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

#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));

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);

#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

#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)

#endif /* CONFIG_SMP */

#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:
		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("@	__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;
}

#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
	6	#include <linux/config.h>
	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
	50	#define read_cpuid(reg) \
	51	({ \
	52	unsigned int __val; \
	53	asm("mrc p15, 0, %0, c0, c0, " __stringify(reg) \
	54	: "=r" (__val) \
	55	: \
	56	: "cc"); \
	57	__val; \
	58	})
	59
	60	/*
	61	* This is used to ensure the compiler did actually allocate the register we
	62	* asked it for some inline assembly sequences. Apparently we can't trust
	63	* the compiler from one version to another so a bit of paranoia won't hurt.
	64	* This string is meant to be concatenated with the inline asm string and
65	* will cause compilation to stop on mismatch.
66	* (for details, see gcc PR 15089)
67	*/
68	#define __asmeq(x, y) ".ifnc " x "," y " ; .err ; .endif\n\t"
69
70	#ifndef __ASSEMBLY__
71
72	#include <linux/linkage.h>
73
74	struct thread_info;
75	struct task_struct;
76
77	/* information about the system we're running on */
78	extern unsigned int system_rev;
79	extern unsigned int system_serial_low;
80	extern unsigned int system_serial_high;
81	extern unsigned int mem_fclk_21285;
82
83	struct pt_regs;
84
85	void die(const char msg, struct pt_regs regs, int err)
86	__attribute__((noreturn));
87
cfb0810e RK	88	struct siginfo;
	89	void notify_die(const char str, struct pt_regs regs, struct siginfo *info,
	90	unsigned long err, unsigned long trap);
1da177e4 LT	91
	92	void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
	93	struct pt_regs *),
	94	int sig, const char *name);
	95
	96	#include <asm/proc-fns.h>
	97
	98	#define xchg(ptr,x) \
	99	((__typeof__((ptr)))__xchg((unsigned long)(x),(ptr),sizeof((ptr))))
	100
	101	#define tas(ptr) (xchg((ptr),1))
	102
	103	extern asmlinkage void __backtrace(void);
652a12ef RK	104	extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
	105	extern void show_pte(struct mm_struct *mm, unsigned long addr);
	106	extern void __show_regs(struct pt_regs *);
1da177e4 LT	107
1da177e4 LT	108	extern int cpu_architecture(void);
36c5ed23	109	extern void cpu_init(void);
1da177e4 LT	110
	111	#define set_cr(x) \
	112	__asm__ __volatile__( \
	113	"mcr p15, 0, %0, c1, c0, 0 @ set CR" \
	114	: : "r" (x) : "cc")
	115
	116	#define get_cr() \
	117	({ \
	118	unsigned int __val; \
	119	__asm__ __volatile__( \
	120	"mrc p15, 0, %0, c1, c0, 0 @ get CR" \
	121	: "=r" (__val) : : "cc"); \
	122	__val; \
	123	})
	124
	125	extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
	126	extern unsigned long cr_alignment; /* defined in entry-armv.S */
	127
	128	#define UDBG_UNDEFINED (1 << 0)
	129	#define UDBG_SYSCALL (1 << 1)
	130	#define UDBG_BADABORT (1 << 2)
	131	#define UDBG_SEGV (1 << 3)
	132	#define UDBG_BUS (1 << 4)
	133
	134	extern unsigned int user_debug;
	135
	136	#if __LINUX_ARM_ARCH__ >= 4
	137	#define vectors_high() (cr_alignment & CR_V)
	138	#else
	139	#define vectors_high() (0)
	140	#endif
	141
	142	#define mb() __asm__ __volatile__ ("" : : : "memory")
	143	#define rmb() mb()
	144	#define wmb() mb()
	145	#define read_barrier_depends() do { } while(0)
	146	#define set_mb(var, value) do { var = value; mb(); } while (0)
	147	#define set_wmb(var, value) do { var = value; wmb(); } while (0)
	148	#define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
	149
1da177e4	150	/*
4866cde0 NP	151	* switch_mm() may do a full cache flush over the context switch,
	152	* so enable interrupts over the context switch to avoid high
	153	* latency.
1da177e4	154	*/
4866cde0	155	#define __ARCH_WANT_INTERRUPTS_ON_CTXSW
1da177e4 LT	156
	157	/*
	158	* switch_to(prev, next) should switch from task `prev' to `next'
	159	* `prev' will never be the same as `next'. schedule() itself
	160	* contains the memory barrier to tell GCC not to cache `current'.
	161	*/
	162	extern struct task_struct __switch_to(struct task_struct , struct thread_info , struct thread_info );
	163
	164	#define switch_to(prev,next,last) \
	165	do { \
	166	last = __switch_to(prev,prev->thread_info,next->thread_info); \
	167	} while (0)
	168
	169	/*
	170	* CPU interrupt mask handling.
	171	*/
	172	#if __LINUX_ARM_ARCH__ >= 6
	173
	174	#define local_irq_save(x) \
	175	({ \
	176	__asm__ __volatile__( \
	177	"mrs %0, cpsr @ local_irq_save\n" \
	178	"cpsid i" \
	179	: "=r" (x) : : "memory", "cc"); \
	180	})
	181
	182	#define local_irq_enable() __asm__("cpsie i @ __sti" : : : "memory", "cc")
	183	#define local_irq_disable() __asm__("cpsid i @ __cli" : : : "memory", "cc")
	184	#define local_fiq_enable() __asm__("cpsie f @ __stf" : : : "memory", "cc")
	185	#define local_fiq_disable() __asm__("cpsid f @ __clf" : : : "memory", "cc")
	186
	187	#else
	188
	189	/*
	190	* Save the current interrupt enable state & disable IRQs
	191	*/
	192	#define local_irq_save(x) \
	193	({ \
	194	unsigned long temp; \
	195	(void) (&temp == &x); \
	196	__asm__ __volatile__( \
	197	"mrs %0, cpsr @ local_irq_save\n" \
	198	" orr %1, %0, #128\n" \
	199	" msr cpsr_c, %1" \
	200	: "=r" (x), "=r" (temp) \
	201	: \
	202	: "memory", "cc"); \
	203	})
	204
	205	/*
	206	* Enable IRQs
	207	*/
	208	#define local_irq_enable() \
	209	({ \
	210	unsigned long temp; \
	211	__asm__ __volatile__( \
	212	"mrs %0, cpsr @ local_irq_enable\n" \
	213	" bic %0, %0, #128\n" \
	214	" msr cpsr_c, %0" \
	215	: "=r" (temp) \
	216	: \
	217	: "memory", "cc"); \
	218	})
	219
220	/*
221	* Disable IRQs
222	*/
223	#define local_irq_disable() \
224	({ \
225	unsigned long temp; \
226	__asm__ __volatile__( \
227	"mrs %0, cpsr @ local_irq_disable\n" \
228	" orr %0, %0, #128\n" \
229	" msr cpsr_c, %0" \
230	: "=r" (temp) \
231	: \
232	: "memory", "cc"); \
233	})
234
235	/*
236	* Enable FIQs
237	*/
238	#define local_fiq_enable() \
239	({ \
240	unsigned long temp; \
241	__asm__ __volatile__( \
242	"mrs %0, cpsr @ stf\n" \
243	" bic %0, %0, #64\n" \
244	" msr cpsr_c, %0" \
245	: "=r" (temp) \
246	: \
247	: "memory", "cc"); \
248	})
249
250	/*
251	* Disable FIQs
252	*/
253	#define local_fiq_disable() \
254	({ \
255	unsigned long temp; \
256	__asm__ __volatile__( \
257	"mrs %0, cpsr @ clf\n" \
258	" orr %0, %0, #64\n" \
259	" msr cpsr_c, %0" \
260	: "=r" (temp) \
261	: \
262	: "memory", "cc"); \
263	})
264
265	#endif
266
267	/*
268	* Save the current interrupt enable state.
269	*/
270	#define local_save_flags(x) \
271	({ \
272	__asm__ __volatile__( \
273	"mrs %0, cpsr @ local_save_flags" \
274	: "=r" (x) : : "memory", "cc"); \
275	})
276
277	/*
278	* restore saved IRQ & FIQ state
279	*/
280	#define local_irq_restore(x) \
281	__asm__ __volatile__( \
282	"msr cpsr_c, %0 @ local_irq_restore\n" \
283	: \
284	: "r" (x) \
285	: "memory", "cc")
286
287	#define irqs_disabled() \
288	({ \
289	unsigned long flags; \
290	local_save_flags(flags); \
9a558cb4	291	(int)(flags & PSR_I_BIT); \
1da177e4 LT	292	})
	293
	294	#ifdef CONFIG_SMP
1da177e4 LT	295
	296	#define smp_mb() mb()
	297	#define smp_rmb() rmb()
	298	#define smp_wmb() wmb()
	299	#define smp_read_barrier_depends() read_barrier_depends()
	300
	301	#else
	302
	303	#define smp_mb() barrier()
	304	#define smp_rmb() barrier()
	305	#define smp_wmb() barrier()
	306	#define smp_read_barrier_depends() do { } while(0)
	307
053a7b5b RK	308	#endif /* CONFIG_SMP */
053a7b5b RK	309
1da177e4 LT	310	#if defined(CONFIG_CPU_SA1100) \|\| defined(CONFIG_CPU_SA110)
	311	/*
	312	* On the StrongARM, "swp" is terminally broken since it bypasses the
	313	* cache totally. This means that the cache becomes inconsistent, and,
	314	* since we use normal loads/stores as well, this is really bad.
	315	* Typically, this causes oopsen in filp_close, but could have other,
	316	* more disasterous effects. There are two work-arounds:
	317	* 1. Disable interrupts and emulate the atomic swap
	318	* 2. Clean the cache, perform atomic swap, flush the cache
	319	*
	320	* We choose (1) since its the "easiest" to achieve here and is not
	321	* dependent on the processor type.
053a7b5b RK	322	*
	323	* NOTE that this solution won't work on an SMP system, so explcitly
	324	* forbid it here.
1da177e4 LT	325	*/
	326	#define swp_is_buggy
	327	#endif
	328
	329	static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
	330	{
	331	extern void __bad_xchg(volatile void *, int);
	332	unsigned long ret;
	333	#ifdef swp_is_buggy
	334	unsigned long flags;
	335	#endif
9560782f RK	336	#if __LINUX_ARM_ARCH__ >= 6
	337	unsigned int tmp;
	338	#endif
1da177e4 LT	339
1da177e4 LT	340	switch (size) {
9560782f RK	341	#if __LINUX_ARM_ARCH__ >= 6
	342	case 1:
	343	asm volatile("@ __xchg1\n"
	344	"1: ldrexb %0, [%3]\n"
	345	" strexb %1, %2, [%3]\n"
	346	" teq %1, #0\n"
	347	" bne 1b"
	348	: "=&r" (ret), "=&r" (tmp)
	349	: "r" (x), "r" (ptr)
	350	: "memory", "cc");
	351	break;
	352	case 4:
	353	asm volatile("@ __xchg4\n"
	354	"1: ldrex %0, [%3]\n"
	355	" strex %1, %2, [%3]\n"
	356	" teq %1, #0\n"
	357	" bne 1b"
	358	: "=&r" (ret), "=&r" (tmp)
	359	: "r" (x), "r" (ptr)
	360	: "memory", "cc");
	361	break;
	362	#elif defined(swp_is_buggy)
	363	#ifdef CONFIG_SMP
	364	#error SMP is not supported on this platform
	365	#endif
	366	case 1:
	367	local_irq_save(flags);
	368	ret = (volatile unsigned char )ptr;
	369	(volatile unsigned char )ptr = x;
	370	local_irq_restore(flags);
	371	break;
	372
	373	case 4:
	374	local_irq_save(flags);
	375	ret = (volatile unsigned long )ptr;
	376	(volatile unsigned long )ptr = x;
	377	local_irq_restore(flags);
	378	break;
1da177e4	379	#else
9560782f RK	380	case 1:
	381	asm volatile("@ __xchg1\n"
	382	" swpb %0, %1, [%2]"
	383	: "=&r" (ret)
	384	: "r" (x), "r" (ptr)
	385	: "memory", "cc");
	386	break;
	387	case 4:
	388	asm volatile("@ __xchg4\n"
	389	" swp %0, %1, [%2]"
	390	: "=&r" (ret)
	391	: "r" (x), "r" (ptr)
	392	: "memory", "cc");
	393	break;
1da177e4	394	#endif
9560782f RK	395	default:
	396	__bad_xchg(ptr, size), ret = 0;
	397	break;
1da177e4 LT	398	}
	399
	400	return ret;
	401	}
	402
1da177e4 LT	403	#endif /* __ASSEMBLY__ */
	404
	405	#define arch_align_stack(x) (x)
	406
	407	#endif /* __KERNEL__ */
	408
	409	#endif