More AP / SP bits for the 34K, the Malta bits and things. Still wants

a little polishing.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 1295 insertions, 0 deletions

diff --git a/arch/mips/kernel/vpe.c b/arch/mips/kernel/vpe.c
new file mode 100644
index 0000000..6bf42ba
--- /dev/null
+++ b/arch/mips/kernel/vpe.c
@@ -0,0 +1,1295 @@
+/*
+ * Copyright (C) 2004, 2005 MIPS Technologies, Inc.  All rights reserved.
+ *
+ *  This program is free software; you can distribute it and/or modify it
+ *  under the terms of the GNU General Public License (Version 2) as
+ *  published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ */
+
+/*
+ * VPE support module
+ *
+ * Provides support for loading a MIPS SP program on VPE1.
+ * The SP enviroment is rather simple, no tlb's.  It needs to be relocatable
+ * (or partially linked). You should initialise your stack in the startup
+ * code. This loader looks for the symbol __start and sets up
+ * execution to resume from there. The MIPS SDE kit contains suitable examples.
+ *
+ * To load and run, simply cat a SP 'program file' to /dev/vpe1.
+ * i.e cat spapp >/dev/vpe1.
+ *
+ * You'll need to have the following device files.
+ * mknod /dev/vpe0 c 63 0
+ * mknod /dev/vpe1 c 63 1
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <asm/uaccess.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/vmalloc.h>
+#include <linux/elf.h>
+#include <linux/seq_file.h>
+#include <linux/syscalls.h>
+#include <linux/moduleloader.h>
+#include <linux/interrupt.h>
+#include <linux/poll.h>
+#include <linux/bootmem.h>
+#include <asm/mipsregs.h>
+#include <asm/cacheflush.h>
+#include <asm/atomic.h>
+#include <asm/cpu.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+
+typedef void *vpe_handle;
+
+// defined here because the kernel module loader doesn't have
+// anything to do with it.
+#define SHN_MIPS_SCOMMON 0xff03
+
+#ifndef ARCH_SHF_SMALL
+#define ARCH_SHF_SMALL 0
+#endif
+
+/* If this is set, the section belongs in the init part of the module */
+#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
+
+// temp number,
+#define VPE_MAJOR 63
+
+static char module_name[] = "vpe";
+static int major = 0;
+
+/* grab the likely amount of memory we will need. */
+#ifdef CONFIG_MIPS_VPE_LOADER_TOM
+#define P_SIZE (2 * 1024 * 1024)
+#else
+/* add an overhead to the max kmalloc size for non-striped symbols/etc */
+#define P_SIZE (256 * 1024)
+#endif
+
+#define MAX_VPES 16
+
+enum vpe_state {
+	VPE_STATE_UNUSED = 0,
+	VPE_STATE_INUSE,
+	VPE_STATE_RUNNING
+};
+
+enum tc_state {
+	TC_STATE_UNUSED = 0,
+	TC_STATE_INUSE,
+	TC_STATE_RUNNING,
+	TC_STATE_DYNAMIC
+};
+
+struct vpe;
+typedef struct tc {
+	enum tc_state state;
+	int index;
+
+	/* parent VPE */
+	struct vpe *pvpe;
+
+	/* The list of TC's with this VPE */
+	struct list_head tc;
+
+	/* The global list of tc's */
+	struct list_head list;
+} tc_t;
+
+typedef struct vpe {
+	enum vpe_state state;
+
+	/* (device) minor associated with this vpe */
+	int minor;
+
+	/* elfloader stuff */
+	void *load_addr;
+	u32 len;
+	char *pbuffer;
+	u32 plen;
+
+	unsigned long __start;
+
+	/* tc's associated with this vpe */
+	struct list_head tc;
+
+	/* The list of vpe's */
+	struct list_head list;
+
+	/* shared symbol address */
+	void *shared_ptr;
+} vpe_t;
+
+struct vpecontrol_ {
+	/* Virtual processing elements */
+	struct list_head vpe_list;
+
+	/* Thread contexts */
+	struct list_head tc_list;
+} vpecontrol;
+
+static void release_progmem(void *ptr);
+static void dump_vpe(vpe_t * v);
+extern void save_gp_address(unsigned int secbase, unsigned int rel);
+
+/* get the vpe associated with this minor */
+struct vpe *get_vpe(int minor)
+{
+	struct vpe *v;
+
+	list_for_each_entry(v, &vpecontrol.vpe_list, list) {
+		if (v->minor == minor)
+			return v;
+	}
+
+	printk(KERN_DEBUG "VPE: get_vpe minor %d not found\n", minor);
+	return NULL;
+}
+
+/* get the vpe associated with this minor */
+struct tc *get_tc(int index)
+{
+	struct tc *t;
+
+	list_for_each_entry(t, &vpecontrol.tc_list, list) {
+		if (t->index == index)
+			return t;
+	}
+
+	printk(KERN_DEBUG "VPE: get_tc index %d not found\n", index);
+
+	return NULL;
+}
+
+struct tc *get_tc_unused(void)
+{
+	struct tc *t;
+
+	list_for_each_entry(t, &vpecontrol.tc_list, list) {
+		if (t->state == TC_STATE_UNUSED)
+			return t;
+	}
+
+	printk(KERN_DEBUG "VPE: All TC's are in use\n");
+
+	return NULL;
+}
+
+/* allocate a vpe and associate it with this minor (or index) */
+struct vpe *alloc_vpe(int minor)
+{
+	struct vpe *v;
+
+	if ((v = kmalloc(sizeof(struct vpe), GFP_KERNEL)) == NULL) {
+		printk(KERN_WARNING "VPE: alloc_vpe no mem\n");
+		return NULL;
+	}
+
+	memset(v, 0, sizeof(struct vpe));
+
+	INIT_LIST_HEAD(&v->tc);
+	list_add_tail(&v->list, &vpecontrol.vpe_list);
+
+	v->minor = minor;
+	return v;
+}
+
+/* allocate a tc. At startup only tc0 is running, all other can be halted. */
+struct tc *alloc_tc(int index)
+{
+	struct tc *t;
+
+	if ((t = kmalloc(sizeof(struct tc), GFP_KERNEL)) == NULL) {
+		printk(KERN_WARNING "VPE: alloc_tc no mem\n");
+		return NULL;
+	}
+
+	memset(t, 0, sizeof(struct tc));
+
+	INIT_LIST_HEAD(&t->tc);
+	list_add_tail(&t->list, &vpecontrol.tc_list);
+
+	t->index = index;
+
+	return t;
+}
+
+/* clean up and free everything */
+void release_vpe(struct vpe *v)
+{
+	list_del(&v->list);
+	if (v->load_addr)
+		release_progmem(v);
+	kfree(v);
+}
+
+void dump_mtregs(void)
+{
+	unsigned long val;
+
+	val = read_c0_config3();
+	printk("config3 0x%lx MT %ld\n", val,
+	       (val & CONFIG3_MT) >> CONFIG3_MT_SHIFT);
+
+	val = read_c0_mvpconf0();
+	printk("mvpconf0 0x%lx, PVPE %ld PTC %ld M %ld\n", val,
+	       (val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT,
+	       val & MVPCONF0_PTC, (val & MVPCONF0_M) >> MVPCONF0_M_SHIFT);
+
+	val = read_c0_mvpcontrol();
+	printk("MVPControl 0x%lx, STLB %ld VPC %ld EVP %ld\n", val,
+	       (val & MVPCONTROL_STLB) >> MVPCONTROL_STLB_SHIFT,
+	       (val & MVPCONTROL_VPC) >> MVPCONTROL_VPC_SHIFT,
+	       (val & MVPCONTROL_EVP));
+
+	val = read_c0_vpeconf0();
+	printk("VPEConf0 0x%lx MVP %ld\n", val,
+	       (val & VPECONF0_MVP) >> VPECONF0_MVP_SHIFT);
+}
+
+/* Find some VPE program space  */
+static void *alloc_progmem(u32 len)
+{
+#ifdef CONFIG_MIPS_VPE_LOADER_TOM
+	/* this means you must tell linux to use less memory than you physically have */
+	return (void *)((max_pfn * PAGE_SIZE) + KSEG0);
+#else
+	// simple grab some mem for now
+	return kmalloc(len, GFP_KERNEL);
+#endif
+}
+
+static void release_progmem(void *ptr)
+{
+#ifndef CONFIG_MIPS_VPE_LOADER_TOM
+	kfree(ptr);
+#endif
+}
+
+/* Update size with this section: return offset. */
+static long get_offset(unsigned long *size, Elf_Shdr * sechdr)
+{
+	long ret;
+
+	ret = ALIGN(*size, sechdr->sh_addralign ? : 1);
+	*size = ret + sechdr->sh_size;
+	return ret;
+}
+
+/* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
+   might -- code, read-only data, read-write data, small data.  Tally
+   sizes, and place the offsets into sh_entsize fields: high bit means it
+   belongs in init. */
+static void layout_sections(struct module *mod, const Elf_Ehdr * hdr,
+			    Elf_Shdr * sechdrs, const char *secstrings)
+{
+	static unsigned long const masks[][2] = {
+		/* NOTE: all executable code must be the first section
+		 * in this array; otherwise modify the text_size
+		 * finder in the two loops below */
+		{SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL},
+		{SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL},
+		{SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL},
+		{ARCH_SHF_SMALL | SHF_ALLOC, 0}
+	};
+	unsigned int m, i;
+
+	for (i = 0; i < hdr->e_shnum; i++)
+		sechdrs[i].sh_entsize = ~0UL;
+
+	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
+		for (i = 0; i < hdr->e_shnum; ++i) {
+			Elf_Shdr *s = &sechdrs[i];
+
+			//  || strncmp(secstrings + s->sh_name, ".init", 5) == 0)
+			if ((s->sh_flags & masks[m][0]) != masks[m][0]
+			    || (s->sh_flags & masks[m][1])
+			    || s->sh_entsize != ~0UL)
+				continue;
+			s->sh_entsize = get_offset(&mod->core_size, s);
+		}
+
+		if (m == 0)
+			mod->core_text_size = mod->core_size;
+
+	}
+}
+
+
+/* from module-elf32.c, but subverted a little */
+
+struct mips_hi16 {
+	struct mips_hi16 *next;
+	Elf32_Addr *addr;
+	Elf32_Addr value;
+};
+
+static struct mips_hi16 *mips_hi16_list;
+static unsigned int gp_offs, gp_addr;
+
+static int apply_r_mips_none(struct module *me, uint32_t *location,
+			     Elf32_Addr v)
+{
+	return 0;
+}
+
+static int apply_r_mips_gprel16(struct module *me, uint32_t *location,
+				Elf32_Addr v)
+{
+	int rel;
+
+	if( !(*location & 0xffff) ) {
+		rel = (int)v - gp_addr;
+	}
+	else {
+		/* .sbss + gp(relative) + offset */
+		/* kludge! */
+		rel =  (int)(short)((int)v + gp_offs +
+				    (int)(short)(*location & 0xffff) - gp_addr);
+	}
+
+	if( (rel > 32768) || (rel < -32768) ) {
+		printk(KERN_ERR
+		       "apply_r_mips_gprel16: relative address out of range 0x%x %d\n",
+		       rel, rel);
+		return -ENOEXEC;
+	}
+
+	*location = (*location & 0xffff0000) | (rel & 0xffff);
+
+	return 0;
+}
+
+static int apply_r_mips_pc16(struct module *me, uint32_t *location,
+			     Elf32_Addr v)
+{
+	int rel;
+	rel = (((unsigned int)v - (unsigned int)location));
+	rel >>= 2;		// because the offset is in _instructions_ not bytes.
+	rel -= 1;		// and one instruction less due to the branch delay slot.
+
+	if( (rel > 32768) || (rel < -32768) ) {
+		printk(KERN_ERR
+		       "apply_r_mips_pc16: relative address out of range 0x%x\n", rel);
+		return -ENOEXEC;
+	}
+
+	*location = (*location & 0xffff0000) | (rel & 0xffff);
+
+	return 0;
+}
+
+static int apply_r_mips_32(struct module *me, uint32_t *location,
+			   Elf32_Addr v)
+{
+	*location += v;
+
+	return 0;
+}
+
+static int apply_r_mips_26(struct module *me, uint32_t *location,
+			   Elf32_Addr v)
+{
+	if (v % 4) {
+		printk(KERN_ERR "module %s: dangerous relocation mod4\n", me->name);
+		return -ENOEXEC;
+	}
+
+/* Not desperately convinced this is a good check of an overflow condition
+   anyway. But it gets in the way of handling undefined weak symbols which
+   we want to set to zero.
+   if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
+   printk(KERN_ERR
+   "module %s: relocation overflow\n",
+   me->name);
+   return -ENOEXEC;
+   }
+*/
+
+	*location = (*location & ~0x03ffffff) |
+		((*location + (v >> 2)) & 0x03ffffff);
+	return 0;
+}
+
+static int apply_r_mips_hi16(struct module *me, uint32_t *location,
+			     Elf32_Addr v)
+{
+	struct mips_hi16 *n;
+
+	/*
+	 * We cannot relocate this one now because we don't know the value of
+	 * the carry we need to add.  Save the information, and let LO16 do the
+	 * actual relocation.
+	 */
+	n = kmalloc(sizeof *n, GFP_KERNEL);
+	if (!n)
+		return -ENOMEM;
+
+	n->addr = location;
+	n->value = v;
+	n->next = mips_hi16_list;
+	mips_hi16_list = n;
+
+	return 0;
+}
+
+static int apply_r_mips_lo16(struct module *me, uint32_t *location,
+			     Elf32_Addr v)
+{
+	unsigned long insnlo = *location;
+	Elf32_Addr val, vallo;
+
+	/* Sign extend the addend we extract from the lo insn.  */
+	vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
+
+	if (mips_hi16_list != NULL) {
+		struct mips_hi16 *l;
+
+		l = mips_hi16_list;
+		while (l != NULL) {
+			struct mips_hi16 *next;
+			unsigned long insn;
+
+			/*
+			 * The value for the HI16 had best be the same.
+			 */
+			if (v != l->value) {
+				printk("%d != %d\n", v, l->value);
+				goto out_danger;
+			}
+
+
+			/*
+			 * Do the HI16 relocation.  Note that we actually don't
+			 * need to know anything about the LO16 itself, except
+			 * where to find the low 16 bits of the addend needed
+			 * by the LO16.
+			 */
+			insn = *l->addr;
+			val = ((insn & 0xffff) << 16) + vallo;
+			val += v;
+
+			/*
+			 * Account for the sign extension that will happen in
+			 * the low bits.
+			 */
+			val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
+
+			insn = (insn & ~0xffff) | val;
+			*l->addr = insn;
+
+			next = l->next;
+			kfree(l);
+			l = next;
+		}
+
+		mips_hi16_list = NULL;
+	}
+
+	/*
+	 * Ok, we're done with the HI16 relocs.  Now deal with the LO16.
+	 */
+	val = v + vallo;
+	insnlo = (insnlo & ~0xffff) | (val & 0xffff);
+	*location = insnlo;
+
+	return 0;
+
+out_danger:
+	printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name);
+
+	return -ENOEXEC;
+}
+
+static int (*reloc_handlers[]) (struct module *me, uint32_t *location,
+				Elf32_Addr v) = {
+	[R_MIPS_NONE]	= apply_r_mips_none,
+	[R_MIPS_32]	= apply_r_mips_32,
+	[R_MIPS_26]	= apply_r_mips_26,
+	[R_MIPS_HI16]	= apply_r_mips_hi16,
+	[R_MIPS_LO16]	= apply_r_mips_lo16,
+	[R_MIPS_GPREL16] = apply_r_mips_gprel16,
+	[R_MIPS_PC16] = apply_r_mips_pc16
+};
+
+
+int apply_relocations(Elf32_Shdr *sechdrs,
+		      const char *strtab,
+		      unsigned int symindex,
+		      unsigned int relsec,
+		      struct module *me)
+{
+	Elf32_Rel *rel = (void *) sechdrs[relsec].sh_addr;
+	Elf32_Sym *sym;
+	uint32_t *location;
+	unsigned int i;
+	Elf32_Addr v;
+	int res;
+
+	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
+		Elf32_Word r_info = rel[i].r_info;
+
+		/* This is where to make the change */
+		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+			+ rel[i].r_offset;
+		/* This is the symbol it is referring to */
+		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+			+ ELF32_R_SYM(r_info);
+
+		if (!sym->st_value) {
+			printk(KERN_DEBUG "%s: undefined weak symbol %s\n",
+			       me->name, strtab + sym->st_name);
+			/* just print the warning, dont barf */
+		}
+
+		v = sym->st_value;
+
+		res = reloc_handlers[ELF32_R_TYPE(r_info)](me, location, v);
+		if( res ) {
+			printk(KERN_DEBUG
+			       "relocation error 0x%x sym refer <%s> value 0x%x "
+			       "type 0x%x r_info 0x%x\n",
+			       (unsigned int)location, strtab + sym->st_name, v,
+			       r_info, ELF32_R_TYPE(r_info));
+		}
+
+		if (res)
+			return res;
+	}
+
+	return 0;
+}
+
+void save_gp_address(unsigned int secbase, unsigned int rel)
+{
+	gp_addr = secbase + rel;
+	gp_offs = gp_addr - (secbase & 0xffff0000);
+}
+/* end module-elf32.c */
+
+
+
+/* Change all symbols so that sh_value encodes the pointer directly. */
+static int simplify_symbols(Elf_Shdr * sechdrs,
+			    unsigned int symindex,
+			    const char *strtab,
+			    const char *secstrings,
+			    unsigned int nsecs, struct module *mod)
+{
+	Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
+	unsigned long secbase, bssbase = 0;
+	unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
+	int ret = 0, size;
+
+	/* find the .bss section for COMMON symbols */
+	for (i = 0; i < nsecs; i++) {
+		if (strncmp(secstrings + sechdrs[i].sh_name, ".bss", 4) == 0)
+			bssbase = sechdrs[i].sh_addr;
+	}
+
+	for (i = 1; i < n; i++) {
+		switch (sym[i].st_shndx) {
+		case SHN_COMMON:
+			/* Allocate space for the symbol in the .bss section. st_value is currently size.
+			   We want it to have the address of the symbol. */
+
+			size = sym[i].st_value;
+			sym[i].st_value = bssbase;
+
+			bssbase += size;
+			break;
+
+		case SHN_ABS:
+			/* Don't need to do anything */
+			break;
+
+		case SHN_UNDEF:
+			/* ret = -ENOENT; */
+			break;
+
+		case SHN_MIPS_SCOMMON:
+
+			printk(KERN_DEBUG
+			       "simplify_symbols: ignoring SHN_MIPS_SCOMMON symbol <%s> st_shndx %d\n",
+			       strtab + sym[i].st_name, sym[i].st_shndx);
+
+			// .sbss section
+			break;
+
+		default:
+			secbase = sechdrs[sym[i].st_shndx].sh_addr;
+
+			if (strncmp(strtab + sym[i].st_name, "_gp", 3) == 0) {
+				save_gp_address(secbase, sym[i].st_value);
+			}
+
+			sym[i].st_value += secbase;
+			break;
+		}
+
+	}
+
+	return ret;
+}
+
+#ifdef DEBUG_ELFLOADER
+static void dump_elfsymbols(Elf_Shdr * sechdrs, unsigned int symindex,
+			    const char *strtab, struct module *mod)
+{
+	Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
+	unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
+
+	printk(KERN_DEBUG "dump_elfsymbols: n %d\n", n);
+	for (i = 1; i < n; i++) {
+		printk(KERN_DEBUG " i %d name <%s> 0x%x\n", i,
+		       strtab + sym[i].st_name, sym[i].st_value);
+	}
+}
+#endif
+
+static void dump_tc(struct tc *t)
+{
+	printk(KERN_WARNING "VPE: TC index %d TCStatus 0x%lx halt 0x%lx\n",
+	       t->index, read_tc_c0_tcstatus(), read_tc_c0_tchalt());
+	printk(KERN_WARNING "VPE: tcrestart 0x%lx\n", read_tc_c0_tcrestart());
+}
+
+static void dump_tclist(void)
+{
+	struct tc *t;
+
+	list_for_each_entry(t, &vpecontrol.tc_list, list) {
+		dump_tc(t);
+	}
+}
+
+/* We are prepared so configure and start the VPE... */
+int vpe_run(vpe_t * v)
+{
+	unsigned long val;
+	struct tc *t;
+
+	/* check we are the Master VPE */
+	val = read_c0_vpeconf0();
+	if (!(val & VPECONF0_MVP)) {
+		printk(KERN_WARNING
+		       "VPE: only Master VPE's are allowed to configure MT\n");
+		return -1;
+	}
+
+	/* disable MT (using dvpe) */
+	dvpe();
+
+	/* Put MVPE's into 'configuration state' */
+	write_c0_mvpcontrol(read_c0_mvpcontrol() | MVPCONTROL_VPC);
+
+	if (!list_empty(&v->tc)) {
+		if ((t = list_entry(v->tc.next, struct tc, tc)) == NULL) {
+			printk(KERN_WARNING "VPE: TC %d is already in use.\n",
+			       t->index);
+			return -ENOEXEC;
+		}
+	} else {
+		printk(KERN_WARNING "VPE: No TC's associated with VPE %d\n",
+		       v->minor);
+		return -ENOEXEC;
+	}
+
+	settc(t->index);
+
+	val = read_vpe_c0_vpeconf0();
+
+	/* should check it is halted, and not activated */
+	if ((read_tc_c0_tcstatus() & TCSTATUS_A) || !(read_tc_c0_tchalt() & TCHALT_H)) {
+		printk(KERN_WARNING "VPE: TC %d is already doing something!\n",
+		       t->index);
+
+		dump_tclist();
+		return -ENOEXEC;
+	}
+
+	/* Write the address we want it to start running from in the TCPC register. */
+	write_tc_c0_tcrestart((unsigned long)v->__start);
+
+	/* write the sivc_info address to tccontext */
+	write_tc_c0_tccontext((unsigned long)0);
+
+	/* Set up the XTC bit in vpeconf0 to point at our tc */
+	write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | (t->index << VPECONF0_XTC_SHIFT));
+
+	/* mark the TC as activated, not interrupt exempt and not dynamically allocatable */
+	val = read_tc_c0_tcstatus();
+	val = (val & ~(TCSTATUS_DA | TCSTATUS_IXMT)) | TCSTATUS_A;
+	write_tc_c0_tcstatus(val);
+
+	write_tc_c0_tchalt(read_tc_c0_tchalt() & ~TCHALT_H);
+
+	/* set up VPE1 */
+	write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() & ~VPECONTROL_TE);	// no multiple TC's
+	write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);	// enable this VPE
+
+	/*
+	 * The sde-kit passes 'memsize' to __start in $a3, so set something
+	 * here...
+	 * Or set $a3 (register 7) to zero and define DFLT_STACK_SIZE and
+	 * DFLT_HEAP_SIZE when you compile your program
+	 */
+
+	mttgpr(7, 0);
+
+	/* set config to be the same as vpe0, particularly kseg0 coherency alg */
+	write_vpe_c0_config(read_c0_config());
+
+	/* clear out any left overs from a previous program */
+	write_vpe_c0_cause(0);
+
+	/* take system out of configuration state */
+	write_c0_mvpcontrol(read_c0_mvpcontrol() & ~MVPCONTROL_VPC);
+
+	/* clear interrupts enabled IE, ERL, EXL, and KSU from c0 status */
+	write_vpe_c0_status(read_vpe_c0_status() & ~(ST0_ERL | ST0_KSU | ST0_IE | ST0_EXL));
+
+	/* set it running */
+	evpe(EVPE_ENABLE);
+
+	return 0;
+}
+
+static unsigned long find_vpe_symbols(vpe_t * v, Elf_Shdr * sechdrs,
+				      unsigned int symindex, const char *strtab,
+				      struct module *mod)
+{
+	Elf_Sym *sym = (void *)sechdrs[symindex].sh_addr;
+	unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
+
+	for (i = 1; i < n; i++) {
+		if (strcmp(strtab + sym[i].st_name, "__start") == 0) {
+			v->__start = sym[i].st_value;
+		}
+
+		if (strcmp(strtab + sym[i].st_name, "vpe_shared") == 0) {
+			v->shared_ptr = (void *)sym[i].st_value;
+		}
+	}
+
+	return 0;
+}
+
+/* Allocates a VPE with some program code space(the load address), copies the contents
+   of the program (p)buffer performing relocatations/etc, free's it when finished.
+*/
+int vpe_elfload(vpe_t * v)
+{
+	Elf_Ehdr *hdr;
+	Elf_Shdr *sechdrs;
+	long err = 0;
+	char *secstrings, *strtab = NULL;
+	unsigned int len, i, symindex = 0, strindex = 0;
+
+	struct module mod;	// so we can re-use the relocations code
+
+	memset(&mod, 0, sizeof(struct module));
+	strcpy(mod.name, "VPE dummy prog module");
+
+	hdr = (Elf_Ehdr *) v->pbuffer;
+	len = v->plen;
+
+	/* Sanity checks against insmoding binaries or wrong arch,
+	   weird elf version */
+	if (memcmp(hdr->e_ident, ELFMAG, 4) != 0
+	    || hdr->e_type != ET_REL || !elf_check_arch(hdr)
+	    || hdr->e_shentsize != sizeof(*sechdrs)) {
+		printk(KERN_WARNING
+		       "VPE program, wrong arch or weird elf version\n");
+
+		return -ENOEXEC;
+	}
+
+	if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr)) {
+		printk(KERN_ERR "VPE program length %u truncated\n", len);
+		return -ENOEXEC;
+	}
+
+	/* Convenience variables */
+	sechdrs = (void *)hdr + hdr->e_shoff;
+	secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+	sechdrs[0].sh_addr = 0;
+
+	/* And these should exist, but gcc whinges if we don't init them */
+	symindex = strindex = 0;
+
+	for (i = 1; i < hdr->e_shnum; i++) {
+
+		if (sechdrs[i].sh_type != SHT_NOBITS
+		    && len < sechdrs[i].sh_offset + sechdrs[i].sh_size) {
+			printk(KERN_ERR "VPE program length %u truncated\n",
+			       len);
+			return -ENOEXEC;
+		}
+
+		/* Mark all sections sh_addr with their address in the
+		   temporary image. */
+		sechdrs[i].sh_addr = (size_t) hdr + sechdrs[i].sh_offset;
+
+		/* Internal symbols and strings. */
+		if (sechdrs[i].sh_type == SHT_SYMTAB) {
+			symindex = i;
+			strindex = sechdrs[i].sh_link;
+			strtab = (char *)hdr + sechdrs[strindex].sh_offset;
+		}
+	}
+
+	layout_sections(&mod, hdr, sechdrs, secstrings);
+
+	v->load_addr = alloc_progmem(mod.core_size);
+	memset(v->load_addr, 0, mod.core_size);
+
+	printk("VPE elf_loader: loading to %p\n", v->load_addr);
+
+	for (i = 0; i < hdr->e_shnum; i++) {
+		void *dest;
+
+		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+			continue;
+
+		dest = v->load_addr + sechdrs[i].sh_entsize;
+
+		if (sechdrs[i].sh_type != SHT_NOBITS)
+			memcpy(dest, (void *)sechdrs[i].sh_addr,
+			       sechdrs[i].sh_size);
+		/* Update sh_addr to point to copy in image. */
+		sechdrs[i].sh_addr = (unsigned long)dest;
+	}
+
+	/* Fix up syms, so that st_value is a pointer to location. */
+	err =
+		simplify_symbols(sechdrs, symindex, strtab, secstrings,
+				 hdr->e_shnum, &mod);
+	if (err < 0) {
+		printk(KERN_WARNING "VPE: unable to simplify symbols\n");
+		goto cleanup;
+	}
+
+	/* Now do relocations. */
+	for (i = 1; i < hdr->e_shnum; i++) {
+		const char *strtab = (char *)sechdrs[strindex].sh_addr;
+		unsigned int info = sechdrs[i].sh_info;
+
+		/* Not a valid relocation section? */
+		if (info >= hdr->e_shnum)
+			continue;
+
+		/* Don't bother with non-allocated sections */
+		if (!(sechdrs[info].sh_flags & SHF_ALLOC))
+			continue;
+
+		if (sechdrs[i].sh_type == SHT_REL)
+			err =
+				apply_relocations(sechdrs, strtab, symindex, i, &mod);
+		else if (sechdrs[i].sh_type == SHT_RELA)
+			err = apply_relocate_add(sechdrs, strtab, symindex, i,
+						 &mod);
+		if (err < 0) {
+			printk(KERN_WARNING
+			       "vpe_elfload: error in relocations err %ld\n",
+			       err);
+			goto cleanup;
+		}
+	}
+
+	/* make sure it's physically written out */
+	flush_icache_range((unsigned long)v->load_addr,
+			   (unsigned long)v->load_addr + v->len);
+
+	if ((find_vpe_symbols(v, sechdrs, symindex, strtab, &mod)) < 0) {
+
+		printk(KERN_WARNING
+		       "VPE: program doesn't contain __start or vpe_shared symbols\n");
+		err = -ENOEXEC;
+	}
+
+	printk(" elf loaded\n");
+
+cleanup:
+	return err;
+}
+
+static void dump_vpe(vpe_t * v)
+{
+	struct tc *t;
+
+	printk(KERN_DEBUG "VPEControl 0x%lx\n", read_vpe_c0_vpecontrol());
+	printk(KERN_DEBUG "VPEConf0 0x%lx\n", read_vpe_c0_vpeconf0());
+
+	list_for_each_entry(t, &vpecontrol.tc_list, list) {
+		dump_tc(t);
+	}
+}
+
+/* checks for VPE is unused and gets ready to load program	 */
+static int vpe_open(struct inode *inode, struct file *filp)
+{
+	int minor;
+	vpe_t *v;
+
+	/* assume only 1 device at the mo. */
+	if ((minor = MINOR(inode->i_rdev)) != 1) {
+		printk(KERN_WARNING "VPE: only vpe1 is supported\n");
+		return -ENODEV;
+	}
+
+	if ((v = get_vpe(minor)) == NULL) {
+		printk(KERN_WARNING "VPE: unable to get vpe\n");
+		return -ENODEV;
+	}
+
+	if (v->state != VPE_STATE_UNUSED) {
+		unsigned long tmp;
+		struct tc *t;
+
+		printk(KERN_WARNING "VPE: device %d already in use\n", minor);
+
+		dvpe();
+		dump_vpe(v);
+
+		printk(KERN_WARNING "VPE: re-initialising %d\n", minor);
+
+		release_progmem(v->load_addr);
+
+		t = get_tc(minor);
+		settc(minor);
+		tmp = read_tc_c0_tcstatus();
+
+		/* mark not allocated and not dynamically allocatable */
+		tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
+		tmp |= TCSTATUS_IXMT;	/* interrupt exempt */
+		write_tc_c0_tcstatus(tmp);
+
+		write_tc_c0_tchalt(TCHALT_H);
+
+	}
+
+	// allocate it so when we get write ops we know it's expected.
+	v->state = VPE_STATE_INUSE;
+
+	/* this of-course trashes what was there before... */
+	v->pbuffer = vmalloc(P_SIZE);
+	v->plen = P_SIZE;
+	v->load_addr = NULL;
+	v->len = 0;
+
+	return 0;
+}
+
+static int vpe_release(struct inode *inode, struct file *filp)
+{
+	int minor, ret = 0;
+	vpe_t *v;
+	Elf_Ehdr *hdr;
+
+	minor = MINOR(inode->i_rdev);
+	if ((v = get_vpe(minor)) == NULL)
+		return -ENODEV;
+
+	// simple case of fire and forget, so tell the VPE to run...
+
+	hdr = (Elf_Ehdr *) v->pbuffer;
+	if (memcmp(hdr->e_ident, ELFMAG, 4) == 0) {
+		if (vpe_elfload(v) >= 0)
+			vpe_run(v);
+		else {
+			printk(KERN_WARNING "VPE: ELF load failed.\n");
+			ret = -ENOEXEC;
+		}
+	} else {
+		printk(KERN_WARNING "VPE: only elf files are supported\n");
+		ret = -ENOEXEC;
+	}
+
+	// cleanup any temp buffers
+	if (v->pbuffer)
+		vfree(v->pbuffer);
+	v->plen = 0;
+	return ret;
+}
+
+static ssize_t vpe_write(struct file *file, const char __user * buffer,
+			 size_t count, loff_t * ppos)
+{
+	int minor;
+	size_t ret = count;
+	vpe_t *v;
+
+	minor = MINOR(file->f_dentry->d_inode->i_rdev);
+	if ((v = get_vpe(minor)) == NULL)
+		return -ENODEV;
+
+	if (v->pbuffer == NULL) {
+		printk(KERN_ERR "vpe_write: no pbuffer\n");
+		return -ENOMEM;
+	}
+
+	if ((count + v->len) > v->plen) {
+		printk(KERN_WARNING
+		       "VPE Loader: elf size too big. Perhaps strip uneeded symbols\n");
+		return -ENOMEM;
+	}
+
+	count -= copy_from_user(v->pbuffer + v->len, buffer, count);
+	if (!count) {
+		printk("vpe_write: copy_to_user failed\n");
+		return -EFAULT;
+	}
+
+	v->len += count;
+	return ret;
+}
+
+static struct file_operations vpe_fops = {
+	.owner = THIS_MODULE,
+	.open = vpe_open,
+	.release = vpe_release,
+	.write = vpe_write
+};
+
+/* module wrapper entry points */
+/* give me a vpe */
+vpe_handle vpe_alloc(void)
+{
+	int i;
+	struct vpe *v;
+
+	/* find a vpe */
+	for (i = 1; i < MAX_VPES; i++) {
+		if ((v = get_vpe(i)) != NULL) {
+			v->state = VPE_STATE_INUSE;
+			return v;
+		}
+	}
+	return NULL;
+}
+
+EXPORT_SYMBOL(vpe_alloc);
+
+/* start running from here */
+int vpe_start(vpe_handle vpe, unsigned long start)
+{
+	struct vpe *v = vpe;
+
+	v->__start = start;
+	return vpe_run(v);
+}
+
+EXPORT_SYMBOL(vpe_start);
+
+/* halt it for now */
+int vpe_stop(vpe_handle vpe)
+{
+	struct vpe *v = vpe;
+	struct tc *t;
+	unsigned int evpe_flags;
+
+	evpe_flags = dvpe();
+
+	if ((t = list_entry(v->tc.next, struct tc, tc)) != NULL) {
+
+		settc(t->index);
+		write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
+	}
+
+	evpe(evpe_flags);
+
+	return 0;
+}
+
+EXPORT_SYMBOL(vpe_stop);
+
+/* I've done with it thank you */
+int vpe_free(vpe_handle vpe)
+{
+	struct vpe *v = vpe;
+	struct tc *t;
+	unsigned int evpe_flags;
+
+	if ((t = list_entry(v->tc.next, struct tc, tc)) == NULL) {
+		return -ENOEXEC;
+	}
+
+	evpe_flags = dvpe();
+
+	/* Put MVPE's into 'configuration state' */
+	write_c0_mvpcontrol(read_c0_mvpcontrol() | MVPCONTROL_VPC);
+
+	settc(t->index);
+	write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
+
+	/* mark the TC unallocated and halt'ed */
+	write_tc_c0_tcstatus(read_tc_c0_tcstatus() & ~TCSTATUS_A);
+	write_tc_c0_tchalt(TCHALT_H);
+
+	v->state = VPE_STATE_UNUSED;
+
+	write_c0_mvpcontrol(read_c0_mvpcontrol() & ~MVPCONTROL_VPC);
+	evpe(evpe_flags);
+
+	return 0;
+}
+
+EXPORT_SYMBOL(vpe_free);
+
+void *vpe_get_shared(int index)
+{
+	struct vpe *v;
+
+	if ((v = get_vpe(index)) == NULL) {
+		printk(KERN_WARNING "vpe: invalid vpe index %d\n", index);
+		return NULL;
+	}
+
+	return v->shared_ptr;
+}
+
+EXPORT_SYMBOL(vpe_get_shared);
+
+static int __init vpe_module_init(void)
+{
+	struct vpe *v = NULL;
+	struct tc *t;
+	unsigned long val;
+	int i;
+
+	if (!cpu_has_mipsmt) {
+		printk("VPE loader: not a MIPS MT capable processor\n");
+		return -ENODEV;
+	}
+
+	if ((major = register_chrdev(VPE_MAJOR, module_name, &vpe_fops) < 0)) {
+		printk("VPE loader: unable to register character device\n");
+		return -EBUSY;
+	}
+
+	if (major == 0)
+		major = VPE_MAJOR;
+
+	dmt();
+	dvpe();
+
+	/* Put MVPE's into 'configuration state' */
+	write_c0_mvpcontrol(read_c0_mvpcontrol() | MVPCONTROL_VPC);
+
+	/* dump_mtregs(); */
+
+	INIT_LIST_HEAD(&vpecontrol.vpe_list);
+	INIT_LIST_HEAD(&vpecontrol.tc_list);
+
+	val = read_c0_mvpconf0();
+	for (i = 0; i < ((val & MVPCONF0_PTC) + 1); i++) {
+		t = alloc_tc(i);
+
+		/* VPE's */
+		if (i < ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1) {
+			settc(i);
+
+			if ((v = alloc_vpe(i)) == NULL) {
+				printk(KERN_WARNING "VPE: unable to allocate VPE\n");
+				return -ENODEV;
+			}
+
+			list_add(&t->tc, &v->tc);	/* add the tc to the list of this vpe's tc's. */
+
+			/* deactivate all but vpe0 */
+			if (i != 0) {
+				unsigned long tmp = read_vpe_c0_vpeconf0();
+
+				tmp &= ~VPECONF0_VPA;
+
+				/* master VPE */
+				tmp |= VPECONF0_MVP;
+				write_vpe_c0_vpeconf0(tmp);
+			}
+
+			/* disable multi-threading with TC's */
+			write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() & ~VPECONTROL_TE);
+
+			if (i != 0) {
+				write_vpe_c0_status((read_c0_status() &
+						     ~(ST0_IM | ST0_IE | ST0_KSU))
+						    | ST0_CU0);
+
+				/* set config to be the same as vpe0, particularly kseg0 coherency alg */
+				write_vpe_c0_config(read_c0_config());
+			}
+
+		}
+
+		/* TC's */
+		t->pvpe = v;	/* set the parent vpe */
+
+		if (i != 0) {
+			unsigned long tmp;
+
+			/* tc 0 will of course be running.... */
+			if (i == 0)
+				t->state = TC_STATE_RUNNING;
+
+			settc(i);
+
+			/* bind a TC to each VPE, May as well put all excess TC's
+			   on the last VPE */
+			if (i >= (((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1))
+				write_tc_c0_tcbind(read_tc_c0_tcbind() |
+						   ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT));
+			else
+				write_tc_c0_tcbind(read_tc_c0_tcbind() | i);
+
+			tmp = read_tc_c0_tcstatus();
+
+			/* mark not allocated and not dynamically allocatable */
+			tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
+			tmp |= TCSTATUS_IXMT;	/* interrupt exempt */
+			write_tc_c0_tcstatus(tmp);
+
+			write_tc_c0_tchalt(TCHALT_H);
+		}
+	}
+
+	/* release config state */
+	write_c0_mvpcontrol(read_c0_mvpcontrol() & ~MVPCONTROL_VPC);
+
+	return 0;
+}
+
+static void __exit vpe_module_exit(void)
+{
+	struct vpe *v, *n;
+
+	list_for_each_entry_safe(v, n, &vpecontrol.vpe_list, list) {
+		if (v->state != VPE_STATE_UNUSED) {
+			release_vpe(v);
+		}
+	}
+
+	unregister_chrdev(major, module_name);
+}
+
+module_init(vpe_module_init);
+module_exit(vpe_module_exit);
+MODULE_DESCRIPTION("MIPS VPE Loader");
+MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc");
+MODULE_LICENSE("GPL");