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

{
	if (ARCH_SUN4) {
		switch (idprom->id_machtype) {
		case (SM_SUN4|SM_4_110):
			prom_printf("No support for 4100 yet\n");
			prom_halt();
			num_segmaps = 256;
			num_contexts = 8;
			break;

		case (SM_SUN4|SM_4_260):
			/* should be 512 segmaps. when it get fixed */
			num_segmaps = 256;
			num_contexts = 16;
			break;

		case (SM_SUN4|SM_4_330):
			num_segmaps = 256;
			num_contexts = 16;
			break;

		case (SM_SUN4|SM_4_470):
			/* should be 1024 segmaps. when it get fixed */
			num_segmaps = 256;
			num_contexts = 64;
			break;
		default:
			prom_printf("Invalid SUN4 model\n");
			prom_halt();
		};
	} else {
		if ((idprom->id_machtype == (SM_SUN4C | SM_4C_SS1)) ||
		    (idprom->id_machtype == (SM_SUN4C | SM_4C_SS1PLUS))) {
			/* Hardcode these just to be safe, PROM on SS1 does
		 	* not have this info available in the root node.
		 	*/
			num_segmaps = 128;
			num_contexts = 8;
		} else {
			num_segmaps =
			    prom_getintdefault(prom_root_node, "mmu-npmg", 128);
			num_contexts =
			    prom_getintdefault(prom_root_node, "mmu-nctx", 0x8);
		}
	}
	patch_kernel_fault_handler();
}

volatile unsigned long *sun4c_memerr_reg = 0;

void __init sun4c_probe_memerr_reg(void)
{
	int node;
	struct linux_prom_registers regs[1];

	if (ARCH_SUN4) {
		sun4c_memerr_reg = ioremap(sun4_memreg_physaddr, PAGE_SIZE);
	} else {
		node = prom_getchild(prom_root_node);
		node = prom_searchsiblings(prom_root_node, "memory-error");
		if (!node)
			return;
		prom_getproperty(node, "reg", (char *)regs, sizeof(regs));
		/* hmm I think regs[0].which_io is zero here anyways */
		sun4c_memerr_reg = ioremap(regs[0].phys_addr, regs[0].reg_size);
	}
}

static inline void sun4c_init_ss2_cache_bug(void)
{
	extern unsigned long start;

	if ((idprom->id_machtype == (SM_SUN4C | SM_4C_SS2)) ||
	    (idprom->id_machtype == (SM_SUN4C | SM_4C_IPX)) ||
	    (idprom->id_machtype == (SM_SUN4 | SM_4_330)) ||
	    (idprom->id_machtype == (SM_SUN4C | SM_4C_ELC))) {
		/* Whee.. */
		printk("SS2 cache bug detected, uncaching trap table page\n");
		sun4c_flush_page((unsigned int) &start);
		sun4c_put_pte(((unsigned long) &start),
			(sun4c_get_pte((unsigned long) &start) | _SUN4C_PAGE_NOCACHE));
	}
}

/* Addr is always aligned on a page boundry for us already. */
static void sun4c_map_dma_area(unsigned long va, u32 addr, int len)
{
	unsigned long page, end;

	end = PAGE_ALIGN((addr + len));
	while (addr < end) {
		page = va;
		sun4c_flush_page(page);
		page -= PAGE_OFFSET;
		page >>= PAGE_SHIFT;
		page |= (_SUN4C_PAGE_VALID | _SUN4C_PAGE_DIRTY |
			 _SUN4C_PAGE_NOCACHE | _SUN4C_PAGE_PRIV);
		sun4c_put_pte(addr, page);
		addr += PAGE_SIZE;
		va += PAGE_SIZE;
	}
}

static unsigned long sun4c_translate_dvma(unsigned long busa)
{
	/* Fortunately for us, bus_addr == uncached_virt in sun4c. */
	unsigned long pte = sun4c_get_pte(busa);
	return (pte << PAGE_SHIFT) + PAGE_OFFSET;
}

static void sun4c_unmap_dma_area(unsigned long busa, int len)
{
	/* Fortunately for us, bus_addr == uncached_virt in sun4c. */
	/* XXX Implement this */
}

/* TLB management. */

/* Don't change this struct without changing entry.S. This is used
 * in the in-window kernel fault handler, and you don't want to mess
 * with that. (See sun4c_fault in entry.S).
 */
struct sun4c_mmu_entry {
	struct sun4c_mmu_entry *next;
	struct sun4c_mmu_entry *prev;
	unsigned long vaddr;
	unsigned char pseg;
	unsigned char locked;

	/* For user mappings only, and completely hidden from kernel
	 * TLB miss code.
	 */
	unsigned char ctx;
	struct sun4c_mmu_entry *lru_next;
	struct sun4c_mmu_entry *lru_prev;
};

static struct sun4c_mmu_entry mmu_entry_pool[SUN4C_MAX_SEGMAPS];

static void __init sun4c_init_mmu_entry_pool(void)
{
	int i;

	for (i=0; i < SUN4C_MAX_SEGMAPS; i++) {
		mmu_entry_pool[i].pseg = i;
		mmu_entry_pool[i].next = 0;
		mmu_entry_pool[i].prev = 0;
		mmu_entry_pool[i].vaddr = 0;
		mmu_entry_pool[i].locked = 0;
		mmu_entry_pool[i].ctx = 0;
		mmu_entry_pool[i].lru_next = 0;
		mmu_entry_pool[i].lru_prev = 0;
	}
	mmu_entry_pool[invalid_segment].locked = 1;
}

static inline void fix_permissions(unsigned long vaddr, unsigned long bits_on,
				   unsigned long bits_off)
{
	unsigned long start, end;

	end = vaddr + SUN4C_REAL_PGDIR_SIZE;
	for (start = vaddr; start < end; start += PAGE_SIZE)
		if (sun4c_get_pte(start) & _SUN4C_PAGE_VALID)
			sun4c_put_pte(start, (sun4c_get_pte(start) | bits_on) &
				      ~bits_off);
}

static inline void sun4c_init_map_kernelprom(unsigned long kernel_end)
{
	unsigned long vaddr;
	unsigned char pseg, ctx;
#ifdef CONFIG_SUN4
	/* sun4/110 and 260 have no kadb. */
	if ((idprom->id_machtype != (SM_SUN4 | SM_4_260)) && 
	    (idprom->id_machtype != (SM_SUN4 | SM_4_110))) {
#endif
	for (vaddr = KADB_DEBUGGER_BEGVM;
	     vaddr < LINUX_OPPROM_ENDVM;
	     vaddr += SUN4C_REAL_PGDIR_SIZE) {
		pseg = sun4c_get_segmap(vaddr);
		if (pseg != invalid_segment) {
			mmu_entry_pool[pseg].locked = 1;
			for (ctx = 0; ctx < num_contexts; ctx++)
				prom_putsegment(ctx, vaddr, pseg);
			fix_permissions(vaddr, _SUN4C_PAGE_PRIV, 0);
		}
	}
#ifdef CONFIG_SUN4
	}
#endif
	for (vaddr = KERNBASE; vaddr < kernel_end; vaddr += SUN4C_REAL_PGDIR_SIZE) {
		pseg = sun4c_get_segmap(vaddr);
		mmu_entry_pool[pseg].locked = 1;
		for (ctx = 0; ctx < num_contexts; ctx++)
			prom_putsegment(ctx, vaddr, pseg);
		fix_permissions(vaddr, _SUN4C_PAGE_PRIV, _SUN4C_PAGE_NOCACHE);
	}
}

static void __init sun4c_init_lock_area(unsigned long start, unsigned long end)
{
	int i, ctx;

	while (start < end) {
		for (i = 0; i < invalid_segment; i++)
			if (!mmu_entry_pool[i].locked)
				break;
		mmu_entry_pool[i].locked = 1;
		sun4c_init_clean_segmap(i);
		for (ctx = 0; ctx < num_contexts; ctx++)
			prom_putsegment(ctx, start, mmu_entry_pool[i].pseg);
		start += SUN4C_REAL_PGDIR_SIZE;
	}
}

/* Don't change this struct without changing entry.S. This is used
 * in the in-window kernel fault handler, and you don't want to mess
 * with that. (See sun4c_fault in entry.S).
 */
struct sun4c_mmu_ring {
	struct sun4c_mmu_entry ringhd;
	int num_entries;
};

static struct sun4c_mmu_ring sun4c_context_ring[SUN4C_MAX_CONTEXTS]; /* used user entries */
static struct sun4c_mmu_ring sun4c_ufree_ring;       /* free user entries */
static struct sun4c_mmu_ring sun4c_ulru_ring;	     /* LRU user entries */
struct sun4c_mmu_ring sun4c_kernel_ring;      /* used kernel entries */
struct sun4c_mmu_ring sun4c_kfree_ring;       /* free kernel entries */

static inline void sun4c_init_rings(void)
{
	int i;

	for (i = 0; i < SUN4C_MAX_CONTEXTS; i++) {
		sun4c_context_ring[i].ringhd.next =
			sun4c_context_ring[i].ringhd.prev =
			&sun4c_context_ring[i].ringhd;
		sun4c_context_ring[i].num_entries = 0;
	}
	sun4c_ufree_ring.ringhd.next = sun4c_ufree_ring.ringhd.prev =
		&sun4c_ufree_ring.ringhd;
	sun4c_ufree_ring.num_entries = 0;
	sun4c_ulru_ring.ringhd.lru_next = sun4c_ulru_ring.ringhd.lru_prev =
		&sun4c_ulru_ring.ringhd;
	sun4c_ulru_ring.num_entries = 0;
	sun4c_kernel_ring.ringhd.next = sun4c_kernel_ring.ringhd.prev =
		&sun4c_kernel_ring.ringhd;
	sun4c_kernel_ring.num_entries = 0;
	sun4c_kfree_ring.ringhd.next = sun4c_kfree_ring.ringhd.prev =
		&sun4c_kfree_ring.ringhd;
	sun4c_kfree_ring.num_entries = 0;
}

static void add_ring(struct sun4c_mmu_ring *ring,
		     struct sun4c_mmu_entry *entry)
{
	struct sun4c_mmu_entry *head = &ring->ringhd;

	entry->prev = head;
	(entry->next = head->next)->prev = entry;
	head->next = entry;
	ring->num_entries++;
}

static __inline__ void add_lru(struct sun4c_mmu_entry *entry)
{
	struct sun4c_mmu_ring *ring = &sun4c_ulru_ring;
	struct sun4c_mmu_entry *head = &ring->ringhd;

	entry->lru_next = head;
	(entry->lru_prev = head->lru_prev)->lru_next = entry;
	head->lru_prev = entry;
}

static void add_ring_ordered(struct sun4c_mmu_ring *ring,
			     struct sun4c_mmu_entry *entry)
{
	struct sun4c_mmu_entry *head = &ring->ringhd;
	unsigned long addr = entry->vaddr;

	while ((head->next != &ring->ringhd) && (head->next->vaddr < addr))
		head = head->next;

	entry->prev = head;
	(entry->next = head->next)->prev = entry;
	head->next = entry;
	ring->num_entries++;

	add_lru(entry);
}

static __inline__ void remove_ring(struct sun4c_mmu_ring *ring,
				   struct sun4c_mmu_entry *entry)
{
	struct sun4c_mmu_entry *next = entry->next;

	(next->prev = entry->prev)->next = next;
	ring->num_entries--;
}

static void remove_lru(struct sun4c_mmu_entry *entry)
{
	struct sun4c_mmu_entry *next = entry->lru_next;

	(next->lru_prev = entry->lru_prev)->lru_next = next;
}

static void free_user_entry(int ctx, struct sun4c_mmu_entry *entry)
{
        remove_ring(sun4c_context_ring+ctx, entry);
	remove_lru(entry);
        add_ring(&sun4c_ufree_ring, entry);
}

static void free_kernel_entry(struct sun4c_mmu_entry *entry,
			      struct sun4c_mmu_ring *ring)
{
        remove_ring(ring, entry);
        add_ring(&sun4c_kfree_ring, entry);
}

static void __init sun4c_init_fill_kernel_ring(int howmany)
{
	int i;

	while (howmany) {
		for (i = 0; i < invalid_segment; i++)
			if (!mmu_entry_pool[i].locked)
				break;
		mmu_entry_pool[i].locked = 1;
		sun4c_init_clean_segmap(i);
		add_ring(&sun4c_kfree_ring, &mmu_entry_pool[i]);
		howmany--;
	}
}

static void __init sun4c_init_fill_user_ring(void)
{
	int i;

	for (i = 0; i < invalid_segment; i++) {
		if (mmu_entry_pool[i].locked)
			continue;
		sun4c_init_clean_segmap(i);
		add_ring(&sun4c_ufree_ring, &mmu_entry_pool[i]);
	}
}

static void sun4c_kernel_unmap(struct sun4c_mmu_entry *kentry)
{
	int savectx, ctx;

	savectx = sun4c_get_context();
	for (ctx = 0; ctx < num_contexts; ctx++) {
		sun4c_set_context(ctx);
		sun4c_put_segmap(kentry->vaddr, invalid_segment);
	}
	sun4c_set_context(savectx);
}

static void sun4c_kernel_map(struct sun4c_mmu_entry *kentry)
{
	int savectx, ctx;

	savectx = sun4c_get_context();
	for (ctx = 0; ctx < num_contexts; ctx++) {
		sun4c_set_context(ctx);
		sun4c_put_segmap(kentry->vaddr, kentry->pseg);
	}
	sun4c_set_context(savectx);
}

#define sun4c_user_unmap(__entry) \
	sun4c_put_segmap((__entry)->vaddr, invalid_segment)

static void sun4c_demap_context_hw(struct sun4c_mmu_ring *crp, unsigned char ctx)
{
	struct sun4c_mmu_entry *head = &crp->ringhd;
	unsigned long flags;

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

		flush_user_windows();
		sun4c_set_context(ctx);
		sun4c_flush_context_hw();
		do {
			struct sun4c_mmu_entry *next = entry->next;

			sun4c_user_unmap(entry);
			free_user_entry(ctx, entry);

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

static void sun4c_demap_context_sw(struct sun4c_mmu_ring *crp, unsigned char ctx)
{
	struct sun4c_mmu_entry *head = &crp->ringhd;
	unsigned long flags;

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

		flush_user_windows();
		sun4c_set_context(ctx);
		sun4c_flush_context_sw();
		do {
			struct sun4c_mmu_entry *next = entry->next;

			sun4c_user_unmap(entry);
			free_user_entry(ctx, entry);

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

static int sun4c_user_taken_entries = 0;  /* This is how much we have.             */
static int max_user_taken_entries = 0;    /* This limits us and prevents deadlock. */

static struct sun4c_mmu_entry *sun4c_kernel_strategy(void)
{
	struct sun4c_mmu_entry *this_entry;

	/* If some are free, return first one. */
	if (sun4c_kfree_ring.num_entries) {
		this_entry = sun4c_kfree_ring.ringhd.next;
		return this_entry;
	}

	/* Else free one up. */
	this_entry = sun4c_kernel_ring.ringhd.prev;
	if (sun4c_vacinfo.do_hwflushes)
		sun4c_flush_segment_hw(this_entry->vaddr);
	else
		sun4c_flush_segment_sw(this_entry->vaddr);
	sun4c_kernel_unmap(this_entry);
	free_kernel_entry(this_entry, &sun4c_kernel_ring);
	this_entry = sun4c_kfree_ring.ringhd.next;

	return this_entry;
}

/* Using this method to free up mmu entries eliminates a lot of
 * potential races since we have a kernel that incurs tlb
 * replacement faults.  There may be performance penalties.
 *
 * NOTE: Must be called with interrupts disabled.
 */
static struct sun4c_mmu_entry *sun4c_user_strategy(void)
{
	struct sun4c_mmu_entry *entry;
	unsigned char ctx;
	int savectx;

	/* If some are free, return first one. */
	if (sun4c_ufree_ring.num_entries) {
		entry = sun4c_ufree_ring.ringhd.next;
		goto unlink_out;
	}

	if (sun4c_user_taken_entries) {
		entry = sun4c_kernel_strategy();
		sun4c_user_taken_entries--;
		goto kunlink_out;
	}

	/* Grab from the beginning of the LRU list. */
	entry = sun4c_ulru_ring.ringhd.lru_next;
	ctx = entry->ctx;

	savectx = sun4c_get_context();
	flush_user_windows();
	sun4c_set_context(ctx);
	if (sun4c_vacinfo.do_hwflushes)
		sun4c_flush_segment_hw(entry->vaddr);
	else
		sun4c_flush_segment_sw(entry->vaddr);
	sun4c_user_unmap(entry);
	remove_ring(sun4c_context_ring + ctx, entry);