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>

#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);

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

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

#define xchg(ptr,x)							  \
({									  \
	__typeof__(*(ptr)) __ret;					  \
	__ret = (__typeof__(*(ptr)))					  \
		__xchg((unsigned long)(x), (void *)(ptr),sizeof(*(ptr))); \
	__ret;								  \
})

extern void __xchg_called_with_bad_pointer(void);

static inline unsigned long __xchg(unsigned long x, void * ptr, int size)
{
	unsigned long addr, old;
	int shift;

        switch (size) {
	case 1:
		addr = (unsigned long) ptr;
		shift = (3 ^ (addr & 3)) << 3;
		addr ^= addr & 3;
		asm volatile(
			"	l	%0,%4\n"
			"0:	lr	0,%0\n"
			"	nr	0,%3\n"
			"	or	0,%2\n"
			"	cs	%0,0,%4\n"
			"	jl	0b\n"
			: "=&d" (old), "=Q" (*(int *) addr)
			: "d" (x << shift), "d" (~(255 << shift)),
			  "Q" (*(int *) addr) : "memory", "cc", "0");
		return old >> shift;
	case 2:
		addr = (unsigned long) ptr;
		shift = (2 ^ (addr & 2)) << 3;
		addr ^= addr & 2;
		asm volatile(
			"	l	%0,%4\n"
			"0:	lr	0,%0\n"
			"	nr	0,%3\n"
			"	or	0,%2\n"
			"	cs	%0,0,%4\n"
			"	jl	0b\n"
			: "=&d" (old), "=Q" (*(int *) addr)
			: "d" (x << shift), "d" (~(65535 << shift)),
			  "Q" (*(int *) addr) : "memory", "cc", "0");
		return old >> shift;
	case 4:
		asm volatile(
			"	l	%0,%3\n"
			"0:	cs	%0,%2,%3\n"
			"	jl	0b\n"
			: "=&d" (old), "=Q" (*(int *) ptr)
			: "d" (x), "Q" (*(int *) ptr)
			: "memory", "cc");
		return old;
#ifdef __s390x__
	case 8:
		asm volatile(
			"	lg	%0,%3\n"
			"0:	csg	%0,%2,%3\n"
			"	jl	0b\n"
			: "=&d" (old), "=m" (*(long *) ptr)
			: "d" (x), "Q" (*(long *) ptr)
			: "memory", "cc");
		return old;
#endif /* __s390x__ */
	}
	__xchg_called_with_bad_pointer();
	return x;
}

/*
 * Atomic compare and exchange.  Compare OLD with MEM, if identical,
 * store NEW in MEM.  Return the initial value in MEM.  Success is
 * indicated by comparing RETURN with OLD.
 */

#define __HAVE_ARCH_CMPXCHG 1

#define cmpxchg(ptr, o, n)						\
	((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o),	\
					(unsigned long)(n), sizeof(*(ptr))))

extern void __cmpxchg_called_with_bad_pointer(void);

static inline unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
{
	unsigned long addr, prev, tmp;
	int shift;

        switch (size) {
	case 1:
		addr = (unsigned long) ptr;
		shift = (3 ^ (addr & 3)) << 3;
		addr ^= addr & 3;
		asm volatile(
			"	l	%0,%2\n"
			"0:	nr	%0,%5\n"
			"	lr	%1,%0\n"
			"	or	%0,%3\n"
			"	or	%1,%4\n"
			"	cs	%0,%1,%2\n"
			"	jnl	1f\n"
			"	xr	%1,%0\n"
			"	nr	%1,%5\n"
			"	jnz	0b\n"
			"1:"
			: "=&d" (prev), "=&d" (tmp), "=Q" (*(int *) ptr)
			: "d" (old << shift), "d" (new << shift),
			  "d" (~(255 << shift)), "Q" (*(int *) ptr)
			: "memory", "cc");
		return prev >> shift;
	case 2:
		addr = (unsigned long) ptr;
		shift = (2 ^ (addr & 2)) << 3;
		addr ^= addr & 2;
		asm volatile(
			"	l	%0,%2\n"
			"0:	nr	%0,%5\n"
			"	lr	%1,%0\n"
			"	or	%0,%3\n"
			"	or	%1,%4\n"
			"	cs	%0,%1,%2\n"
			"	jnl	1f\n"
			"	xr	%1,%0\n"
			"	nr	%1,%5\n"
			"	jnz	0b\n"
			"1:"
			: "=&d" (prev), "=&d" (tmp), "=Q" (*(int *) ptr)
			: "d" (old << shift), "d" (new << shift),
			  "d" (~(65535 << shift)), "Q" (*(int *) ptr)
			: "memory", "cc");
		return prev >> shift;
	case 4:
		asm volatile(
			"	cs	%0,%3,%1\n"
			: "=&d" (prev), "=Q" (*(int *) ptr)
			: "0" (old), "d" (new), "Q" (*(int *) ptr)
			: "memory", "cc");
		return prev;
#ifdef __s390x__
	case 8:
		asm volatile(
			"	csg	%0,%3,%1\n"
			: "=&d" (prev), "=Q" (*(long *) ptr)
			: "0" (old), "d" (new), "Q" (*(long *) ptr)
			: "memory", "cc");
		return prev;
#endif /* __s390x__ */
        }
	__cmpxchg_called_with_bad_pointer();
	return old;
}

/*
 * 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);	\
})

#include <linux/irqflags.h>

#include <asm-generic/cmpxchg-local.h>

static inline unsigned long __cmpxchg_local(volatile void *ptr,
				      unsigned long old,
				      unsigned long new, int size)
{
	switch (size) {
	case 1:
	case 2:
	case 4:
#ifdef __s390x__
	case 8:
#endif
		return __cmpxchg(ptr, old, new, size);
	default:
		return __cmpxchg_local_generic(ptr, old, new, size);
	}

	return old;
}

/*
 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 * them available.
 */
#define cmpxchg_local(ptr, o, n)					\
	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\
			(unsigned long)(n), sizeof(*(ptr))))
#ifdef __s390x__
#define cmpxchg64_local(ptr, o, n)					\
  ({									\
	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
	cmpxchg_local((ptr), (o), (n));					\
  })
#else
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
#endif

/*
 * 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)
#define local_mcck_disable() __set_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK)

#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