1 files changed, 320 insertions, 0 deletions
diff --git a/arch/m68k/include/asm/mmu_context.h b/arch/m68k/include/asm/mmu_context.h
new file mode 100644
index 000000000..8ed6ac14d
--- /dev/null
+++ b/arch/m68k/include/asm/mmu_context.h
@@ -0,0 +1,320 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __M68K_MMU_CONTEXT_H
+#define __M68K_MMU_CONTEXT_H
+
+#include <asm-generic/mm_hooks.h>
+#include <linux/mm_types.h>
+
+#ifdef CONFIG_MMU
+
+#if defined(CONFIG_COLDFIRE)
+
+#include <asm/atomic.h>
+#include <asm/bitops.h>
+#include <asm/mcfmmu.h>
+#include <asm/mmu.h>
+
+#define NO_CONTEXT		256
+#define LAST_CONTEXT		255
+#define FIRST_CONTEXT		1
+
+extern unsigned long context_map[];
+extern mm_context_t next_mmu_context;
+
+extern atomic_t nr_free_contexts;
+extern struct mm_struct *context_mm[LAST_CONTEXT+1];
+extern void steal_context(void);
+
+static inline void get_mmu_context(struct mm_struct *mm)
+{
+	mm_context_t ctx;
+
+	if (mm->context != NO_CONTEXT)
+		return;
+	while (arch_atomic_dec_and_test_lt(&nr_free_contexts)) {
+		atomic_inc(&nr_free_contexts);
+		steal_context();
+	}
+	ctx = next_mmu_context;
+	while (test_and_set_bit(ctx, context_map)) {
+		ctx = find_next_zero_bit(context_map, LAST_CONTEXT+1, ctx);
+		if (ctx > LAST_CONTEXT)
+			ctx = 0;
+	}
+	next_mmu_context = (ctx + 1) & LAST_CONTEXT;
+	mm->context = ctx;
+	context_mm[ctx] = mm;
+}
+
+/*
+ * Set up the context for a new address space.
+ */
+#define init_new_context(tsk, mm)	(((mm)->context = NO_CONTEXT), 0)
+
+/*
+ * We're finished using the context for an address space.
+ */
+#define destroy_context destroy_context
+static inline void destroy_context(struct mm_struct *mm)
+{
+	if (mm->context != NO_CONTEXT) {
+		clear_bit(mm->context, context_map);
+		mm->context = NO_CONTEXT;
+		atomic_inc(&nr_free_contexts);
+	}
+}
+
+static inline void set_context(mm_context_t context, pgd_t *pgd)
+{
+	__asm__ __volatile__ ("movec %0,%%asid" : : "d" (context));
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+	struct task_struct *tsk)
+{
+	get_mmu_context(tsk->mm);
+	set_context(tsk->mm->context, next->pgd);
+}
+
+/*
+ * After we have set current->mm to a new value, this activates
+ * the context for the new mm so we see the new mappings.
+ */
+#define activate_mm activate_mm
+static inline void activate_mm(struct mm_struct *active_mm,
+	struct mm_struct *mm)
+{
+	get_mmu_context(mm);
+	set_context(mm->context, mm->pgd);
+}
+
+#define prepare_arch_switch(next) load_ksp_mmu(next)
+
+static inline void load_ksp_mmu(struct task_struct *task)
+{
+	unsigned long flags;
+	struct mm_struct *mm;
+	int asid;
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+	unsigned long mmuar;
+
+	local_irq_save(flags);
+	mmuar = task->thread.ksp;
+
+	/* Search for a valid TLB entry, if one is found, don't remap */
+	mmu_write(MMUAR, mmuar);
+	mmu_write(MMUOR, MMUOR_STLB | MMUOR_ADR);
+	if (mmu_read(MMUSR) & MMUSR_HIT)
+		goto end;
+
+	if (mmuar >= PAGE_OFFSET) {
+		mm = &init_mm;
+	} else {
+		pr_info("load_ksp_mmu: non-kernel mm found: 0x%p\n", task->mm);
+		mm = task->mm;
+	}
+
+	if (!mm)
+		goto bug;
+
+	pgd = pgd_offset(mm, mmuar);
+	if (pgd_none(*pgd))
+		goto bug;
+
+	p4d = p4d_offset(pgd, mmuar);
+	if (p4d_none(*p4d))
+		goto bug;
+
+	pud = pud_offset(p4d, mmuar);
+	if (pud_none(*pud))
+		goto bug;
+
+	pmd = pmd_offset(pud, mmuar);
+	if (pmd_none(*pmd))
+		goto bug;
+
+	pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
+				     : pte_offset_map(pmd, mmuar);
+	if (pte_none(*pte) || !pte_present(*pte))
+		goto bug;
+
+	set_pte(pte, pte_mkyoung(*pte));
+	asid = mm->context & 0xff;
+	if (!pte_dirty(*pte) && mmuar <= PAGE_OFFSET)
+		set_pte(pte, pte_wrprotect(*pte));
+
+	mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) |
+		(((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK)
+		>> CF_PAGE_MMUTR_SHIFT) | MMUTR_V);
+
+	mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
+		((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
+
+	mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
+
+	goto end;
+
+bug:
+	pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
+end:
+	local_irq_restore(flags);
+}
+
+#elif defined(CONFIG_SUN3)
+#include <asm/sun3mmu.h>
+#include <linux/sched.h>
+
+extern unsigned long get_free_context(struct mm_struct *mm);
+extern void clear_context(unsigned long context);
+
+/* set the context for a new task to unmapped */
+#define init_new_context init_new_context
+static inline int init_new_context(struct task_struct *tsk,
+				   struct mm_struct *mm)
+{
+	mm->context = SUN3_INVALID_CONTEXT;
+	return 0;
+}
+
+/* find the context given to this process, and if it hasn't already
+   got one, go get one for it. */
+static inline void get_mmu_context(struct mm_struct *mm)
+{
+	if (mm->context == SUN3_INVALID_CONTEXT)
+		mm->context = get_free_context(mm);
+}
+
+/* flush context if allocated... */
+#define destroy_context destroy_context
+static inline void destroy_context(struct mm_struct *mm)
+{
+	if (mm->context != SUN3_INVALID_CONTEXT)
+		clear_context(mm->context);
+}
+
+static inline void activate_context(struct mm_struct *mm)
+{
+	get_mmu_context(mm);
+	sun3_put_context(mm->context);
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+			     struct task_struct *tsk)
+{
+	activate_context(tsk->mm);
+}
+
+#define activate_mm activate_mm
+static inline void activate_mm(struct mm_struct *prev_mm,
+			       struct mm_struct *next_mm)
+{
+	activate_context(next_mm);
+}
+
+#else
+
+#include <asm/setup.h>
+#include <asm/page.h>
+#include <asm/cacheflush.h>
+
+#define init_new_context init_new_context
+static inline int init_new_context(struct task_struct *tsk,
+				   struct mm_struct *mm)
+{
+	mm->context = virt_to_phys(mm->pgd);
+	return 0;
+}
+
+static inline void switch_mm_0230(struct mm_struct *mm)
+{
+	unsigned long crp[2] = {
+		0x80000000 | _PAGE_TABLE, mm->context
+	};
+	unsigned long tmp;
+
+	asm volatile (".chip 68030");
+
+	/* flush MC68030/MC68020 caches (they are virtually addressed) */
+	asm volatile (
+		"movec %%cacr,%0;"
+		"orw %1,%0; "
+		"movec %0,%%cacr"
+		: "=d" (tmp) : "di" (FLUSH_I_AND_D));
+
+	/* Switch the root pointer. For a 030-only kernel,
+	 * avoid flushing the whole ATC, we only need to
+	 * flush the user entries. The 68851 does this by
+	 * itself. Avoid a runtime check here.
+	 */
+	asm volatile (
+#ifdef CPU_M68030_ONLY
+		"pmovefd %0,%%crp; "
+		"pflush #0,#4"
+#else
+		"pmove %0,%%crp"
+#endif
+		: : "m" (crp[0]));
+
+	asm volatile (".chip 68k");
+}
+
+static inline void switch_mm_0460(struct mm_struct *mm)
+{
+	asm volatile (".chip 68040");
+
+	/* flush address translation cache (user entries) */
+	asm volatile ("pflushan");
+
+	/* switch the root pointer */
+	asm volatile ("movec %0,%%urp" : : "r" (mm->context));
+
+	if (CPU_IS_060) {
+		unsigned long tmp;
+
+		/* clear user entries in the branch cache */
+		asm volatile (
+			"movec %%cacr,%0; "
+		        "orl %1,%0; "
+		        "movec %0,%%cacr"
+			: "=d" (tmp): "di" (0x00200000));
+	}
+
+	asm volatile (".chip 68k");
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
+{
+	if (prev != next) {
+		if (CPU_IS_020_OR_030)
+			switch_mm_0230(next);
+		else
+			switch_mm_0460(next);
+	}
+}
+
+#define activate_mm activate_mm
+static inline void activate_mm(struct mm_struct *prev_mm,
+			       struct mm_struct *next_mm)
+{
+	next_mm->context = virt_to_phys(next_mm->pgd);
+
+	if (CPU_IS_020_OR_030)
+		switch_mm_0230(next_mm);
+	else
+		switch_mm_0460(next_mm);
+}
+
+#endif
+
+#include <asm-generic/mmu_context.h>
+
+#else /* !CONFIG_MMU */
+
+#include <asm-generic/nommu_context.h>
+
+#endif /* CONFIG_MMU */
+#endif /* __M68K_MMU_CONTEXT_H */