arch/powerpc/kernel/vdso.c - linux/kernel/git/bpf/bpf-next - Git at Google

 /*
  *  linux/arch/ppc64/kernel/vdso.c
  *
  *    Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
  *			 <benh@kernel.crashing.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.
  */

 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/smp_lock.h>
 #include <linux/stddef.h>
 #include <linux/unistd.h>
 #include <linux/slab.h>
 #include <linux/user.h>
 #include <linux/elf.h>
 #include <linux/security.h>
 #include <linux/bootmem.h>

 #include <asm/pgtable.h>
 #include <asm/system.h>
 #include <asm/processor.h>
 #include <asm/mmu.h>
 #include <asm/mmu_context.h>
 #include <asm/lmb.h>
 #include <asm/machdep.h>
 #include <asm/cputable.h>
 #include <asm/sections.h>
 #include <asm/vdso.h>
 #include <asm/vdso_datapage.h>

 #undef DEBUG

 #ifdef DEBUG
 #define DBG(fmt...) printk(fmt)
 #else
 #define DBG(fmt...)
 #endif

 /* Max supported size for symbol names */
 #define MAX_SYMNAME	64

 extern char vdso32_start, vdso32_end;
 static void *vdso32_kbase = &vdso32_start;
 unsigned int vdso32_pages;
 unsigned long vdso32_sigtramp;
 unsigned long vdso32_rt_sigtramp;

 #ifdef CONFIG_PPC64
 extern char vdso64_start, vdso64_end;
 static void *vdso64_kbase = &vdso64_start;
 unsigned int vdso64_pages;
 unsigned long vdso64_rt_sigtramp;
 #endif /* CONFIG_PPC64 */

 /*
  * The vdso data page (aka. systemcfg for old ppc64 fans) is here.
  * Once the early boot kernel code no longer needs to muck around
  * with it, it will become dynamically allocated
  */
 static union {
 	struct vdso_data	data;
 	u8			page[PAGE_SIZE];
 } vdso_data_store __attribute__((__section__(".data.page_aligned")));
 struct vdso_data *vdso_data = &vdso_data_store.data;

 /* Format of the patch table */
 struct vdso_patch_def
 {
 	unsigned long	ftr_mask, ftr_value;
 	const char	*gen_name;
 	const char	*fix_name;
 };

 /* Table of functions to patch based on the CPU type/revision
  *
  * Currently, we only change sync_dicache to do nothing on processors
  * with a coherent icache
  */
 static struct vdso_patch_def vdso_patches[] = {
 	{
 		CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE,
 		"__kernel_sync_dicache", "__kernel_sync_dicache_p5"
 	},
 	{
 		CPU_FTR_USE_TB, 0,
 		"__kernel_gettimeofday", NULL
 	},
 };

 /*
  * Some infos carried around for each of them during parsing at
  * boot time.
  */
 struct lib32_elfinfo
 {
 	Elf32_Ehdr	*hdr;		/* ptr to ELF */
 	Elf32_Sym	*dynsym;	/* ptr to .dynsym section */
 	unsigned long	dynsymsize;	/* size of .dynsym section */
 	char		*dynstr;	/* ptr to .dynstr section */
 	unsigned long	text;		/* offset of .text section in .so */
 };

 struct lib64_elfinfo
 {
 	Elf64_Ehdr	*hdr;
 	Elf64_Sym	*dynsym;
 	unsigned long	dynsymsize;
 	char		*dynstr;
 	unsigned long	text;
 };


 #ifdef __DEBUG
 static void dump_one_vdso_page(struct page *pg, struct page *upg)
 {
 	printk("kpg: %p (c:%d,f:%08lx)", __va(page_to_pfn(pg) << PAGE_SHIFT),
 	       page_count(pg),
 	       pg->flags);
 	if (upg/* && pg != upg*/) {
 		printk(" upg: %p (c:%d,f:%08lx)", __va(page_to_pfn(upg)
 						       << PAGE_SHIFT),
 		       page_count(upg),
 		       upg->flags);
 	}
 	printk("\n");
 }

 static void dump_vdso_pages(struct vm_area_struct * vma)
 {
 	int i;

 	if (!vma || test_thread_flag(TIF_32BIT)) {
 		printk("vDSO32 @ %016lx:\n", (unsigned long)vdso32_kbase);
 		for (i=0; i<vdso32_pages; i++) {
 			struct page *pg = virt_to_page(vdso32_kbase +
 						       i*PAGE_SIZE);
 			struct page *upg = (vma && vma->vm_mm) ?
 				follow_page(vma, vma->vm_start + i*PAGE_SIZE, 0)
 				: NULL;
 			dump_one_vdso_page(pg, upg);
 		}
 	}
 	if (!vma || !test_thread_flag(TIF_32BIT)) {
 		printk("vDSO64 @ %016lx:\n", (unsigned long)vdso64_kbase);
 		for (i=0; i<vdso64_pages; i++) {
 			struct page *pg = virt_to_page(vdso64_kbase +
 						       i*PAGE_SIZE);
 			struct page *upg = (vma && vma->vm_mm) ?
 				follow_page(vma, vma->vm_start + i*PAGE_SIZE, 0)
 				: NULL;
 			dump_one_vdso_page(pg, upg);
 		}
 	}
 }
 #endif /* DEBUG */

 /*
  * Keep a dummy vma_close for now, it will prevent VMA merging.
  */
 static void vdso_vma_close(struct vm_area_struct * vma)
 {
 }

 /*
  * Our nopage() function, maps in the actual vDSO kernel pages, they will
  * be mapped read-only by do_no_page(), and eventually COW'ed, either
  * right away for an initial write access, or by do_wp_page().
  */
 static struct page * vdso_vma_nopage(struct vm_area_struct * vma,
 				     unsigned long address, int *type)
 {
 	unsigned long offset = address - vma->vm_start;
 	struct page *pg;
 #ifdef CONFIG_PPC64
 	void *vbase = test_thread_flag(TIF_32BIT) ?
 		vdso32_kbase : vdso64_kbase;
 #else
 	void *vbase = vdso32_kbase;
 #endif

 	DBG("vdso_vma_nopage(current: %s, address: %016lx, off: %lx)\n",
 	    current->comm, address, offset);

 	if (address < vma->vm_start || address > vma->vm_end)
 		return NOPAGE_SIGBUS;

 	/*
 	 * Last page is systemcfg.
 	 */
 	if ((vma->vm_end - address) <= PAGE_SIZE)
 		pg = virt_to_page(vdso_data);
 	else
 		pg = virt_to_page(vbase + offset);

 	get_page(pg);
 	DBG(" ->page count: %d\n", page_count(pg));

 	return pg;
 }

 static struct vm_operations_struct vdso_vmops = {
 	.close	= vdso_vma_close,
 	.nopage	= vdso_vma_nopage,
 };

 /*
  * This is called from binfmt_elf, we create the special vma for the
  * vDSO and insert it into the mm struct tree
  */
 int arch_setup_additional_pages(struct linux_binprm *bprm,
 				int executable_stack)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	unsigned long vdso_pages;
 	unsigned long vdso_base;

 #ifdef CONFIG_PPC64
 	if (test_thread_flag(TIF_32BIT)) {
 		vdso_pages = vdso32_pages;
 		vdso_base = VDSO32_MBASE;
 	} else {
 		vdso_pages = vdso64_pages;
 		vdso_base = VDSO64_MBASE;
 	}
 #else
 	vdso_pages = vdso32_pages;
 	vdso_base = VDSO32_MBASE;
 #endif

 	current->thread.vdso_base = 0;

 	/* vDSO has a problem and was disabled, just don't "enable" it for the
 	 * process
 	 */
 	if (vdso_pages == 0)
 		return 0;

 	vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 	if (vma == NULL)
 		return -ENOMEM;

 	memset(vma, 0, sizeof(*vma));

 	/* Add a page to the vdso size for the data page */
 	vdso_pages ++;

 	/*
 	 * pick a base address for the vDSO in process space. We try to put it
 	 * at vdso_base which is the "natural" base for it, but we might fail
 	 * and end up putting it elsewhere.
 	 */
 	vdso_base = get_unmapped_area(NULL, vdso_base,
 				      vdso_pages << PAGE_SHIFT, 0, 0);
 	if (vdso_base & ~PAGE_MASK) {
 		kmem_cache_free(vm_area_cachep, vma);
 		return (int)vdso_base;
 	}

 	current->thread.vdso_base = vdso_base;

 	vma->vm_mm = mm;
 	vma->vm_start = current->thread.vdso_base;
 	vma->vm_end = vma->vm_start + (vdso_pages << PAGE_SHIFT);

 	/*
 	 * our vma flags don't have VM_WRITE so by default, the process isn't
 	 * allowed to write those pages.
 	 * gdb can break that with ptrace interface, and thus trigger COW on
 	 * those pages but it's then your responsibility to never do that on
 	 * the "data" page of the vDSO or you'll stop getting kernel updates
 	 * and your nice userland gettimeofday will be totally dead.
 	 * It's fine to use that for setting breakpoints in the vDSO code
 	 * pages though
 	 */
 	vma->vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
 	vma->vm_flags |= mm->def_flags;
 	vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
 	vma->vm_ops = &vdso_vmops;

 	down_write(&mm->mmap_sem);
 	if (insert_vm_struct(mm, vma)) {
 		up_write(&mm->mmap_sem);
 		kmem_cache_free(vm_area_cachep, vma);
 		return -ENOMEM;
 	}
 	mm->total_vm += (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 	up_write(&mm->mmap_sem);

 	return 0;
 }

 static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
 				  unsigned long *size)
 {
 	Elf32_Shdr *sechdrs;
 	unsigned int i;
 	char *secnames;

 	/* Grab section headers and strings so we can tell who is who */
 	sechdrs = (void *)ehdr + ehdr->e_shoff;
 	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;

 	/* Find the section they want */
 	for (i = 1; i < ehdr->e_shnum; i++) {
 		if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
 			if (size)
 				*size = sechdrs[i].sh_size;
 			return (void *)ehdr + sechdrs[i].sh_offset;
 		}
 	}
 	*size = 0;
 	return NULL;
 }

 static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib,
 					const char *symname)
 {
 	unsigned int i;
 	char name[MAX_SYMNAME], *c;

 	for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
 		if (lib->dynsym[i].st_name == 0)
 			continue;
 		strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
 			MAX_SYMNAME);
 		c = strchr(name, '@');
 		if (c)
 			*c = 0;
 		if (strcmp(symname, name) == 0)
 			return &lib->dynsym[i];
 	}
 	return NULL;
 }

 /* Note that we assume the section is .text and the symbol is relative to
  * the library base
  */
 static unsigned long __init find_function32(struct lib32_elfinfo *lib,
 					    const char *symname)
 {
 	Elf32_Sym *sym = find_symbol32(lib, symname);

 	if (sym == NULL) {
 		printk(KERN_WARNING "vDSO32: function %s not found !\n",
 		       symname);
 		return 0;
 	}
 	return sym->st_value - VDSO32_LBASE;
 }

 static int vdso_do_func_patch32(struct lib32_elfinfo *v32,
 				struct lib64_elfinfo *v64,
 				const char *orig, const char *fix)
 {
 	Elf32_Sym *sym32_gen, *sym32_fix;

 	sym32_gen = find_symbol32(v32, orig);
 	if (sym32_gen == NULL) {
 		printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig);
 		return -1;
 	}
 	if (fix == NULL) {
 		sym32_gen->st_name = 0;
 		return 0;
 	}
 	sym32_fix = find_symbol32(v32, fix);
 	if (sym32_fix == NULL) {
 		printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix);
 		return -1;
 	}
 	sym32_gen->st_value = sym32_fix->st_value;
 	sym32_gen->st_size = sym32_fix->st_size;
 	sym32_gen->st_info = sym32_fix->st_info;
 	sym32_gen->st_other = sym32_fix->st_other;
 	sym32_gen->st_shndx = sym32_fix->st_shndx;

 	return 0;
 }


 #ifdef CONFIG_PPC64

 static void * __init find_section64(Elf64_Ehdr *ehdr, const char *secname,
 				  unsigned long *size)
 {
 	Elf64_Shdr *sechdrs;
 	unsigned int i;
 	char *secnames;

 	/* Grab section headers and strings so we can tell who is who */
 	sechdrs = (void *)ehdr + ehdr->e_shoff;
 	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;

 	/* Find the section they want */
 	for (i = 1; i < ehdr->e_shnum; i++) {
 		if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
 			if (size)
 				*size = sechdrs[i].sh_size;
 			return (void *)ehdr + sechdrs[i].sh_offset;
 		}
 	}
 	if (size)
 		*size = 0;
 	return NULL;
 }

 static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib,
 					const char *symname)
 {
 	unsigned int i;
 	char name[MAX_SYMNAME], *c;

 	for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) {
 		if (lib->dynsym[i].st_name == 0)
 			continue;
 		strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
 			MAX_SYMNAME);
 		c = strchr(name, '@');
 		if (c)
 			*c = 0;
 		if (strcmp(symname, name) == 0)
 			return &lib->dynsym[i];
 	}
 	return NULL;
 }

 /* Note that we assume the section is .text and the symbol is relative to
  * the library base
  */
 static unsigned long __init find_function64(struct lib64_elfinfo *lib,
 					    const char *symname)
 {
 	Elf64_Sym *sym = find_symbol64(lib, symname);

 	if (sym == NULL) {
 		printk(KERN_WARNING "vDSO64: function %s not found !\n",
 		       symname);
 		return 0;
 	}
 #ifdef VDS64_HAS_DESCRIPTORS
 	return *((u64 *)(vdso64_kbase + sym->st_value - VDSO64_LBASE)) -
 		VDSO64_LBASE;
 #else
 	return sym->st_value - VDSO64_LBASE;
 #endif
 }

 static int vdso_do_func_patch64(struct lib32_elfinfo *v32,
 				struct lib64_elfinfo *v64,
 				const char *orig, const char *fix)
 {
 	Elf64_Sym *sym64_gen, *sym64_fix;

 	sym64_gen = find_symbol64(v64, orig);
 	if (sym64_gen == NULL) {
 		printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig);
 		return -1;
 	}
 	if (fix == NULL) {
 		sym64_gen->st_name = 0;
 		return 0;
 	}
 	sym64_fix = find_symbol64(v64, fix);
 	if (sym64_fix == NULL) {
 		printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix);
 		return -1;
 	}
 	sym64_gen->st_value = sym64_fix->st_value;
 	sym64_gen->st_size = sym64_fix->st_size;
 	sym64_gen->st_info = sym64_fix->st_info;
 	sym64_gen->st_other = sym64_fix->st_other;
 	sym64_gen->st_shndx = sym64_fix->st_shndx;

 	return 0;
 }

 #endif /* CONFIG_PPC64 */


 static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
 					struct lib64_elfinfo *v64)
 {
 	void *sect;

 	/*
 	 * Locate symbol tables & text section
 	 */

 	v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
 	v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
 	if (v32->dynsym == NULL || v32->dynstr == NULL) {
 		printk(KERN_ERR "vDSO32: required symbol section not found\n");
 		return -1;
 	}
 	sect = find_section32(v32->hdr, ".text", NULL);
 	if (sect == NULL) {
 		printk(KERN_ERR "vDSO32: the .text section was not found\n");
 		return -1;
 	}
 	v32->text = sect - vdso32_kbase;

 #ifdef CONFIG_PPC64
 	v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
 	v64->dynstr = find_section64(v64->hdr, ".dynstr", NULL);
 	if (v64->dynsym == NULL || v64->dynstr == NULL) {
 		printk(KERN_ERR "vDSO64: required symbol section not found\n");
 		return -1;
 	}
 	sect = find_section64(v64->hdr, ".text", NULL);
 	if (sect == NULL) {
 		printk(KERN_ERR "vDSO64: the .text section was not found\n");
 		return -1;
 	}
 	v64->text = sect - vdso64_kbase;
 #endif /* CONFIG_PPC64 */

 	return 0;
 }

 static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
 					  struct lib64_elfinfo *v64)
 {
 	/*
 	 * Find signal trampolines
 	 */

 #ifdef CONFIG_PPC64
 	vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64");
 #endif
 	vdso32_sigtramp	   = find_function32(v32, "__kernel_sigtramp32");
 	vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
 }

 static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
 				       struct lib64_elfinfo *v64)
 {
 	Elf32_Sym *sym32;
 #ifdef CONFIG_PPC64
 	Elf64_Sym *sym64;

        	sym64 = find_symbol64(v64, "__kernel_datapage_offset");
 	if (sym64 == NULL) {
 		printk(KERN_ERR "vDSO64: Can't find symbol "
 		       "__kernel_datapage_offset !\n");
 		return -1;
 	}
 	*((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
 		(vdso64_pages << PAGE_SHIFT) -
 		(sym64->st_value - VDSO64_LBASE);
 #endif /* CONFIG_PPC64 */

 	sym32 = find_symbol32(v32, "__kernel_datapage_offset");
 	if (sym32 == NULL) {
 		printk(KERN_ERR "vDSO32: Can't find symbol "
 		       "__kernel_datapage_offset !\n");
 		return -1;
 	}
 	*((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
 		(vdso32_pages << PAGE_SHIFT) -
 		(sym32->st_value - VDSO32_LBASE);

 	return 0;
 }

 static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
 				       struct lib64_elfinfo *v64)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) {
 		struct vdso_patch_def *patch = &vdso_patches[i];
 		int match = (cur_cpu_spec->cpu_features & patch->ftr_mask)
 			== patch->ftr_value;
 		if (!match)
 			continue;

 		DBG("replacing %s with %s...\n", patch->gen_name,
 		    patch->fix_name ? "NONE" : patch->fix_name);

 		/*
 		 * Patch the 32 bits and 64 bits symbols. Note that we do not
 		 * patch the "." symbol on 64 bits.
 		 * It would be easy to do, but doesn't seem to be necessary,
 		 * patching the OPD symbol is enough.
 		 */
 		vdso_do_func_patch32(v32, v64, patch->gen_name,
 				     patch->fix_name);
 #ifdef CONFIG_PPC64
 		vdso_do_func_patch64(v32, v64, patch->gen_name,
 				     patch->fix_name);
 #endif /* CONFIG_PPC64 */
 	}

 	return 0;
 }


 static __init int vdso_setup(void)
 {
 	struct lib32_elfinfo	v32;
 	struct lib64_elfinfo	v64;

 	v32.hdr = vdso32_kbase;
 #ifdef CONFIG_PPC64
 	v64.hdr = vdso64_kbase;
 #endif
 	if (vdso_do_find_sections(&v32, &v64))
 		return -1;

 	if (vdso_fixup_datapage(&v32, &v64))
 		return -1;

 	if (vdso_fixup_alt_funcs(&v32, &v64))
 		return -1;

 	vdso_setup_trampolines(&v32, &v64);

 	return 0;
 }

 /*
  * Called from setup_arch to initialize the bitmap of available
  * syscalls in the systemcfg page
  */
 static void __init vdso_setup_syscall_map(void)
 {
 	unsigned int i;
 	extern unsigned long *sys_call_table;
 	extern unsigned long sys_ni_syscall;


 	for (i = 0; i < __NR_syscalls; i++) {
 #ifdef CONFIG_PPC64
 		if (sys_call_table[i*2] != sys_ni_syscall)
 			vdso_data->syscall_map_64[i >> 5] |=
 				0x80000000UL >> (i & 0x1f);
 		if (sys_call_table[i*2+1] != sys_ni_syscall)
 			vdso_data->syscall_map_32[i >> 5] |=
 				0x80000000UL >> (i & 0x1f);
 #else /* CONFIG_PPC64 */
 		if (sys_call_table[i] != sys_ni_syscall)
 			vdso_data->syscall_map_32[i >> 5] |=
 				0x80000000UL >> (i & 0x1f);
 #endif /* CONFIG_PPC64 */
 	}
 }


 void __init vdso_init(void)
 {
 	int i;

 #ifdef CONFIG_PPC64
 	/*
 	 * Fill up the "systemcfg" stuff for backward compatiblity
 	 */
 	strcpy(vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
 	vdso_data->version.major = SYSTEMCFG_MAJOR;
 	vdso_data->version.minor = SYSTEMCFG_MINOR;
 	vdso_data->processor = mfspr(SPRN_PVR);
 	vdso_data->platform = _machine;
 	vdso_data->physicalMemorySize = lmb_phys_mem_size();
 	vdso_data->dcache_size = ppc64_caches.dsize;
 	vdso_data->dcache_line_size = ppc64_caches.dline_size;
 	vdso_data->icache_size = ppc64_caches.isize;
 	vdso_data->icache_line_size = ppc64_caches.iline_size;

 	/*
 	 * Calculate the size of the 64 bits vDSO
 	 */
 	vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
 	DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages);
 #endif /* CONFIG_PPC64 */


 	/*
 	 * Calculate the size of the 32 bits vDSO
 	 */
 	vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
 	DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);


 	/*
 	 * Setup the syscall map in the vDOS
 	 */
 	vdso_setup_syscall_map();
 	/*
 	 * Initialize the vDSO images in memory, that is do necessary
 	 * fixups of vDSO symbols, locate trampolines, etc...
 	 */
 	if (vdso_setup()) {
 		printk(KERN_ERR "vDSO setup failure, not enabled !\n");
 		vdso32_pages = 0;
 #ifdef CONFIG_PPC64
 		vdso64_pages = 0;
 #endif
 		return;
 	}

 	/* Make sure pages are in the correct state */
 	for (i = 0; i < vdso32_pages; i++) {
 		struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
 		ClearPageReserved(pg);
 		get_page(pg);

 	}
 #ifdef CONFIG_PPC64
 	for (i = 0; i < vdso64_pages; i++) {
 		struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
 		ClearPageReserved(pg);
 		get_page(pg);
 	}
 #endif /* CONFIG_PPC64 */

 	get_page(virt_to_page(vdso_data));
 }

 int in_gate_area_no_task(unsigned long addr)
 {
 	return 0;
 }

 int in_gate_area(struct task_struct *task, unsigned long addr)
 {
 	return 0;
 }

 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
 {
 	return NULL;
 }
	/*
	* linux/arch/ppc64/kernel/vdso.c
	*
	* Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
	* <benh@kernel.crashing.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.
	*/

	#include <linux/config.h>
	#include <linux/module.h>
	#include <linux/errno.h>
	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/smp.h>
	#include <linux/smp_lock.h>
	#include <linux/stddef.h>
	#include <linux/unistd.h>
	#include <linux/slab.h>
	#include <linux/user.h>
	#include <linux/elf.h>
	#include <linux/security.h>
	#include <linux/bootmem.h>

	#include <asm/pgtable.h>
	#include <asm/system.h>
	#include <asm/processor.h>
	#include <asm/mmu.h>
	#include <asm/mmu_context.h>
	#include <asm/lmb.h>
	#include <asm/machdep.h>
	#include <asm/cputable.h>
	#include <asm/sections.h>
	#include <asm/vdso.h>
	#include <asm/vdso_datapage.h>

	#undef DEBUG

	#ifdef DEBUG
	#define DBG(fmt...) printk(fmt)
	#else
	#define DBG(fmt...)
	#endif

	/* Max supported size for symbol names */
	#define MAX_SYMNAME 64

	extern char vdso32_start, vdso32_end;
	static void *vdso32_kbase = &vdso32_start;
	unsigned int vdso32_pages;
	unsigned long vdso32_sigtramp;
	unsigned long vdso32_rt_sigtramp;

	#ifdef CONFIG_PPC64
	extern char vdso64_start, vdso64_end;
	static void *vdso64_kbase = &vdso64_start;
	unsigned int vdso64_pages;
	unsigned long vdso64_rt_sigtramp;
	#endif /* CONFIG_PPC64 */

	/*
	* The vdso data page (aka. systemcfg for old ppc64 fans) is here.
	* Once the early boot kernel code no longer needs to muck around
	* with it, it will become dynamically allocated
	*/
	static union {
	struct vdso_data data;
	u8 page[PAGE_SIZE];
	} vdso_data_store __attribute__((__section__(".data.page_aligned")));
	struct vdso_data *vdso_data = &vdso_data_store.data;

	/* Format of the patch table */
	struct vdso_patch_def
	{
	unsigned long ftr_mask, ftr_value;
	const char *gen_name;
	const char *fix_name;
	};

	/* Table of functions to patch based on the CPU type/revision
	*
	* Currently, we only change sync_dicache to do nothing on processors
	* with a coherent icache
	*/
	static struct vdso_patch_def vdso_patches[] = {
	{
	CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE,
	"__kernel_sync_dicache", "__kernel_sync_dicache_p5"
	},
	{
	CPU_FTR_USE_TB, 0,
	"__kernel_gettimeofday", NULL
	},
	};

	/*
	* Some infos carried around for each of them during parsing at
	* boot time.
	*/
	struct lib32_elfinfo
	{
	Elf32_Ehdr hdr; / ptr to ELF */
	Elf32_Sym dynsym; / ptr to .dynsym section */
	unsigned long dynsymsize; /* size of .dynsym section */
	char dynstr; / ptr to .dynstr section */
	unsigned long text; /* offset of .text section in .so */
	};

	struct lib64_elfinfo
	{
	Elf64_Ehdr *hdr;
	Elf64_Sym *dynsym;
	unsigned long dynsymsize;
	char *dynstr;
	unsigned long text;
	};


	#ifdef __DEBUG
	static void dump_one_vdso_page(struct page pg, struct page upg)
	{
	printk("kpg: %p (c:%d,f:%08lx)", __va(page_to_pfn(pg) << PAGE_SHIFT),
	page_count(pg),
	pg->flags);
	if (upg/* && pg != upg*/) {
	printk(" upg: %p (c:%d,f:%08lx)", __va(page_to_pfn(upg)
	<< PAGE_SHIFT),
	page_count(upg),
	upg->flags);
	}
	printk("\n");
	}

	static void dump_vdso_pages(struct vm_area_struct * vma)
	{
	int i;

	if (!vma \|\| test_thread_flag(TIF_32BIT)) {
	printk("vDSO32 @ %016lx:\n", (unsigned long)vdso32_kbase);
	for (i=0; i<vdso32_pages; i++) {
	struct page *pg = virt_to_page(vdso32_kbase +
	i*PAGE_SIZE);
	struct page *upg = (vma && vma->vm_mm) ?
	follow_page(vma, vma->vm_start + i*PAGE_SIZE, 0)
	: NULL;
	dump_one_vdso_page(pg, upg);
	}
	}
	if (!vma \|\| !test_thread_flag(TIF_32BIT)) {
	printk("vDSO64 @ %016lx:\n", (unsigned long)vdso64_kbase);
	for (i=0; i<vdso64_pages; i++) {
	struct page *pg = virt_to_page(vdso64_kbase +
	i*PAGE_SIZE);
	struct page *upg = (vma && vma->vm_mm) ?
	follow_page(vma, vma->vm_start + i*PAGE_SIZE, 0)
	: NULL;
	dump_one_vdso_page(pg, upg);
	}
	}
	}
	#endif /* DEBUG */

	/*
	* Keep a dummy vma_close for now, it will prevent VMA merging.
	*/
	static void vdso_vma_close(struct vm_area_struct * vma)
	{
	}

	/*
	* Our nopage() function, maps in the actual vDSO kernel pages, they will
	* be mapped read-only by do_no_page(), and eventually COW'ed, either
	* right away for an initial write access, or by do_wp_page().
	*/
	static struct page * vdso_vma_nopage(struct vm_area_struct * vma,
	unsigned long address, int *type)
	{
	unsigned long offset = address - vma->vm_start;
	struct page *pg;
	#ifdef CONFIG_PPC64
	void *vbase = test_thread_flag(TIF_32BIT) ?
	vdso32_kbase : vdso64_kbase;
	#else
	void *vbase = vdso32_kbase;
	#endif

	DBG("vdso_vma_nopage(current: %s, address: %016lx, off: %lx)\n",
	current->comm, address, offset);

	if (address < vma->vm_start \|\| address > vma->vm_end)
	return NOPAGE_SIGBUS;

	/*
	* Last page is systemcfg.
	*/
	if ((vma->vm_end - address) <= PAGE_SIZE)
	pg = virt_to_page(vdso_data);
	else
	pg = virt_to_page(vbase + offset);

	get_page(pg);
	DBG(" ->page count: %d\n", page_count(pg));

	return pg;
	}

	static struct vm_operations_struct vdso_vmops = {
	.close = vdso_vma_close,
	.nopage = vdso_vma_nopage,
	};

	/*
	* This is called from binfmt_elf, we create the special vma for the
	* vDSO and insert it into the mm struct tree
	*/
	int arch_setup_additional_pages(struct linux_binprm *bprm,
	int executable_stack)
	{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma;
	unsigned long vdso_pages;
	unsigned long vdso_base;

	#ifdef CONFIG_PPC64
	if (test_thread_flag(TIF_32BIT)) {
	vdso_pages = vdso32_pages;
	vdso_base = VDSO32_MBASE;
	} else {
	vdso_pages = vdso64_pages;
	vdso_base = VDSO64_MBASE;
	}
	#else
	vdso_pages = vdso32_pages;
	vdso_base = VDSO32_MBASE;
	#endif

	current->thread.vdso_base = 0;

	/* vDSO has a problem and was disabled, just don't "enable" it for the
	* process
	*/
	if (vdso_pages == 0)
	return 0;

	vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
	if (vma == NULL)
	return -ENOMEM;

	memset(vma, 0, sizeof(*vma));

	/* Add a page to the vdso size for the data page */
	vdso_pages ++;

	/*
	* pick a base address for the vDSO in process space. We try to put it
	* at vdso_base which is the "natural" base for it, but we might fail
	* and end up putting it elsewhere.
	*/
	vdso_base = get_unmapped_area(NULL, vdso_base,
	vdso_pages << PAGE_SHIFT, 0, 0);
	if (vdso_base & ~PAGE_MASK) {
	kmem_cache_free(vm_area_cachep, vma);
	return (int)vdso_base;
	}

	current->thread.vdso_base = vdso_base;

	vma->vm_mm = mm;
	vma->vm_start = current->thread.vdso_base;
	vma->vm_end = vma->vm_start + (vdso_pages << PAGE_SHIFT);

	/*
	* our vma flags don't have VM_WRITE so by default, the process isn't
	* allowed to write those pages.
	* gdb can break that with ptrace interface, and thus trigger COW on
	* those pages but it's then your responsibility to never do that on
	* the "data" page of the vDSO or you'll stop getting kernel updates
	* and your nice userland gettimeofday will be totally dead.
	* It's fine to use that for setting breakpoints in the vDSO code
	* pages though
	*/
	vma->vm_flags = VM_READ \| VM_EXEC \| VM_MAYREAD \| VM_MAYWRITE \| VM_MAYEXEC;
	vma->vm_flags \|= mm->def_flags;
	vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
	vma->vm_ops = &vdso_vmops;

	down_write(&mm->mmap_sem);
	if (insert_vm_struct(mm, vma)) {
	up_write(&mm->mmap_sem);
	kmem_cache_free(vm_area_cachep, vma);
	return -ENOMEM;
	}
	mm->total_vm += (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
	up_write(&mm->mmap_sem);

	return 0;
	}

	static void * __init find_section32(Elf32_Ehdr ehdr, const char secname,
	unsigned long *size)
	{
	Elf32_Shdr *sechdrs;
	unsigned int i;
	char *secnames;

	/* Grab section headers and strings so we can tell who is who */
	sechdrs = (void *)ehdr + ehdr->e_shoff;
	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;

	/* Find the section they want */
	for (i = 1; i < ehdr->e_shnum; i++) {
	if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
	if (size)
	*size = sechdrs[i].sh_size;
	return (void *)ehdr + sechdrs[i].sh_offset;
	}
	}
	*size = 0;
	return NULL;
	}

	static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib,
	const char *symname)
	{
	unsigned int i;
	char name[MAX_SYMNAME], *c;

	for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
	if (lib->dynsym[i].st_name == 0)
	continue;
	strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
	MAX_SYMNAME);
	c = strchr(name, '@');
	if (c)
	*c = 0;
	if (strcmp(symname, name) == 0)
	return &lib->dynsym[i];
	}
	return NULL;
	}

	/* Note that we assume the section is .text and the symbol is relative to
	* the library base
	*/
	static unsigned long __init find_function32(struct lib32_elfinfo *lib,
	const char *symname)
	{
	Elf32_Sym *sym = find_symbol32(lib, symname);

	if (sym == NULL) {
	printk(KERN_WARNING "vDSO32: function %s not found !\n",
	symname);
	return 0;
	}
	return sym->st_value - VDSO32_LBASE;
	}

	static int vdso_do_func_patch32(struct lib32_elfinfo *v32,
	struct lib64_elfinfo *v64,
	const char orig, const char fix)
	{
	Elf32_Sym sym32_gen, sym32_fix;

	sym32_gen = find_symbol32(v32, orig);
	if (sym32_gen == NULL) {
	printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig);
	return -1;
	}
	if (fix == NULL) {
	sym32_gen->st_name = 0;
	return 0;
	}
	sym32_fix = find_symbol32(v32, fix);
	if (sym32_fix == NULL) {
	printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix);
	return -1;
	}
	sym32_gen->st_value = sym32_fix->st_value;
	sym32_gen->st_size = sym32_fix->st_size;
	sym32_gen->st_info = sym32_fix->st_info;
	sym32_gen->st_other = sym32_fix->st_other;
	sym32_gen->st_shndx = sym32_fix->st_shndx;

	return 0;
	}


	#ifdef CONFIG_PPC64

	static void * __init find_section64(Elf64_Ehdr ehdr, const char secname,
	unsigned long *size)
	{
	Elf64_Shdr *sechdrs;
	unsigned int i;
	char *secnames;

	/* Grab section headers and strings so we can tell who is who */
	sechdrs = (void *)ehdr + ehdr->e_shoff;
	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;

	/* Find the section they want */
	for (i = 1; i < ehdr->e_shnum; i++) {
	if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
	if (size)
	*size = sechdrs[i].sh_size;
	return (void *)ehdr + sechdrs[i].sh_offset;
	}
	}
	if (size)
	*size = 0;
	return NULL;
	}

	static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib,
	const char *symname)
	{
	unsigned int i;
	char name[MAX_SYMNAME], *c;

	for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) {
	if (lib->dynsym[i].st_name == 0)
	continue;
	strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
	MAX_SYMNAME);
	c = strchr(name, '@');
	if (c)
	*c = 0;
	if (strcmp(symname, name) == 0)
	return &lib->dynsym[i];
	}
	return NULL;
	}

	/* Note that we assume the section is .text and the symbol is relative to
	* the library base
	*/
	static unsigned long __init find_function64(struct lib64_elfinfo *lib,
	const char *symname)
	{
	Elf64_Sym *sym = find_symbol64(lib, symname);

	if (sym == NULL) {
	printk(KERN_WARNING "vDSO64: function %s not found !\n",
	symname);
	return 0;
	}
	#ifdef VDS64_HAS_DESCRIPTORS
	return ((u64 )(vdso64_kbase + sym->st_value - VDSO64_LBASE)) -
	VDSO64_LBASE;
	#else
	return sym->st_value - VDSO64_LBASE;
	#endif
	}

	static int vdso_do_func_patch64(struct lib32_elfinfo *v32,
	struct lib64_elfinfo *v64,
	const char orig, const char fix)
	{
	Elf64_Sym sym64_gen, sym64_fix;

	sym64_gen = find_symbol64(v64, orig);
	if (sym64_gen == NULL) {
	printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig);
	return -1;
	}
	if (fix == NULL) {
	sym64_gen->st_name = 0;
	return 0;
	}
	sym64_fix = find_symbol64(v64, fix);
	if (sym64_fix == NULL) {
	printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix);
	return -1;
	}
	sym64_gen->st_value = sym64_fix->st_value;
	sym64_gen->st_size = sym64_fix->st_size;
	sym64_gen->st_info = sym64_fix->st_info;
	sym64_gen->st_other = sym64_fix->st_other;
	sym64_gen->st_shndx = sym64_fix->st_shndx;

	return 0;
	}

	#endif /* CONFIG_PPC64 */


	static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
	struct lib64_elfinfo *v64)
	{
	void *sect;

	/*
	* Locate symbol tables & text section
	*/

	v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
	v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
	if (v32->dynsym == NULL \|\| v32->dynstr == NULL) {
	printk(KERN_ERR "vDSO32: required symbol section not found\n");
	return -1;
	}
	sect = find_section32(v32->hdr, ".text", NULL);
	if (sect == NULL) {
	printk(KERN_ERR "vDSO32: the .text section was not found\n");
	return -1;
	}
	v32->text = sect - vdso32_kbase;

	#ifdef CONFIG_PPC64
	v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
	v64->dynstr = find_section64(v64->hdr, ".dynstr", NULL);
	if (v64->dynsym == NULL \|\| v64->dynstr == NULL) {
	printk(KERN_ERR "vDSO64: required symbol section not found\n");
	return -1;
	}
	sect = find_section64(v64->hdr, ".text", NULL);
	if (sect == NULL) {
	printk(KERN_ERR "vDSO64: the .text section was not found\n");
	return -1;
	}
	v64->text = sect - vdso64_kbase;
	#endif /* CONFIG_PPC64 */

	return 0;
	}

	static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
	struct lib64_elfinfo *v64)
	{
	/*
	* Find signal trampolines
	*/

	#ifdef CONFIG_PPC64
	vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64");
	#endif
	vdso32_sigtramp = find_function32(v32, "__kernel_sigtramp32");
	vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
	}

	static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
	struct lib64_elfinfo *v64)
	{
	Elf32_Sym *sym32;
	#ifdef CONFIG_PPC64
	Elf64_Sym *sym64;

	sym64 = find_symbol64(v64, "__kernel_datapage_offset");
	if (sym64 == NULL) {
	printk(KERN_ERR "vDSO64: Can't find symbol "
	"__kernel_datapage_offset !\n");
	return -1;
	}
	((int )(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
	(vdso64_pages << PAGE_SHIFT) -
	(sym64->st_value - VDSO64_LBASE);
	#endif /* CONFIG_PPC64 */

	sym32 = find_symbol32(v32, "__kernel_datapage_offset");
	if (sym32 == NULL) {
	printk(KERN_ERR "vDSO32: Can't find symbol "
	"__kernel_datapage_offset !\n");
	return -1;
	}
	((int )(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
	(vdso32_pages << PAGE_SHIFT) -
	(sym32->st_value - VDSO32_LBASE);

	return 0;
	}

	static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
	struct lib64_elfinfo *v64)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) {
	struct vdso_patch_def *patch = &vdso_patches[i];
	int match = (cur_cpu_spec->cpu_features & patch->ftr_mask)
	== patch->ftr_value;
	if (!match)
	continue;

	DBG("replacing %s with %s...\n", patch->gen_name,
	patch->fix_name ? "NONE" : patch->fix_name);

	/*
	* Patch the 32 bits and 64 bits symbols. Note that we do not
	* patch the "." symbol on 64 bits.
	* It would be easy to do, but doesn't seem to be necessary,
	* patching the OPD symbol is enough.
	*/
	vdso_do_func_patch32(v32, v64, patch->gen_name,
	patch->fix_name);
	#ifdef CONFIG_PPC64
	vdso_do_func_patch64(v32, v64, patch->gen_name,
	patch->fix_name);
	#endif /* CONFIG_PPC64 */
	}

	return 0;
	}


	static __init int vdso_setup(void)
	{
	struct lib32_elfinfo v32;
	struct lib64_elfinfo v64;

	v32.hdr = vdso32_kbase;
	#ifdef CONFIG_PPC64
	v64.hdr = vdso64_kbase;
	#endif
	if (vdso_do_find_sections(&v32, &v64))
	return -1;

	if (vdso_fixup_datapage(&v32, &v64))
	return -1;

	if (vdso_fixup_alt_funcs(&v32, &v64))
	return -1;

	vdso_setup_trampolines(&v32, &v64);

	return 0;
	}

	/*
	* Called from setup_arch to initialize the bitmap of available
	* syscalls in the systemcfg page
	*/
	static void __init vdso_setup_syscall_map(void)
	{
	unsigned int i;
	extern unsigned long *sys_call_table;
	extern unsigned long sys_ni_syscall;


	for (i = 0; i < __NR_syscalls; i++) {
	#ifdef CONFIG_PPC64
	if (sys_call_table[i*2] != sys_ni_syscall)
	vdso_data->syscall_map_64[i >> 5] \|=
	0x80000000UL >> (i & 0x1f);
	if (sys_call_table[i*2+1] != sys_ni_syscall)
	vdso_data->syscall_map_32[i >> 5] \|=
	0x80000000UL >> (i & 0x1f);
	#else /* CONFIG_PPC64 */
	if (sys_call_table[i] != sys_ni_syscall)
	vdso_data->syscall_map_32[i >> 5] \|=
	0x80000000UL >> (i & 0x1f);
	#endif /* CONFIG_PPC64 */
	}
	}


	void __init vdso_init(void)
	{
	int i;

	#ifdef CONFIG_PPC64
	/*
	* Fill up the "systemcfg" stuff for backward compatiblity
	*/
	strcpy(vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
	vdso_data->version.major = SYSTEMCFG_MAJOR;
	vdso_data->version.minor = SYSTEMCFG_MINOR;
	vdso_data->processor = mfspr(SPRN_PVR);
	vdso_data->platform = _machine;
	vdso_data->physicalMemorySize = lmb_phys_mem_size();
	vdso_data->dcache_size = ppc64_caches.dsize;
	vdso_data->dcache_line_size = ppc64_caches.dline_size;
	vdso_data->icache_size = ppc64_caches.isize;
	vdso_data->icache_line_size = ppc64_caches.iline_size;

	/*
	* Calculate the size of the 64 bits vDSO
	*/
	vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
	DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages);
	#endif /* CONFIG_PPC64 */


	/*
	* Calculate the size of the 32 bits vDSO
	*/
	vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
	DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);


	/*
	* Setup the syscall map in the vDOS
	*/
	vdso_setup_syscall_map();
	/*
	* Initialize the vDSO images in memory, that is do necessary
	* fixups of vDSO symbols, locate trampolines, etc...
	*/
	if (vdso_setup()) {
	printk(KERN_ERR "vDSO setup failure, not enabled !\n");
	vdso32_pages = 0;
	#ifdef CONFIG_PPC64
	vdso64_pages = 0;
	#endif
	return;
	}

	/* Make sure pages are in the correct state */
	for (i = 0; i < vdso32_pages; i++) {
	struct page pg = virt_to_page(vdso32_kbase + iPAGE_SIZE);
	ClearPageReserved(pg);
	get_page(pg);

	}
	#ifdef CONFIG_PPC64
	for (i = 0; i < vdso64_pages; i++) {
	struct page pg = virt_to_page(vdso64_kbase + iPAGE_SIZE);
	ClearPageReserved(pg);
	get_page(pg);
	}
	#endif /* CONFIG_PPC64 */

	get_page(virt_to_page(vdso_data));
	}

	int in_gate_area_no_task(unsigned long addr)
	{
	return 0;
	}

	int in_gate_area(struct task_struct *task, unsigned long addr)
	{
	return 0;
	}

	struct vm_area_struct get_gate_vma(struct task_struct tsk)
	{
	return NULL;
	}