sun4c.c

一个2.4.21版本的嵌入式linux内核

			begin += 512;
		}
	} else {
		while (begin < end) {
			__asm__ __volatile__(
			"ld	[%0 + 0x00], %%g0\n\t"
			"ld	[%0 + 0x10], %%g0\n\t"
			"ld	[%0 + 0x20], %%g0\n\t"
			"ld	[%0 + 0x30], %%g0\n\t"
			"ld	[%0 + 0x40], %%g0\n\t"
			"ld	[%0 + 0x50], %%g0\n\t"
			"ld	[%0 + 0x60], %%g0\n\t"
			"ld	[%0 + 0x70], %%g0\n\t"
			"ld	[%0 + 0x80], %%g0\n\t"
			"ld	[%0 + 0x90], %%g0\n\t"
			"ld	[%0 + 0xa0], %%g0\n\t"
			"ld	[%0 + 0xb0], %%g0\n\t"
			"ld	[%0 + 0xc0], %%g0\n\t"
			"ld	[%0 + 0xd0], %%g0\n\t"
			"ld	[%0 + 0xe0], %%g0\n\t"
			"ld	[%0 + 0xf0], %%g0\n"
			: : "r" (begin));
			begin += 256;
		}
	}
}

static void sun4c_flush_cache_mm(struct mm_struct *mm)
{
	int new_ctx = mm->context;

	if (new_ctx != NO_CONTEXT) {
		flush_user_windows();

		if (sun4c_context_ring[new_ctx].num_entries) {
			struct sun4c_mmu_entry *head = &sun4c_context_ring[new_ctx].ringhd;
			unsigned long flags;

			save_and_cli(flags);
			if (head->next != head) {
				struct sun4c_mmu_entry *entry = head->next;
				int savectx = sun4c_get_context();

				sun4c_set_context(new_ctx);
				sun4c_flush_context();
				do {
					struct sun4c_mmu_entry *next = entry->next;

					sun4c_user_unmap(entry);
					free_user_entry(new_ctx, entry);

					entry = next;
				} while (entry != head);
				sun4c_set_context(savectx);
			}
			restore_flags(flags);
		}
	}
}

static void sun4c_flush_cache_range(struct mm_struct *mm, unsigned long start, unsigned long end)
{
	int new_ctx = mm->context;

	if (new_ctx != NO_CONTEXT) {
		struct sun4c_mmu_entry *head = &sun4c_context_ring[new_ctx].ringhd;
		struct sun4c_mmu_entry *entry;
		unsigned long flags;

		flush_user_windows();

		save_and_cli(flags);
		/* All user segmap chains are ordered on entry->vaddr. */
		for (entry = head->next;
		     (entry != head) && ((entry->vaddr+SUN4C_REAL_PGDIR_SIZE) < start);
		     entry = entry->next)
			;

		/* Tracing various job mixtures showed that this conditional
		 * only passes ~35% of the time for most worse case situations,
		 * therefore we avoid all of this gross overhead ~65% of the time.
		 */
		if ((entry != head) && (entry->vaddr < end)) {
			int octx = sun4c_get_context();
			sun4c_set_context(new_ctx);

			/* At this point, always, (start >= entry->vaddr) and
			 * (entry->vaddr < end), once the latter condition
			 * ceases to hold, or we hit the end of the list, we
			 * exit the loop.  The ordering of all user allocated
			 * segmaps makes this all work out so beautifully.
			 */
			do {
				struct sun4c_mmu_entry *next = entry->next;
				unsigned long realend;

				/* "realstart" is always >= entry->vaddr */
				realend = entry->vaddr + SUN4C_REAL_PGDIR_SIZE;
				if (end < realend)
					realend = end;
				if ((realend - entry->vaddr) <= (PAGE_SIZE << 3)) {
					unsigned long page = entry->vaddr;
					while (page < realend) {
						sun4c_flush_page(page);
						page += PAGE_SIZE;
					}
				} else {
					sun4c_flush_segment(entry->vaddr);
					sun4c_user_unmap(entry);
					free_user_entry(new_ctx, entry);
				}
				entry = next;
			} while ((entry != head) && (entry->vaddr < end));
			sun4c_set_context(octx);
		}
		restore_flags(flags);
	}
}

static void sun4c_flush_cache_page(struct vm_area_struct *vma, unsigned long page)
{
	struct mm_struct *mm = vma->vm_mm;
	int new_ctx = mm->context;

	/* Sun4c has no separate I/D caches so cannot optimize for non
	 * text page flushes.
	 */
	if (new_ctx != NO_CONTEXT) {
		int octx = sun4c_get_context();
		unsigned long flags;

		flush_user_windows();
		save_and_cli(flags);
		sun4c_set_context(new_ctx);
		sun4c_flush_page(page);
		sun4c_set_context(octx);
		restore_flags(flags);
	}
}

static void sun4c_flush_page_to_ram(unsigned long page)
{
	unsigned long flags;

	save_and_cli(flags);
	sun4c_flush_page(page);
	restore_flags(flags);
}

/* Sun4c cache is unified, both instructions and data live there, so
 * no need to flush the on-stack instructions for new signal handlers.
 */
static void sun4c_flush_sig_insns(struct mm_struct *mm, unsigned long insn_addr)
{
}

/* TLB flushing on the sun4c.  These routines count on the cache
 * flushing code to flush the user register windows so that we need
 * not do so when we get here.
 */

static void sun4c_flush_tlb_all(void)
{
	struct sun4c_mmu_entry *this_entry, *next_entry;
	unsigned long flags;
	int savectx, ctx;

	save_and_cli(flags);
	this_entry = sun4c_kernel_ring.ringhd.next;
	savectx = sun4c_get_context();
	flush_user_windows();
	while (sun4c_kernel_ring.num_entries) {
		next_entry = this_entry->next;
		sun4c_flush_segment(this_entry->vaddr);
		for (ctx = 0; ctx < num_contexts; ctx++) {
			sun4c_set_context(ctx);
			sun4c_put_segmap(this_entry->vaddr, invalid_segment);
		}
		free_kernel_entry(this_entry, &sun4c_kernel_ring);
		this_entry = next_entry;
	}
	sun4c_set_context(savectx);
	restore_flags(flags);
}

static void sun4c_flush_tlb_mm(struct mm_struct *mm)
{
	int new_ctx = mm->context;

	if (new_ctx != NO_CONTEXT) {
		struct sun4c_mmu_entry *head = &sun4c_context_ring[new_ctx].ringhd;
		unsigned long flags;

		save_and_cli(flags);
		if (head->next != head) {
			struct sun4c_mmu_entry *entry = head->next;
			int savectx = sun4c_get_context();

			sun4c_set_context(new_ctx);
			sun4c_flush_context();
			do {
				struct sun4c_mmu_entry *next = entry->next;

				sun4c_user_unmap(entry);
				free_user_entry(new_ctx, entry);

				entry = next;
			} while (entry != head);
			sun4c_set_context(savectx);
		}
		restore_flags(flags);
	}
}

static void sun4c_flush_tlb_range(struct mm_struct *mm, unsigned long start, unsigned long end)
{
	int new_ctx = mm->context;

	if (new_ctx != NO_CONTEXT) {
		struct sun4c_mmu_entry *head = &sun4c_context_ring[new_ctx].ringhd;
		struct sun4c_mmu_entry *entry;
		unsigned long flags;

		save_and_cli(flags);
		/* See commentary in sun4c_flush_cache_range(). */
		for (entry = head->next;
		     (entry != head) && ((entry->vaddr+SUN4C_REAL_PGDIR_SIZE) < start);
		     entry = entry->next)
			;

		if ((entry != head) && (entry->vaddr < end)) {
			int octx = sun4c_get_context();

			sun4c_set_context(new_ctx);
			do {
				struct sun4c_mmu_entry *next = entry->next;

				sun4c_flush_segment(entry->vaddr);
				sun4c_user_unmap(entry);
				free_user_entry(new_ctx, entry);

				entry = next;
			} while ((entry != head) && (entry->vaddr < end));
			sun4c_set_context(octx);
		}
		restore_flags(flags);
	}
}

static void sun4c_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
	struct mm_struct *mm = vma->vm_mm;
	int new_ctx = mm->context;

	if (new_ctx != NO_CONTEXT) {
		int savectx = sun4c_get_context();
		unsigned long flags;

		save_and_cli(flags);
		sun4c_set_context(new_ctx);
		page &= PAGE_MASK;
		sun4c_flush_page(page);
		sun4c_put_pte(page, 0);
		sun4c_set_context(savectx);
		restore_flags(flags);
	}
}

void sun4c_mapioaddr(unsigned long physaddr, unsigned long virt_addr,
		     int bus_type, int rdonly)
{
	unsigned long page_entry;

	page_entry = ((physaddr >> PAGE_SHIFT) & SUN4C_PFN_MASK);
	page_entry |= ((pg_iobits | _SUN4C_PAGE_PRIV) & ~(_SUN4C_PAGE_PRESENT));
	if (rdonly)
		page_entry &= ~_SUN4C_WRITEABLE;
	sun4c_put_pte(virt_addr, page_entry);
}

void sun4c_unmapioaddr(unsigned long virt_addr)
{
	sun4c_put_pte(virt_addr, 0);
}

static void sun4c_alloc_context(struct mm_struct *old_mm, struct mm_struct *mm)
{
	struct ctx_list *ctxp;

	ctxp = ctx_free.next;
	if (ctxp != &ctx_free) {
		remove_from_ctx_list(ctxp);
		add_to_used_ctxlist(ctxp);
		mm->context = ctxp->ctx_number;
		ctxp->ctx_mm = mm;
		return;
	}
	ctxp = ctx_used.next;
	if (ctxp->ctx_mm == old_mm)
		ctxp = ctxp->next;
	remove_from_ctx_list(ctxp);
	add_to_used_ctxlist(ctxp);
	ctxp->ctx_mm->context = NO_CONTEXT;
	ctxp->ctx_mm = mm;
	mm->context = ctxp->ctx_number;
	sun4c_demap_context(&sun4c_context_ring[ctxp->ctx_number],
			       ctxp->ctx_number);
}

/* Switch the current MM context. */
static void sun4c_switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk, int cpu)
{
	struct ctx_list *ctx;
	int dirty = 0;

	if (mm->context == NO_CONTEXT) {
		dirty = 1;
		sun4c_alloc_context(old_mm, mm);
	} else {
		/* Update the LRU ring of contexts. */
		ctx = ctx_list_pool + mm->context;
		remove_from_ctx_list(ctx);
		add_to_used_ctxlist(ctx);
	}
	if (dirty || old_mm != mm)
		sun4c_set_context(mm->context);
}

static void sun4c_destroy_context(struct mm_struct *mm)
{
	struct ctx_list *ctx_old;

	if (mm->context != NO_CONTEXT) {
		sun4c_demap_context(&sun4c_context_ring[mm->context], mm->context);
		ctx_old = ctx_list_pool + mm->context;
		remove_from_ctx_list(ctx_old);
		add_to_free_ctxlist(ctx_old);
		mm->context = NO_CONTEXT;
	}
}

static void sun4c_mmu_info(struct seq_file *m)
{
	int used_user_entries, i;

	used_user_entries = 0;
	for (i = 0; i < num_contexts; i++)
		used_user_entries += sun4c_context_ring[i].num_entries;

	seq_printf(m, 
		   "vacsize\t\t: %d bytes\n"
		   "vachwflush\t: %s\n"
		   "vaclinesize\t: %d bytes\n"
		   "mmuctxs\t\t: %d\n"
		   "mmupsegs\t: %d\n"
		   "kernelpsegs\t: %d\n"
		   "kfreepsegs\t: %d\n"
		   "usedpsegs\t: %d\n"
		   "ufreepsegs\t: %d\n"
		   "user_taken\t: %d\n"
		   "max_taken\t: %d\n",
		   sun4c_vacinfo.num_bytes,
		   (sun4c_vacinfo.do_hwflushes ? "yes" : "no"),
		   sun4c_vacinfo.linesize,
		   num_contexts,
		   (invalid_segment + 1),
		   sun4c_kernel_ring.num_entries,
		   sun4c_kfree_ring.num_entries,
		   used_user_entries,
		   sun4c_ufree_ring.num_entries,
		   sun4c_user_taken_entries,
		   max_user_taken_entries);
}

/* Nothing below here should touch the mmu hardware nor the mmu_entry
 * data structures.
 */

/* First the functions which the mid-level code uses to directly
 * manipulate the software page tables.  Some defines since we are
 * emulating the i386 page directory layout.
 */
#define PGD_PRESENT  0x001
#define PGD_RW       0x002
#define PGD_USER     0x004
#define PGD_ACCESSED 0x020
#define PGD_DIRTY    0x040
#define PGD_TABLE    (PGD_PRESENT | PGD_RW | PGD_USER | PGD_ACCESSED | PGD_DIRTY)

static void sun4c_set_pte(pte_t *ptep, pte_t pte)
{
	*ptep = pte;
}

static void sun4c_pgd_set(pgd_t * pgdp, pmd_t * pmdp)
{
}

static void sun4c_pmd_set(pmd_t * pmdp, pte_t * ptep)
{
	*pmdp = __pmd(PGD_TABLE | (unsigned long) ptep);
}

static int sun4c_pte_present(pte_t pte)
{
	return ((pte_val(pte) & (_SUN4C_PAGE_PRESENT | _SUN4C_PAGE_PRIV)) != 0);
}
static void sun4c_pte_clear(pte_t *ptep)	{ *ptep = __pte(0); }

static int sun4c_pmd_bad(pmd_t pmd)
{
	return (((pmd_val(pmd) & ~PAGE_MASK) != PGD_TABLE) ||
		(!VALID_PAGE(virt_to_page(pmd_val(pmd)))));
}

static int sun4c_pmd_present(pmd_t pmd)
{
	return ((pmd_val(pmd) & PGD_PRESENT) != 0);
}
static void sun4c_pmd_clear(pmd_t *pmdp)	{ *pmdp = __pmd(0); }

static int sun4c_pgd_none(pgd_t pgd)		{ return 0; }
static int sun4c_pgd_bad(pgd_t pgd)		{ return 0; }
static int sun4c_pgd_present(pgd_t pgd)	        { return 1; }
static void sun4c_pgd_clear(pgd_t * pgdp)	{ }

/*
 * The following only work if pte_present() is true.
 * Undefined behaviour if not..
 */
static pte_t sun4c_pte_mkwrite(pte_t pte)
{
	pte = __pte(pte_val(pte) | _SUN4C_PAGE_WRITE);
	if (pte_val(pte) & _SUN4C_PAGE_MODIFIED)
		pte = __pte(pte_val(pte) | _SUN4C_PAGE_SILENT_WRITE);
	return pte;
}

static pte_t sun4c_pte_mkdirty(pte_t pte)