* linux/arch/i386/kernel/sysenter.c
*
* (C) Copyright 2002 Linus Torvalds
- * Portions based on the vdso-randomization code from exec-shield:
- * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
*
* This file contains the needed initializations to support sysenter.
*/
#include <linux/gfp.h>
#include <linux/string.h>
#include <linux/elf.h>
-#include <linux/mm.h>
-#include <linux/mman.h>
-#include <linux/module.h>
-#include <linux/vs_memory.h>
#include <asm/cpufeature.h>
#include <asm/msr.h>
#include <asm/pgtable.h>
#include <asm/unistd.h>
-#ifdef CONFIG_XEN
-#include <xen/interface/callback.h>
-#endif
-
-/*
- * Should the kernel map a VDSO page into processes and pass its
- * address down to glibc upon exec()?
- */
-unsigned int __read_mostly vdso_enabled = 1;
-
-EXPORT_SYMBOL_GPL(vdso_enabled);
-
-static int __init vdso_setup(char *s)
-{
- vdso_enabled = simple_strtoul(s, NULL, 0);
-
- return 1;
-}
-
-__setup("vdso=", vdso_setup);
-
extern asmlinkage void sysenter_entry(void);
void enable_sep_cpu(void)
{
-#ifndef CONFIG_X86_NO_TSS
int cpu = get_cpu();
struct tss_struct *tss = &per_cpu(init_tss, cpu);
wrmsr(MSR_IA32_SYSENTER_ESP, tss->esp1, 0);
wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long) sysenter_entry, 0);
put_cpu();
-#endif
}
/*
*/
extern const char vsyscall_int80_start, vsyscall_int80_end;
extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
-static void *syscall_page;
int __init sysenter_setup(void)
{
- syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
-
-#ifdef CONFIG_XEN
- if (boot_cpu_has(X86_FEATURE_SEP)) {
- struct callback_register sysenter = {
- .type = CALLBACKTYPE_sysenter,
- .address = { __KERNEL_CS, (unsigned long)sysenter_entry },
- };
+ void *page = (void *)get_zeroed_page(GFP_ATOMIC);
- if (HYPERVISOR_callback_op(CALLBACKOP_register, &sysenter) < 0)
- clear_bit(X86_FEATURE_SEP, boot_cpu_data.x86_capability);
- }
-#endif
-
-#ifdef CONFIG_COMPAT_VDSO
- __set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_READONLY);
- printk("Compat vDSO mapped to %08lx.\n", __fix_to_virt(FIX_VDSO));
-#else
- /*
- * In the non-compat case the ELF coredumping code needs the fixmap:
- */
-#ifdef CONFIG_XEN
- __set_fixmap(FIX_VDSO, virt_to_machine(syscall_page), PAGE_KERNEL_RO);
-#else
- __set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_KERNEL_RO);
-#endif
-#endif
+ __set_fixmap(FIX_VSYSCALL, __pa(page), PAGE_READONLY_EXEC);
if (!boot_cpu_has(X86_FEATURE_SEP)) {
- memcpy(syscall_page,
+ memcpy(page,
&vsyscall_int80_start,
&vsyscall_int80_end - &vsyscall_int80_start);
return 0;
}
- memcpy(syscall_page,
+ memcpy(page,
&vsyscall_sysenter_start,
&vsyscall_sysenter_end - &vsyscall_sysenter_start);
return 0;
}
-
-static struct page *syscall_nopage(struct vm_area_struct *vma,
- unsigned long adr, int *type)
-{
- struct page *p = virt_to_page(adr - vma->vm_start + syscall_page);
- get_page(p);
- return p;
-}
-
-/* Prevent VMA merging */
-static void syscall_vma_close(struct vm_area_struct *vma)
-{
-}
-
-static struct vm_operations_struct syscall_vm_ops = {
- .close = syscall_vma_close,
- .nopage = syscall_nopage,
-};
-
-/* Defined in vsyscall-sysenter.S */
-extern void SYSENTER_RETURN;
-
-/* Setup a VMA at program startup for the vsyscall page */
-int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack,
- unsigned long start_code, unsigned long interp_map_address)
-{
- struct vm_area_struct *vma;
- struct mm_struct *mm = current->mm;
- unsigned long addr;
- int ret;
-
- down_write(&mm->mmap_sem);
- addr = get_unmapped_area_prot(NULL, 0, PAGE_SIZE, 0, 0, 1);
- if (IS_ERR_VALUE(addr)) {
- ret = addr;
- goto up_fail;
- }
-
- vma = kmem_cache_zalloc(vm_area_cachep, SLAB_KERNEL);
- if (!vma) {
- ret = -ENOMEM;
- goto up_fail;
- }
-
- vma->vm_start = addr;
- vma->vm_end = addr + PAGE_SIZE;
- /* MAYWRITE to allow gdb to COW and set breakpoints */
- vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
- vma->vm_flags |= mm->def_flags;
- vma->vm_page_prot = protection_map[vma->vm_flags & 7];
- vma->vm_ops = &syscall_vm_ops;
- vma->vm_mm = mm;
-
- ret = insert_vm_struct(mm, vma);
- if (unlikely(ret)) {
- kmem_cache_free(vm_area_cachep, vma);
- goto up_fail;
- }
-
- current->mm->context.vdso = (void *)addr;
- current_thread_info()->sysenter_return =
- (void *)VDSO_SYM(&SYSENTER_RETURN);
- vx_vmpages_inc(mm);
-up_fail:
- up_write(&mm->mmap_sem);
- return ret;
-}
-
-const char *arch_vma_name(struct vm_area_struct *vma)
-{
- if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
- return "[vdso]";
- return NULL;
-}
-
-struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
-{
- return NULL;
-}
-
-int in_gate_area(struct task_struct *task, unsigned long addr)
-{
- return 0;
-}
-
-int in_gate_area_no_task(unsigned long addr)
-{
- return 0;
-}
git://git.onelab.eu / linux-2.6.git / blobdiff