diff options
Diffstat (limited to 'kernel/arch/x86/vdso/vma.c')
| -rw-r--r-- | kernel/arch/x86/vdso/vma.c | 300 |
1 files changed, 0 insertions, 300 deletions
diff --git a/kernel/arch/x86/vdso/vma.c b/kernel/arch/x86/vdso/vma.c deleted file mode 100644 index 1c9f750c3..000000000 --- a/kernel/arch/x86/vdso/vma.c +++ /dev/null @@ -1,300 +0,0 @@ -/* - * Copyright 2007 Andi Kleen, SUSE Labs. - * Subject to the GPL, v.2 - * - * This contains most of the x86 vDSO kernel-side code. - */ -#include <linux/mm.h> -#include <linux/err.h> -#include <linux/sched.h> -#include <linux/slab.h> -#include <linux/init.h> -#include <linux/random.h> -#include <linux/elf.h> -#include <linux/cpu.h> -#include <asm/vgtod.h> -#include <asm/proto.h> -#include <asm/vdso.h> -#include <asm/vvar.h> -#include <asm/page.h> -#include <asm/hpet.h> -#include <asm/desc.h> - -#if defined(CONFIG_X86_64) -unsigned int __read_mostly vdso64_enabled = 1; -#endif - -void __init init_vdso_image(const struct vdso_image *image) -{ - int i; - int npages = (image->size) / PAGE_SIZE; - - BUG_ON(image->size % PAGE_SIZE != 0); - for (i = 0; i < npages; i++) - image->text_mapping.pages[i] = - virt_to_page(image->data + i*PAGE_SIZE); - - apply_alternatives((struct alt_instr *)(image->data + image->alt), - (struct alt_instr *)(image->data + image->alt + - image->alt_len)); -} - -struct linux_binprm; - -/* - * Put the vdso above the (randomized) stack with another randomized - * offset. This way there is no hole in the middle of address space. - * To save memory make sure it is still in the same PTE as the stack - * top. This doesn't give that many random bits. - * - * Note that this algorithm is imperfect: the distribution of the vdso - * start address within a PMD is biased toward the end. - * - * Only used for the 64-bit and x32 vdsos. - */ -static unsigned long vdso_addr(unsigned long start, unsigned len) -{ -#ifdef CONFIG_X86_32 - return 0; -#else - unsigned long addr, end; - unsigned offset; - - /* - * Round up the start address. It can start out unaligned as a result - * of stack start randomization. - */ - start = PAGE_ALIGN(start); - - /* Round the lowest possible end address up to a PMD boundary. */ - end = (start + len + PMD_SIZE - 1) & PMD_MASK; - if (end >= TASK_SIZE_MAX) - end = TASK_SIZE_MAX; - end -= len; - - if (end > start) { - offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1); - addr = start + (offset << PAGE_SHIFT); - } else { - addr = start; - } - - /* - * Forcibly align the final address in case we have a hardware - * issue that requires alignment for performance reasons. - */ - addr = align_vdso_addr(addr); - - return addr; -#endif -} - -static int map_vdso(const struct vdso_image *image, bool calculate_addr) -{ - struct mm_struct *mm = current->mm; - struct vm_area_struct *vma; - unsigned long addr, text_start; - int ret = 0; - static struct page *no_pages[] = {NULL}; - static struct vm_special_mapping vvar_mapping = { - .name = "[vvar]", - .pages = no_pages, - }; - - if (calculate_addr) { - addr = vdso_addr(current->mm->start_stack, - image->size - image->sym_vvar_start); - } else { - addr = 0; - } - - down_write(&mm->mmap_sem); - - addr = get_unmapped_area(NULL, addr, - image->size - image->sym_vvar_start, 0, 0); - if (IS_ERR_VALUE(addr)) { - ret = addr; - goto up_fail; - } - - text_start = addr - image->sym_vvar_start; - current->mm->context.vdso = (void __user *)text_start; - - /* - * MAYWRITE to allow gdb to COW and set breakpoints - */ - vma = _install_special_mapping(mm, - text_start, - image->size, - VM_READ|VM_EXEC| - VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, - &image->text_mapping); - - if (IS_ERR(vma)) { - ret = PTR_ERR(vma); - goto up_fail; - } - - vma = _install_special_mapping(mm, - addr, - -image->sym_vvar_start, - VM_READ|VM_MAYREAD, - &vvar_mapping); - - if (IS_ERR(vma)) { - ret = PTR_ERR(vma); - goto up_fail; - } - - if (image->sym_vvar_page) - ret = remap_pfn_range(vma, - text_start + image->sym_vvar_page, - __pa_symbol(&__vvar_page) >> PAGE_SHIFT, - PAGE_SIZE, - PAGE_READONLY); - - if (ret) - goto up_fail; - -#ifdef CONFIG_HPET_TIMER - if (hpet_address && image->sym_hpet_page) { - ret = io_remap_pfn_range(vma, - text_start + image->sym_hpet_page, - hpet_address >> PAGE_SHIFT, - PAGE_SIZE, - pgprot_noncached(PAGE_READONLY)); - - if (ret) - goto up_fail; - } -#endif - -up_fail: - if (ret) - current->mm->context.vdso = NULL; - - up_write(&mm->mmap_sem); - return ret; -} - -#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT) -static int load_vdso32(void) -{ - int ret; - - if (vdso32_enabled != 1) /* Other values all mean "disabled" */ - return 0; - - ret = map_vdso(selected_vdso32, false); - if (ret) - return ret; - - if (selected_vdso32->sym_VDSO32_SYSENTER_RETURN) - current_thread_info()->sysenter_return = - current->mm->context.vdso + - selected_vdso32->sym_VDSO32_SYSENTER_RETURN; - - return 0; -} -#endif - -#ifdef CONFIG_X86_64 -int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) -{ - if (!vdso64_enabled) - return 0; - - return map_vdso(&vdso_image_64, true); -} - -#ifdef CONFIG_COMPAT -int compat_arch_setup_additional_pages(struct linux_binprm *bprm, - int uses_interp) -{ -#ifdef CONFIG_X86_X32_ABI - if (test_thread_flag(TIF_X32)) { - if (!vdso64_enabled) - return 0; - - return map_vdso(&vdso_image_x32, true); - } -#endif - - return load_vdso32(); -} -#endif -#else -int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) -{ - return load_vdso32(); -} -#endif - -#ifdef CONFIG_X86_64 -static __init int vdso_setup(char *s) -{ - vdso64_enabled = simple_strtoul(s, NULL, 0); - return 0; -} -__setup("vdso=", vdso_setup); -#endif - -#ifdef CONFIG_X86_64 -static void vgetcpu_cpu_init(void *arg) -{ - int cpu = smp_processor_id(); - struct desc_struct d = { }; - unsigned long node = 0; -#ifdef CONFIG_NUMA - node = cpu_to_node(cpu); -#endif - if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP)) - write_rdtscp_aux((node << 12) | cpu); - - /* - * Store cpu number in limit so that it can be loaded - * quickly in user space in vgetcpu. (12 bits for the CPU - * and 8 bits for the node) - */ - d.limit0 = cpu | ((node & 0xf) << 12); - d.limit = node >> 4; - d.type = 5; /* RO data, expand down, accessed */ - d.dpl = 3; /* Visible to user code */ - d.s = 1; /* Not a system segment */ - d.p = 1; /* Present */ - d.d = 1; /* 32-bit */ - - write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S); -} - -static int -vgetcpu_cpu_notifier(struct notifier_block *n, unsigned long action, void *arg) -{ - long cpu = (long)arg; - - if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) - smp_call_function_single(cpu, vgetcpu_cpu_init, NULL, 1); - - return NOTIFY_DONE; -} - -static int __init init_vdso(void) -{ - init_vdso_image(&vdso_image_64); - -#ifdef CONFIG_X86_X32_ABI - init_vdso_image(&vdso_image_x32); -#endif - - cpu_notifier_register_begin(); - - on_each_cpu(vgetcpu_cpu_init, NULL, 1); - /* notifier priority > KVM */ - __hotcpu_notifier(vgetcpu_cpu_notifier, 30); - - cpu_notifier_register_done(); - - return 0; -} -subsys_initcall(init_vdso); -#endif /* CONFIG_X86_64 */ |