[GitHub/mt8127/android_kernel_alcatel_ttab.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

/*
 * 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 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))))

#define tas(ptr) (xchg((ptr),1))

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 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)

/*
 * On SMP systems, when the scheduler does migration-cost autodetection,
 * it needs a way to flush as much of the CPU's caches as possible.
 *
 * TODO: fill this in!
 */
static inline void sched_cacheflush(void)
{
}

#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
	17
	18	/*
	19	* CR1 bits (CP#15 CR1)
	20	*/
	21	#define CR_M (1 << 0) /* MMU enable */
	22	#define CR_A (1 << 1) /* Alignment abort enable */
	23	#define CR_C (1 << 2) /* Dcache enable */
	24	#define CR_W (1 << 3) /* Write buffer enable */
	25	#define CR_P (1 << 4) /* 32-bit exception handler */
	26	#define CR_D (1 << 5) /* 32-bit data address range */
	27	#define CR_L (1 << 6) /* Implementation defined */
	28	#define CR_B (1 << 7) /* Big endian */
	29	#define CR_S (1 << 8) /* System MMU protection */
	30	#define CR_R (1 << 9) /* ROM MMU protection */
	31	#define CR_F (1 << 10) /* Implementation defined */
	32	#define CR_Z (1 << 11) /* Implementation defined */
	33	#define CR_I (1 << 12) /* Icache enable */
	34	#define CR_V (1 << 13) /* Vectors relocated to 0xffff0000 */
	35	#define CR_RR (1 << 14) /* Round Robin cache replacement */
	36	#define CR_L4 (1 << 15) /* LDR pc can set T bit */
	37	#define CR_DT (1 << 16)
	38	#define CR_IT (1 << 18)
	39	#define CR_ST (1 << 19)
	40	#define CR_FI (1 << 21) /* Fast interrupt (lower latency mode) */
	41	#define CR_U (1 << 22) /* Unaligned access operation */
	42	#define CR_XP (1 << 23) /* Extended page tables */
	43	#define CR_VE (1 << 24) /* Vectored interrupts */
	44
	45	#define CPUID_ID 0
	46	#define CPUID_CACHETYPE 1
	47	#define CPUID_TCM 2
	48	#define CPUID_TLBTYPE 3
	49
f12d0d7c	50	#ifdef CONFIG_CPU_CP15
1da177e4 LT	51	#define read_cpuid(reg) \
	52	({ \
	53	unsigned int __val; \
	54	asm("mrc p15, 0, %0, c0, c0, " __stringify(reg) \
	55	: "=r" (__val) \
	56	: \
	57	: "cc"); \
	58	__val; \
	59	})
f12d0d7c HC	60	#else
	61	#define read_cpuid(reg) (processor_id)
	62	#endif
1da177e4 LT	63
	64	/*
	65	* This is used to ensure the compiler did actually allocate the register we
	66	* asked it for some inline assembly sequences. Apparently we can't trust
	67	* the compiler from one version to another so a bit of paranoia won't hurt.
	68	* This string is meant to be concatenated with the inline asm string and
	69	* will cause compilation to stop on mismatch.
	70	* (for details, see gcc PR 15089)
	71	*/
	72	#define __asmeq(x, y) ".ifnc " x "," y " ; .err ; .endif\n\t"
	73
	74	#ifndef __ASSEMBLY__
	75
	76	#include <linux/linkage.h>
255d1f86	77	#include <linux/irqflags.h>
1da177e4	78
7ab3f8d5 RK	79	#define __exception __attribute__((section(".exception.text")))
7ab3f8d5 RK	80
1da177e4 LT	81	struct thread_info;
	82	struct task_struct;
	83
	84	/* information about the system we're running on */
	85	extern unsigned int system_rev;
	86	extern unsigned int system_serial_low;
	87	extern unsigned int system_serial_high;
	88	extern unsigned int mem_fclk_21285;
	89
	90	struct pt_regs;
	91
	92	void die(const char msg, struct pt_regs regs, int err)
	93	__attribute__((noreturn));
	94
cfb0810e RK	95	struct siginfo;
	96	void notify_die(const char str, struct pt_regs regs, struct siginfo *info,
	97	unsigned long err, unsigned long trap);
1da177e4 LT	98
	99	void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
	100	struct pt_regs *),
	101	int sig, const char *name);
	102
1da177e4 LT	103	#define xchg(ptr,x) \
	104	((__typeof__((ptr)))__xchg((unsigned long)(x),(ptr),sizeof((ptr))))
	105
	106	#define tas(ptr) (xchg((ptr),1))
	107
	108	extern asmlinkage void __backtrace(void);
652a12ef	109	extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
5470dc65 RK	110
5470dc65 RK	111	struct mm_struct;
652a12ef RK	112	extern void show_pte(struct mm_struct *mm, unsigned long addr);
652a12ef RK	113	extern void __show_regs(struct pt_regs *);
1da177e4 LT	114
1da177e4 LT	115	extern int cpu_architecture(void);
36c5ed23	116	extern void cpu_init(void);
1da177e4	117
74617fb6 RP	118	void arm_machine_restart(char mode);
	119	extern void (*arm_pm_restart)(char str);
	120
23bdf86a LB	121	/*
	122	* Intel's XScale3 core supports some v6 features (supersections, L2)
	123	* but advertises itself as v5 as it does not support the v6 ISA. For
	124	* this reason, we need a way to explicitly test for this type of CPU.
	125	*/
	126	#ifndef CONFIG_CPU_XSC3
	127	#define cpu_is_xsc3() 0
	128	#else
	129	static inline int cpu_is_xsc3(void)
	130	{
	131	extern unsigned int processor_id;
	132
	133	if ((processor_id & 0xffffe000) == 0x69056000)
	134	return 1;
	135
	136	return 0;
	137	}
	138	#endif
	139
5cedae9c DS	140	#if !defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_CPU_XSC3)
	141	#define cpu_is_xscale() 0
	142	#else
	143	#define cpu_is_xscale() 1
	144	#endif
	145
56660faf CM	146	#define UDBG_UNDEFINED (1 << 0)
	147	#define UDBG_SYSCALL (1 << 1)
	148	#define UDBG_BADABORT (1 << 2)
	149	#define UDBG_SEGV (1 << 3)
	150	#define UDBG_BUS (1 << 4)
	151
	152	extern unsigned int user_debug;
	153
	154	#if __LINUX_ARM_ARCH__ >= 4
	155	#define vectors_high() (cr_alignment & CR_V)
	156	#else
	157	#define vectors_high() (0)
	158	#endif
	159
398e692f	160	#if defined(CONFIG_CPU_XSC3) \|\| __LINUX_ARM_ARCH__ >= 6
56660faf CM	161	#define isb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c5, 4" \
	162	: : "r" (0) : "memory")
	163	#define dsb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
	164	: : "r" (0) : "memory")
	165	#define dmb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" \
	166	: : "r" (0) : "memory")
	167	#else
	168	#define isb() __asm__ __volatile__ ("" : : : "memory")
	169	#define dsb() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 4" \
	170	: : "r" (0) : "memory")
	171	#define dmb() __asm__ __volatile__ ("" : : : "memory")
	172	#endif
9623b373	173
398e692f LB	174	#ifndef CONFIG_SMP
	175	#define mb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
	176	#define rmb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
	177	#define wmb() do { if (arch_is_coherent()) dmb(); else barrier(); } while (0)
	178	#define smp_mb() barrier()
	179	#define smp_rmb() barrier()
	180	#define smp_wmb() barrier()
9623b373	181	#else
398e692f LB	182	#define mb() dmb()
	183	#define rmb() dmb()
	184	#define wmb() dmb()
	185	#define smp_mb() dmb()
	186	#define smp_rmb() dmb()
	187	#define smp_wmb() dmb()
	188	#endif
	189	#define read_barrier_depends() do { } while(0)
	190	#define smp_read_barrier_depends() do { } while(0)
9623b373 CM	191
9623b373 CM	192	#define set_mb(var, value) do { var = value; smp_mb(); } while (0)
56660faf CM	193	#define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
56660faf CM	194
255d1f86 RK	195	extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
	196	extern unsigned long cr_alignment; /* defined in entry-armv.S */
	197
efe90d27 RK	198	static inline unsigned int get_cr(void)
	199	{
	200	unsigned int val;
	201	asm("mrc p15, 0, %0, c1, c0, 0 @ get CR" : "=r" (val) : : "cc");
	202	return val;
	203	}
	204
	205	static inline void set_cr(unsigned int val)
	206	{
	207	asm volatile("mcr p15, 0, %0, c1, c0, 0 @ set CR"
	208	: : "r" (val) : "cc");
56660faf	209	isb();
efe90d27 RK	210	}
efe90d27 RK	211
255d1f86 RK	212	#ifndef CONFIG_SMP
	213	extern void adjust_cr(unsigned long mask, unsigned long set);
	214	#endif
	215
efe90d27 RK	216	#define CPACC_FULL(n) (3 << (n * 2))
	217	#define CPACC_SVC(n) (1 << (n * 2))
	218	#define CPACC_DISABLE(n) (0 << (n * 2))
	219
	220	static inline unsigned int get_copro_access(void)
	221	{
	222	unsigned int val;
	223	asm("mrc p15, 0, %0, c1, c0, 2 @ get copro access"
	224	: "=r" (val) : : "cc");
	225	return val;
	226	}
	227
	228	static inline void set_copro_access(unsigned int val)
	229	{
	230	asm volatile("mcr p15, 0, %0, c1, c0, 2 @ set copro access"
	231	: : "r" (val) : "cc");
56660faf	232	isb();
efe90d27	233	}
1da177e4	234
1da177e4	235	/*
4866cde0 NP	236	* switch_mm() may do a full cache flush over the context switch,
	237	* so enable interrupts over the context switch to avoid high
	238	* latency.
1da177e4	239	*/
4866cde0	240	#define __ARCH_WANT_INTERRUPTS_ON_CTXSW
1da177e4 LT	241
	242	/*
	243	* switch_to(prev, next) should switch from task `prev' to `next'
	244	* `prev' will never be the same as `next'. schedule() itself
	245	* contains the memory barrier to tell GCC not to cache `current'.
	246	*/
	247	extern struct task_struct __switch_to(struct task_struct , struct thread_info , struct thread_info );
	248
	249	#define switch_to(prev,next,last) \
	250	do { \
e7c1b32f	251	last = __switch_to(prev,task_thread_info(prev), task_thread_info(next)); \
1da177e4 LT	252	} while (0)
1da177e4 LT	253
4dc7a0bb IM	254	/*
	255	* On SMP systems, when the scheduler does migration-cost autodetection,
	256	* it needs a way to flush as much of the CPU's caches as possible.
	257	*
	258	* TODO: fill this in!
	259	*/
	260	static inline void sched_cacheflush(void)
	261	{
	262	}
	263
1da177e4 LT	264	#if defined(CONFIG_CPU_SA1100) \|\| defined(CONFIG_CPU_SA110)
	265	/*
	266	* On the StrongARM, "swp" is terminally broken since it bypasses the
	267	* cache totally. This means that the cache becomes inconsistent, and,
	268	* since we use normal loads/stores as well, this is really bad.
	269	* Typically, this causes oopsen in filp_close, but could have other,
	270	* more disasterous effects. There are two work-arounds:
	271	* 1. Disable interrupts and emulate the atomic swap
	272	* 2. Clean the cache, perform atomic swap, flush the cache
	273	*
	274	* We choose (1) since its the "easiest" to achieve here and is not
	275	* dependent on the processor type.
053a7b5b RK	276	*
	277	* NOTE that this solution won't work on an SMP system, so explcitly
	278	* forbid it here.
1da177e4 LT	279	*/
	280	#define swp_is_buggy
	281	#endif
	282
	283	static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
	284	{
	285	extern void __bad_xchg(volatile void *, int);
	286	unsigned long ret;
	287	#ifdef swp_is_buggy
	288	unsigned long flags;
	289	#endif
9560782f RK	290	#if __LINUX_ARM_ARCH__ >= 6
	291	unsigned int tmp;
	292	#endif
1da177e4 LT	293
1da177e4 LT	294	switch (size) {
9560782f RK	295	#if __LINUX_ARM_ARCH__ >= 6
	296	case 1:
	297	asm volatile("@ __xchg1\n"
	298	"1: ldrexb %0, [%3]\n"
	299	" strexb %1, %2, [%3]\n"
	300	" teq %1, #0\n"
	301	" bne 1b"
	302	: "=&r" (ret), "=&r" (tmp)
	303	: "r" (x), "r" (ptr)
	304	: "memory", "cc");
	305	break;
	306	case 4:
	307	asm volatile("@ __xchg4\n"
	308	"1: ldrex %0, [%3]\n"
	309	" strex %1, %2, [%3]\n"
	310	" teq %1, #0\n"
	311	" bne 1b"
	312	: "=&r" (ret), "=&r" (tmp)
	313	: "r" (x), "r" (ptr)
	314	: "memory", "cc");
	315	break;
	316	#elif defined(swp_is_buggy)
	317	#ifdef CONFIG_SMP
	318	#error SMP is not supported on this platform
	319	#endif
	320	case 1:
e7cc2c59	321	raw_local_irq_save(flags);
9560782f RK	322	ret = (volatile unsigned char )ptr;
9560782f RK	323	(volatile unsigned char )ptr = x;
e7cc2c59	324	raw_local_irq_restore(flags);
9560782f RK	325	break;
	326
	327	case 4:
e7cc2c59	328	raw_local_irq_save(flags);
9560782f RK	329	ret = (volatile unsigned long )ptr;
9560782f RK	330	(volatile unsigned long )ptr = x;
e7cc2c59	331	raw_local_irq_restore(flags);
9560782f	332	break;
1da177e4	333	#else
9560782f RK	334	case 1:
	335	asm volatile("@ __xchg1\n"
	336	" swpb %0, %1, [%2]"
	337	: "=&r" (ret)
	338	: "r" (x), "r" (ptr)
	339	: "memory", "cc");
	340	break;
	341	case 4:
	342	asm volatile("@ __xchg4\n"
	343	" swp %0, %1, [%2]"
	344	: "=&r" (ret)
	345	: "r" (x), "r" (ptr)
	346	: "memory", "cc");
	347	break;
1da177e4	348	#endif
9560782f RK	349	default:
	350	__bad_xchg(ptr, size), ret = 0;
	351	break;
1da177e4 LT	352	}
	353
	354	return ret;
	355	}
	356
dabaeff0 BD	357	extern void disable_hlt(void);
	358	extern void enable_hlt(void);
	359
1da177e4 LT	360	#endif /* __ASSEMBLY__ */
	361
	362	#define arch_align_stack(x) (x)
	363
	364	#endif /* __KERNEL__ */
	365
	366	#endif