tlb.c

  1/*
  2 * Nios2 TLB handling
  3 *
  4 * Copyright (C) 2009, Wind River Systems Inc
  5 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
  6 *
  7 * This file is subject to the terms and conditions of the GNU General Public
  8 * License.  See the file "COPYING" in the main directory of this archive
  9 * for more details.
 10 */
 11
 12#include <linux/init.h>
 13#include <linux/sched.h>
 14#include <linux/mm.h>
 15#include <linux/pagemap.h>
 16
 17#include <asm/tlb.h>
 18#include <asm/mmu_context.h>
 19#include <asm/cpuinfo.h>
 20
 21#define TLB_INDEX_MASK		\
 22	((((1UL << (cpuinfo.tlb_ptr_sz - cpuinfo.tlb_num_ways_log2))) - 1) \
 23		<< PAGE_SHIFT)
 24
 25static void get_misc_and_pid(unsigned long *misc, unsigned long *pid)
 26{
 27	*misc  = RDCTL(CTL_TLBMISC);
 28	*misc &= (TLBMISC_PID | TLBMISC_WAY);
 29	*pid  = *misc & TLBMISC_PID;
 30}
 31
 32/*
 33 * This provides a PTEADDR value for addr that will cause a TLB miss
 34 * (fast TLB miss). TLB invalidation replaces entries with this value.
 35 */
 36static unsigned long pteaddr_invalid(unsigned long addr)
 37{
 38	return ((addr | 0xC0000000UL) >> PAGE_SHIFT) << 2;
 39}
 40
 41/*
 42 * This one is only used for pages with the global bit set so we don't care
 43 * much about the ASID.
 44 */
 45static void replace_tlb_one_pid(unsigned long addr, unsigned long mmu_pid, unsigned long tlbacc)
 46{
 47	unsigned int way;
 48	unsigned long org_misc, pid_misc;
 49
 50	/* remember pid/way until we return. */
 51	get_misc_and_pid(&org_misc, &pid_misc);
 52
 53	WRCTL(CTL_PTEADDR, (addr >> PAGE_SHIFT) << 2);
 54
 55	for (way = 0; way < cpuinfo.tlb_num_ways; way++) {
 56		unsigned long pteaddr;
 57		unsigned long tlbmisc;
 58		unsigned long pid;
 59
 60		tlbmisc = TLBMISC_RD | (way << TLBMISC_WAY_SHIFT);
 61		WRCTL(CTL_TLBMISC, tlbmisc);
 62
 63		pteaddr = RDCTL(CTL_PTEADDR);
 64		if (((pteaddr >> 2) & 0xfffff) != (addr >> PAGE_SHIFT))
 65			continue;
 66
 67		tlbmisc = RDCTL(CTL_TLBMISC);
 68		pid = (tlbmisc >> TLBMISC_PID_SHIFT) & TLBMISC_PID_MASK;
 69		if (pid != mmu_pid)
 70			continue;
 71
 72		tlbmisc = (mmu_pid << TLBMISC_PID_SHIFT) | TLBMISC_WE |
 73			  (way << TLBMISC_WAY_SHIFT);
 74		WRCTL(CTL_TLBMISC, tlbmisc);
 75		if (tlbacc == 0)
 76			WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
 77		WRCTL(CTL_TLBACC, tlbacc);
 78		/*
 79		 * There should be only a single entry that maps a
 80		 * particular {address,pid} so break after a match.
 81		 */
 82		break;
 83	}
 84
 85	WRCTL(CTL_TLBMISC, org_misc);
 86}
 87
 88static void flush_tlb_one_pid(unsigned long addr, unsigned long mmu_pid)
 89{
 90	pr_debug("Flush tlb-entry for vaddr=%#lx\n", addr);
 91
 92	replace_tlb_one_pid(addr, mmu_pid, 0);
 93}
 94
 95static void reload_tlb_one_pid(unsigned long addr, unsigned long mmu_pid, pte_t pte)
 96{
 97	pr_debug("Reload tlb-entry for vaddr=%#lx\n", addr);
 98
 99	replace_tlb_one_pid(addr, mmu_pid, pte_val(pte));
100}
101
102void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
103			unsigned long end)
104{
105	unsigned long mmu_pid = get_pid_from_context(&vma->vm_mm->context);
106
107	while (start < end) {
108		flush_tlb_one_pid(start, mmu_pid);
109		start += PAGE_SIZE;
110	}
111}
112
113void reload_tlb_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
114{
115	unsigned long mmu_pid = get_pid_from_context(&vma->vm_mm->context);
116
117	reload_tlb_one_pid(addr, mmu_pid, pte);
118}
119
120/*
121 * This one is only used for pages with the global bit set so we don't care
122 * much about the ASID.
123 */
124static void flush_tlb_one(unsigned long addr)
125{
126	unsigned int way;
127	unsigned long org_misc, pid_misc;
128
129	pr_debug("Flush tlb-entry for vaddr=%#lx\n", addr);
130
131	/* remember pid/way until we return. */
132	get_misc_and_pid(&org_misc, &pid_misc);
133
134	WRCTL(CTL_PTEADDR, (addr >> PAGE_SHIFT) << 2);
135
136	for (way = 0; way < cpuinfo.tlb_num_ways; way++) {
137		unsigned long pteaddr;
138		unsigned long tlbmisc;
139
140		tlbmisc = TLBMISC_RD | (way << TLBMISC_WAY_SHIFT);
141		WRCTL(CTL_TLBMISC, tlbmisc);
142
143		pteaddr = RDCTL(CTL_PTEADDR);
144		if (((pteaddr >> 2) & 0xfffff) != (addr >> PAGE_SHIFT))
145			continue;
146
147		tlbmisc = RDCTL(CTL_TLBMISC);
148		pr_debug("Flush entry by writing way=%dl pid=%ld\n",
149			 way, ((tlbmisc >> TLBMISC_PID_SHIFT) & TLBMISC_PID_MASK));
150
151		tlbmisc = TLBMISC_WE | (way << TLBMISC_WAY_SHIFT) | (tlbmisc & TLBMISC_PID);
152		WRCTL(CTL_TLBMISC, tlbmisc);
153		WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
154		WRCTL(CTL_TLBACC, 0);
155	}
156
157	WRCTL(CTL_TLBMISC, org_misc);
158}
159
160void flush_tlb_kernel_range(unsigned long start, unsigned long end)
161{
162	while (start < end) {
163		flush_tlb_one(start);
164		start += PAGE_SIZE;
165	}
166}
167
168void dump_tlb_line(unsigned long line)
169{
170	unsigned int way;
171	unsigned long org_misc;
172
173	pr_debug("dump tlb-entries for line=%#lx (addr %08lx)\n", line,
174		line << (PAGE_SHIFT + cpuinfo.tlb_num_ways_log2));
175
176	/* remember pid/way until we return */
177	org_misc = (RDCTL(CTL_TLBMISC) & (TLBMISC_PID | TLBMISC_WAY));
178
179	WRCTL(CTL_PTEADDR, line << 2);
180
181	for (way = 0; way < cpuinfo.tlb_num_ways; way++) {
182		unsigned long pteaddr;
183		unsigned long tlbmisc;
184		unsigned long tlbacc;
185
186		WRCTL(CTL_TLBMISC, TLBMISC_RD | (way << TLBMISC_WAY_SHIFT));
187		pteaddr = RDCTL(CTL_PTEADDR);
188		tlbmisc = RDCTL(CTL_TLBMISC);
189		tlbacc = RDCTL(CTL_TLBACC);
190
191		if ((tlbacc << PAGE_SHIFT) != 0) {
192			pr_debug("-- way:%02x vpn:0x%08lx phys:0x%08lx pid:0x%02lx flags:%c%c%c%c%c\n",
193				way,
194				(pteaddr << (PAGE_SHIFT-2)),
195				(tlbacc << PAGE_SHIFT),
196				((tlbmisc >> TLBMISC_PID_SHIFT) &
197				TLBMISC_PID_MASK),
198				(tlbacc & _PAGE_READ ? 'r' : '-'),
199				(tlbacc & _PAGE_WRITE ? 'w' : '-'),
200				(tlbacc & _PAGE_EXEC ? 'x' : '-'),
201				(tlbacc & _PAGE_GLOBAL ? 'g' : '-'),
202				(tlbacc & _PAGE_CACHED ? 'c' : '-'));
203		}
204	}
205
206	WRCTL(CTL_TLBMISC, org_misc);
207}
208
209void dump_tlb(void)
210{
211	unsigned int i;
212
213	for (i = 0; i < cpuinfo.tlb_num_lines; i++)
214		dump_tlb_line(i);
215}
216
217void flush_tlb_pid(unsigned long mmu_pid)
218{
219	unsigned long addr = 0;
220	unsigned int line;
221	unsigned int way;
222	unsigned long org_misc, pid_misc;
223
224	/* remember pid/way until we return */
225	get_misc_and_pid(&org_misc, &pid_misc);
226
227	for (line = 0; line < cpuinfo.tlb_num_lines; line++) {
228		WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
229
230		for (way = 0; way < cpuinfo.tlb_num_ways; way++) {
231			unsigned long tlbmisc;
232			unsigned long pid;
233
234			tlbmisc = TLBMISC_RD | (way << TLBMISC_WAY_SHIFT);
235			WRCTL(CTL_TLBMISC, tlbmisc);
236			tlbmisc = RDCTL(CTL_TLBMISC);
237			pid = (tlbmisc >> TLBMISC_PID_SHIFT) & TLBMISC_PID_MASK;
238			if (pid != mmu_pid)
239				continue;
240
241			tlbmisc = TLBMISC_WE | (way << TLBMISC_WAY_SHIFT) |
242				  (pid << TLBMISC_PID_SHIFT);
243			WRCTL(CTL_TLBMISC, tlbmisc);
244			WRCTL(CTL_TLBACC, 0);
245		}
246
247		addr += PAGE_SIZE;
248	}
249
250	WRCTL(CTL_TLBMISC, org_misc);
251}
252
253/*
254 * All entries common to a mm share an asid.  To effectively flush these
255 * entries, we just bump the asid.
256 */
257void flush_tlb_mm(struct mm_struct *mm)
258{
259	if (current->mm == mm) {
260		unsigned long mmu_pid = get_pid_from_context(&mm->context);
261		flush_tlb_pid(mmu_pid);
262	} else {
263		memset(&mm->context, 0, sizeof(mm_context_t));
264	}
265}
266
267void flush_tlb_all(void)
268{
269	unsigned long addr = 0;
270	unsigned int line;
271	unsigned int way;
272	unsigned long org_misc, pid_misc;
273
274	/* remember pid/way until we return */
275	get_misc_and_pid(&org_misc, &pid_misc);
276
277	/* Map each TLB entry to physcal address 0 with no-access and a
278	   bad ptbase */
279	for (line = 0; line < cpuinfo.tlb_num_lines; line++) {
280		WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
281		for (way = 0; way < cpuinfo.tlb_num_ways; way++) {
282			// Code such as replace_tlb_one_pid assumes that no duplicate entries exist
283			// for a single address across ways, so also use way as a dummy PID
284			WRCTL(CTL_TLBMISC, TLBMISC_WE | (way << TLBMISC_WAY_SHIFT) |
285					   (way << TLBMISC_PID_SHIFT));
286			WRCTL(CTL_TLBACC, 0);
287		}
288
289		addr += PAGE_SIZE;
290	}
291
292	/* restore pid/way */
293	WRCTL(CTL_TLBMISC, org_misc);
294}
295
296void set_mmu_pid(unsigned long pid)
297{
298	unsigned long tlbmisc;
299
300	tlbmisc = RDCTL(CTL_TLBMISC);
301	tlbmisc = (tlbmisc & TLBMISC_WAY);
302	tlbmisc |= (pid & TLBMISC_PID_MASK) << TLBMISC_PID_SHIFT;
303	WRCTL(CTL_TLBMISC, tlbmisc);
304}