sun4c.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

	remove_lru(entry);
	sun4c_set_context(savectx);

	return entry;

unlink_out:
	remove_ring(&sun4c_ufree_ring, entry);
	return entry;
kunlink_out:
	remove_ring(&sun4c_kfree_ring, entry);
	return entry;
}

/* NOTE: Must be called with interrupts disabled. */
void sun4c_grow_kernel_ring(void)
{
	struct sun4c_mmu_entry *entry;

	/* Prevent deadlock condition. */
	if (sun4c_user_taken_entries >= max_user_taken_entries)
		return;

	if (sun4c_ufree_ring.num_entries) {
		entry = sun4c_ufree_ring.ringhd.next;
        	remove_ring(&sun4c_ufree_ring, entry);
		add_ring(&sun4c_kfree_ring, entry);
		sun4c_user_taken_entries++;
	}
}

/* 2 page buckets for task struct and kernel stack allocation.
 *
 * TASK_STACK_BEGIN
 * bucket[0]
 * bucket[1]
 *   [ ... ]
 * bucket[NR_TASK_BUCKETS-1]
 * TASK_STACK_BEGIN + (sizeof(struct task_bucket) * NR_TASK_BUCKETS)
 *
 * Each slot looks like:
 *
 *  page 1 --  task struct + beginning of kernel stack
 *  page 2 --  rest of kernel stack
 */

union task_union *sun4c_bucket[NR_TASK_BUCKETS];

static int sun4c_lowbucket_avail;

#define BUCKET_EMPTY     ((union task_union *) 0)
#define BUCKET_SHIFT     (PAGE_SHIFT + 1)        /* log2(sizeof(struct task_bucket)) */
#define BUCKET_SIZE      (1 << BUCKET_SHIFT)
#define BUCKET_NUM(addr) ((((addr) - SUN4C_LOCK_VADDR) >> BUCKET_SHIFT))
#define BUCKET_ADDR(num) (((num) << BUCKET_SHIFT) + SUN4C_LOCK_VADDR)
#define BUCKET_PTE(page)       \
        ((((page) - PAGE_OFFSET) >> PAGE_SHIFT) | pgprot_val(SUN4C_PAGE_KERNEL))
#define BUCKET_PTE_PAGE(pte)   \
        (PAGE_OFFSET + (((pte) & SUN4C_PFN_MASK) << PAGE_SHIFT))

static void get_locked_segment(unsigned long addr)
{
	struct sun4c_mmu_entry *stolen;
	unsigned long flags;

	save_and_cli(flags);
	addr &= SUN4C_REAL_PGDIR_MASK;
	stolen = sun4c_user_strategy();
	max_user_taken_entries--;
	stolen->vaddr = addr;
	flush_user_windows();
	sun4c_kernel_map(stolen);
	restore_flags(flags);
}

static void free_locked_segment(unsigned long addr)
{
	struct sun4c_mmu_entry *entry;
	unsigned long flags;
	unsigned char pseg;

	save_and_cli(flags);
	addr &= SUN4C_REAL_PGDIR_MASK;
	pseg = sun4c_get_segmap(addr);
	entry = &mmu_entry_pool[pseg];

	flush_user_windows();
	if (sun4c_vacinfo.do_hwflushes)
		sun4c_flush_segment_hw(addr);
	else
		sun4c_flush_segment_sw(addr);
	sun4c_kernel_unmap(entry);
	add_ring(&sun4c_ufree_ring, entry);
	max_user_taken_entries++;
	restore_flags(flags);
}

static inline void garbage_collect(int entry)
{
	int start, end;

	/* 32 buckets per segment... */
	entry &= ~31;
	start = entry;
	for (end = (start + 32); start < end; start++)
		if (sun4c_bucket[start] != BUCKET_EMPTY)
			return;

	/* Entire segment empty, release it. */
	free_locked_segment(BUCKET_ADDR(entry));
}

#ifdef CONFIG_SUN4
#define TASK_STRUCT_ORDER	0
#else
#define TASK_STRUCT_ORDER	1
#endif

static struct task_struct *sun4c_alloc_task_struct(void)
{
	unsigned long addr, pages;
	int entry;

	pages = __get_free_pages(GFP_KERNEL, TASK_STRUCT_ORDER);
	if (!pages)
		return (struct task_struct *) 0;

	for (entry = sun4c_lowbucket_avail; entry < NR_TASK_BUCKETS; entry++)
		if (sun4c_bucket[entry] == BUCKET_EMPTY)
			break;
	if (entry == NR_TASK_BUCKETS) {
		free_pages(pages, TASK_STRUCT_ORDER);
		return (struct task_struct *) 0;
	}
	if (entry >= sun4c_lowbucket_avail)
		sun4c_lowbucket_avail = entry + 1;

	addr = BUCKET_ADDR(entry);
	sun4c_bucket[entry] = (union task_union *) addr;
	if(sun4c_get_segmap(addr) == invalid_segment)
		get_locked_segment(addr);

	/* We are changing the virtual color of the page(s)
	 * so we must flush the cache to guarentee consistancy.
	 */
	if (sun4c_vacinfo.do_hwflushes) {
		sun4c_flush_page_hw(pages);
#ifndef CONFIG_SUN4	
		sun4c_flush_page_hw(pages + PAGE_SIZE);
#endif
	} else {
		sun4c_flush_page_sw(pages);
#ifndef CONFIG_SUN4	
		sun4c_flush_page_sw(pages + PAGE_SIZE);
#endif
	}

	sun4c_put_pte(addr, BUCKET_PTE(pages));
#ifndef CONFIG_SUN4	
	sun4c_put_pte(addr + PAGE_SIZE, BUCKET_PTE(pages + PAGE_SIZE));
#endif
	return (struct task_struct *) addr;
}

static void sun4c_free_task_struct_hw(struct task_struct *tsk)
{
	unsigned long tsaddr = (unsigned long) tsk;
	unsigned long pages = BUCKET_PTE_PAGE(sun4c_get_pte(tsaddr));
	int entry = BUCKET_NUM(tsaddr);

	if (atomic_dec_and_test(&(tsk)->thread.refcount)) {
		/* We are deleting a mapping, so the flush here is mandatory. */
		sun4c_flush_page_hw(tsaddr);
#ifndef CONFIG_SUN4	
		sun4c_flush_page_hw(tsaddr + PAGE_SIZE);
#endif
		sun4c_put_pte(tsaddr, 0);
#ifndef CONFIG_SUN4	
		sun4c_put_pte(tsaddr + PAGE_SIZE, 0);
#endif
		sun4c_bucket[entry] = BUCKET_EMPTY;
		if (entry < sun4c_lowbucket_avail)
			sun4c_lowbucket_avail = entry;

		free_pages(pages, TASK_STRUCT_ORDER);
		garbage_collect(entry);
	}
}

static void sun4c_free_task_struct_sw(struct task_struct *tsk)
{
	unsigned long tsaddr = (unsigned long) tsk;
	unsigned long pages = BUCKET_PTE_PAGE(sun4c_get_pte(tsaddr));
	int entry = BUCKET_NUM(tsaddr);

	if (atomic_dec_and_test(&(tsk)->thread.refcount)) {
		/* We are deleting a mapping, so the flush here is mandatory. */
		sun4c_flush_page_sw(tsaddr);
#ifndef CONFIG_SUN4	
		sun4c_flush_page_sw(tsaddr + PAGE_SIZE);
#endif
		sun4c_put_pte(tsaddr, 0);
#ifndef CONFIG_SUN4	
		sun4c_put_pte(tsaddr + PAGE_SIZE, 0);
#endif
		sun4c_bucket[entry] = BUCKET_EMPTY;
		if (entry < sun4c_lowbucket_avail)
			sun4c_lowbucket_avail = entry;

		free_pages(pages, TASK_STRUCT_ORDER);
		garbage_collect(entry);
	}
}

static void sun4c_get_task_struct(struct task_struct *tsk)
{
		atomic_inc(&(tsk)->thread.refcount);
}

static void __init sun4c_init_buckets(void)
{
	int entry;

	if (sizeof(union task_union) != (PAGE_SIZE << TASK_STRUCT_ORDER)) {
		prom_printf("task union not %d page(s)!\n", 1 << TASK_STRUCT_ORDER);
	}
	for (entry = 0; entry < NR_TASK_BUCKETS; entry++)
		sun4c_bucket[entry] = BUCKET_EMPTY;
	sun4c_lowbucket_avail = 0;
}

static unsigned long sun4c_iobuffer_start;
static unsigned long sun4c_iobuffer_end;
static unsigned long sun4c_iobuffer_high;
static unsigned long *sun4c_iobuffer_map;
static int iobuffer_map_size;

/*
 * Alias our pages so they do not cause a trap.
 * Also one page may be aliased into several I/O areas and we may
 * finish these I/O separately.
 */
static char *sun4c_lockarea(char *vaddr, unsigned long size)
{
	unsigned long base, scan;
	unsigned long npages;
	unsigned long vpage;
	unsigned long pte;
	unsigned long apage;
	unsigned long high;
	unsigned long flags;

	npages = (((unsigned long)vaddr & ~PAGE_MASK) +
		  size + (PAGE_SIZE-1)) >> PAGE_SHIFT;

	scan = 0;
	save_and_cli(flags);
	for (;;) {
		scan = find_next_zero_bit(sun4c_iobuffer_map,
					  iobuffer_map_size, scan);
		if ((base = scan) + npages > iobuffer_map_size) goto abend;
		for (;;) {
			if (scan >= base + npages) goto found;
			if (test_bit(scan, sun4c_iobuffer_map)) break;
			scan++;
		}
	}

found:
	high = ((base + npages) << PAGE_SHIFT) + sun4c_iobuffer_start;
	high = SUN4C_REAL_PGDIR_ALIGN(high);
	while (high > sun4c_iobuffer_high) {
		get_locked_segment(sun4c_iobuffer_high);
		sun4c_iobuffer_high += SUN4C_REAL_PGDIR_SIZE;
	}

	vpage = ((unsigned long) vaddr) & PAGE_MASK;
	for (scan = base; scan < base+npages; scan++) {
		pte = ((vpage-PAGE_OFFSET) >> PAGE_SHIFT);
 		pte |= pgprot_val(SUN4C_PAGE_KERNEL);
		pte |= _SUN4C_PAGE_NOCACHE;
		set_bit(scan, sun4c_iobuffer_map);
		apage = (scan << PAGE_SHIFT) + sun4c_iobuffer_start;

		/* Flush original mapping so we see the right things later. */
		sun4c_flush_page(vpage);

		sun4c_put_pte(apage, pte);
		vpage += PAGE_SIZE;
	}
	restore_flags(flags);
	return (char *) ((base << PAGE_SHIFT) + sun4c_iobuffer_start +
			 (((unsigned long) vaddr) & ~PAGE_MASK));

abend:
	restore_flags(flags);
	printk("DMA vaddr=0x%p size=%08lx\n", vaddr, size);
	panic("Out of iobuffer table");
	return 0;
}

static void sun4c_unlockarea(char *vaddr, unsigned long size)
{
	unsigned long vpage, npages;
	unsigned long flags;
	int scan, high;

	vpage = (unsigned long)vaddr & PAGE_MASK;
	npages = (((unsigned long)vaddr & ~PAGE_MASK) +
		  size + (PAGE_SIZE-1)) >> PAGE_SHIFT;

	save_and_cli(flags);
	while (npages != 0) {
		--npages;

		/* This mapping is marked non-cachable, no flush necessary. */
		sun4c_put_pte(vpage, 0);
		clear_bit((vpage - sun4c_iobuffer_start) >> PAGE_SHIFT,
			  sun4c_iobuffer_map);
		vpage += PAGE_SIZE;
	}

	/* garbage collect */
	scan = (sun4c_iobuffer_high - sun4c_iobuffer_start) >> PAGE_SHIFT;
	while (scan >= 0 && !sun4c_iobuffer_map[scan >> 5])
		scan -= 32;
	scan += 32;
	high = sun4c_iobuffer_start + (scan << PAGE_SHIFT);
	high = SUN4C_REAL_PGDIR_ALIGN(high) + SUN4C_REAL_PGDIR_SIZE;
	while (high < sun4c_iobuffer_high) {
		sun4c_iobuffer_high -= SUN4C_REAL_PGDIR_SIZE;
		free_locked_segment(sun4c_iobuffer_high);
	}
	restore_flags(flags);
}

/* Note the scsi code at init time passes to here buffers
 * which sit on the kernel stack, those are already locked
 * by implication and fool the page locking code above
 * if passed to by mistake.
 */
static __u32 sun4c_get_scsi_one(char *bufptr, unsigned long len, struct sbus_bus *sbus)
{
	unsigned long page;

	page = ((unsigned long)bufptr) & PAGE_MASK;
	if (!VALID_PAGE(virt_to_page(page))) {
		sun4c_flush_page(page);
		return (__u32)bufptr; /* already locked */
	}
	return (__u32)sun4c_lockarea(bufptr, len);
}

static void sun4c_get_scsi_sgl(struct scatterlist *sg, int sz, struct sbus_bus *sbus)
{
	while (sz >= 0) {
		sg[sz].dvma_address = (__u32)sun4c_lockarea(sg[sz].address, sg[sz].length);
		sg[sz].dvma_length = sg[sz].length;
		sz--;
	}
}

static void sun4c_release_scsi_one(__u32 bufptr, unsigned long len, struct sbus_bus *sbus)
{
	if (bufptr < sun4c_iobuffer_start)
		return; /* On kernel stack or similar, see above */
	sun4c_unlockarea((char *)bufptr, len);
}

static void sun4c_release_scsi_sgl(struct scatterlist *sg, int sz, struct sbus_bus *sbus)
{
	while (sz >= 0) {
		sun4c_unlockarea((char *)sg[sz].dvma_address, sg[sz].length);
		sz--;
	}
}

#define TASK_ENTRY_SIZE    BUCKET_SIZE /* see above */
#define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))

struct vm_area_struct sun4c_kstack_vma;

static void __init sun4c_init_lock_areas(void)
{
	unsigned long sun4c_taskstack_start;
	unsigned long sun4c_taskstack_end;
	int bitmap_size;

	sun4c_init_buckets();
	sun4c_taskstack_start = SUN4C_LOCK_VADDR;
	sun4c_taskstack_end = (sun4c_taskstack_start +
			       (TASK_ENTRY_SIZE * NR_TASK_BUCKETS));
	if (sun4c_taskstack_end >= SUN4C_LOCK_END) {
		prom_printf("Too many tasks, decrease NR_TASK_BUCKETS please.\n");
		prom_halt();
	}

	sun4c_iobuffer_start = sun4c_iobuffer_high =
				SUN4C_REAL_PGDIR_ALIGN(sun4c_taskstack_end);
	sun4c_iobuffer_end = SUN4C_LOCK_END;
	bitmap_size = (sun4c_iobuffer_end - sun4c_iobuffer_start) >> PAGE_SHIFT;
	bitmap_size = (bitmap_size + 7) >> 3;
	bitmap_size = LONG_ALIGN(bitmap_size);
	iobuffer_map_size = bitmap_size << 3;
	sun4c_iobuffer_map = __alloc_bootmem(bitmap_size, SMP_CACHE_BYTES, 0UL);
	memset((void *) sun4c_iobuffer_map, 0, bitmap_size);

	sun4c_kstack_vma.vm_mm = &init_mm;
	sun4c_kstack_vma.vm_start = sun4c_taskstack_start;
	sun4c_kstack_vma.vm_end = sun4c_taskstack_end;
	sun4c_kstack_vma.vm_page_prot = PAGE_SHARED;
	sun4c_kstack_vma.vm_flags = VM_READ | VM_WRITE | VM_EXEC;
	insert_vm_struct(&init_mm, &sun4c_kstack_vma);
}

/* Cache flushing on the sun4c. */
static void sun4c_flush_cache_all(void)
{
	unsigned long begin, end;

	flush_user_windows();
	begin = (KERNBASE + SUN4C_REAL_PGDIR_SIZE);
	end = (begin + SUN4C_VAC_SIZE);

	if (sun4c_vacinfo.linesize == 32) {
		while (begin < end) {
			__asm__ __volatile__(
			"ld	[%0 + 0x00], %%g0\n\t"
			"ld	[%0 + 0x20], %%g0\n\t"
			"ld	[%0 + 0x40], %%g0\n\t"
			"ld	[%0 + 0x60], %%g0\n\t"
			"ld	[%0 + 0x80], %%g0\n\t"
			"ld	[%0 + 0xa0], %%g0\n\t"
			"ld	[%0 + 0xc0], %%g0\n\t"
			"ld	[%0 + 0xe0], %%g0\n\t"
			"ld	[%0 + 0x100], %%g0\n\t"
			"ld	[%0 + 0x120], %%g0\n\t"
			"ld	[%0 + 0x140], %%g0\n\t"
			"ld	[%0 + 0x160], %%g0\n\t"
			"ld	[%0 + 0x180], %%g0\n\t"
			"ld	[%0 + 0x1a0], %%g0\n\t"
			"ld	[%0 + 0x1c0], %%g0\n\t"
			"ld	[%0 + 0x1e0], %%g0\n"
			: : "r" (begin));
			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_hw(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_hw();
				do {
					struct sun4c_mmu_entry *next = entry->next;

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