xref: /openbmc/linux/arch/nios2/mm/tlb.c (revision e31cf2f4)
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 
get_misc_and_pid(unsigned long * misc,unsigned long * pid)25 static 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  */
pteaddr_invalid(unsigned long addr)36 static 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  */
replace_tlb_one_pid(unsigned long addr,unsigned long mmu_pid,unsigned long tlbacc)45 static 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 
flush_tlb_one_pid(unsigned long addr,unsigned long mmu_pid)88 static 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 
reload_tlb_one_pid(unsigned long addr,unsigned long mmu_pid,pte_t pte)95 static 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 
flush_tlb_range(struct vm_area_struct * vma,unsigned long start,unsigned long end)102 void 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 
reload_tlb_page(struct vm_area_struct * vma,unsigned long addr,pte_t pte)113 void 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  */
flush_tlb_one(unsigned long addr)124 static 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 		pr_debug("Flush entry by writing way=%dl pid=%ld\n",
148 			 way, (pid_misc >> TLBMISC_PID_SHIFT));
149 
150 		tlbmisc = TLBMISC_WE | (way << TLBMISC_WAY_SHIFT);
151 		WRCTL(CTL_TLBMISC, tlbmisc);
152 		WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
153 		WRCTL(CTL_TLBACC, 0);
154 	}
155 
156 	WRCTL(CTL_TLBMISC, org_misc);
157 }
158 
flush_tlb_kernel_range(unsigned long start,unsigned long end)159 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
160 {
161 	while (start < end) {
162 		flush_tlb_one(start);
163 		start += PAGE_SIZE;
164 	}
165 }
166 
dump_tlb_line(unsigned long line)167 void dump_tlb_line(unsigned long line)
168 {
169 	unsigned int way;
170 	unsigned long org_misc;
171 
172 	pr_debug("dump tlb-entries for line=%#lx (addr %08lx)\n", line,
173 		line << (PAGE_SHIFT + cpuinfo.tlb_num_ways_log2));
174 
175 	/* remember pid/way until we return */
176 	org_misc = (RDCTL(CTL_TLBMISC) & (TLBMISC_PID | TLBMISC_WAY));
177 
178 	WRCTL(CTL_PTEADDR, line << 2);
179 
180 	for (way = 0; way < cpuinfo.tlb_num_ways; way++) {
181 		unsigned long pteaddr;
182 		unsigned long tlbmisc;
183 		unsigned long tlbacc;
184 
185 		WRCTL(CTL_TLBMISC, TLBMISC_RD | (way << TLBMISC_WAY_SHIFT));
186 		pteaddr = RDCTL(CTL_PTEADDR);
187 		tlbmisc = RDCTL(CTL_TLBMISC);
188 		tlbacc = RDCTL(CTL_TLBACC);
189 
190 		if ((tlbacc << PAGE_SHIFT) != 0) {
191 			pr_debug("-- way:%02x vpn:0x%08lx phys:0x%08lx pid:0x%02lx flags:%c%c%c%c%c\n",
192 				way,
193 				(pteaddr << (PAGE_SHIFT-2)),
194 				(tlbacc << PAGE_SHIFT),
195 				((tlbmisc >> TLBMISC_PID_SHIFT) &
196 				TLBMISC_PID_MASK),
197 				(tlbacc & _PAGE_READ ? 'r' : '-'),
198 				(tlbacc & _PAGE_WRITE ? 'w' : '-'),
199 				(tlbacc & _PAGE_EXEC ? 'x' : '-'),
200 				(tlbacc & _PAGE_GLOBAL ? 'g' : '-'),
201 				(tlbacc & _PAGE_CACHED ? 'c' : '-'));
202 		}
203 	}
204 
205 	WRCTL(CTL_TLBMISC, org_misc);
206 }
207 
dump_tlb(void)208 void dump_tlb(void)
209 {
210 	unsigned int i;
211 
212 	for (i = 0; i < cpuinfo.tlb_num_lines; i++)
213 		dump_tlb_line(i);
214 }
215 
flush_tlb_pid(unsigned long mmu_pid)216 void flush_tlb_pid(unsigned long mmu_pid)
217 {
218 	unsigned long addr = 0;
219 	unsigned int line;
220 	unsigned int way;
221 	unsigned long org_misc, pid_misc;
222 
223 	/* remember pid/way until we return */
224 	get_misc_and_pid(&org_misc, &pid_misc);
225 
226 	for (line = 0; line < cpuinfo.tlb_num_lines; line++) {
227 		WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
228 
229 		for (way = 0; way < cpuinfo.tlb_num_ways; way++) {
230 			unsigned long tlbmisc;
231 			unsigned long pid;
232 
233 			tlbmisc = TLBMISC_RD | (way << TLBMISC_WAY_SHIFT);
234 			WRCTL(CTL_TLBMISC, tlbmisc);
235 			tlbmisc = RDCTL(CTL_TLBMISC);
236 			pid = (tlbmisc >> TLBMISC_PID_SHIFT) & TLBMISC_PID_MASK;
237 			if (pid != mmu_pid)
238 				continue;
239 
240 			tlbmisc = TLBMISC_WE | (way << TLBMISC_WAY_SHIFT);
241 			WRCTL(CTL_TLBMISC, tlbmisc);
242 			WRCTL(CTL_TLBACC, 0);
243 		}
244 
245 		addr += PAGE_SIZE;
246 	}
247 
248 	WRCTL(CTL_TLBMISC, org_misc);
249 }
250 
251 /*
252  * All entries common to a mm share an asid.  To effectively flush these
253  * entries, we just bump the asid.
254  */
flush_tlb_mm(struct mm_struct * mm)255 void flush_tlb_mm(struct mm_struct *mm)
256 {
257 	if (current->mm == mm) {
258 		unsigned long mmu_pid = get_pid_from_context(&mm->context);
259 		flush_tlb_pid(mmu_pid);
260 	} else {
261 		memset(&mm->context, 0, sizeof(mm_context_t));
262 	}
263 }
264 
flush_tlb_all(void)265 void flush_tlb_all(void)
266 {
267 	unsigned long addr = 0;
268 	unsigned int line;
269 	unsigned int way;
270 	unsigned long org_misc, pid_misc;
271 
272 	/* remember pid/way until we return */
273 	get_misc_and_pid(&org_misc, &pid_misc);
274 
275 	/* Start at way 0, way is auto-incremented after each TLBACC write */
276 	WRCTL(CTL_TLBMISC, TLBMISC_WE);
277 
278 	/* Map each TLB entry to physcal address 0 with no-access and a
279 	   bad ptbase */
280 	for (line = 0; line < cpuinfo.tlb_num_lines; line++) {
281 		WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
282 		for (way = 0; way < cpuinfo.tlb_num_ways; way++)
283 			WRCTL(CTL_TLBACC, 0);
284 
285 		addr += PAGE_SIZE;
286 	}
287 
288 	/* restore pid/way */
289 	WRCTL(CTL_TLBMISC, org_misc);
290 }
291 
set_mmu_pid(unsigned long pid)292 void set_mmu_pid(unsigned long pid)
293 {
294 	unsigned long tlbmisc;
295 
296 	tlbmisc = RDCTL(CTL_TLBMISC);
297 	tlbmisc = (tlbmisc & TLBMISC_WAY);
298 	tlbmisc |= (pid & TLBMISC_PID_MASK) << TLBMISC_PID_SHIFT;
299 	WRCTL(CTL_TLBMISC, tlbmisc);
300 }
301