAULT */

extern void cmma_init(void);
extern int memcpy_real(void *, void *, size_t);
extern void copy_to_absolute_zero(void *dest, void *src, size_t count);
extern int copy_to_user_real(void __user *dest, void *src, size_t count);
extern int copy_from_user_real(void *dest, void __user *src, size_t count);

#define finish_arch_switch(prev) do {					     \
	set_fs(current->thread.mm_segment);				     \
	account_vtime(prev, current);					     \
} while (0)

#define nop() asm volatile("nop")

/*
 * Force strict CPU ordering.
 * And yes, this is required on UP too when we're talking
 * to devices.
 *
 * This is very similar to the ppc eieio/sync instruction in that is
 * does a checkpoint syncronisation & makes sure that 
 * all memory ops have completed wrt other CPU's ( see 7-15 POP  DJB ).
 */

#define eieio()	asm volatile("bcr 15,0" : : : "memory")
#define SYNC_OTHER_CORES(x)   eieio()
#define mb()    eieio()
#define rmb()   eieio()
#define wmb()   eieio()
#define read_barrier_depends() do { } while(0)
#define smp_mb()       mb()
#define smp_rmb()      rmb()
#define smp_wmb()      wmb()
#define smp_read_barrier_depends()    read_barrier_depends()
#define smp_mb__before_clear_bit()     smp_mb()
#define smp_mb__after_clear_bit()      smp_mb()


#define set_mb(var, value)      do { var = value; mb(); } while (0)

#ifdef __s390x__

#define __ctl_load(array, low, high) ({				\
	typedef struct { char _[sizeof(array)]; } addrtype;	\
	asm volatile(						\
		"	lctlg	%1,%2,%0\n"			\
		: : "Q" (*(addrtype *)(&array)),		\
		    "i" (low), "i" (high));			\
	})

#define __ctl_store(array, low, high) ({			\
	typedef struct { char _[sizeof(array)]; } addrtype;	\
	asm volatile(						\
		"	stctg	%1,%2,%0\n"			\
		: "=Q" (*(addrtype *)(&array))			\
		: "i" (low), "i" (high));			\
	})

#else /* __s390x__ */

#define __ctl_load(array, low, high) ({				\
	typedef struct { char _[sizeof(array)]; } addrtype;	\
	asm volatile(						\
		"	lctl	%1,%2,%0\n"			\
		: : "Q" (*(addrtype *)(&array)),		\
		    "i" (low), "i" (high));			\
})

#define __ctl_store(array, low, high) ({			\
	typedef struct { char _[sizeof(array)]; } addrtype;	\
	asm volatile(						\
		"	stctl	%1,%2,%0\n"			\
		: "=Q" (*(addrtype *)(&array))			\
		: "i" (low), "i" (high));			\
	})

#endif /* __s390x__ */

#define __ctl_set_bit(cr, bit) ({	\
	unsigned long __dummy;		\
	__ctl_store(__dummy, cr, cr);	\
	__dummy |= 1UL << (bit);	\
	__ctl_load(__dummy, cr, cr);	\
})

#define __ctl_clear_bit(cr, bit) ({	\
	unsigned long __dummy;		\
	__ctl_store(__dummy, cr, cr);	\
	__dummy &= ~(1UL << (bit));	\
	__ctl_load(__dummy, cr, cr);	\
})

/*
 * Use to set psw mask except for the first byte which
 * won't be changed by this function.
 */
static inline void
__set_psw_mask(unsigned long mask)
{
	__load_psw_mask(mask | (arch_local_save_flags() & ~(-1UL >> 8)));
}

#define local_mcck_enable() \
	__set_psw_mask(psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK)
#define local_mcck_disable() \
	__set_psw_mask(psw_kernel_bits | PSW_MASK_DAT)

#ifdef CONFIG_SMP

extern void smp_ctl_set_bit(int cr, int bit);
extern void smp_ctl_clear_bit(int cr, int bit);
#define ctl_set_bit(cr, bit) smp_ctl_set_bit(cr, bit)
#define ctl_clear_bit(cr, bit) smp_ctl_clear_bit(cr, bit)

#else

#define ctl_set_bit(cr, bit) __ctl_set_bit(cr, bit)
#define ctl_clear_bit(cr, bit) __ctl_clear_bit(cr, bit)

#endif /* CONFIG_SMP */

#define MAX_FACILITY_BIT (256*8)	/* stfle_fac_list has 256 bytes */

/*
 * The test_facility function uses the bit odering where the MSB is bit 0.
 * That makes it easier to query facility bits with the bit number as
 * documented in the Principles of Operation.
 */
static inline int test_facility(unsigned long nr)
{
	unsigned char *ptr;

	if (nr >= MAX_FACILITY_BIT)
		return 0;
	ptr = (unsigned char *) &S390_lowcore.stfle_fac_list + (nr >> 3);
	return (*ptr & (0x80 >> (nr & 7))) != 0;
}

static inline unsigned short stap(void)
{
	unsigned short cpu_address;

	asm volatile("stap %0" : "=m" (cpu_address));
	return cpu_address;
}

extern void (*_machine_restart)(char *command);
extern void (*_machine_halt)(void);
extern void (*_machine_power_off)(void);

extern unsigned long arch_align_stack(unsigned long sp);

static inline int tprot(unsigned long addr)
{
	int rc = -EFAULT;

	asm volatile(
		"	tprot	0(%1),0\n"
		"0:	ipm	%0\n"
		"	srl	%0,28\n"
		"1:\n"
		EX_TABLE(0b,1b)
		: "+d" (rc) : "a" (addr) : "cc");
	return rc;
}

#endif /* __KERNEL__ */

#endif