[deliverable/linux.git] / arch / sparc64 / mm / tsb.c

/* arch/sparc64/mm/tsb.c
 *
 * Copyright (C) 2006 David S. Miller <davem@davemloft.net>
 */

#include <linux/kernel.h>
#include <asm/system.h>
#include <asm/page.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tsb.h>

extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];

static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long nentries)
{
	vaddr >>= PAGE_SHIFT;
	return vaddr & (nentries - 1);
}

static inline int tag_compare(unsigned long tag, unsigned long vaddr, unsigned long context)
{
	return (tag == ((vaddr >> 22) | (context << 48)));
}

/* TSB flushes need only occur on the processor initiating the address
 * space modification, not on each cpu the address space has run on.
 * Only the TLB flush needs that treatment.
 */

void flush_tsb_kernel_range(unsigned long start, unsigned long end)
{
	unsigned long v;

	for (v = start; v < end; v += PAGE_SIZE) {
		unsigned long hash = tsb_hash(v, KERNEL_TSB_NENTRIES);
		struct tsb *ent = &swapper_tsb[hash];

		if (tag_compare(ent->tag, v, 0)) {
			ent->tag = 0UL;
			membar_storeload_storestore();
		}
	}
}

void flush_tsb_user(struct mmu_gather *mp)
{
	struct mm_struct *mm = mp->mm;
	struct tsb *tsb = mm->context.tsb;
	unsigned long nentries = mm->context.tsb_nentries;
	unsigned long ctx, base;
	int i;

	if (unlikely(!CTX_VALID(mm->context)))
		return;

	ctx = CTX_HWBITS(mm->context);

	if (tlb_type == cheetah_plus)
		base = __pa(tsb);
	else
		base = (unsigned long) tsb;
	
	for (i = 0; i < mp->tlb_nr; i++) {
		unsigned long v = mp->vaddrs[i];
		unsigned long tag, ent, hash;

		v &= ~0x1UL;

		hash = tsb_hash(v, nentries);
		ent = base + (hash * sizeof(struct tsb));
		tag = (v >> 22UL) | (ctx << 48UL);

		tsb_flush(ent, tag);
	}
}

static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes)
{
	unsigned long tsb_reg, base, tsb_paddr;
	unsigned long page_sz, tte;

	mm->context.tsb_nentries = tsb_bytes / sizeof(struct tsb);

	base = TSBMAP_BASE;
	tte = (_PAGE_VALID | _PAGE_L | _PAGE_CP |
	       _PAGE_CV    | _PAGE_P | _PAGE_W);
	tsb_paddr = __pa(mm->context.tsb);
	BUG_ON(tsb_paddr & (tsb_bytes - 1UL));

	/* Use the smallest page size that can map the whole TSB
	 * in one TLB entry.
	 */
	switch (tsb_bytes) {
	case 8192 << 0:
		tsb_reg = 0x0UL;
#ifdef DCACHE_ALIASING_POSSIBLE
		base += (tsb_paddr & 8192);
#endif
		tte |= _PAGE_SZ8K;
		page_sz = 8192;
		break;

	case 8192 << 1:
		tsb_reg = 0x1UL;
		tte |= _PAGE_SZ64K;
		page_sz = 64 * 1024;
		break;

	case 8192 << 2:
		tsb_reg = 0x2UL;
		tte |= _PAGE_SZ64K;
		page_sz = 64 * 1024;
		break;

	case 8192 << 3:
		tsb_reg = 0x3UL;
		tte |= _PAGE_SZ64K;
		page_sz = 64 * 1024;
		break;

	case 8192 << 4:
		tsb_reg = 0x4UL;
		tte |= _PAGE_SZ512K;
		page_sz = 512 * 1024;
		break;

	case 8192 << 5:
		tsb_reg = 0x5UL;
		tte |= _PAGE_SZ512K;
		page_sz = 512 * 1024;
		break;

	case 8192 << 6:
		tsb_reg = 0x6UL;
		tte |= _PAGE_SZ512K;
		page_sz = 512 * 1024;
		break;

	case 8192 << 7:
		tsb_reg = 0x7UL;
		tte |= _PAGE_SZ4MB;
		page_sz = 4 * 1024 * 1024;
		break;

	default:
		BUG();
	};

	if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
		/* Physical mapping, no locked TLB entry for TSB.  */
		tsb_reg |= tsb_paddr;

		mm->context.tsb_reg_val = tsb_reg;
		mm->context.tsb_map_vaddr = 0;
		mm->context.tsb_map_pte = 0;
	} else {
		tsb_reg |= base;
		tsb_reg |= (tsb_paddr & (page_sz - 1UL));
		tte |= (tsb_paddr & ~(page_sz - 1UL));

		mm->context.tsb_reg_val = tsb_reg;
		mm->context.tsb_map_vaddr = base;
		mm->context.tsb_map_pte = tte;
	}

	/* Setup the Hypervisor TSB descriptor.  */
	if (tlb_type == hypervisor) {
		struct hv_tsb_descr *hp = &mm->context.tsb_descr;

		switch (PAGE_SIZE) {
		case 8192:
		default:
			hp->pgsz_idx = HV_PGSZ_IDX_8K;
			break;

		case 64 * 1024:
			hp->pgsz_idx = HV_PGSZ_IDX_64K;
			break;

		case 512 * 1024:
			hp->pgsz_idx = HV_PGSZ_IDX_512K;
			break;

		case 4 * 1024 * 1024:
			hp->pgsz_idx = HV_PGSZ_IDX_4MB;
			break;
		};
		hp->assoc = 1;
		hp->num_ttes = tsb_bytes / 16;
		hp->ctx_idx = 0;
		switch (PAGE_SIZE) {
		case 8192:
		default:
			hp->pgsz_mask = HV_PGSZ_MASK_8K;
			break;

		case 64 * 1024:
			hp->pgsz_mask = HV_PGSZ_MASK_64K;
			break;

		case 512 * 1024:
			hp->pgsz_mask = HV_PGSZ_MASK_512K;
			break;

		case 4 * 1024 * 1024:
			hp->pgsz_mask = HV_PGSZ_MASK_4MB;
			break;
		};
		hp->tsb_base = tsb_paddr;
		hp->resv = 0;
	}
}

/* The page tables are locked against modifications while this
 * runs.
 *
 * XXX do some prefetching...
 */
static void copy_tsb(struct tsb *old_tsb, unsigned long old_size,
		     struct tsb *new_tsb, unsigned long new_size)
{
	unsigned long old_nentries = old_size / sizeof(struct tsb);
	unsigned long new_nentries = new_size / sizeof(struct tsb);
	unsigned long i;

	for (i = 0; i < old_nentries; i++) {
		register unsigned long tag asm("o4");
		register unsigned long pte asm("o5");
		unsigned long v, hash;

		if (tlb_type == hypervisor) {
			__asm__ __volatile__(
				"ldda [%2] %3, %0"
				: "=r" (tag), "=r" (pte)
				: "r" (__pa(&old_tsb[i])),
				  "i" (ASI_QUAD_LDD_PHYS_4V));
		} else if (tlb_type == cheetah_plus) {
			__asm__ __volatile__(
				"ldda [%2] %3, %0"
				: "=r" (tag), "=r" (pte)
				: "r" (__pa(&old_tsb[i])),
				  "i" (ASI_QUAD_LDD_PHYS));
		} else {
			__asm__ __volatile__(
				"ldda [%2] %3, %0"
				: "=r" (tag), "=r" (pte)
				: "r" (&old_tsb[i]),
				  "i" (ASI_NUCLEUS_QUAD_LDD));
		}

		if (!tag || (tag & (1UL << TSB_TAG_LOCK_BIT)))
			continue;

		/* We only put base page size PTEs into the TSB,
		 * but that might change in the future.  This code
		 * would need to be changed if we start putting larger
		 * page size PTEs into there.
		 */
		WARN_ON((pte & _PAGE_ALL_SZ_BITS) != _PAGE_SZBITS);

		/* The tag holds bits 22 to 63 of the virtual address
		 * and the context.  Clear out the context, and shift
		 * up to make a virtual address.
		 */
		v = (tag & ((1UL << 42UL) - 1UL)) << 22UL;

		/* The implied bits of the tag (bits 13 to 21) are
		 * determined by the TSB entry index, so fill that in.
		 */
		v |= (i & (512UL - 1UL)) << 13UL;

		hash = tsb_hash(v, new_nentries);
		if (tlb_type == cheetah_plus ||
		    tlb_type == hypervisor) {
			__asm__ __volatile__(
				"stxa	%0, [%1] %2\n\t"
				"stxa	%3, [%4] %2"
				: /* no outputs */
				: "r" (tag),
				  "r" (__pa(&new_tsb[hash].tag)),
				  "i" (ASI_PHYS_USE_EC),
				  "r" (pte),
				  "r" (__pa(&new_tsb[hash].pte)));
		} else {
			new_tsb[hash].tag = tag;
			new_tsb[hash].pte = pte;
		}
	}
}

/* When the RSS of an address space exceeds mm->context.tsb_rss_limit,
 * update_mmu_cache() invokes this routine to try and grow the TSB.
 * When we reach the maximum TSB size supported, we stick ~0UL into
 * mm->context.tsb_rss_limit so the grow checks in update_mmu_cache()
 * will not trigger any longer.
 *
 * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
 * of two.  The TSB must be aligned to it's size, so f.e. a 512K TSB
 * must be 512K aligned.
 *
 * The idea here is to grow the TSB when the RSS of the process approaches
 * the number of entries that the current TSB can hold at once.  Currently,
 * we trigger when the RSS hits 3/4 of the TSB capacity.
 */
void tsb_grow(struct mm_struct *mm, unsigned long rss, gfp_t gfp_flags)
{
	unsigned long max_tsb_size = 1 * 1024 * 1024;
	unsigned long size, old_size;
	struct page *page;
	struct tsb *old_tsb;

	if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
		max_tsb_size = (PAGE_SIZE << MAX_ORDER);

	for (size = PAGE_SIZE; size < max_tsb_size; size <<= 1UL) {
		unsigned long n_entries = size / sizeof(struct tsb);

		n_entries = (n_entries * 3) / 4;
		if (n_entries > rss)
			break;
	}

	page = alloc_pages(gfp_flags | __GFP_ZERO, get_order(size));
	if (unlikely(!page))
		return;

	if (size == max_tsb_size)
		mm->context.tsb_rss_limit = ~0UL;
	else
		mm->context.tsb_rss_limit =
			((size / sizeof(struct tsb)) * 3) / 4;

	old_tsb = mm->context.tsb;
	old_size = mm->context.tsb_nentries * sizeof(struct tsb);

	if (old_tsb)
		copy_tsb(old_tsb, old_size, page_address(page), size);

	mm->context.tsb = page_address(page);
	setup_tsb_params(mm, size);

	/* If old_tsb is NULL, we're being invoked for the first time
	 * from init_new_context().
	 */
	if (old_tsb) {
		/* Now force all other processors to reload the new
		 * TSB state.
		 */
		smp_tsb_sync(mm);

		/* Finally reload it on the local cpu.  No further
		 * references will remain to the old TSB and we can
		 * thus free it up.
		 */
		tsb_context_switch(mm);

		free_pages((unsigned long) old_tsb, get_order(old_size));
	}
}

int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{

	mm->context.sparc64_ctx_val = 0UL;

	/* copy_mm() copies over the parent's mm_struct before calling
	 * us, so we need to zero out the TSB pointer or else tsb_grow()
	 * will be confused and think there is an older TSB to free up.
	 */
	mm->context.tsb = NULL;
	tsb_grow(mm, 0, GFP_KERNEL);

	if (unlikely(!mm->context.tsb))
		return -ENOMEM;

	return 0;
}

void destroy_context(struct mm_struct *mm)
{
	unsigned long size = mm->context.tsb_nentries * sizeof(struct tsb);

	free_pages((unsigned long) mm->context.tsb, get_order(size));

	/* We can remove these later, but for now it's useful
	 * to catch any bogus post-destroy_context() references
	 * to the TSB.
	 */
	mm->context.tsb = NULL;
	mm->context.tsb_reg_val = 0UL;

	spin_lock(&ctx_alloc_lock);

	if (CTX_VALID(mm->context)) {
		unsigned long nr = CTX_NRBITS(mm->context);
		mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
	}

	spin_unlock(&ctx_alloc_lock);
}
Commit	Line	Data
74bf4312 DM	1	/* arch/sparc64/mm/tsb.c
	2	*
	3	* Copyright (C) 2006 David S. Miller <davem@davemloft.net>
	4	*/
	5
	6	#include <linux/kernel.h>
	7	#include <asm/system.h>
	8	#include <asm/page.h>
	9	#include <asm/tlbflush.h>
	10	#include <asm/tlb.h>
09f94287	11	#include <asm/mmu_context.h>
98c5584c	12	#include <asm/pgtable.h>
bd40791e	13	#include <asm/tsb.h>
74bf4312	14
74bf4312 DM	15	extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
74bf4312 DM	16
98c5584c	17	static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long nentries)
74bf4312 DM	18	{
74bf4312 DM	19	vaddr >>= PAGE_SHIFT;
98c5584c	20	return vaddr & (nentries - 1);
74bf4312 DM	21	}
74bf4312 DM	22
517af332	23	static inline int tag_compare(unsigned long tag, unsigned long vaddr, unsigned long context)
74bf4312	24	{
517af332	25	return (tag == ((vaddr >> 22) \| (context << 48)));
74bf4312 DM	26	}
	27
	28	/* TSB flushes need only occur on the processor initiating the address
	29	* space modification, not on each cpu the address space has run on.
	30	* Only the TLB flush needs that treatment.
	31	*/
	32
	33	void flush_tsb_kernel_range(unsigned long start, unsigned long end)
	34	{
	35	unsigned long v;
	36
	37	for (v = start; v < end; v += PAGE_SIZE) {
98c5584c DM	38	unsigned long hash = tsb_hash(v, KERNEL_TSB_NENTRIES);
98c5584c DM	39	struct tsb *ent = &swapper_tsb[hash];
74bf4312	40
517af332	41	if (tag_compare(ent->tag, v, 0)) {
74bf4312 DM	42	ent->tag = 0UL;
	43	membar_storeload_storestore();
	44	}
	45	}
	46	}
	47
	48	void flush_tsb_user(struct mmu_gather *mp)
	49	{
	50	struct mm_struct *mm = mp->mm;
98c5584c	51	struct tsb *tsb = mm->context.tsb;
98c5584c	52	unsigned long nentries = mm->context.tsb_nentries;
517af332	53	unsigned long ctx, base;
74bf4312 DM	54	int i;
74bf4312 DM	55
517af332 DM	56	if (unlikely(!CTX_VALID(mm->context)))
	57	return;
	58
	59	ctx = CTX_HWBITS(mm->context);
74bf4312	60
517af332 DM	61	if (tlb_type == cheetah_plus)
	62	base = __pa(tsb);
	63	else
	64	base = (unsigned long) tsb;
	65
74bf4312 DM	66	for (i = 0; i < mp->tlb_nr; i++) {
74bf4312 DM	67	unsigned long v = mp->vaddrs[i];
517af332	68	unsigned long tag, ent, hash;
74bf4312 DM	69
	70	v &= ~0x1UL;
	71
517af332 DM	72	hash = tsb_hash(v, nentries);
	73	ent = base + (hash * sizeof(struct tsb));
	74	tag = (v >> 22UL) \| (ctx << 48UL);
	75
	76	tsb_flush(ent, tag);
74bf4312 DM	77	}
74bf4312 DM	78	}
09f94287	79
98c5584c DM	80	static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes)
	81	{
	82	unsigned long tsb_reg, base, tsb_paddr;
	83	unsigned long page_sz, tte;
	84
	85	mm->context.tsb_nentries = tsb_bytes / sizeof(struct tsb);
	86
	87	base = TSBMAP_BASE;
	88	tte = (_PAGE_VALID \| _PAGE_L \| _PAGE_CP \|
	89	_PAGE_CV \| _PAGE_P \| _PAGE_W);
	90	tsb_paddr = __pa(mm->context.tsb);
517af332	91	BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
98c5584c DM	92
	93	/* Use the smallest page size that can map the whole TSB
	94	* in one TLB entry.
	95	*/
	96	switch (tsb_bytes) {
	97	case 8192 << 0:
	98	tsb_reg = 0x0UL;
	99	#ifdef DCACHE_ALIASING_POSSIBLE
	100	base += (tsb_paddr & 8192);
	101	#endif
	102	tte \|= _PAGE_SZ8K;
	103	page_sz = 8192;
	104	break;
	105
	106	case 8192 << 1:
	107	tsb_reg = 0x1UL;
	108	tte \|= _PAGE_SZ64K;
	109	page_sz = 64 * 1024;
	110	break;
	111
	112	case 8192 << 2:
	113	tsb_reg = 0x2UL;
	114	tte \|= _PAGE_SZ64K;
	115	page_sz = 64 * 1024;
	116	break;
	117
	118	case 8192 << 3:
	119	tsb_reg = 0x3UL;
	120	tte \|= _PAGE_SZ64K;
	121	page_sz = 64 * 1024;
	122	break;
	123
	124	case 8192 << 4:
	125	tsb_reg = 0x4UL;
	126	tte \|= _PAGE_SZ512K;
	127	page_sz = 512 * 1024;
	128	break;
	129
	130	case 8192 << 5:
	131	tsb_reg = 0x5UL;
	132	tte \|= _PAGE_SZ512K;
	133	page_sz = 512 * 1024;
	134	break;
	135
	136	case 8192 << 6:
	137	tsb_reg = 0x6UL;
	138	tte \|= _PAGE_SZ512K;
	139	page_sz = 512 * 1024;
	140	break;
	141
	142	case 8192 << 7:
	143	tsb_reg = 0x7UL;
	144	tte \|= _PAGE_SZ4MB;
	145	page_sz = 4 * 1024 * 1024;
	146	break;
bd40791e DM	147
	148	default:
	149	BUG();
98c5584c DM	150	};
98c5584c DM	151
618e9ed9	152	if (tlb_type == cheetah_plus \|\| tlb_type == hypervisor) {
517af332 DM	153	/* Physical mapping, no locked TLB entry for TSB. */
	154	tsb_reg \|= tsb_paddr;
	155
	156	mm->context.tsb_reg_val = tsb_reg;
	157	mm->context.tsb_map_vaddr = 0;
	158	mm->context.tsb_map_pte = 0;
	159	} else {
	160	tsb_reg \|= base;
	161	tsb_reg \|= (tsb_paddr & (page_sz - 1UL));
	162	tte \|= (tsb_paddr & ~(page_sz - 1UL));
	163
	164	mm->context.tsb_reg_val = tsb_reg;
	165	mm->context.tsb_map_vaddr = base;
	166	mm->context.tsb_map_pte = tte;
	167	}
98c5584c	168
618e9ed9 DM	169	/* Setup the Hypervisor TSB descriptor. */
	170	if (tlb_type == hypervisor) {
	171	struct hv_tsb_descr *hp = &mm->context.tsb_descr;
	172
	173	switch (PAGE_SIZE) {
	174	case 8192:
	175	default:
	176	hp->pgsz_idx = HV_PGSZ_IDX_8K;
	177	break;
	178
	179	case 64 * 1024:
	180	hp->pgsz_idx = HV_PGSZ_IDX_64K;
	181	break;
	182
	183	case 512 * 1024:
	184	hp->pgsz_idx = HV_PGSZ_IDX_512K;
	185	break;
	186
	187	case 4 * 1024 * 1024:
	188	hp->pgsz_idx = HV_PGSZ_IDX_4MB;
	189	break;
	190	};
	191	hp->assoc = 1;
	192	hp->num_ttes = tsb_bytes / 16;
	193	hp->ctx_idx = 0;
	194	switch (PAGE_SIZE) {
	195	case 8192:
	196	default:
	197	hp->pgsz_mask = HV_PGSZ_MASK_8K;
	198	break;
	199
	200	case 64 * 1024:
	201	hp->pgsz_mask = HV_PGSZ_MASK_64K;
	202	break;
	203
	204	case 512 * 1024:
	205	hp->pgsz_mask = HV_PGSZ_MASK_512K;
	206	break;
	207
	208	case 4 * 1024 * 1024:
	209	hp->pgsz_mask = HV_PGSZ_MASK_4MB;
	210	break;
	211	};
	212	hp->tsb_base = tsb_paddr;
	213	hp->resv = 0;
	214	}
98c5584c DM	215	}
98c5584c DM	216
bd40791e DM	217	/* The page tables are locked against modifications while this
	218	* runs.
	219	*
	220	* XXX do some prefetching...
	221	*/
	222	static void copy_tsb(struct tsb *old_tsb, unsigned long old_size,
	223	struct tsb *new_tsb, unsigned long new_size)
	224	{
	225	unsigned long old_nentries = old_size / sizeof(struct tsb);
	226	unsigned long new_nentries = new_size / sizeof(struct tsb);
	227	unsigned long i;
	228
	229	for (i = 0; i < old_nentries; i++) {
	230	register unsigned long tag asm("o4");
	231	register unsigned long pte asm("o5");
517af332 DM	232	unsigned long v, hash;
517af332 DM	233
e92b9257 DM	234	if (tlb_type == hypervisor) {
	235	__asm__ __volatile__(
	236	"ldda [%2] %3, %0"
	237	: "=r" (tag), "=r" (pte)
	238	: "r" (__pa(&old_tsb[i])),
	239	"i" (ASI_QUAD_LDD_PHYS_4V));
	240	} else if (tlb_type == cheetah_plus) {
517af332 DM	241	__asm__ __volatile__(
	242	"ldda [%2] %3, %0"
	243	: "=r" (tag), "=r" (pte)
	244	: "r" (__pa(&old_tsb[i])),
	245	"i" (ASI_QUAD_LDD_PHYS));
	246	} else {
	247	__asm__ __volatile__(
	248	"ldda [%2] %3, %0"
	249	: "=r" (tag), "=r" (pte)
	250	: "r" (&old_tsb[i]),
	251	"i" (ASI_NUCLEUS_QUAD_LDD));
	252	}
bd40791e	253
4753eb2a	254	if (!tag \|\| (tag & (1UL << TSB_TAG_LOCK_BIT)))
bd40791e DM	255	continue;
	256
	257	/* We only put base page size PTEs into the TSB,
	258	* but that might change in the future. This code
	259	* would need to be changed if we start putting larger
	260	* page size PTEs into there.
	261	*/
	262	WARN_ON((pte & _PAGE_ALL_SZ_BITS) != _PAGE_SZBITS);
	263
	264	/* The tag holds bits 22 to 63 of the virtual address
	265	* and the context. Clear out the context, and shift
	266	* up to make a virtual address.
	267	*/
	268	v = (tag & ((1UL << 42UL) - 1UL)) << 22UL;
	269
	270	/* The implied bits of the tag (bits 13 to 21) are
	271	* determined by the TSB entry index, so fill that in.
	272	*/
	273	v \|= (i & (512UL - 1UL)) << 13UL;
	274
	275	hash = tsb_hash(v, new_nentries);
e92b9257 DM	276	if (tlb_type == cheetah_plus \|\|
e92b9257 DM	277	tlb_type == hypervisor) {
517af332 DM	278	__asm__ __volatile__(
	279	"stxa %0, [%1] %2\n\t"
	280	"stxa %3, [%4] %2"
	281	: /* no outputs */
	282	: "r" (tag),
	283	"r" (__pa(&new_tsb[hash].tag)),
	284	"i" (ASI_PHYS_USE_EC),
	285	"r" (pte),
	286	"r" (__pa(&new_tsb[hash].pte)));
	287	} else {
	288	new_tsb[hash].tag = tag;
	289	new_tsb[hash].pte = pte;
	290	}
bd40791e DM	291	}
	292	}
	293
	294	/* When the RSS of an address space exceeds mm->context.tsb_rss_limit,
	295	* update_mmu_cache() invokes this routine to try and grow the TSB.
	296	* When we reach the maximum TSB size supported, we stick ~0UL into
	297	* mm->context.tsb_rss_limit so the grow checks in update_mmu_cache()
	298	* will not trigger any longer.
	299	*
	300	* The TSB can be anywhere from 8K to 1MB in size, in increasing powers
	301	* of two. The TSB must be aligned to it's size, so f.e. a 512K TSB
	302	* must be 512K aligned.
	303	*
	304	* The idea here is to grow the TSB when the RSS of the process approaches
	305	* the number of entries that the current TSB can hold at once. Currently,
	306	* we trigger when the RSS hits 3/4 of the TSB capacity.
	307	*/
	308	void tsb_grow(struct mm_struct *mm, unsigned long rss, gfp_t gfp_flags)
	309	{
	310	unsigned long max_tsb_size = 1 * 1024 * 1024;
	311	unsigned long size, old_size;
	312	struct page *page;
	313	struct tsb *old_tsb;
	314
	315	if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
	316	max_tsb_size = (PAGE_SIZE << MAX_ORDER);
	317
	318	for (size = PAGE_SIZE; size < max_tsb_size; size <<= 1UL) {
	319	unsigned long n_entries = size / sizeof(struct tsb);
	320
	321	n_entries = (n_entries * 3) / 4;
	322	if (n_entries > rss)
	323	break;
	324	}
	325
	326	page = alloc_pages(gfp_flags \| __GFP_ZERO, get_order(size));
	327	if (unlikely(!page))
	328	return;
	329
	330	if (size == max_tsb_size)
	331	mm->context.tsb_rss_limit = ~0UL;
	332	else
	333	mm->context.tsb_rss_limit =
	334	((size / sizeof(struct tsb)) * 3) / 4;
	335
	336	old_tsb = mm->context.tsb;
	337	old_size = mm->context.tsb_nentries * sizeof(struct tsb);
	338
	339	if (old_tsb)
	340	copy_tsb(old_tsb, old_size, page_address(page), size);
	341
	342	mm->context.tsb = page_address(page);
	343	setup_tsb_params(mm, size);
	344
	345	/* If old_tsb is NULL, we're being invoked for the first time
	346	* from init_new_context().
	347	*/
	348	if (old_tsb) {
	349	/* Now force all other processors to reload the new
	350	* TSB state.
	351	*/
	352	smp_tsb_sync(mm);
	353
	354	/* Finally reload it on the local cpu. No further
355	* references will remain to the old TSB and we can
356	* thus free it up.
357	*/
358	tsb_context_switch(mm);
359
360	free_pages((unsigned long) old_tsb, get_order(old_size));
361	}
362	}
363
09f94287 DM	364	int init_new_context(struct task_struct tsk, struct mm_struct mm)
09f94287 DM	365	{
09f94287 DM	366
09f94287 DM	367	mm->context.sparc64_ctx_val = 0UL;
09f94287	368
bd40791e DM	369	/* copy_mm() copies over the parent's mm_struct before calling
	370	* us, so we need to zero out the TSB pointer or else tsb_grow()
	371	* will be confused and think there is an older TSB to free up.
	372	*/
	373	mm->context.tsb = NULL;
f4e841da	374	tsb_grow(mm, 0, GFP_KERNEL);
bd40791e DM	375
	376	if (unlikely(!mm->context.tsb))
	377	return -ENOMEM;
09f94287 DM	378
	379	return 0;
	380	}
	381
	382	void destroy_context(struct mm_struct *mm)
	383	{
bd40791e DM	384	unsigned long size = mm->context.tsb_nentries * sizeof(struct tsb);
	385
	386	free_pages((unsigned long) mm->context.tsb, get_order(size));
98c5584c DM	387
	388	/* We can remove these later, but for now it's useful
	389	* to catch any bogus post-destroy_context() references
	390	* to the TSB.
	391	*/
	392	mm->context.tsb = NULL;
	393	mm->context.tsb_reg_val = 0UL;
09f94287 DM	394
	395	spin_lock(&ctx_alloc_lock);
	396
	397	if (CTX_VALID(mm->context)) {
	398	unsigned long nr = CTX_NRBITS(mm->context);
	399	mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
	400	}
	401
	402	spin_unlock(&ctx_alloc_lock);
	403	}