1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __M68K_MMU_CONTEXT_H
3 #define __M68K_MMU_CONTEXT_H
4 
5 #include <asm-generic/mm_hooks.h>
6 #include <linux/mm_types.h>
7 
8 #ifdef CONFIG_MMU
9 
10 #if defined(CONFIG_COLDFIRE)
11 
12 #include <asm/atomic.h>
13 #include <asm/bitops.h>
14 #include <asm/mcfmmu.h>
15 #include <asm/mmu.h>
16 
17 #define NO_CONTEXT		256
18 #define LAST_CONTEXT		255
19 #define FIRST_CONTEXT		1
20 
21 extern unsigned long context_map[];
22 extern mm_context_t next_mmu_context;
23 
24 extern atomic_t nr_free_contexts;
25 extern struct mm_struct *context_mm[LAST_CONTEXT+1];
26 extern void steal_context(void);
27 
28 static inline void get_mmu_context(struct mm_struct *mm)
29 {
30 	mm_context_t ctx;
31 
32 	if (mm->context != NO_CONTEXT)
33 		return;
34 	while (arch_atomic_dec_and_test_lt(&nr_free_contexts)) {
35 		atomic_inc(&nr_free_contexts);
36 		steal_context();
37 	}
38 	ctx = next_mmu_context;
39 	while (test_and_set_bit(ctx, context_map)) {
40 		ctx = find_next_zero_bit(context_map, LAST_CONTEXT+1, ctx);
41 		if (ctx > LAST_CONTEXT)
42 			ctx = 0;
43 	}
44 	next_mmu_context = (ctx + 1) & LAST_CONTEXT;
45 	mm->context = ctx;
46 	context_mm[ctx] = mm;
47 }
48 
49 /*
50  * Set up the context for a new address space.
51  */
52 #define init_new_context(tsk, mm)	(((mm)->context = NO_CONTEXT), 0)
53 
54 /*
55  * We're finished using the context for an address space.
56  */
57 #define destroy_context destroy_context
58 static inline void destroy_context(struct mm_struct *mm)
59 {
60 	if (mm->context != NO_CONTEXT) {
61 		clear_bit(mm->context, context_map);
62 		mm->context = NO_CONTEXT;
63 		atomic_inc(&nr_free_contexts);
64 	}
65 }
66 
67 static inline void set_context(mm_context_t context, pgd_t *pgd)
68 {
69 	__asm__ __volatile__ ("movec %0,%%asid" : : "d" (context));
70 }
71 
72 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
73 	struct task_struct *tsk)
74 {
75 	get_mmu_context(tsk->mm);
76 	set_context(tsk->mm->context, next->pgd);
77 }
78 
79 /*
80  * After we have set current->mm to a new value, this activates
81  * the context for the new mm so we see the new mappings.
82  */
83 #define activate_mm activate_mm
84 static inline void activate_mm(struct mm_struct *active_mm,
85 	struct mm_struct *mm)
86 {
87 	get_mmu_context(mm);
88 	set_context(mm->context, mm->pgd);
89 }
90 
91 #define prepare_arch_switch(next) load_ksp_mmu(next)
92 
93 static inline void load_ksp_mmu(struct task_struct *task)
94 {
95 	unsigned long flags;
96 	struct mm_struct *mm;
97 	int asid;
98 	pgd_t *pgd;
99 	p4d_t *p4d;
100 	pud_t *pud;
101 	pmd_t *pmd;
102 	pte_t *pte;
103 	unsigned long mmuar;
104 
105 	local_irq_save(flags);
106 	mmuar = task->thread.ksp;
107 
108 	/* Search for a valid TLB entry, if one is found, don't remap */
109 	mmu_write(MMUAR, mmuar);
110 	mmu_write(MMUOR, MMUOR_STLB | MMUOR_ADR);
111 	if (mmu_read(MMUSR) & MMUSR_HIT)
112 		goto end;
113 
114 	if (mmuar >= PAGE_OFFSET) {
115 		mm = &init_mm;
116 	} else {
117 		pr_info("load_ksp_mmu: non-kernel mm found: 0x%p\n", task->mm);
118 		mm = task->mm;
119 	}
120 
121 	if (!mm)
122 		goto bug;
123 
124 	pgd = pgd_offset(mm, mmuar);
125 	if (pgd_none(*pgd))
126 		goto bug;
127 
128 	p4d = p4d_offset(pgd, mmuar);
129 	if (p4d_none(*p4d))
130 		goto bug;
131 
132 	pud = pud_offset(p4d, mmuar);
133 	if (pud_none(*pud))
134 		goto bug;
135 
136 	pmd = pmd_offset(pud, mmuar);
137 	if (pmd_none(*pmd))
138 		goto bug;
139 
140 	pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
141 				     : pte_offset_map(pmd, mmuar);
142 	if (pte_none(*pte) || !pte_present(*pte))
143 		goto bug;
144 
145 	set_pte(pte, pte_mkyoung(*pte));
146 	asid = mm->context & 0xff;
147 	if (!pte_dirty(*pte) && mmuar <= PAGE_OFFSET)
148 		set_pte(pte, pte_wrprotect(*pte));
149 
150 	mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) |
151 		(((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK)
152 		>> CF_PAGE_MMUTR_SHIFT) | MMUTR_V);
153 
154 	mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
155 		((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
156 
157 	mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
158 
159 	goto end;
160 
161 bug:
162 	pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
163 end:
164 	local_irq_restore(flags);
165 }
166 
167 #elif defined(CONFIG_SUN3)
168 #include <asm/sun3mmu.h>
169 #include <linux/sched.h>
170 
171 extern unsigned long get_free_context(struct mm_struct *mm);
172 extern void clear_context(unsigned long context);
173 
174 /* set the context for a new task to unmapped */
175 #define init_new_context init_new_context
176 static inline int init_new_context(struct task_struct *tsk,
177 				   struct mm_struct *mm)
178 {
179 	mm->context = SUN3_INVALID_CONTEXT;
180 	return 0;
181 }
182 
183 /* find the context given to this process, and if it hasn't already
184    got one, go get one for it. */
185 static inline void get_mmu_context(struct mm_struct *mm)
186 {
187 	if (mm->context == SUN3_INVALID_CONTEXT)
188 		mm->context = get_free_context(mm);
189 }
190 
191 /* flush context if allocated... */
192 #define destroy_context destroy_context
193 static inline void destroy_context(struct mm_struct *mm)
194 {
195 	if (mm->context != SUN3_INVALID_CONTEXT)
196 		clear_context(mm->context);
197 }
198 
199 static inline void activate_context(struct mm_struct *mm)
200 {
201 	get_mmu_context(mm);
202 	sun3_put_context(mm->context);
203 }
204 
205 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
206 			     struct task_struct *tsk)
207 {
208 	activate_context(tsk->mm);
209 }
210 
211 #define activate_mm activate_mm
212 static inline void activate_mm(struct mm_struct *prev_mm,
213 			       struct mm_struct *next_mm)
214 {
215 	activate_context(next_mm);
216 }
217 
218 #else
219 
220 #include <asm/setup.h>
221 #include <asm/page.h>
222 #include <asm/cacheflush.h>
223 
224 #define init_new_context init_new_context
225 static inline int init_new_context(struct task_struct *tsk,
226 				   struct mm_struct *mm)
227 {
228 	mm->context = virt_to_phys(mm->pgd);
229 	return 0;
230 }
231 
232 static inline void switch_mm_0230(struct mm_struct *mm)
233 {
234 	unsigned long crp[2] = {
235 		0x80000000 | _PAGE_TABLE, mm->context
236 	};
237 	unsigned long tmp;
238 
239 	asm volatile (".chip 68030");
240 
241 	/* flush MC68030/MC68020 caches (they are virtually addressed) */
242 	asm volatile (
243 		"movec %%cacr,%0;"
244 		"orw %1,%0; "
245 		"movec %0,%%cacr"
246 		: "=d" (tmp) : "di" (FLUSH_I_AND_D));
247 
248 	/* Switch the root pointer. For a 030-only kernel,
249 	 * avoid flushing the whole ATC, we only need to
250 	 * flush the user entries. The 68851 does this by
251 	 * itself. Avoid a runtime check here.
252 	 */
253 	asm volatile (
254 #ifdef CPU_M68030_ONLY
255 		"pmovefd %0,%%crp; "
256 		"pflush #0,#4"
257 #else
258 		"pmove %0,%%crp"
259 #endif
260 		: : "m" (crp[0]));
261 
262 	asm volatile (".chip 68k");
263 }
264 
265 static inline void switch_mm_0460(struct mm_struct *mm)
266 {
267 	asm volatile (".chip 68040");
268 
269 	/* flush address translation cache (user entries) */
270 	asm volatile ("pflushan");
271 
272 	/* switch the root pointer */
273 	asm volatile ("movec %0,%%urp" : : "r" (mm->context));
274 
275 	if (CPU_IS_060) {
276 		unsigned long tmp;
277 
278 		/* clear user entries in the branch cache */
279 		asm volatile (
280 			"movec %%cacr,%0; "
281 		        "orl %1,%0; "
282 		        "movec %0,%%cacr"
283 			: "=d" (tmp): "di" (0x00200000));
284 	}
285 
286 	asm volatile (".chip 68k");
287 }
288 
289 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
290 {
291 	if (prev != next) {
292 		if (CPU_IS_020_OR_030)
293 			switch_mm_0230(next);
294 		else
295 			switch_mm_0460(next);
296 	}
297 }
298 
299 #define activate_mm activate_mm
300 static inline void activate_mm(struct mm_struct *prev_mm,
301 			       struct mm_struct *next_mm)
302 {
303 	next_mm->context = virt_to_phys(next_mm->pgd);
304 
305 	if (CPU_IS_020_OR_030)
306 		switch_mm_0230(next_mm);
307 	else
308 		switch_mm_0460(next_mm);
309 }
310 
311 #endif
312 
313 #include <asm-generic/mmu_context.h>
314 
315 #else /* !CONFIG_MMU */
316 
317 #include <asm-generic/nommu_context.h>
318 
319 #endif /* CONFIG_MMU */
320 #endif /* __M68K_MMU_CONTEXT_H */
321