[mirror_ubuntu-artful-kernel.git] / arch / powerpc / mm / stab.c

/*
 * PowerPC64 Segment Translation Support.
 *
 * Dave Engebretsen and Mike Corrigan {engebret|mikejc}@us.ibm.com
 *    Copyright (c) 2001 Dave Engebretsen
 *
 * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/config.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/paca.h>
#include <asm/cputable.h>
#include <asm/lmb.h>
#include <asm/abs_addr.h>
#include <asm/firmware.h>

struct stab_entry {
	unsigned long esid_data;
	unsigned long vsid_data;
};

#define NR_STAB_CACHE_ENTRIES 8
DEFINE_PER_CPU(long, stab_cache_ptr);
DEFINE_PER_CPU(long, stab_cache[NR_STAB_CACHE_ENTRIES]);

/*
 * Create a segment table entry for the given esid/vsid pair.
 */
static int make_ste(unsigned long stab, unsigned long esid, unsigned long vsid)
{
	unsigned long esid_data, vsid_data;
	unsigned long entry, group, old_esid, castout_entry, i;
	unsigned int global_entry;
	struct stab_entry *ste, *castout_ste;
	unsigned long kernel_segment = (esid << SID_SHIFT) >= PAGE_OFFSET;

	vsid_data = vsid << STE_VSID_SHIFT;
	esid_data = esid << SID_SHIFT | STE_ESID_KP | STE_ESID_V;
	if (! kernel_segment)
		esid_data |= STE_ESID_KS;

	/* Search the primary group first. */
	global_entry = (esid & 0x1f) << 3;
	ste = (struct stab_entry *)(stab | ((esid & 0x1f) << 7));

	/* Find an empty entry, if one exists. */
	for (group = 0; group < 2; group++) {
		for (entry = 0; entry < 8; entry++, ste++) {
			if (!(ste->esid_data & STE_ESID_V)) {
				ste->vsid_data = vsid_data;
				asm volatile("eieio":::"memory");
				ste->esid_data = esid_data;
				return (global_entry | entry);
			}
		}
		/* Now search the secondary group. */
		global_entry = ((~esid) & 0x1f) << 3;
		ste = (struct stab_entry *)(stab | (((~esid) & 0x1f) << 7));
	}

	/*
	 * Could not find empty entry, pick one with a round robin selection.
	 * Search all entries in the two groups.
	 */
	castout_entry = get_paca()->stab_rr;
	for (i = 0; i < 16; i++) {
		if (castout_entry < 8) {
			global_entry = (esid & 0x1f) << 3;
			ste = (struct stab_entry *)(stab | ((esid & 0x1f) << 7));
			castout_ste = ste + castout_entry;
		} else {
			global_entry = ((~esid) & 0x1f) << 3;
			ste = (struct stab_entry *)(stab | (((~esid) & 0x1f) << 7));
			castout_ste = ste + (castout_entry - 8);
		}

		/* Dont cast out the first kernel segment */
		if ((castout_ste->esid_data & ESID_MASK) != PAGE_OFFSET)
			break;

		castout_entry = (castout_entry + 1) & 0xf;
	}

	get_paca()->stab_rr = (castout_entry + 1) & 0xf;

	/* Modify the old entry to the new value. */

	/* Force previous translations to complete. DRENG */
	asm volatile("isync" : : : "memory");

	old_esid = castout_ste->esid_data >> SID_SHIFT;
	castout_ste->esid_data = 0;		/* Invalidate old entry */

	asm volatile("sync" : : : "memory");    /* Order update */

	castout_ste->vsid_data = vsid_data;
	asm volatile("eieio" : : : "memory");   /* Order update */
	castout_ste->esid_data = esid_data;

	asm volatile("slbie  %0" : : "r" (old_esid << SID_SHIFT));
	/* Ensure completion of slbie */
	asm volatile("sync" : : : "memory");

	return (global_entry | (castout_entry & 0x7));
}

/*
 * Allocate a segment table entry for the given ea and mm
 */
static int __ste_allocate(unsigned long ea, struct mm_struct *mm)
{
	unsigned long vsid;
	unsigned char stab_entry;
	unsigned long offset;

	/* Kernel or user address? */
	if (is_kernel_addr(ea)) {
		vsid = get_kernel_vsid(ea);
	} else {
		if ((ea >= TASK_SIZE_USER64) || (! mm))
			return 1;

		vsid = get_vsid(mm->context.id, ea);
	}

	stab_entry = make_ste(get_paca()->stab_addr, GET_ESID(ea), vsid);

	if (!is_kernel_addr(ea)) {
		offset = __get_cpu_var(stab_cache_ptr);
		if (offset < NR_STAB_CACHE_ENTRIES)
			__get_cpu_var(stab_cache[offset++]) = stab_entry;
		else
			offset = NR_STAB_CACHE_ENTRIES+1;
		__get_cpu_var(stab_cache_ptr) = offset;

		/* Order update */
		asm volatile("sync":::"memory");
	}

	return 0;
}

int ste_allocate(unsigned long ea)
{
	return __ste_allocate(ea, current->mm);
}

/*
 * Do the segment table work for a context switch: flush all user
 * entries from the table, then preload some probably useful entries
 * for the new task
 */
void switch_stab(struct task_struct *tsk, struct mm_struct *mm)
{
	struct stab_entry *stab = (struct stab_entry *) get_paca()->stab_addr;
	struct stab_entry *ste;
	unsigned long offset = __get_cpu_var(stab_cache_ptr);
	unsigned long pc = KSTK_EIP(tsk);
	unsigned long stack = KSTK_ESP(tsk);
	unsigned long unmapped_base;

	/* Force previous translations to complete. DRENG */
	asm volatile("isync" : : : "memory");

	if (offset <= NR_STAB_CACHE_ENTRIES) {
		int i;

		for (i = 0; i < offset; i++) {
			ste = stab + __get_cpu_var(stab_cache[i]);
			ste->esid_data = 0; /* invalidate entry */
		}
	} else {
		unsigned long entry;

		/* Invalidate all entries. */
		ste = stab;

		/* Never flush the first entry. */
		ste += 1;
		for (entry = 1;
		     entry < (HW_PAGE_SIZE / sizeof(struct stab_entry));
		     entry++, ste++) {
			unsigned long ea;
			ea = ste->esid_data & ESID_MASK;
			if (!is_kernel_addr(ea)) {
				ste->esid_data = 0;
			}
		}
	}

	asm volatile("sync; slbia; sync":::"memory");

	__get_cpu_var(stab_cache_ptr) = 0;

#ifdef CONFIG_PPC_64K_PAGES
	get_paca()->pgdir = mm->pgd;
#endif /* CONFIG_PPC_64K_PAGES */

	/* Now preload some entries for the new task */
	if (test_tsk_thread_flag(tsk, TIF_32BIT))
		unmapped_base = TASK_UNMAPPED_BASE_USER32;
	else
		unmapped_base = TASK_UNMAPPED_BASE_USER64;

	__ste_allocate(pc, mm);

	if (GET_ESID(pc) == GET_ESID(stack))
		return;

	__ste_allocate(stack, mm);

	if ((GET_ESID(pc) == GET_ESID(unmapped_base))
	    || (GET_ESID(stack) == GET_ESID(unmapped_base)))
		return;

	__ste_allocate(unmapped_base, mm);

	/* Order update */
	asm volatile("sync" : : : "memory");
}

/*
 * Allocate segment tables for secondary CPUs.  These must all go in
 * the first (bolted) segment, so that do_stab_bolted won't get a
 * recursive segment miss on the segment table itself.
 */
void stabs_alloc(void)
{
	int cpu;

	if (cpu_has_feature(CPU_FTR_SLB))
		return;

	for_each_possible_cpu(cpu) {
		unsigned long newstab;

		if (cpu == 0)
			continue; /* stab for CPU 0 is statically allocated */

		newstab = lmb_alloc_base(HW_PAGE_SIZE, HW_PAGE_SIZE,
					 1<<SID_SHIFT);
		newstab = (unsigned long)__va(newstab);

		memset((void *)newstab, 0, HW_PAGE_SIZE);

		paca[cpu].stab_addr = newstab;
		paca[cpu].stab_real = virt_to_abs(newstab);
		printk(KERN_INFO "Segment table for CPU %d at 0x%lx "
		       "virtual, 0x%lx absolute\n",
		       cpu, paca[cpu].stab_addr, paca[cpu].stab_real);
	}
}

/*
 * Build an entry for the base kernel segment and put it into
 * the segment table or SLB.  All other segment table or SLB
 * entries are faulted in.
 */
void stab_initialize(unsigned long stab)
{
	unsigned long vsid = get_kernel_vsid(PAGE_OFFSET);
	unsigned long stabreal;

	asm volatile("isync; slbia; isync":::"memory");
	make_ste(stab, GET_ESID(PAGE_OFFSET), vsid);

	/* Order update */
	asm volatile("sync":::"memory");

	/* Set ASR */
	stabreal = get_paca()->stab_real | 0x1ul;

#ifdef CONFIG_PPC_ISERIES
	if (firmware_has_feature(FW_FEATURE_ISERIES)) {
		HvCall1(HvCallBaseSetASR, stabreal);
		return;
	}
#endif /* CONFIG_PPC_ISERIES */

	mtspr(SPRN_ASR, stabreal);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* PowerPC64 Segment Translation Support.
	3	*
	4	* Dave Engebretsen and Mike Corrigan {engebret\|mikejc}@us.ibm.com
	5	* Copyright (c) 2001 Dave Engebretsen
	6	*
	7	* Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* as published by the Free Software Foundation; either version
	12	* 2 of the License, or (at your option) any later version.
	13	*/
	14
	15	#include <linux/config.h>
	16	#include <asm/pgtable.h>
	17	#include <asm/mmu.h>
	18	#include <asm/mmu_context.h>
	19	#include <asm/paca.h>
	20	#include <asm/cputable.h>
533f0817 DG	21	#include <asm/lmb.h>
533f0817 DG	22	#include <asm/abs_addr.h>
799d6046	23	#include <asm/firmware.h>
1da177e4	24
1f8d419e DG	25	struct stab_entry {
	26	unsigned long esid_data;
	27	unsigned long vsid_data;
	28	};
	29
1da177e4 LT	30	#define NR_STAB_CACHE_ENTRIES 8
	31	DEFINE_PER_CPU(long, stab_cache_ptr);
	32	DEFINE_PER_CPU(long, stab_cache[NR_STAB_CACHE_ENTRIES]);
	33
	34	/*
	35	* Create a segment table entry for the given esid/vsid pair.
	36	*/
	37	static int make_ste(unsigned long stab, unsigned long esid, unsigned long vsid)
	38	{
	39	unsigned long esid_data, vsid_data;
	40	unsigned long entry, group, old_esid, castout_entry, i;
	41	unsigned int global_entry;
	42	struct stab_entry ste, castout_ste;
b5666f70	43	unsigned long kernel_segment = (esid << SID_SHIFT) >= PAGE_OFFSET;
1da177e4 LT	44
	45	vsid_data = vsid << STE_VSID_SHIFT;
	46	esid_data = esid << SID_SHIFT \| STE_ESID_KP \| STE_ESID_V;
	47	if (! kernel_segment)
	48	esid_data \|= STE_ESID_KS;
	49
	50	/* Search the primary group first. */
	51	global_entry = (esid & 0x1f) << 3;
	52	ste = (struct stab_entry *)(stab \| ((esid & 0x1f) << 7));
	53
	54	/* Find an empty entry, if one exists. */
	55	for (group = 0; group < 2; group++) {
	56	for (entry = 0; entry < 8; entry++, ste++) {
	57	if (!(ste->esid_data & STE_ESID_V)) {
	58	ste->vsid_data = vsid_data;
	59	asm volatile("eieio":::"memory");
	60	ste->esid_data = esid_data;
	61	return (global_entry \| entry);
	62	}
	63	}
	64	/* Now search the secondary group. */
	65	global_entry = ((~esid) & 0x1f) << 3;
	66	ste = (struct stab_entry *)(stab \| (((~esid) & 0x1f) << 7));
	67	}
	68
	69	/*
	70	* Could not find empty entry, pick one with a round robin selection.
	71	* Search all entries in the two groups.
	72	*/
	73	castout_entry = get_paca()->stab_rr;
	74	for (i = 0; i < 16; i++) {
	75	if (castout_entry < 8) {
	76	global_entry = (esid & 0x1f) << 3;
	77	ste = (struct stab_entry *)(stab \| ((esid & 0x1f) << 7));
	78	castout_ste = ste + castout_entry;
	79	} else {
	80	global_entry = ((~esid) & 0x1f) << 3;
	81	ste = (struct stab_entry *)(stab \| (((~esid) & 0x1f) << 7));
	82	castout_ste = ste + (castout_entry - 8);
	83	}
	84
	85	/* Dont cast out the first kernel segment */
b5666f70	86	if ((castout_ste->esid_data & ESID_MASK) != PAGE_OFFSET)
1da177e4 LT	87	break;
	88
	89	castout_entry = (castout_entry + 1) & 0xf;
	90	}
	91
	92	get_paca()->stab_rr = (castout_entry + 1) & 0xf;
	93
	94	/* Modify the old entry to the new value. */
	95
	96	/* Force previous translations to complete. DRENG */
	97	asm volatile("isync" : : : "memory");
	98
	99	old_esid = castout_ste->esid_data >> SID_SHIFT;
	100	castout_ste->esid_data = 0; /* Invalidate old entry */
	101
	102	asm volatile("sync" : : : "memory"); /* Order update */
	103
	104	castout_ste->vsid_data = vsid_data;
	105	asm volatile("eieio" : : : "memory"); /* Order update */
	106	castout_ste->esid_data = esid_data;
	107
	108	asm volatile("slbie %0" : : "r" (old_esid << SID_SHIFT));
	109	/* Ensure completion of slbie */
	110	asm volatile("sync" : : : "memory");
	111
	112	return (global_entry \| (castout_entry & 0x7));
	113	}
	114
	115	/*
	116	* Allocate a segment table entry for the given ea and mm
	117	*/
	118	static int __ste_allocate(unsigned long ea, struct mm_struct *mm)
	119	{
	120	unsigned long vsid;
	121	unsigned char stab_entry;
	122	unsigned long offset;
	123
	124	/* Kernel or user address? */
51fae6de	125	if (is_kernel_addr(ea)) {
1da177e4 LT	126	vsid = get_kernel_vsid(ea);
	127	} else {
	128	if ((ea >= TASK_SIZE_USER64) \|\| (! mm))
	129	return 1;
	130
	131	vsid = get_vsid(mm->context.id, ea);
	132	}
	133
	134	stab_entry = make_ste(get_paca()->stab_addr, GET_ESID(ea), vsid);
	135
51fae6de	136	if (!is_kernel_addr(ea)) {
1da177e4 LT	137	offset = __get_cpu_var(stab_cache_ptr);
	138	if (offset < NR_STAB_CACHE_ENTRIES)
	139	__get_cpu_var(stab_cache[offset++]) = stab_entry;
	140	else
	141	offset = NR_STAB_CACHE_ENTRIES+1;
	142	__get_cpu_var(stab_cache_ptr) = offset;
	143
	144	/* Order update */
	145	asm volatile("sync":::"memory");
	146	}
	147
	148	return 0;
	149	}
	150
	151	int ste_allocate(unsigned long ea)
	152	{
	153	return __ste_allocate(ea, current->mm);
	154	}
	155
	156	/*
	157	* Do the segment table work for a context switch: flush all user
	158	* entries from the table, then preload some probably useful entries
	159	* for the new task
	160	*/
	161	void switch_stab(struct task_struct tsk, struct mm_struct mm)
	162	{
	163	struct stab_entry stab = (struct stab_entry ) get_paca()->stab_addr;
	164	struct stab_entry *ste;
	165	unsigned long offset = __get_cpu_var(stab_cache_ptr);
	166	unsigned long pc = KSTK_EIP(tsk);
	167	unsigned long stack = KSTK_ESP(tsk);
	168	unsigned long unmapped_base;
	169
	170	/* Force previous translations to complete. DRENG */
	171	asm volatile("isync" : : : "memory");
	172
	173	if (offset <= NR_STAB_CACHE_ENTRIES) {
	174	int i;
	175
	176	for (i = 0; i < offset; i++) {
	177	ste = stab + __get_cpu_var(stab_cache[i]);
	178	ste->esid_data = 0; /* invalidate entry */
	179	}
	180	} else {
	181	unsigned long entry;
	182
	183	/* Invalidate all entries. */
	184	ste = stab;
	185
	186	/* Never flush the first entry. */
	187	ste += 1;
	188	for (entry = 1;
3c726f8d	189	entry < (HW_PAGE_SIZE / sizeof(struct stab_entry));
1da177e4 LT	190	entry++, ste++) {
	191	unsigned long ea;
	192	ea = ste->esid_data & ESID_MASK;
51fae6de	193	if (!is_kernel_addr(ea)) {
1da177e4 LT	194	ste->esid_data = 0;
	195	}
	196	}
	197	}
	198
	199	asm volatile("sync; slbia; sync":::"memory");
	200
	201	__get_cpu_var(stab_cache_ptr) = 0;
	202
3c726f8d BH	203	#ifdef CONFIG_PPC_64K_PAGES
	204	get_paca()->pgdir = mm->pgd;
	205	#endif /* CONFIG_PPC_64K_PAGES */
	206
1da177e4 LT	207	/* Now preload some entries for the new task */
	208	if (test_tsk_thread_flag(tsk, TIF_32BIT))
	209	unmapped_base = TASK_UNMAPPED_BASE_USER32;
	210	else
	211	unmapped_base = TASK_UNMAPPED_BASE_USER64;
	212
	213	__ste_allocate(pc, mm);
	214
	215	if (GET_ESID(pc) == GET_ESID(stack))
	216	return;
	217
	218	__ste_allocate(stack, mm);
	219
	220	if ((GET_ESID(pc) == GET_ESID(unmapped_base))
	221	\|\| (GET_ESID(stack) == GET_ESID(unmapped_base)))
	222	return;
	223
	224	__ste_allocate(unmapped_base, mm);
	225
	226	/* Order update */
	227	asm volatile("sync" : : : "memory");
	228	}
	229
533f0817 DG	230	/*
	231	* Allocate segment tables for secondary CPUs. These must all go in
	232	* the first (bolted) segment, so that do_stab_bolted won't get a
	233	* recursive segment miss on the segment table itself.
	234	*/
	235	void stabs_alloc(void)
	236	{
	237	int cpu;
	238
	239	if (cpu_has_feature(CPU_FTR_SLB))
	240	return;
	241
0e551954	242	for_each_possible_cpu(cpu) {
533f0817 DG	243	unsigned long newstab;
	244
	245	if (cpu == 0)
	246	continue; /* stab for CPU 0 is statically allocated */
	247
3c726f8d BH	248	newstab = lmb_alloc_base(HW_PAGE_SIZE, HW_PAGE_SIZE,
3c726f8d BH	249	1<<SID_SHIFT);
b5666f70	250	newstab = (unsigned long)__va(newstab);
533f0817	251
3c726f8d	252	memset((void *)newstab, 0, HW_PAGE_SIZE);
533f0817 DG	253
	254	paca[cpu].stab_addr = newstab;
	255	paca[cpu].stab_real = virt_to_abs(newstab);
799d6046	256	printk(KERN_INFO "Segment table for CPU %d at 0x%lx "
3c726f8d BH	257	"virtual, 0x%lx absolute\n",
3c726f8d BH	258	cpu, paca[cpu].stab_addr, paca[cpu].stab_real);
533f0817 DG	259	}
	260	}
	261
1da177e4 LT	262	/*
	263	* Build an entry for the base kernel segment and put it into
	264	* the segment table or SLB. All other segment table or SLB
	265	* entries are faulted in.
	266	*/
	267	void stab_initialize(unsigned long stab)
	268	{
b5666f70	269	unsigned long vsid = get_kernel_vsid(PAGE_OFFSET);
799d6046	270	unsigned long stabreal;
1da177e4	271
3c726f8d	272	asm volatile("isync; slbia; isync":::"memory");
b5666f70	273	make_ste(stab, GET_ESID(PAGE_OFFSET), vsid);
1da177e4	274
3c726f8d BH	275	/* Order update */
3c726f8d BH	276	asm volatile("sync":::"memory");
799d6046 PM	277
	278	/* Set ASR */
	279	stabreal = get_paca()->stab_real \| 0x1ul;
	280
	281	#ifdef CONFIG_PPC_ISERIES
	282	if (firmware_has_feature(FW_FEATURE_ISERIES)) {
	283	HvCall1(HvCallBaseSetASR, stabreal);
	284	return;
	285	}
	286	#endif /* CONFIG_PPC_ISERIES */
ca507eaf	287
799d6046	288	mtspr(SPRN_ASR, stabreal);
1da177e4	289	}