[deliverable/linux.git] / include / asm-arm / system.h

#ifndef __ASM_ARM_SYSTEM_H
#define __ASM_ARM_SYSTEM_H

#ifdef __KERNEL__

#include <asm/memory.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
#define CPU_ARCH_ARMv7		9

/*
 * 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

#ifdef CONFIG_CPU_CP15
#define read_cpuid(reg)							\
	({								\
		unsigned int __val;					\
		asm("mrc	p15, 0, %0, c0, c0, " __stringify(reg)	\
		    : "=r" (__val)					\
		    :							\
		    : "cc");						\
		__val;							\
	})
#else
#define read_cpuid(reg) (processor_id)
#endif

/*
 * 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>
#include <linux/irqflags.h>

#define __exception	__attribute__((section(".exception.text")))

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));

struct siginfo;
void arm_notify_die(const char *str, struct pt_regs *regs, struct siginfo *info,
		unsigned long err, unsigned long trap);

void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
				       struct pt_regs *),
		     int sig, const char *name);

#define xchg(ptr,x) \
	((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

extern asmlinkage void __backtrace(void);
extern asmlinkage void c_backtrace(unsigned long fp, int pmode);

struct mm_struct;
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);

void arm_machine_restart(char mode);
extern void (*arm_pm_restart)(char str);

/*
 * Intel's XScale3 core supports some v6 features (supersections, L2)
 * but advertises itself as v5 as it does not support the v6 ISA.  For
 * this reason, we need a way to explicitly test for this type of CPU.
 */
#ifndef CONFIG_CPU_XSC3
#define cpu_is_xsc3()	0
#else
static inline int cpu_is_xsc3(void)
{
	extern unsigned int processor_id;

	if ((processor_id & 0xffffe000) == 0x69056000)
		return 1;

	return 0;
}
#endif

#if !defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_CPU_XSC3)
#define	cpu_is_xscale()	0
#else
#define	cpu_is_xscale()	1
#endif

#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

#if __LINUX_ARM_ARCH__ >= 7
#define isb() __asm__ __volatile__ ("isb" : : : "memory")
#define dsb() __asm__ __volatile__ ("dsb" : : : "memory")
#define dmb() __asm__ __volatile__ ("dmb" : : : "memory")
#elif defined(CONFIG_CPU_XSC3) || __LINUX_ARM_ARCH__ == 6
#define isb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c5, 4" \
				    : : "r" (0) : "memory")
#define dsb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
				    : : "r" (0) : "memory")
#define dmb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" \
				    : : "r" (0) : "memory")
#else
#define isb() __asm__ __volatile__ ("" : : : "memory")
#define dsb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
				    : : "r" (0) : "memory")
#define dmb() __asm__ __volatile__ ("" : : : "memory")
#endif

#ifndef CONFIG_SMP
#define mb()	do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
#define rmb()	do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
#define wmb()	do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
#define smp_mb()	barrier()
#define smp_rmb()	barrier()
#define smp_wmb()	barrier()
#else
#define mb()		dmb()
#define rmb()		dmb()
#define wmb()		dmb()
#define smp_mb()	dmb()
#define smp_rmb()	dmb()
#define smp_wmb()	dmb()
#endif
#define read_barrier_depends()		do { } while(0)
#define smp_read_barrier_depends()	do { } while(0)

#define set_mb(var, value)	do { var = value; smp_mb(); } while (0)
#define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");

extern unsigned long cr_no_alignment;	/* defined in entry-armv.S */
extern unsigned long cr_alignment;	/* defined in entry-armv.S */

static inline unsigned int get_cr(void)
{
	unsigned int val;
	asm("mrc p15, 0, %0, c1, c0, 0	@ get CR" : "=r" (val) : : "cc");
	return val;
}

static inline void set_cr(unsigned int val)
{
	asm volatile("mcr p15, 0, %0, c1, c0, 0	@ set CR"
	  : : "r" (val) : "cc");
	isb();
}

#ifndef CONFIG_SMP
extern void adjust_cr(unsigned long mask, unsigned long set);
#endif

#define CPACC_FULL(n)		(3 << (n * 2))
#define CPACC_SVC(n)		(1 << (n * 2))
#define CPACC_DISABLE(n)	(0 << (n * 2))

static inline unsigned int get_copro_access(void)
{
	unsigned int val;
	asm("mrc p15, 0, %0, c1, c0, 2 @ get copro access"
	  : "=r" (val) : : "cc");
	return val;
}

static inline void set_copro_access(unsigned int val)
{
	asm volatile("mcr p15, 0, %0, c1, c0, 2 @ set copro access"
	  : : "r" (val) : "cc");
	isb();
}

/*
 * 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,task_thread_info(prev), task_thread_info(next));	\
} 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.
 *
 * NOTE that this solution won't work on an SMP system, so explcitly
 * forbid it here.
 */
#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
#if __LINUX_ARM_ARCH__ >= 6
	unsigned int tmp;
#endif

	switch (size) {
#if __LINUX_ARM_ARCH__ >= 6
	case 1:
		asm volatile("@	__xchg1\n"
		"1:	ldrexb	%0, [%3]\n"
		"	strexb	%1, %2, [%3]\n"
		"	teq	%1, #0\n"
		"	bne	1b"
			: "=&r" (ret), "=&r" (tmp)
			: "r" (x), "r" (ptr)
			: "memory", "cc");
		break;
	case 4:
		asm volatile("@	__xchg4\n"
		"1:	ldrex	%0, [%3]\n"
		"	strex	%1, %2, [%3]\n"
		"	teq	%1, #0\n"
		"	bne	1b"
			: "=&r" (ret), "=&r" (tmp)
			: "r" (x), "r" (ptr)
			: "memory", "cc");
		break;
#elif defined(swp_is_buggy)
#ifdef CONFIG_SMP
#error SMP is not supported on this platform
#endif
	case 1:
		raw_local_irq_save(flags);
		ret = *(volatile unsigned char *)ptr;
		*(volatile unsigned char *)ptr = x;
		raw_local_irq_restore(flags);
		break;

	case 4:
		raw_local_irq_save(flags);
		ret = *(volatile unsigned long *)ptr;
		*(volatile unsigned long *)ptr = x;
		raw_local_irq_restore(flags);
		break;
#else
	case 1:
		asm volatile("@	__xchg1\n"
		"	swpb	%0, %1, [%2]"
			: "=&r" (ret)
			: "r" (x), "r" (ptr)
			: "memory", "cc");
		break;
	case 4:
		asm volatile("@	__xchg4\n"
		"	swp	%0, %1, [%2]"
			: "=&r" (ret)
			: "r" (x), "r" (ptr)
			: "memory", "cc");
		break;
#endif
	default:
		__bad_xchg(ptr, size), ret = 0;
		break;
	}

	return ret;
}

extern void disable_hlt(void);
extern void enable_hlt(void);

#endif /* __ASSEMBLY__ */

#define arch_align_stack(x) (x)

#endif /* __KERNEL__ */

#endif
Commit	Line	Data
1da177e4 LT	1	#ifndef __ASM_ARM_SYSTEM_H
	2	#define __ASM_ARM_SYSTEM_H
	3
	4	#ifdef __KERNEL__
	5
398e692f	6	#include <asm/memory.h>
1da177e4 LT	7
	8	#define CPU_ARCH_UNKNOWN 0
	9	#define CPU_ARCH_ARMv3 1
	10	#define CPU_ARCH_ARMv4 2
	11	#define CPU_ARCH_ARMv4T 3
	12	#define CPU_ARCH_ARMv5 4
	13	#define CPU_ARCH_ARMv5T 5
	14	#define CPU_ARCH_ARMv5TE 6
	15	#define CPU_ARCH_ARMv5TEJ 7
	16	#define CPU_ARCH_ARMv6 8
bbe88886	17	#define CPU_ARCH_ARMv7 9
1da177e4 LT	18
	19	/*
	20	* CR1 bits (CP#15 CR1)
	21	*/
	22	#define CR_M (1 << 0) /* MMU enable */
	23	#define CR_A (1 << 1) /* Alignment abort enable */
	24	#define CR_C (1 << 2) /* Dcache enable */
	25	#define CR_W (1 << 3) /* Write buffer enable */
	26	#define CR_P (1 << 4) /* 32-bit exception handler */
	27	#define CR_D (1 << 5) /* 32-bit data address range */
	28	#define CR_L (1 << 6) /* Implementation defined */
	29	#define CR_B (1 << 7) /* Big endian */
	30	#define CR_S (1 << 8) /* System MMU protection */
	31	#define CR_R (1 << 9) /* ROM MMU protection */
	32	#define CR_F (1 << 10) /* Implementation defined */
	33	#define CR_Z (1 << 11) /* Implementation defined */
	34	#define CR_I (1 << 12) /* Icache enable */
	35	#define CR_V (1 << 13) /* Vectors relocated to 0xffff0000 */
	36	#define CR_RR (1 << 14) /* Round Robin cache replacement */
	37	#define CR_L4 (1 << 15) /* LDR pc can set T bit */
	38	#define CR_DT (1 << 16)
	39	#define CR_IT (1 << 18)
	40	#define CR_ST (1 << 19)
	41	#define CR_FI (1 << 21) /* Fast interrupt (lower latency mode) */
	42	#define CR_U (1 << 22) /* Unaligned access operation */
	43	#define CR_XP (1 << 23) /* Extended page tables */
	44	#define CR_VE (1 << 24) /* Vectored interrupts */
	45
	46	#define CPUID_ID 0
	47	#define CPUID_CACHETYPE 1
	48	#define CPUID_TCM 2
	49	#define CPUID_TLBTYPE 3
	50
f12d0d7c	51	#ifdef CONFIG_CPU_CP15
1da177e4 LT	52	#define read_cpuid(reg) \
	53	({ \
	54	unsigned int __val; \
	55	asm("mrc p15, 0, %0, c0, c0, " __stringify(reg) \
	56	: "=r" (__val) \
	57	: \
	58	: "cc"); \
	59	__val; \
	60	})
f12d0d7c HC	61	#else
	62	#define read_cpuid(reg) (processor_id)
	63	#endif
1da177e4 LT	64
	65	/*
	66	* This is used to ensure the compiler did actually allocate the register we
	67	* asked it for some inline assembly sequences. Apparently we can't trust
	68	* the compiler from one version to another so a bit of paranoia won't hurt.
	69	* This string is meant to be concatenated with the inline asm string and
	70	* will cause compilation to stop on mismatch.
	71	* (for details, see gcc PR 15089)
	72	*/
	73	#define __asmeq(x, y) ".ifnc " x "," y " ; .err ; .endif\n\t"
	74
	75	#ifndef __ASSEMBLY__
	76
	77	#include <linux/linkage.h>
255d1f86	78	#include <linux/irqflags.h>
1da177e4	79
7ab3f8d5 RK	80	#define __exception __attribute__((section(".exception.text")))
7ab3f8d5 RK	81
1da177e4 LT	82	struct thread_info;
	83	struct task_struct;
	84
	85	/* information about the system we're running on */
	86	extern unsigned int system_rev;
	87	extern unsigned int system_serial_low;
	88	extern unsigned int system_serial_high;
	89	extern unsigned int mem_fclk_21285;
	90
	91	struct pt_regs;
	92
	93	void die(const char msg, struct pt_regs regs, int err)
	94	__attribute__((noreturn));
	95
cfb0810e	96	struct siginfo;
1eeb66a1	97	void arm_notify_die(const char str, struct pt_regs regs, struct siginfo *info,
cfb0810e	98	unsigned long err, unsigned long trap);
1da177e4 LT	99
	100	void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
	101	struct pt_regs *),
	102	int sig, const char *name);
	103
1da177e4 LT	104	#define xchg(ptr,x) \
	105	((__typeof__((ptr)))__xchg((unsigned long)(x),(ptr),sizeof((ptr))))
	106
1da177e4	107	extern asmlinkage void __backtrace(void);
652a12ef	108	extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
5470dc65 RK	109
5470dc65 RK	110	struct mm_struct;
652a12ef RK	111	extern void show_pte(struct mm_struct *mm, unsigned long addr);
652a12ef RK	112	extern void __show_regs(struct pt_regs *);
1da177e4 LT	113
1da177e4 LT	114	extern int cpu_architecture(void);
36c5ed23	115	extern void cpu_init(void);
1da177e4	116
74617fb6 RP	117	void arm_machine_restart(char mode);
	118	extern void (*arm_pm_restart)(char str);
	119
23bdf86a LB	120	/*
	121	* Intel's XScale3 core supports some v6 features (supersections, L2)
	122	* but advertises itself as v5 as it does not support the v6 ISA. For
	123	* this reason, we need a way to explicitly test for this type of CPU.
	124	*/
	125	#ifndef CONFIG_CPU_XSC3
	126	#define cpu_is_xsc3() 0
	127	#else
	128	static inline int cpu_is_xsc3(void)
	129	{
	130	extern unsigned int processor_id;
	131
	132	if ((processor_id & 0xffffe000) == 0x69056000)
	133	return 1;
	134
	135	return 0;
	136	}
	137	#endif
	138
5cedae9c DS	139	#if !defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_CPU_XSC3)
	140	#define cpu_is_xscale() 0
	141	#else
	142	#define cpu_is_xscale() 1
	143	#endif
	144
56660faf CM	145	#define UDBG_UNDEFINED (1 << 0)
	146	#define UDBG_SYSCALL (1 << 1)
	147	#define UDBG_BADABORT (1 << 2)
	148	#define UDBG_SEGV (1 << 3)
	149	#define UDBG_BUS (1 << 4)
	150
	151	extern unsigned int user_debug;
	152
	153	#if __LINUX_ARM_ARCH__ >= 4
	154	#define vectors_high() (cr_alignment & CR_V)
	155	#else
	156	#define vectors_high() (0)
	157	#endif
	158
56163fcf CM	159	#if __LINUX_ARM_ARCH__ >= 7
	160	#define isb() __asm__ __volatile__ ("isb" : : : "memory")
	161	#define dsb() __asm__ __volatile__ ("dsb" : : : "memory")
	162	#define dmb() __asm__ __volatile__ ("dmb" : : : "memory")
	163	#elif defined(CONFIG_CPU_XSC3) \|\| __LINUX_ARM_ARCH__ == 6
56660faf CM	164	#define isb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c5, 4" \
	165	: : "r" (0) : "memory")
	166	#define dsb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
	167	: : "r" (0) : "memory")
	168	#define dmb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" \
	169	: : "r" (0) : "memory")
	170	#else
	171	#define isb() __asm__ __volatile__ ("" : : : "memory")
	172	#define dsb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
	173	: : "r" (0) : "memory")
	174	#define dmb() __asm__ __volatile__ ("" : : : "memory")
	175	#endif
9623b373	176
398e692f LB	177	#ifndef CONFIG_SMP
	178	#define mb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
	179	#define rmb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
	180	#define wmb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
	181	#define smp_mb() barrier()
	182	#define smp_rmb() barrier()
	183	#define smp_wmb() barrier()
9623b373	184	#else
398e692f LB	185	#define mb() dmb()
	186	#define rmb() dmb()
	187	#define wmb() dmb()
	188	#define smp_mb() dmb()
	189	#define smp_rmb() dmb()
	190	#define smp_wmb() dmb()
	191	#endif
	192	#define read_barrier_depends() do { } while(0)
	193	#define smp_read_barrier_depends() do { } while(0)
9623b373 CM	194
9623b373 CM	195	#define set_mb(var, value) do { var = value; smp_mb(); } while (0)
56660faf CM	196	#define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
56660faf CM	197
255d1f86 RK	198	extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
	199	extern unsigned long cr_alignment; /* defined in entry-armv.S */
	200
efe90d27 RK	201	static inline unsigned int get_cr(void)
	202	{
	203	unsigned int val;
	204	asm("mrc p15, 0, %0, c1, c0, 0 @ get CR" : "=r" (val) : : "cc");
	205	return val;
	206	}
	207
	208	static inline void set_cr(unsigned int val)
	209	{
	210	asm volatile("mcr p15, 0, %0, c1, c0, 0 @ set CR"
	211	: : "r" (val) : "cc");
56660faf	212	isb();
efe90d27 RK	213	}
efe90d27 RK	214
255d1f86 RK	215	#ifndef CONFIG_SMP
	216	extern void adjust_cr(unsigned long mask, unsigned long set);
	217	#endif
	218
efe90d27 RK	219	#define CPACC_FULL(n) (3 << (n * 2))
	220	#define CPACC_SVC(n) (1 << (n * 2))
	221	#define CPACC_DISABLE(n) (0 << (n * 2))
	222
	223	static inline unsigned int get_copro_access(void)
	224	{
	225	unsigned int val;
	226	asm("mrc p15, 0, %0, c1, c0, 2 @ get copro access"
	227	: "=r" (val) : : "cc");
	228	return val;
	229	}
	230
	231	static inline void set_copro_access(unsigned int val)
	232	{
	233	asm volatile("mcr p15, 0, %0, c1, c0, 2 @ set copro access"
	234	: : "r" (val) : "cc");
56660faf	235	isb();
efe90d27	236	}
1da177e4	237
1da177e4	238	/*
4866cde0 NP	239	* switch_mm() may do a full cache flush over the context switch,
	240	* so enable interrupts over the context switch to avoid high
	241	* latency.
1da177e4	242	*/
4866cde0	243	#define __ARCH_WANT_INTERRUPTS_ON_CTXSW
1da177e4 LT	244
	245	/*
	246	* switch_to(prev, next) should switch from task `prev' to `next'
	247	* `prev' will never be the same as `next'. schedule() itself
	248	* contains the memory barrier to tell GCC not to cache `current'.
	249	*/
	250	extern struct task_struct __switch_to(struct task_struct , struct thread_info , struct thread_info );
	251
	252	#define switch_to(prev,next,last) \
	253	do { \
e7c1b32f	254	last = __switch_to(prev,task_thread_info(prev), task_thread_info(next)); \
1da177e4 LT	255	} while (0)
1da177e4 LT	256
1da177e4 LT	257	#if defined(CONFIG_CPU_SA1100) \|\| defined(CONFIG_CPU_SA110)
	258	/*
	259	* On the StrongARM, "swp" is terminally broken since it bypasses the
	260	* cache totally. This means that the cache becomes inconsistent, and,
	261	* since we use normal loads/stores as well, this is really bad.
	262	* Typically, this causes oopsen in filp_close, but could have other,
	263	* more disasterous effects. There are two work-arounds:
	264	* 1. Disable interrupts and emulate the atomic swap
	265	* 2. Clean the cache, perform atomic swap, flush the cache
	266	*
	267	* We choose (1) since its the "easiest" to achieve here and is not
	268	* dependent on the processor type.
053a7b5b RK	269	*
	270	* NOTE that this solution won't work on an SMP system, so explcitly
	271	* forbid it here.
1da177e4 LT	272	*/
	273	#define swp_is_buggy
	274	#endif
	275
	276	static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
	277	{
	278	extern void __bad_xchg(volatile void *, int);
	279	unsigned long ret;
	280	#ifdef swp_is_buggy
	281	unsigned long flags;
	282	#endif
9560782f RK	283	#if __LINUX_ARM_ARCH__ >= 6
	284	unsigned int tmp;
	285	#endif
1da177e4 LT	286
1da177e4 LT	287	switch (size) {
9560782f RK	288	#if __LINUX_ARM_ARCH__ >= 6
	289	case 1:
	290	asm volatile("@ __xchg1\n"
	291	"1: ldrexb %0, [%3]\n"
	292	" strexb %1, %2, [%3]\n"
	293	" teq %1, #0\n"
	294	" bne 1b"
	295	: "=&r" (ret), "=&r" (tmp)
	296	: "r" (x), "r" (ptr)
	297	: "memory", "cc");
	298	break;
	299	case 4:
	300	asm volatile("@ __xchg4\n"
	301	"1: ldrex %0, [%3]\n"
	302	" strex %1, %2, [%3]\n"
	303	" teq %1, #0\n"
	304	" bne 1b"
	305	: "=&r" (ret), "=&r" (tmp)
	306	: "r" (x), "r" (ptr)
	307	: "memory", "cc");
	308	break;
	309	#elif defined(swp_is_buggy)
	310	#ifdef CONFIG_SMP
	311	#error SMP is not supported on this platform
	312	#endif
	313	case 1:
e7cc2c59	314	raw_local_irq_save(flags);
9560782f RK	315	ret = (volatile unsigned char )ptr;
9560782f RK	316	(volatile unsigned char )ptr = x;
e7cc2c59	317	raw_local_irq_restore(flags);
9560782f RK	318	break;
	319
	320	case 4:
e7cc2c59	321	raw_local_irq_save(flags);
9560782f RK	322	ret = (volatile unsigned long )ptr;
9560782f RK	323	(volatile unsigned long )ptr = x;
e7cc2c59	324	raw_local_irq_restore(flags);
9560782f	325	break;
1da177e4	326	#else
9560782f RK	327	case 1:
	328	asm volatile("@ __xchg1\n"
	329	" swpb %0, %1, [%2]"
	330	: "=&r" (ret)
	331	: "r" (x), "r" (ptr)
	332	: "memory", "cc");
	333	break;
	334	case 4:
	335	asm volatile("@ __xchg4\n"
	336	" swp %0, %1, [%2]"
	337	: "=&r" (ret)
	338	: "r" (x), "r" (ptr)
	339	: "memory", "cc");
	340	break;
1da177e4	341	#endif
9560782f RK	342	default:
	343	__bad_xchg(ptr, size), ret = 0;
	344	break;
1da177e4 LT	345	}
	346
	347	return ret;
	348	}
	349
dabaeff0 BD	350	extern void disable_hlt(void);
	351	extern void enable_hlt(void);
	352
1da177e4 LT	353	#endif /* __ASSEMBLY__ */
	354
	355	#define arch_align_stack(x) (x)
	356
	357	#endif /* __KERNEL__ */
	358
	359	#endif