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
21extern unsigned long context_map[];
22extern mm_context_t next_mmu_context;
23
24extern atomic_t nr_free_contexts;
25extern struct mm_struct *context_mm[LAST_CONTEXT+1];
26extern void steal_context(void);
27
28static 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
58static 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
67static inline void set_context(mm_context_t context, pgd_t *pgd)
68{
69	__asm__ __volatile__ ("movec %0,%%asid" : : "d" (context));
70}
71
72static 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
84static 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
93static 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 = NULL;
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 || 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
161bug:
162	pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
163end:
164	if (pte && mmuar < PAGE_OFFSET)
165		pte_unmap(pte);
166	local_irq_restore(flags);
167}
168
169#elif defined(CONFIG_SUN3)
170#include <asm/sun3mmu.h>
171#include <linux/sched.h>
172
173extern unsigned long get_free_context(struct mm_struct *mm);
174extern void clear_context(unsigned long context);
175
176/* set the context for a new task to unmapped */
177#define init_new_context init_new_context
178static inline int init_new_context(struct task_struct *tsk,
179				   struct mm_struct *mm)
180{
181	mm->context = SUN3_INVALID_CONTEXT;
182	return 0;
183}
184
185/* find the context given to this process, and if it hasn't already
186   got one, go get one for it. */
187static inline void get_mmu_context(struct mm_struct *mm)
188{
189	if (mm->context == SUN3_INVALID_CONTEXT)
190		mm->context = get_free_context(mm);
191}
192
193/* flush context if allocated... */
194#define destroy_context destroy_context
195static inline void destroy_context(struct mm_struct *mm)
196{
197	if (mm->context != SUN3_INVALID_CONTEXT)
198		clear_context(mm->context);
199}
200
201static inline void activate_context(struct mm_struct *mm)
202{
203	get_mmu_context(mm);
204	sun3_put_context(mm->context);
205}
206
207static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
208			     struct task_struct *tsk)
209{
210	activate_context(tsk->mm);
211}
212
213#define activate_mm activate_mm
214static inline void activate_mm(struct mm_struct *prev_mm,
215			       struct mm_struct *next_mm)
216{
217	activate_context(next_mm);
218}
219
220#else
221
222#include <asm/setup.h>
223#include <asm/page.h>
224#include <asm/cacheflush.h>
225
226#define init_new_context init_new_context
227static inline int init_new_context(struct task_struct *tsk,
228				   struct mm_struct *mm)
229{
230	mm->context = virt_to_phys(mm->pgd);
231	return 0;
232}
233
234static inline void switch_mm_0230(struct mm_struct *mm)
235{
236	unsigned long crp[2] = {
237		0x80000000 | _PAGE_TABLE, mm->context
238	};
239	unsigned long tmp;
240
241	asm volatile (".chip 68030");
242
243	/* flush MC68030/MC68020 caches (they are virtually addressed) */
244	asm volatile (
245		"movec %%cacr,%0;"
246		"orw %1,%0; "
247		"movec %0,%%cacr"
248		: "=d" (tmp) : "di" (FLUSH_I_AND_D));
249
250	/* Switch the root pointer. For a 030-only kernel,
251	 * avoid flushing the whole ATC, we only need to
252	 * flush the user entries. The 68851 does this by
253	 * itself. Avoid a runtime check here.
254	 */
255	asm volatile (
256#ifdef CPU_M68030_ONLY
257		"pmovefd %0,%%crp; "
258		"pflush #0,#4"
259#else
260		"pmove %0,%%crp"
261#endif
262		: : "m" (crp[0]));
263
264	asm volatile (".chip 68k");
265}
266
267static inline void switch_mm_0460(struct mm_struct *mm)
268{
269	asm volatile (".chip 68040");
270
271	/* flush address translation cache (user entries) */
272	asm volatile ("pflushan");
273
274	/* switch the root pointer */
275	asm volatile ("movec %0,%%urp" : : "r" (mm->context));
276
277	if (CPU_IS_060) {
278		unsigned long tmp;
279
280		/* clear user entries in the branch cache */
281		asm volatile (
282			"movec %%cacr,%0; "
283		        "orl %1,%0; "
284		        "movec %0,%%cacr"
285			: "=d" (tmp): "di" (0x00200000));
286	}
287
288	asm volatile (".chip 68k");
289}
290
291static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
292{
293	if (prev != next) {
294		if (CPU_IS_020_OR_030)
295			switch_mm_0230(next);
296		else
297			switch_mm_0460(next);
298	}
299}
300
301#define activate_mm activate_mm
302static inline void activate_mm(struct mm_struct *prev_mm,
303			       struct mm_struct *next_mm)
304{
305	next_mm->context = virt_to_phys(next_mm->pgd);
306
307	if (CPU_IS_020_OR_030)
308		switch_mm_0230(next_mm);
309	else
310		switch_mm_0460(next_mm);
311}
312
313#endif
314
315#include <asm-generic/mmu_context.h>
316
317#else /* !CONFIG_MMU */
318
319#include <asm-generic/nommu_context.h>
320
321#endif /* CONFIG_MMU */
322#endif /* __M68K_MMU_CONTEXT_H */
323