module.c

优龙2410linux2.6.8内核源代码

/*    Kernel dynamically loadable module help for PARISC.
 *
 *    The best reference for this stuff is probably the Processor-
 *    Specific ELF Supplement for PA-RISC:
 *        http://ftp.parisc-linux.org/docs/elf-pa-hp.pdf
 *
 *    Linux/PA-RISC Project (http://www.parisc-linux.org/)
 *    Copyright (C) 2003 Randolph Chung <tausq at debian . org>
 *
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that 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
 */

#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>

#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt...)
#endif

#define CHECK_RELOC(val, bits) \
	if ( ( !((val) & (1<<((bits)-1))) && ((val)>>(bits)) != 0 )  ||	\
	     ( ((val) & (1<<((bits)-1))) && ((val)>>(bits)) != (((__typeof__(val))(~0))>>((bits)+2)))) { \
		printk(KERN_ERR "module %s relocation of symbol %s is out of range (0x%lx in %d bits)\n", \
		me->name, strtab + sym->st_name, (unsigned long)val, bits); \
		return -ENOEXEC;			\
	}

/* Maximum number of GOT entries. We use a long displacement ldd from
 * the bottom of the table, which has a maximum signed displacement of
 * 0x3fff; however, since we're only going forward, this becomes
 * 0x1fff, and thus, since each GOT entry is 8 bytes long we can have
 * at most 1023 entries */
#define MAX_GOTS	1023

/* three functions to determine where in the module core
 * or init pieces the location is */
static inline int is_init(struct module *me, void *loc)
{
	return (loc >= me->module_init &&
		loc <= (me->module_init + me->init_size));
}

static inline int is_core(struct module *me, void *loc)
{
	return (loc >= me->module_core &&
		loc <= (me->module_core + me->core_size));
}

static inline int is_local(struct module *me, void *loc)
{
	return is_init(me, loc) || is_core(me, loc);
}


#ifndef __LP64__
struct got_entry {
	Elf32_Addr addr;
};

#define Elf_Fdesc	Elf32_Fdesc

struct stub_entry {
	Elf32_Word insns[2]; /* each stub entry has two insns */
};
#else
struct got_entry {
	Elf64_Addr addr;
};

#define Elf_Fdesc	Elf64_Fdesc

struct stub_entry {
	Elf64_Word insns[4]; /* each stub entry has four insns */
};
#endif

/* Field selection types defined by hppa */
#define rnd(x)			(((x)+0x1000)&~0x1fff)
/* fsel: full 32 bits */
#define fsel(v,a)		((v)+(a))
/* lsel: select left 21 bits */
#define lsel(v,a)		(((v)+(a))>>11)
/* rsel: select right 11 bits */
#define rsel(v,a)		(((v)+(a))&0x7ff)
/* lrsel with rounding of addend to nearest 8k */
#define lrsel(v,a)		(((v)+rnd(a))>>11)
/* rrsel with rounding of addend to nearest 8k */
#define rrsel(v,a)		((((v)+rnd(a))&0x7ff)+((a)-rnd(a)))

#define mask(x,sz)		((x) & ~((1<<(sz))-1))


/* The reassemble_* functions prepare an immediate value for
   insertion into an opcode. pa-risc uses all sorts of weird bitfields
   in the instruction to hold the value.  */
static inline int reassemble_14(int as14)
{
	return (((as14 & 0x1fff) << 1) |
		((as14 & 0x2000) >> 13));
}

static inline int reassemble_17(int as17)
{
	return (((as17 & 0x10000) >> 16) |
		((as17 & 0x0f800) << 5) |
		((as17 & 0x00400) >> 8) |
		((as17 & 0x003ff) << 3));
}

static inline int reassemble_21(int as21)
{
	return (((as21 & 0x100000) >> 20) |
		((as21 & 0x0ffe00) >> 8) |
		((as21 & 0x000180) << 7) |
		((as21 & 0x00007c) << 14) |
		((as21 & 0x000003) << 12));
}

static inline int reassemble_22(int as22)
{
	return (((as22 & 0x200000) >> 21) |
		((as22 & 0x1f0000) << 5) |
		((as22 & 0x00f800) << 5) |
		((as22 & 0x000400) >> 8) |
		((as22 & 0x0003ff) << 3));
}

void *module_alloc(unsigned long size)
{
	if (size == 0)
		return NULL;
	return vmalloc(size);
}

#ifndef __LP64__
static inline unsigned long count_gots(const Elf_Rela *rela, unsigned long n)
{
	return 0;
}

static inline unsigned long count_fdescs(const Elf_Rela *rela, unsigned long n)
{
	return 0;
}

static inline unsigned long count_stubs(const Elf_Rela *rela, unsigned long n)
{
	unsigned long cnt = 0;

	for (; n > 0; n--, rela++)
	{
		switch (ELF32_R_TYPE(rela->r_info)) {
			case R_PARISC_PCREL17F:
			case R_PARISC_PCREL22F:
				cnt++;
		}
	}

	return cnt;
}
#else
static inline unsigned long count_gots(const Elf_Rela *rela, unsigned long n)
{
	unsigned long cnt = 0;

	for (; n > 0; n--, rela++)
	{
		switch (ELF64_R_TYPE(rela->r_info)) {
			case R_PARISC_LTOFF21L:
			case R_PARISC_LTOFF14R:
			case R_PARISC_PCREL22F:
				cnt++;
		}
	}

	return cnt;
}

static inline unsigned long count_fdescs(const Elf_Rela *rela, unsigned long n)
{
	unsigned long cnt = 0;

	for (; n > 0; n--, rela++)
	{
		switch (ELF64_R_TYPE(rela->r_info)) {
			case R_PARISC_FPTR64:
				cnt++;
		}
	}

	return cnt;
}

static inline unsigned long count_stubs(const Elf_Rela *rela, unsigned long n)
{
	unsigned long cnt = 0;

	for (; n > 0; n--, rela++)
	{
		switch (ELF64_R_TYPE(rela->r_info)) {
			case R_PARISC_PCREL22F:
				cnt++;
		}
	}

	return cnt;
}
#endif


/* Free memory returned from module_alloc */
void module_free(struct module *mod, void *module_region)
{
	vfree(module_region);
	/* FIXME: If module_region == mod->init_region, trim exception
           table entries. */
}

#define CONST 
int module_frob_arch_sections(CONST Elf_Ehdr *hdr,
			      CONST Elf_Shdr *sechdrs,
			      CONST char *secstrings,
			      struct module *me)
{
	unsigned long gots = 0, fdescs = 0, stubs = 0, init_stubs = 0;
	unsigned int i;

	for (i = 1; i < hdr->e_shnum; i++) {
		const Elf_Rela *rels = (void *)hdr + sechdrs[i].sh_offset;
		unsigned long nrels = sechdrs[i].sh_size / sizeof(*rels);

		if (sechdrs[i].sh_type != SHT_RELA)
			continue;

		/* some of these are not relevant for 32-bit/64-bit
		 * we leave them here to make the code common. the
		 * compiler will do its thing and optimize out the
		 * stuff we don't need
		 */
		gots += count_gots(rels, nrels);
		fdescs += count_fdescs(rels, nrels);
		if(strncmp(secstrings + sechdrs[i].sh_name,
			   ".rela.init", 10) == 0)
			init_stubs += count_stubs(rels, nrels);
		else
			stubs += count_stubs(rels, nrels);
	}

	/* align things a bit */
	me->core_size = ALIGN(me->core_size, 16);
	me->arch.got_offset = me->core_size;
	me->core_size += gots * sizeof(struct got_entry);

	me->core_size = ALIGN(me->core_size, 16);
	me->arch.fdesc_offset = me->core_size;
	me->core_size += fdescs * sizeof(Elf_Fdesc);

	me->core_size = ALIGN(me->core_size, 16);
	me->arch.stub_offset = me->core_size;
	me->core_size += stubs * sizeof(struct stub_entry);

	me->init_size = ALIGN(me->init_size, 16);
	me->arch.init_stub_offset = me->init_size;
	me->init_size += init_stubs * sizeof(struct stub_entry);

	me->arch.got_max = gots;
	me->arch.fdesc_max = fdescs;
	me->arch.stub_max = stubs;
	me->arch.init_stub_max = init_stubs;

	return 0;
}

#ifdef __LP64__
static Elf64_Word get_got(struct module *me, unsigned long value, long addend)
{
	unsigned int i;
	struct got_entry *got;

	value += addend;

	BUG_ON(value == 0);

	got = me->module_core + me->arch.got_offset;
	for (i = 0; got[i].addr; i++)
		if (got[i].addr == value)
			goto out;

	BUG_ON(++me->arch.got_count > me->arch.got_max);

	got[i].addr = value;
 out:
	DEBUGP("GOT ENTRY %d[%x] val %lx\n", i, i*sizeof(struct got_entry),
	       value);
	return i * sizeof(struct got_entry);
}
#endif /* __LP64__ */

#ifdef __LP64__
static Elf_Addr get_fdesc(struct module *me, unsigned long value)
{
	Elf_Fdesc *fdesc = me->module_core + me->arch.fdesc_offset;

	if (!value) {
		printk(KERN_ERR "%s: zero OPD requested!\n", me->name);
		return 0;
	}

	/* Look for existing fdesc entry. */
	while (fdesc->addr) {
		if (fdesc->addr == value)
			return (Elf_Addr)fdesc;
		fdesc++;
	}

	BUG_ON(++me->arch.fdesc_count > me->arch.fdesc_max);

	/* Create new one */
	fdesc->addr = value;
	fdesc->gp = (Elf_Addr)me->module_core + me->arch.got_offset;
	return (Elf_Addr)fdesc;
}
#endif /* __LP64__ */

static Elf_Addr get_stub(struct module *me, unsigned long value, long addend,
	int millicode, int init_section)
{
	unsigned long i;
	struct stub_entry *stub;

	if(init_section) {
		i = me->arch.init_stub_count++;
		BUG_ON(me->arch.init_stub_count > me->arch.init_stub_max);
		stub = me->module_init + me->arch.init_stub_offset + 
			i * sizeof(struct stub_entry);
	} else {
		i = me->arch.stub_count++;
		BUG_ON(me->arch.stub_count > me->arch.stub_max);
		stub = me->module_core + me->arch.stub_offset + 
			i * sizeof(struct stub_entry);
	}

#ifndef __LP64__
/* for 32-bit the stub looks like this:
 * 	ldil L'XXX,%r1
 * 	be,n R'XXX(%sr4,%r1)
 */
	//value = *(unsigned long *)((value + addend) & ~3); /* why? */

	stub->insns[0] = 0x20200000;	/* ldil L'XXX,%r1	*/
	stub->insns[1] = 0xe0202002;	/* be,n R'XXX(%sr4,%r1)	*/

	stub->insns[0] |= reassemble_21(lrsel(value, addend));
	stub->insns[1] |= reassemble_17(rrsel(value, addend) / 4);

#else
/* for 64-bit we have two kinds of stubs:
 * for normal function calls:
 * 	ldd 0(%dp),%dp
 * 	ldd 10(%dp), %r1
 * 	bve (%r1)
 * 	ldd 18(%dp), %dp
 *
 * for millicode:
 * 	ldil 0, %r1