Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2276 insertions, 0 deletions

diff --git a/arch/sparc/mm/sun4c.c b/arch/sparc/mm/sun4c.c
new file mode 100644
index 000000000000..1d560390e282
--- /dev/null
+++ b/arch/sparc/mm/sun4c.c
@@ -0,0 +1,2276 @@
+/* $Id: sun4c.c,v 1.212 2001/12/21 04:56:15 davem Exp $
+ * sun4c.c: Doing in software what should be done in hardware.
+ *
+ * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
+ * Copyright (C) 1996 Eddie C. Dost (ecd@skynet.be)
+ * Copyright (C) 1996 Andrew Tridgell (Andrew.Tridgell@anu.edu.au)
+ * Copyright (C) 1997-2000 Anton Blanchard (anton@samba.org)
+ * Copyright (C) 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
+ */
+
+#define NR_TASK_BUCKETS 512
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+
+#include <asm/scatterlist.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/vaddrs.h>
+#include <asm/idprom.h>
+#include <asm/machines.h>
+#include <asm/memreg.h>
+#include <asm/processor.h>
+#include <asm/auxio.h>
+#include <asm/io.h>
+#include <asm/oplib.h>
+#include <asm/openprom.h>
+#include <asm/mmu_context.h>
+#include <asm/sun4paddr.h>
+#include <asm/highmem.h>
+#include <asm/btfixup.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+
+/* Because of our dynamic kernel TLB miss strategy, and how
+ * our DVMA mapping allocation works, you _MUST_:
+ *
+ * 1) Disable interrupts _and_ not touch any dynamic kernel
+ *    memory while messing with kernel MMU state.  By
+ *    dynamic memory I mean any object which is not in
+ *    the kernel image itself or a thread_union (both of
+ *    which are locked into the MMU).
+ * 2) Disable interrupts while messing with user MMU state.
+ */
+
+extern int num_segmaps, num_contexts;
+
+extern unsigned long page_kernel;
+
+#ifdef CONFIG_SUN4
+#define SUN4C_VAC_SIZE sun4c_vacinfo.num_bytes
+#else
+/* That's it, we prom_halt() on sun4c if the cache size is something other than 65536.
+ * So let's save some cycles and just use that everywhere except for that bootup
+ * sanity check.
+ */
+#define SUN4C_VAC_SIZE 65536
+#endif
+
+#define SUN4C_KERNEL_BUCKETS 32
+
+/* Flushing the cache. */
+struct sun4c_vac_props sun4c_vacinfo;
+unsigned long sun4c_kernel_faults;
+
+/* Invalidate every sun4c cache line tag. */
+static void __init sun4c_flush_all(void)
+{
+	unsigned long begin, end;
+
+	if (sun4c_vacinfo.on)
+		panic("SUN4C: AIEEE, trying to invalidate vac while it is on.");
+
+	/* Clear 'valid' bit in all cache line tags */
+	begin = AC_CACHETAGS;
+	end = (AC_CACHETAGS + SUN4C_VAC_SIZE);
+	while (begin < end) {
+		__asm__ __volatile__("sta %%g0, [%0] %1\n\t" : :
+				     "r" (begin), "i" (ASI_CONTROL));
+		begin += sun4c_vacinfo.linesize;
+	}
+}
+
+static void sun4c_flush_context_hw(void)
+{
+	unsigned long end = SUN4C_VAC_SIZE;
+
+	__asm__ __volatile__(
+		"1:	addcc	%0, -4096, %0\n\t"
+		"	bne	1b\n\t"
+		"	 sta	%%g0, [%0] %2"
+	: "=&r" (end)
+	: "0" (end), "i" (ASI_HWFLUSHCONTEXT)
+	: "cc");
+}
+
+/* Must be called minimally with IRQs disabled. */
+static void sun4c_flush_segment_hw(unsigned long addr)
+{
+	if (sun4c_get_segmap(addr) != invalid_segment) {
+		unsigned long vac_size = SUN4C_VAC_SIZE;
+
+		__asm__ __volatile__(
+			"1:	addcc	%0, -4096, %0\n\t"
+			"	bne	1b\n\t"
+			"	 sta	%%g0, [%2 + %0] %3"
+			: "=&r" (vac_size)
+			: "0" (vac_size), "r" (addr), "i" (ASI_HWFLUSHSEG)
+			: "cc");
+	}
+}
+
+/* File local boot time fixups. */
+BTFIXUPDEF_CALL(void, sun4c_flush_page, unsigned long)
+BTFIXUPDEF_CALL(void, sun4c_flush_segment, unsigned long)
+BTFIXUPDEF_CALL(void, sun4c_flush_context, void)
+
+#define sun4c_flush_page(addr) BTFIXUP_CALL(sun4c_flush_page)(addr)
+#define sun4c_flush_segment(addr) BTFIXUP_CALL(sun4c_flush_segment)(addr)
+#define sun4c_flush_context() BTFIXUP_CALL(sun4c_flush_context)()
+
+/* Must be called minimally with interrupts disabled. */
+static void sun4c_flush_page_hw(unsigned long addr)
+{
+	addr &= PAGE_MASK;
+	if ((int)sun4c_get_pte(addr) < 0)
+		__asm__ __volatile__("sta %%g0, [%0] %1"
+				     : : "r" (addr), "i" (ASI_HWFLUSHPAGE));
+}
+
+/* Don't inline the software version as it eats too many cache lines if expanded. */
+static void sun4c_flush_context_sw(void)
+{
+	unsigned long nbytes = SUN4C_VAC_SIZE;
+	unsigned long lsize = sun4c_vacinfo.linesize;
+
+	__asm__ __volatile__(
+	"add	%2, %2, %%g1\n\t"
+	"add	%2, %%g1, %%g2\n\t"
+	"add	%2, %%g2, %%g3\n\t"
+	"add	%2, %%g3, %%g4\n\t"
+	"add	%2, %%g4, %%g5\n\t"
+	"add	%2, %%g5, %%o4\n\t"
+	"add	%2, %%o4, %%o5\n"
+	"1:\n\t"
+	"subcc	%0, %%o5, %0\n\t"
+	"sta	%%g0, [%0] %3\n\t"
+	"sta	%%g0, [%0 + %2] %3\n\t"
+	"sta	%%g0, [%0 + %%g1] %3\n\t"
+	"sta	%%g0, [%0 + %%g2] %3\n\t"
+	"sta	%%g0, [%0 + %%g3] %3\n\t"
+	"sta	%%g0, [%0 + %%g4] %3\n\t"
+	"sta	%%g0, [%0 + %%g5] %3\n\t"
+	"bg	1b\n\t"
+	" sta	%%g0, [%1 + %%o4] %3\n"
+	: "=&r" (nbytes)
+	: "0" (nbytes), "r" (lsize), "i" (ASI_FLUSHCTX)
+	: "g1", "g2", "g3", "g4", "g5", "o4", "o5", "cc");
+}
+
+/* Don't inline the software version as it eats too many cache lines if expanded. */
+static void sun4c_flush_segment_sw(unsigned long addr)
+{
+	if (sun4c_get_segmap(addr) != invalid_segment) {
+		unsigned long nbytes = SUN4C_VAC_SIZE;
+		unsigned long lsize = sun4c_vacinfo.linesize;
+
+		__asm__ __volatile__(
+		"add	%2, %2, %%g1\n\t"
+		"add	%2, %%g1, %%g2\n\t"
+		"add	%2, %%g2, %%g3\n\t"
+		"add	%2, %%g3, %%g4\n\t"
+		"add	%2, %%g4, %%g5\n\t"
+		"add	%2, %%g5, %%o4\n\t"
+		"add	%2, %%o4, %%o5\n"
+		"1:\n\t"
+		"subcc	%1, %%o5, %1\n\t"
+		"sta	%%g0, [%0] %6\n\t"
+		"sta	%%g0, [%0 + %2] %6\n\t"
+		"sta	%%g0, [%0 + %%g1] %6\n\t"
+		"sta	%%g0, [%0 + %%g2] %6\n\t"
+		"sta	%%g0, [%0 + %%g3] %6\n\t"
+		"sta	%%g0, [%0 + %%g4] %6\n\t"
+		"sta	%%g0, [%0 + %%g5] %6\n\t"
+		"sta	%%g0, [%0 + %%o4] %6\n\t"
+		"bg	1b\n\t"
+		" add	%0, %%o5, %0\n"
+		: "=&r" (addr), "=&r" (nbytes), "=&r" (lsize)
+		: "0" (addr), "1" (nbytes), "2" (lsize),
+		  "i" (ASI_FLUSHSEG)
+		: "g1", "g2", "g3", "g4", "g5", "o4", "o5", "cc");
+	}
+}
+
+/* Don't inline the software version as it eats too many cache lines if expanded. */
+static void sun4c_flush_page_sw(unsigned long addr)
+{
+	addr &= PAGE_MASK;
+	if ((sun4c_get_pte(addr) & (_SUN4C_PAGE_NOCACHE | _SUN4C_PAGE_VALID)) ==
+	    _SUN4C_PAGE_VALID) {
+		unsigned long left = PAGE_SIZE;
+		unsigned long lsize = sun4c_vacinfo.linesize;
+
+		__asm__ __volatile__(
+		"add	%2, %2, %%g1\n\t"
+		"add	%2, %%g1, %%g2\n\t"
+		"add	%2, %%g2, %%g3\n\t"
+		"add	%2, %%g3, %%g4\n\t"
+		"add	%2, %%g4, %%g5\n\t"
+		"add	%2, %%g5, %%o4\n\t"
+		"add	%2, %%o4, %%o5\n"
+		"1:\n\t"
+		"subcc	%1, %%o5, %1\n\t"
+		"sta	%%g0, [%0] %6\n\t"
+		"sta	%%g0, [%0 + %2] %6\n\t"
+		"sta	%%g0, [%0 + %%g1] %6\n\t"
+		"sta	%%g0, [%0 + %%g2] %6\n\t"
+		"sta	%%g0, [%0 + %%g3] %6\n\t"
+		"sta	%%g0, [%0 + %%g4] %6\n\t"
+		"sta	%%g0, [%0 + %%g5] %6\n\t"
+		"sta	%%g0, [%0 + %%o4] %6\n\t"
+		"bg	1b\n\t"
+		" add	%0, %%o5, %0\n"
+		: "=&r" (addr), "=&r" (left), "=&r" (lsize)
+		: "0" (addr), "1" (left), "2" (lsize),
+		  "i" (ASI_FLUSHPG)
+		: "g1", "g2", "g3", "g4", "g5", "o4", "o5", "cc");
+	}
+}
+
+/* The sun4c's do have an on chip store buffer.  And the way you
+ * clear them out isn't so obvious.  The only way I can think of
+ * to accomplish this is to read the current context register,
+ * store the same value there, then read an external hardware
+ * register.
+ */
+void sun4c_complete_all_stores(void)
+{
+	volatile int _unused;
+
+	_unused = sun4c_get_context();
+	sun4c_set_context(_unused);
+#ifdef CONFIG_SUN_AUXIO
+	_unused = get_auxio();
+#endif
+}
+
+/* Bootup utility functions. */
+static inline void sun4c_init_clean_segmap(unsigned char pseg)
+{
+	unsigned long vaddr;
+
+	sun4c_put_segmap(0, pseg);
+	for (vaddr = 0; vaddr < SUN4C_REAL_PGDIR_SIZE; vaddr += PAGE_SIZE)
+		sun4c_put_pte(vaddr, 0);
+	sun4c_put_segmap(0, invalid_segment);
+}
+
+static inline void sun4c_init_clean_mmu(unsigned long kernel_end)
+{
+	unsigned long vaddr;
+	unsigned char savectx, ctx;
+
+	savectx = sun4c_get_context();
+	kernel_end = SUN4C_REAL_PGDIR_ALIGN(kernel_end);
+	for (ctx = 0; ctx < num_contexts; ctx++) {
+		sun4c_set_context(ctx);
+		for (vaddr = 0; vaddr < 0x20000000; vaddr += SUN4C_REAL_PGDIR_SIZE)
+			sun4c_put_segmap(vaddr, invalid_segment);
+		for (vaddr = 0xe0000000; vaddr < KERNBASE; vaddr += SUN4C_REAL_PGDIR_SIZE)
+			sun4c_put_segmap(vaddr, invalid_segment);
+		for (vaddr = kernel_end; vaddr < KADB_DEBUGGER_BEGVM; vaddr += SUN4C_REAL_PGDIR_SIZE)
+			sun4c_put_segmap(vaddr, invalid_segment);
+		for (vaddr = LINUX_OPPROM_ENDVM; vaddr; vaddr += SUN4C_REAL_PGDIR_SIZE)
+			sun4c_put_segmap(vaddr, invalid_segment);
+	}
+	sun4c_set_context(savectx);
+}
+
+void __init sun4c_probe_vac(void)
+{
+	sun4c_disable_vac();
+
+	if (ARCH_SUN4) {
+		switch (idprom->id_machtype) {
+
+		case (SM_SUN4|SM_4_110):
+			sun4c_vacinfo.type = VAC_NONE;
+			sun4c_vacinfo.num_bytes = 0;
+			sun4c_vacinfo.linesize = 0;
+			sun4c_vacinfo.do_hwflushes = 0;
+			prom_printf("No VAC. Get some bucks and buy a real computer.");
+			prom_halt();
+			break;
+
+		case (SM_SUN4|SM_4_260):
+			sun4c_vacinfo.type = VAC_WRITE_BACK;
+			sun4c_vacinfo.num_bytes = 128 * 1024;
+			sun4c_vacinfo.linesize = 16;
+			sun4c_vacinfo.do_hwflushes = 0;
+			break;
+
+		case (SM_SUN4|SM_4_330):
+			sun4c_vacinfo.type = VAC_WRITE_THROUGH;
+			sun4c_vacinfo.num_bytes = 128 * 1024;
+			sun4c_vacinfo.linesize = 16;
+			sun4c_vacinfo.do_hwflushes = 0;
+			break;
+
+		case (SM_SUN4|SM_4_470):
+			sun4c_vacinfo.type = VAC_WRITE_BACK;
+			sun4c_vacinfo.num_bytes = 128 * 1024;
+			sun4c_vacinfo.linesize = 32;
+			sun4c_vacinfo.do_hwflushes = 0;
+			break;
+
+		default:
+			prom_printf("Cannot initialize VAC - weird sun4 model idprom->id_machtype = %d", idprom->id_machtype);
+			prom_halt();
+		};
+	} else {
+		sun4c_vacinfo.type = VAC_WRITE_THROUGH;
+
+		if ((idprom->id_machtype == (SM_SUN4C | SM_4C_SS1)) ||
+		    (idprom->id_machtype == (SM_SUN4C | SM_4C_SS1PLUS))) {
+			/* PROM on SS1 lacks this info, to be super safe we
+			 * hard code it here since this arch is cast in stone.
+			 */
+			sun4c_vacinfo.num_bytes = 65536;
+			sun4c_vacinfo.linesize = 16;
+		} else {
+			sun4c_vacinfo.num_bytes =
+			 prom_getintdefault(prom_root_node, "vac-size", 65536);
+			sun4c_vacinfo.linesize =
+			 prom_getintdefault(prom_root_node, "vac-linesize", 16);
+		}
+		sun4c_vacinfo.do_hwflushes =
+		 prom_getintdefault(prom_root_node, "vac-hwflush", 0);
+
+		if (sun4c_vacinfo.do_hwflushes == 0)
+			sun4c_vacinfo.do_hwflushes =
+			 prom_getintdefault(prom_root_node, "vac_hwflush", 0);
+
+		if (sun4c_vacinfo.num_bytes != 65536) {
+			prom_printf("WEIRD Sun4C VAC cache size, "
+				    "tell sparclinux@vger.kernel.org");
+			prom_halt();
+		}
+	}
+
+	sun4c_vacinfo.num_lines =
+		(sun4c_vacinfo.num_bytes / sun4c_vacinfo.linesize);
+	switch (sun4c_vacinfo.linesize) {
+	case 16:
+		sun4c_vacinfo.log2lsize = 4;
+		break;
+	case 32:
+		sun4c_vacinfo.log2lsize = 5;
+		break;
+	default:
+		prom_printf("probe_vac: Didn't expect vac-linesize of %d, halting\n",
+			    sun4c_vacinfo.linesize);
+		prom_halt();
+	};
+
+	sun4c_flush_all();
+	sun4c_enable_vac();
+}
+
+/* Patch instructions for the low level kernel fault handler. */
+extern unsigned long invalid_segment_patch1, invalid_segment_patch1_ff;
+extern unsigned long invalid_segment_patch2, invalid_segment_patch2_ff;
+extern unsigned long invalid_segment_patch1_1ff, invalid_segment_patch2_1ff;
+extern unsigned long num_context_patch1, num_context_patch1_16;
+extern unsigned long num_context_patch2_16;
+extern unsigned long vac_linesize_patch, vac_linesize_patch_32;
+extern unsigned long vac_hwflush_patch1, vac_hwflush_patch1_on;
+extern unsigned long vac_hwflush_patch2, vac_hwflush_patch2_on;
+
+#define PATCH_INSN(src, dst) do {	\
+		daddr = &(dst);		\
+		iaddr = &(src);		\
+		*daddr = *iaddr;	\
+	} while (0)
+
+static void __init patch_kernel_fault_handler(void)
+{
+	unsigned long *iaddr, *daddr;
+
+	switch (num_segmaps) {
+		case 128:
+			/* Default, nothing to do. */
+			break;
+		case 256:
+			PATCH_INSN(invalid_segment_patch1_ff,
+				   invalid_segment_patch1);
+			PATCH_INSN(invalid_segment_patch2_ff,
+				   invalid_segment_patch2);
+			break;
+		case 512:
+			PATCH_INSN(invalid_segment_patch1_1ff,
+				   invalid_segment_patch1);
+			PATCH_INSN(invalid_segment_patch2_1ff,
+				   invalid_segment_patch2);
+			break;
+		default:
+			prom_printf("Unhandled number of segmaps: %d\n",
+				    num_segmaps);
+			prom_halt();
+	};
+	switch (num_contexts) {
+		case 8:
+			/* Default, nothing to do. */
+			break;
+		case 16:
+			PATCH_INSN(num_context_patch1_16,
+				   num_context_patch1);
+			break;
+		default:
+			prom_printf("Unhandled number of contexts: %d\n",
+				    num_contexts);
+			prom_halt();
+	};
+
+	if (sun4c_vacinfo.do_hwflushes != 0) {
+		PATCH_INSN(vac_hwflush_patch1_on, vac_hwflush_patch1);
+		PATCH_INSN(vac_hwflush_patch2_on, vac_hwflush_patch2);
+	} else {
+		switch (sun4c_vacinfo.linesize) {
+		case 16:
+			/* Default, nothing to do. */
+			break;
+		case 32:
+			PATCH_INSN(vac_linesize_patch_32, vac_linesize_patch);
+			break;
+		default:
+			prom_printf("Impossible VAC linesize %d, halting...\n",
+				    sun4c_vacinfo.linesize);
+			prom_halt();
+		};
+	}
+}
+
+static void __init sun4c_probe_mmu(void)
+{
+	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 = NULL;
+
+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;
+		if (prom_getproperty(node, "reg", (char *)regs, sizeof(regs)) <= 0)
+			return;
+		/* 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 boundary for us already. */
+static int sun4c_map_dma_area(dma_addr_t *pba, unsigned long va,
+    unsigned long addr, int len)
+{
+	unsigned long page, end;
+
+	*pba = addr;
+
+	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;
+	}
+
+	return 0;
+}
+
+static struct page *sun4c_translate_dvma(unsigned long busa)
+{
+	/* Fortunately for us, bus_addr == uncached_virt in sun4c. */
+	unsigned long pte = sun4c_get_pte(busa);
+	return pfn_to_page(pte & SUN4C_PFN_MASK);
+}
+
+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 = NULL;
+		mmu_entry_pool[i].prev = NULL;
+		mmu_entry_pool[i].vaddr = 0;
+		mmu_entry_pool[i].locked = 0;
+		mmu_entry_pool[i].ctx = 0;
+		mmu_entry_pool[i].lru_next = NULL;
+		mmu_entry_pool[i].lru_prev = NULL;
+	}
+	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(struct sun4c_mmu_ring *crp, unsigned char ctx)
+{
+	struct sun4c_mmu_entry *head = &crp->ringhd;
+	unsigned long flags;
+
+	local_irq_save(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();
+		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);
+	}
+	local_irq_restore(flags);
+}
+
+static int sun4c_user_taken_entries;  /* This is how much we have.             */
+static int max_user_taken_entries;    /* 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;
+	sun4c_flush_segment(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);
+	sun4c_flush_segment(entry->vaddr);
+	sun4c_user_unmap(entry);
+	remove_ring(sun4c_context_ring + ctx, entry);
+	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;
+
+	local_irq_save(flags);
+	addr &= SUN4C_REAL_PGDIR_MASK;
+	stolen = sun4c_user_strategy();
+	max_user_taken_entries--;
+	stolen->vaddr = addr;
+	flush_user_windows();
+	sun4c_kernel_map(stolen);
+	local_irq_restore(flags);
+}
+
+static void free_locked_segment(unsigned long addr)
+{
+	struct sun4c_mmu_entry *entry;
+	unsigned long flags;
+	unsigned char pseg;
+
+	local_irq_save(flags);
+	addr &= SUN4C_REAL_PGDIR_MASK;
+	pseg = sun4c_get_segmap(addr);
+	entry = &mmu_entry_pool[pseg];
+
+	flush_user_windows();
+	sun4c_flush_segment(addr);
+	sun4c_kernel_unmap(entry);
+	add_ring(&sun4c_ufree_ring, entry);
+	max_user_taken_entries++;
+	local_irq_restore(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));
+}
+
+static struct thread_info *sun4c_alloc_thread_info(void)
+{
+	unsigned long addr, pages;
+	int entry;
+
+	pages = __get_free_pages(GFP_KERNEL, THREAD_INFO_ORDER);
+	if (!pages)
+		return NULL;
+
+	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, THREAD_INFO_ORDER);
+		return NULL;
+	}
+	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 guarantee consistency.
+	 */
+	sun4c_flush_page(pages);
+#ifndef CONFIG_SUN4	
+	sun4c_flush_page(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
+
+#ifdef CONFIG_DEBUG_STACK_USAGE
+	memset((void *)addr, 0, PAGE_SIZE << THREAD_INFO_ORDER);
+#endif /* DEBUG_STACK_USAGE */
+
+	return (struct thread_info *) addr;
+}
+
+static void sun4c_free_thread_info(struct thread_info *ti)
+{
+	unsigned long tiaddr = (unsigned long) ti;
+	unsigned long pages = BUCKET_PTE_PAGE(sun4c_get_pte(tiaddr));
+	int entry = BUCKET_NUM(tiaddr);
+
+	/* We are deleting a mapping, so the flush here is mandatory. */
+	sun4c_flush_page(tiaddr);
+#ifndef CONFIG_SUN4	
+	sun4c_flush_page(tiaddr + PAGE_SIZE);
+#endif
+	sun4c_put_pte(tiaddr, 0);
+#ifndef CONFIG_SUN4	
+	sun4c_put_pte(tiaddr + PAGE_SIZE, 0);
+#endif
+	sun4c_bucket[entry] = BUCKET_EMPTY;
+	if (entry < sun4c_lowbucket_avail)
+		sun4c_lowbucket_avail = entry;
+
+	free_pages(pages, THREAD_INFO_ORDER);
+	garbage_collect(entry);
+}
+
+static void __init sun4c_init_buckets(void)
+{
+	int entry;
+
+	if (sizeof(union thread_union) != (PAGE_SIZE << THREAD_INFO_ORDER)) {
+		extern void thread_info_size_is_bolixed_pete(void);
+		thread_info_size_is_bolixed_pete();
+	}
+
+	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;
+	local_irq_save(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;
+	}
+	local_irq_restore(flags);
+	return (char *) ((base << PAGE_SHIFT) + sun4c_iobuffer_start +
+			 (((unsigned long) vaddr) & ~PAGE_MASK));
+
+abend:
+	local_irq_restore(flags);
+	printk("DMA vaddr=0x%p size=%08lx\n", vaddr, size);
+	panic("Out of iobuffer table");
+	return NULL;
+}
+
+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;
+
+	local_irq_save(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);
+	}
+	local_irq_restore(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 (!virt_addr_valid(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) {
+		--sz;
+		sg[sz].dvma_address = (__u32)sun4c_lockarea(page_address(sg[sz].page) + sg[sz].offset, sg[sz].length);
+		sg[sz].dvma_length = sg[sz].length;
+	}
+}
+
+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) {
+		--sz;
+		sun4c_unlockarea((char *)sg[sz].dvma_address, sg[sz].length);
+	}
+}
+
+#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(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;
+
+			local_irq_save(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);
+			}
+			local_irq_restore(flags);
+		}
+	}
+}
+
+static void sun4c_flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	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();
+
+		local_irq_save(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);
+		}
+		local_irq_restore(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();
+		local_irq_save(flags);
+		sun4c_set_context(new_ctx);
+		sun4c_flush_page(page);
+		sun4c_set_context(octx);
+		local_irq_restore(flags);
+	}
+}
+
+static void sun4c_flush_page_to_ram(unsigned long page)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	sun4c_flush_page(page);
+	local_irq_restore(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;
+
+	local_irq_save(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);
+	local_irq_restore(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;
+
+		local_irq_save(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);
+		}
+		local_irq_restore(flags);
+	}
+}
+
+static void sun4c_flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	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;
+
+		local_irq_save(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);
+		}
+		local_irq_restore(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;
+
+		local_irq_save(flags);
+		sun4c_set_context(new_ctx);
+		page &= PAGE_MASK;
+		sun4c_flush_page(page);
+		sun4c_put_pte(page, 0);
+		sun4c_set_context(savectx);
+		local_irq_restore(flags);
+	}
+}
+
+static inline void sun4c_mapioaddr(unsigned long physaddr, unsigned long virt_addr)
+{
+	unsigned long page_entry;
+
+	page_entry = ((physaddr >> PAGE_SHIFT) & SUN4C_PFN_MASK);
+	page_entry |= ((pg_iobits | _SUN4C_PAGE_PRIV) & ~(_SUN4C_PAGE_PRESENT));
+	sun4c_put_pte(virt_addr, page_entry);
+}
+
+static void sun4c_mapiorange(unsigned int bus, unsigned long xpa,
+    unsigned long xva, unsigned int len)
+{
+	while (len != 0) {
+		len -= PAGE_SIZE;
+		sun4c_mapioaddr(xpa, xva);
+		xva += PAGE_SIZE;
+		xpa += PAGE_SIZE;
+	}
+}
+
+static void sun4c_unmapiorange(unsigned long virt_addr, unsigned int len)
+{
+	while (len != 0) {
+		len -= PAGE_SIZE;
+		sun4c_put_pte(virt_addr, 0);
+		virt_addr += PAGE_SIZE;
+	}
+}
+
+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->pmdv[0] = PGD_TABLE | (unsigned long) ptep;
+}
+
+static void sun4c_pmd_populate(pmd_t * pmdp, struct page * ptep)
+{
+	if (page_address(ptep) == NULL) BUG();	/* No highmem on sun4c */
+	pmdp->pmdv[0] = PGD_TABLE | (unsigned long) page_address(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_pte_read(pte_t pte)
+{
+	return (pte_val(pte) & _SUN4C_PAGE_READ);
+}
+
+static int sun4c_pmd_bad(pmd_t pmd)
+{
+	return (((pmd_val(pmd) & ~PAGE_MASK) != PGD_TABLE) ||
+		(!virt_addr_valid(pmd_val(pmd))));
+}
+
+static int sun4c_pmd_present(pmd_t pmd)
+{
+	return ((pmd_val(pmd) & PGD_PRESENT) != 0);
+}
+
+#if 0 /* if PMD takes one word */
+static void sun4c_pmd_clear(pmd_t *pmdp)	{ *pmdp = __pmd(0); }
+#else /* if pmd_t is a longish aggregate */
+static void sun4c_pmd_clear(pmd_t *pmdp) {
+	memset((void *)pmdp, 0, sizeof(pmd_t));
+}
+#endif
+
+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)
+{
+	pte = __pte(pte_val(pte) | _SUN4C_PAGE_MODIFIED);
+	if (pte_val(pte) & _SUN4C_PAGE_WRITE)
+		pte = __pte(pte_val(pte) | _SUN4C_PAGE_SILENT_WRITE);
+	return pte;
+}
+
+static pte_t sun4c_pte_mkyoung(pte_t pte)
+{
+	pte = __pte(pte_val(pte) | _SUN4C_PAGE_ACCESSED);
+	if (pte_val(pte) & _SUN4C_PAGE_READ)
+		pte = __pte(pte_val(pte) | _SUN4C_PAGE_SILENT_READ);
+	return pte;
+}
+
+/*
+ * Conversion functions: convert a page and protection to a page entry,
+ * and a page entry and page directory to the page they refer to.
+ */
+static pte_t sun4c_mk_pte(struct page *page, pgprot_t pgprot)
+{
+	return __pte(page_to_pfn(page) | pgprot_val(pgprot));
+}
+
+static pte_t sun4c_mk_pte_phys(unsigned long phys_page, pgprot_t pgprot)
+{
+	return __pte((phys_page >> PAGE_SHIFT) | pgprot_val(pgprot));
+}
+
+static pte_t sun4c_mk_pte_io(unsigned long page, pgprot_t pgprot, int space)
+{
+	return __pte(((page - PAGE_OFFSET) >> PAGE_SHIFT) | pgprot_val(pgprot));
+}
+
+static unsigned long sun4c_pte_pfn(pte_t pte)
+{
+	return pte_val(pte) & SUN4C_PFN_MASK;
+}
+
+static pte_t sun4c_pgoff_to_pte(unsigned long pgoff)
+{
+	return __pte(pgoff | _SUN4C_PAGE_FILE);
+}
+
+static unsigned long sun4c_pte_to_pgoff(pte_t pte)
+{
+	return pte_val(pte) & ((1UL << PTE_FILE_MAX_BITS) - 1);
+}
+
+
+static __inline__ unsigned long sun4c_pmd_page_v(pmd_t pmd)
+{
+	return (pmd_val(pmd) & PAGE_MASK);
+}
+
+static struct page *sun4c_pmd_page(pmd_t pmd)
+{
+	return virt_to_page(sun4c_pmd_page_v(pmd));
+}
+
+static unsigned long sun4c_pgd_page(pgd_t pgd) { return 0; }
+
+/* to find an entry in a page-table-directory */
+static inline pgd_t *sun4c_pgd_offset(struct mm_struct * mm, unsigned long address)
+{
+	return mm->pgd + (address >> SUN4C_PGDIR_SHIFT);
+}
+
+/* Find an entry in the second-level page table.. */
+static pmd_t *sun4c_pmd_offset(pgd_t * dir, unsigned long address)
+{
+	return (pmd_t *) dir;
+}
+
+/* Find an entry in the third-level page table.. */ 
+pte_t *sun4c_pte_offset_kernel(pmd_t * dir, unsigned long address)
+{
+	return (pte_t *) sun4c_pmd_page_v(*dir) +
+			((address >> PAGE_SHIFT) & (SUN4C_PTRS_PER_PTE - 1));
+}
+
+static unsigned long sun4c_swp_type(swp_entry_t entry)
+{
+	return (entry.val & SUN4C_SWP_TYPE_MASK);
+}
+
+static unsigned long sun4c_swp_offset(swp_entry_t entry)
+{
+	return (entry.val >> SUN4C_SWP_OFF_SHIFT) & SUN4C_SWP_OFF_MASK;
+}
+
+static swp_entry_t sun4c_swp_entry(unsigned long type, unsigned long offset)
+{
+	return (swp_entry_t) {
+		  (offset & SUN4C_SWP_OFF_MASK) << SUN4C_SWP_OFF_SHIFT
+		| (type & SUN4C_SWP_TYPE_MASK) };
+}
+
+static void sun4c_free_pte_slow(pte_t *pte)
+{
+	free_page((unsigned long)pte);
+}
+
+static void sun4c_free_pgd_slow(pgd_t *pgd)
+{
+	free_page((unsigned long)pgd);
+}
+
+static pgd_t *sun4c_get_pgd_fast(void)
+{
+	unsigned long *ret;
+
+	if ((ret = pgd_quicklist) != NULL) {
+		pgd_quicklist = (unsigned long *)(*ret);
+		ret[0] = ret[1];
+		pgtable_cache_size--;
+	} else {
+		pgd_t *init;
+		
+		ret = (unsigned long *)__get_free_page(GFP_KERNEL);
+		memset (ret, 0, (KERNBASE / SUN4C_PGDIR_SIZE) * sizeof(pgd_t));
+		init = sun4c_pgd_offset(&init_mm, 0);
+		memcpy (((pgd_t *)ret) + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
+			(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
+	}
+	return (pgd_t *)ret;
+}
+
+static void sun4c_free_pgd_fast(pgd_t *pgd)
+{
+	*(unsigned long *)pgd = (unsigned long) pgd_quicklist;
+	pgd_quicklist = (unsigned long *) pgd;
+	pgtable_cache_size++;
+}
+
+
+static __inline__ pte_t *
+sun4c_pte_alloc_one_fast(struct mm_struct *mm, unsigned long address)
+{
+	unsigned long *ret;
+
+	if ((ret = (unsigned long *)pte_quicklist) != NULL) {
+		pte_quicklist = (unsigned long *)(*ret);
+		ret[0] = ret[1];
+		pgtable_cache_size--;
+	}
+	return (pte_t *)ret;
+}
+
+static pte_t *sun4c_pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
+{
+	pte_t *pte;
+
+	if ((pte = sun4c_pte_alloc_one_fast(mm, address)) != NULL)
+		return pte;
+
+	pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
+	if (pte)
+		memset(pte, 0, PAGE_SIZE);
+	return pte;
+}
+
+static struct page *sun4c_pte_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+	pte_t *pte = sun4c_pte_alloc_one_kernel(mm, address);
+	if (pte == NULL)
+		return NULL;
+	return virt_to_page(pte);
+}
+
+static __inline__ void sun4c_free_pte_fast(pte_t *pte)
+{
+	*(unsigned long *)pte = (unsigned long) pte_quicklist;
+	pte_quicklist = (unsigned long *) pte;
+	pgtable_cache_size++;
+}
+
+static void sun4c_pte_free(struct page *pte)
+{
+	sun4c_free_pte_fast(page_address(pte));
+}
+
+/*
+ * allocating and freeing a pmd is trivial: the 1-entry pmd is
+ * inside the pgd, so has no extra memory associated with it.
+ */
+static pmd_t *sun4c_pmd_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+	BUG();
+	return NULL;
+}
+
+static void sun4c_free_pmd_fast(pmd_t * pmd) { }
+
+static void sun4c_check_pgt_cache(int low, int high)
+{
+	if (pgtable_cache_size > high) {
+		do {
+			if (pgd_quicklist)
+				sun4c_free_pgd_slow(sun4c_get_pgd_fast());
+			if (pte_quicklist)
+				sun4c_free_pte_slow(sun4c_pte_alloc_one_fast(NULL, 0));
+		} while (pgtable_cache_size > low);
+	}
+}
+
+/* An experiment, turn off by default for now... -DaveM */
+#define SUN4C_PRELOAD_PSEG
+
+void sun4c_update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t pte)
+{
+	unsigned long flags;
+	int pseg;
+
+	local_irq_save(flags);
+	address &= PAGE_MASK;
+	if ((pseg = sun4c_get_segmap(address)) == invalid_segment) {
+		struct sun4c_mmu_entry *entry = sun4c_user_strategy();
+		struct mm_struct *mm = vma->vm_mm;
+		unsigned long start, end;
+
+		entry->vaddr = start = (address & SUN4C_REAL_PGDIR_MASK);
+		entry->ctx = mm->context;
+		add_ring_ordered(sun4c_context_ring + mm->context, entry);
+		sun4c_put_segmap(entry->vaddr, entry->pseg);
+		end = start + SUN4C_REAL_PGDIR_SIZE;
+		while (start < end) {
+#ifdef SUN4C_PRELOAD_PSEG
+			pgd_t *pgdp = sun4c_pgd_offset(mm, start);
+			pte_t *ptep;
+
+			if (!pgdp)
+				goto no_mapping;
+			ptep = sun4c_pte_offset_kernel((pmd_t *) pgdp, start);
+			if (!ptep || !(pte_val(*ptep) & _SUN4C_PAGE_PRESENT))
+				goto no_mapping;
+			sun4c_put_pte(start, pte_val(*ptep));
+			goto next;
+
+		no_mapping:
+#endif
+			sun4c_put_pte(start, 0);
+#ifdef SUN4C_PRELOAD_PSEG
+		next:
+#endif
+			start += PAGE_SIZE;
+		}
+#ifndef SUN4C_PRELOAD_PSEG
+		sun4c_put_pte(address, pte_val(pte));
+#endif
+		local_irq_restore(flags);
+		return;
+	} else {
+		struct sun4c_mmu_entry *entry = &mmu_entry_pool[pseg];
+
+		remove_lru(entry);
+		add_lru(entry);
+	}
+
+	sun4c_put_pte(address, pte_val(pte));
+	local_irq_restore(flags);
+}
+
+extern void sparc_context_init(int);
+extern unsigned long end;
+extern unsigned long bootmem_init(unsigned long *pages_avail);
+extern unsigned long last_valid_pfn;
+
+void __init sun4c_paging_init(void)
+{
+	int i, cnt;
+	unsigned long kernel_end, vaddr;
+	extern struct resource sparc_iomap;
+	unsigned long end_pfn, pages_avail;
+
+	kernel_end = (unsigned long) &end;
+	kernel_end += (SUN4C_REAL_PGDIR_SIZE * 4);
+	kernel_end = SUN4C_REAL_PGDIR_ALIGN(kernel_end);
+
+	pages_avail = 0;
+	last_valid_pfn = bootmem_init(&pages_avail);
+	end_pfn = last_valid_pfn;
+
+	sun4c_probe_mmu();
+	invalid_segment = (num_segmaps - 1);
+	sun4c_init_mmu_entry_pool();
+	sun4c_init_rings();
+	sun4c_init_map_kernelprom(kernel_end);
+	sun4c_init_clean_mmu(kernel_end);
+	sun4c_init_fill_kernel_ring(SUN4C_KERNEL_BUCKETS);
+	sun4c_init_lock_area(sparc_iomap.start, IOBASE_END);
+	sun4c_init_lock_area(DVMA_VADDR, DVMA_END);
+	sun4c_init_lock_areas();
+	sun4c_init_fill_user_ring();
+
+	sun4c_set_context(0);
+	memset(swapper_pg_dir, 0, PAGE_SIZE);
+	memset(pg0, 0, PAGE_SIZE);
+	memset(pg1, 0, PAGE_SIZE);
+	memset(pg2, 0, PAGE_SIZE);
+	memset(pg3, 0, PAGE_SIZE);
+
+	/* Save work later. */
+	vaddr = VMALLOC_START;
+	swapper_pg_dir[vaddr>>SUN4C_PGDIR_SHIFT] = __pgd(PGD_TABLE | (unsigned long) pg0);
+	vaddr += SUN4C_PGDIR_SIZE;
+	swapper_pg_dir[vaddr>>SUN4C_PGDIR_SHIFT] = __pgd(PGD_TABLE | (unsigned long) pg1);
+	vaddr += SUN4C_PGDIR_SIZE;
+	swapper_pg_dir[vaddr>>SUN4C_PGDIR_SHIFT] = __pgd(PGD_TABLE | (unsigned long) pg2);
+	vaddr += SUN4C_PGDIR_SIZE;
+	swapper_pg_dir[vaddr>>SUN4C_PGDIR_SHIFT] = __pgd(PGD_TABLE | (unsigned long) pg3);
+	sun4c_init_ss2_cache_bug();
+	sparc_context_init(num_contexts);
+
+	{
+		unsigned long zones_size[MAX_NR_ZONES];
+		unsigned long zholes_size[MAX_NR_ZONES];
+		unsigned long npages;
+		int znum;
+
+		for (znum = 0; znum < MAX_NR_ZONES; znum++)
+			zones_size[znum] = zholes_size[znum] = 0;
+
+		npages = max_low_pfn - pfn_base;
+
+		zones_size[ZONE_DMA] = npages;
+		zholes_size[ZONE_DMA] = npages - pages_avail;
+
+		npages = highend_pfn - max_low_pfn;
+		zones_size[ZONE_HIGHMEM] = npages;
+		zholes_size[ZONE_HIGHMEM] = npages - calc_highpages();
+
+		free_area_init_node(0, &contig_page_data, zones_size,
+				    pfn_base, zholes_size);
+	}
+
+	cnt = 0;
+	for (i = 0; i < num_segmaps; i++)
+		if (mmu_entry_pool[i].locked)
+			cnt++;
+
+	max_user_taken_entries = num_segmaps - cnt - 40 - 1;
+
+	printk("SUN4C: %d mmu entries for the kernel\n", cnt);
+}
+
+/* Load up routines and constants for sun4c mmu */
+void __init ld_mmu_sun4c(void)
+{
+	extern void ___xchg32_sun4c(void);
+	
+	printk("Loading sun4c MMU routines\n");
+
+	/* First the constants */
+	BTFIXUPSET_SIMM13(pgdir_shift, SUN4C_PGDIR_SHIFT);
+	BTFIXUPSET_SETHI(pgdir_size, SUN4C_PGDIR_SIZE);
+	BTFIXUPSET_SETHI(pgdir_mask, SUN4C_PGDIR_MASK);
+
+	BTFIXUPSET_SIMM13(ptrs_per_pmd, SUN4C_PTRS_PER_PMD);
+	BTFIXUPSET_SIMM13(ptrs_per_pgd, SUN4C_PTRS_PER_PGD);
+	BTFIXUPSET_SIMM13(user_ptrs_per_pgd, KERNBASE / SUN4C_PGDIR_SIZE);
+
+	BTFIXUPSET_INT(page_none, pgprot_val(SUN4C_PAGE_NONE));
+	BTFIXUPSET_INT(page_shared, pgprot_val(SUN4C_PAGE_SHARED));
+	BTFIXUPSET_INT(page_copy, pgprot_val(SUN4C_PAGE_COPY));
+	BTFIXUPSET_INT(page_readonly, pgprot_val(SUN4C_PAGE_READONLY));
+	BTFIXUPSET_INT(page_kernel, pgprot_val(SUN4C_PAGE_KERNEL));
+	page_kernel = pgprot_val(SUN4C_PAGE_KERNEL);
+	pg_iobits = _SUN4C_PAGE_PRESENT | _SUN4C_READABLE | _SUN4C_WRITEABLE |
+		    _SUN4C_PAGE_IO | _SUN4C_PAGE_NOCACHE;
+
+	/* Functions */
+	BTFIXUPSET_CALL(___xchg32, ___xchg32_sun4c, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(do_check_pgt_cache, sun4c_check_pgt_cache, BTFIXUPCALL_NORM);
+	
+	BTFIXUPSET_CALL(flush_cache_all, sun4c_flush_cache_all, BTFIXUPCALL_NORM);
+
+	if (sun4c_vacinfo.do_hwflushes) {
+		BTFIXUPSET_CALL(sun4c_flush_page, sun4c_flush_page_hw, BTFIXUPCALL_NORM);
+		BTFIXUPSET_CALL(sun4c_flush_segment, sun4c_flush_segment_hw, BTFIXUPCALL_NORM);
+		BTFIXUPSET_CALL(sun4c_flush_context, sun4c_flush_context_hw, BTFIXUPCALL_NORM);
+	} else {
+		BTFIXUPSET_CALL(sun4c_flush_page, sun4c_flush_page_sw, BTFIXUPCALL_NORM);
+		BTFIXUPSET_CALL(sun4c_flush_segment, sun4c_flush_segment_sw, BTFIXUPCALL_NORM);
+		BTFIXUPSET_CALL(sun4c_flush_context, sun4c_flush_context_sw, BTFIXUPCALL_NORM);
+	}
+
+	BTFIXUPSET_CALL(flush_tlb_mm, sun4c_flush_tlb_mm, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(flush_cache_mm, sun4c_flush_cache_mm, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(destroy_context, sun4c_destroy_context, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(switch_mm, sun4c_switch_mm, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(flush_cache_page, sun4c_flush_cache_page, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(flush_tlb_page, sun4c_flush_tlb_page, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(flush_tlb_range, sun4c_flush_tlb_range, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(flush_cache_range, sun4c_flush_cache_range, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(__flush_page_to_ram, sun4c_flush_page_to_ram, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(flush_tlb_all, sun4c_flush_tlb_all, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(flush_sig_insns, sun4c_flush_sig_insns, BTFIXUPCALL_NOP);
+
+	BTFIXUPSET_CALL(set_pte, sun4c_set_pte, BTFIXUPCALL_STO1O0);
+
+	/* The 2.4.18 code does not set this on sun4c, how does it work? XXX */
+	/* BTFIXUPSET_SETHI(none_mask, 0x00000000); */	/* Defaults to zero? */
+
+	BTFIXUPSET_CALL(pte_pfn, sun4c_pte_pfn, BTFIXUPCALL_NORM);
+#if 0 /* PAGE_SHIFT <= 12 */ /* Eek. Investigate. XXX */
+	BTFIXUPSET_CALL(pmd_page, sun4c_pmd_page, BTFIXUPCALL_ANDNINT(PAGE_SIZE - 1));
+#else
+	BTFIXUPSET_CALL(pmd_page, sun4c_pmd_page, BTFIXUPCALL_NORM);
+#endif
+	BTFIXUPSET_CALL(pmd_set, sun4c_pmd_set, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pmd_populate, sun4c_pmd_populate, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(pte_present, sun4c_pte_present, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pte_clear, sun4c_pte_clear, BTFIXUPCALL_STG0O0);
+	BTFIXUPSET_CALL(pte_read, sun4c_pte_read, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(pmd_bad, sun4c_pmd_bad, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pmd_present, sun4c_pmd_present, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pmd_clear, sun4c_pmd_clear, BTFIXUPCALL_STG0O0);
+
+	BTFIXUPSET_CALL(pgd_none, sun4c_pgd_none, BTFIXUPCALL_RETINT(0));
+	BTFIXUPSET_CALL(pgd_bad, sun4c_pgd_bad, BTFIXUPCALL_RETINT(0));
+	BTFIXUPSET_CALL(pgd_present, sun4c_pgd_present, BTFIXUPCALL_RETINT(1));
+	BTFIXUPSET_CALL(pgd_clear, sun4c_pgd_clear, BTFIXUPCALL_NOP);
+
+	BTFIXUPSET_CALL(mk_pte, sun4c_mk_pte, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(mk_pte_phys, sun4c_mk_pte_phys, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(mk_pte_io, sun4c_mk_pte_io, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_INT(pte_modify_mask, _SUN4C_PAGE_CHG_MASK);
+	BTFIXUPSET_CALL(pmd_offset, sun4c_pmd_offset, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pte_offset_kernel, sun4c_pte_offset_kernel, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(free_pte_fast, sun4c_free_pte_fast, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pte_free, sun4c_pte_free, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pte_alloc_one_kernel, sun4c_pte_alloc_one_kernel, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pte_alloc_one, sun4c_pte_alloc_one, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(free_pmd_fast, sun4c_free_pmd_fast, BTFIXUPCALL_NOP);
+	BTFIXUPSET_CALL(pmd_alloc_one, sun4c_pmd_alloc_one, BTFIXUPCALL_RETO0);
+	BTFIXUPSET_CALL(free_pgd_fast, sun4c_free_pgd_fast, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(get_pgd_fast, sun4c_get_pgd_fast, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_HALF(pte_writei, _SUN4C_PAGE_WRITE);
+	BTFIXUPSET_HALF(pte_dirtyi, _SUN4C_PAGE_MODIFIED);
+	BTFIXUPSET_HALF(pte_youngi, _SUN4C_PAGE_ACCESSED);
+	BTFIXUPSET_HALF(pte_filei, _SUN4C_PAGE_FILE);
+	BTFIXUPSET_HALF(pte_wrprotecti, _SUN4C_PAGE_WRITE|_SUN4C_PAGE_SILENT_WRITE);
+	BTFIXUPSET_HALF(pte_mkcleani, _SUN4C_PAGE_MODIFIED|_SUN4C_PAGE_SILENT_WRITE);
+	BTFIXUPSET_HALF(pte_mkoldi, _SUN4C_PAGE_ACCESSED|_SUN4C_PAGE_SILENT_READ);
+	BTFIXUPSET_CALL(pte_mkwrite, sun4c_pte_mkwrite, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pte_mkdirty, sun4c_pte_mkdirty, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pte_mkyoung, sun4c_pte_mkyoung, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(update_mmu_cache, sun4c_update_mmu_cache, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(pte_to_pgoff, sun4c_pte_to_pgoff, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(pgoff_to_pte, sun4c_pgoff_to_pte, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(mmu_lockarea, sun4c_lockarea, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(mmu_unlockarea, sun4c_unlockarea, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(mmu_get_scsi_one, sun4c_get_scsi_one, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(mmu_get_scsi_sgl, sun4c_get_scsi_sgl, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(mmu_release_scsi_one, sun4c_release_scsi_one, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(mmu_release_scsi_sgl, sun4c_release_scsi_sgl, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(mmu_map_dma_area, sun4c_map_dma_area, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(mmu_unmap_dma_area, sun4c_unmap_dma_area, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(mmu_translate_dvma, sun4c_translate_dvma, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(sparc_mapiorange, sun4c_mapiorange, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(sparc_unmapiorange, sun4c_unmapiorange, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(__swp_type, sun4c_swp_type, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(__swp_offset, sun4c_swp_offset, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(__swp_entry, sun4c_swp_entry, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(alloc_thread_info, sun4c_alloc_thread_info, BTFIXUPCALL_NORM);
+	BTFIXUPSET_CALL(free_thread_info, sun4c_free_thread_info, BTFIXUPCALL_NORM);
+
+	BTFIXUPSET_CALL(mmu_info, sun4c_mmu_info, BTFIXUPCALL_NORM);
+
+	/* These should _never_ get called with two level tables. */
+	BTFIXUPSET_CALL(pgd_set, sun4c_pgd_set, BTFIXUPCALL_NOP);
+	BTFIXUPSET_CALL(pgd_page, sun4c_pgd_page, BTFIXUPCALL_RETO0);
+}