vpe.c

linux-2.6.15.6

/*
 * 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/config.h>
#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/mipsmtregs.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;

#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))

static char module_name[] = "vpe";
static int major;

/* 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 {
	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;
};

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;
};

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(struct vpe * 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 = kzalloc(sizeof(struct vpe), GFP_KERNEL)) == NULL) {
		printk(KERN_WARNING "VPE: alloc_vpe no mem\n");
		return NULL;
	}

	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 = kzalloc(sizeof(struct tc), GFP_KERNEL)) == NULL) {
		printk(KERN_WARNING "VPE: alloc_tc no mem\n");
		return NULL;
	}

	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)