X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fi386%2Fkernel%2Fsysenter.c;h=b97719aa4127811ed198af5dce8e06f4191b3418;hb=9464c7cf61b9433057924c36e6e02f303a00e768;hp=765af04c464d06e0397cd38ce16935ac401b96d0;hpb=41689045f6a3cbe0550e1d34e9cc20d2e8c432ba;p=linux-2.6.git diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c index 765af04c4..b97719aa4 100644 --- a/arch/i386/kernel/sysenter.c +++ b/arch/i386/kernel/sysenter.c @@ -2,8 +2,6 @@ * 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. */ @@ -17,10 +15,8 @@ #include #include #include -#include -#include -#include +#include #include #include #include @@ -30,23 +26,6 @@ #include #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) @@ -75,11 +54,13 @@ void enable_sep_cpu(void) */ extern const char vsyscall_int80_start, vsyscall_int80_end; extern const char vsyscall_sysenter_start, vsyscall_sysenter_end; -static void *syscall_page; +static struct page *sysenter_pages[2]; int __init sysenter_setup(void) { - syscall_page = (void *)get_zeroed_page(GFP_ATOMIC); + void *page = (void *)get_zeroed_page(GFP_ATOMIC); + + sysenter_pages[0] = virt_to_page(page); #ifdef CONFIG_XEN if (boot_cpu_has(X86_FEATURE_SEP)) { @@ -93,111 +74,84 @@ int __init sysenter_setup(void) } #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 - - if (!boot_cpu_has(X86_FEATURE_SEP)) { - memcpy(syscall_page, - &vsyscall_int80_start, - &vsyscall_int80_end - &vsyscall_int80_start); + if (boot_cpu_has(X86_FEATURE_SEP)) { + memcpy(page, + &vsyscall_sysenter_start, + &vsyscall_sysenter_end - &vsyscall_sysenter_start); return 0; } - memcpy(syscall_page, - &vsyscall_sysenter_start, - &vsyscall_sysenter_end - &vsyscall_sysenter_start); + memcpy(page, + &vsyscall_int80_start, + &vsyscall_int80_end - &vsyscall_int80_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; -} +extern void SYSENTER_RETURN_OFFSET; -/* Prevent VMA merging */ -static void syscall_vma_close(struct vm_area_struct *vma) -{ -} +unsigned int vdso_enabled = 1; -static struct vm_operations_struct syscall_vm_ops = { - .close = syscall_vma_close, - .nopage = syscall_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, unsigned long start_code, + unsigned long interp_map_address) +{ + struct thread_info *ti = current_thread_info(); + unsigned long addr = 0, len; + unsigned flags = MAP_PRIVATE; + int err; -/* Defined in vsyscall-sysenter.S */ -extern void SYSENTER_RETURN; + current->mm->context.vdso = NULL; + if (unlikely(!vdso_enabled) || unlikely(!sysenter_pages[0])) + return 0; -/* 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; + /* + * Map the vDSO (it will be randomized): + */ + down_write(¤t->mm->mmap_sem); + len = PAGE_SIZE > ELF_EXEC_PAGESIZE ? PAGE_SIZE : ELF_EXEC_PAGESIZE; + if (0==exec_shield) { /* off; %cs limit off */ + addr = STACK_TOP; /* minimal interference with anybody */ + flags = MAP_PRIVATE | MAP_FIXED; } - - vma = kmem_cache_zalloc(vm_area_cachep, SLAB_KERNEL); - if (!vma) { - ret = -ENOMEM; - goto up_fail; + else if ((3<<2) & exec_shield) { /* vdso just below .text */ + addr = (((2<<2) & exec_shield) && interp_map_address) ? + interp_map_address : start_code; + /* 1MB for vm86; 64K for vm86 himem */ + if ((0x110000 + len) <= addr) { + addr = (PAGE_MASK & addr) - len; + } + else { /* start_code is too low */ + addr = 0; + } } - - 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; + addr = get_unmapped_area_prot(NULL, addr, len, 0, + flags, PROT_READ | PROT_EXEC); + if (unlikely(addr & ~PAGE_MASK)) { + up_write(¤t->mm->mmap_sem); + return addr; } - - 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; + err = install_special_mapping(current->mm, addr, len, + VM_DONTEXPAND | VM_READ | VM_EXEC | + VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, + PAGE_READONLY_EXEC, + sysenter_pages); + if (likely(err == 0)) { + current->mm->context.vdso = (void *)addr; + ti->sysenter_return = &SYSENTER_RETURN_OFFSET + addr; + } + up_write(¤t->mm->mmap_sem); + return err; } -struct vm_area_struct *get_gate_vma(struct task_struct *tsk) +#ifndef CONFIG_XEN +int in_gate_area_no_task(unsigned long addr) { - return NULL; + return 0; } int in_gate_area(struct task_struct *task, unsigned long addr) @@ -205,7 +159,8 @@ int in_gate_area(struct task_struct *task, unsigned long addr) return 0; } -int in_gate_area_no_task(unsigned long addr) +struct vm_area_struct *get_gate_vma(struct task_struct *tsk) { - return 0; + return NULL; } +#endif