linux/arch/ia64/ia32/binfmt_elf32.c
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   1/*
   2 * IA-32 ELF support.
   3 *
   4 * Copyright (C) 1999 Arun Sharma <arun.sharma@intel.com>
   5 * Copyright (C) 2001 Hewlett-Packard Co
   6 *      David Mosberger-Tang <davidm@hpl.hp.com>
   7 *
   8 * 06/16/00     A. Mallick      initialize csd/ssd/tssd/cflg for ia32_load_state
   9 * 04/13/01     D. Mosberger    dropped saving tssd in ar.k1---it's not needed
  10 * 09/14/01     D. Mosberger    fixed memory management for gdt/tss page
  11 */
  12
  13#include <linux/types.h>
  14#include <linux/mm.h>
  15#include <linux/security.h>
  16
  17#include <asm/param.h>
  18#include <asm/signal.h>
  19
  20#include "ia32priv.h"
  21#include "elfcore32.h"
  22
  23/* Override some function names */
  24#undef start_thread
  25#define start_thread                    ia32_start_thread
  26#define elf_format                      elf32_format
  27#define init_elf_binfmt                 init_elf32_binfmt
  28#define exit_elf_binfmt                 exit_elf32_binfmt
  29
  30#undef CLOCKS_PER_SEC
  31#define CLOCKS_PER_SEC  IA32_CLOCKS_PER_SEC
  32
  33extern void ia64_elf32_init (struct pt_regs *regs);
  34
  35static void elf32_set_personality (void);
  36
  37static unsigned long __attribute ((unused))
  38randomize_stack_top(unsigned long stack_top);
  39
  40#define setup_arg_pages(bprm,tos,exec)          ia32_setup_arg_pages(bprm,exec)
  41#define elf_map                         elf32_map
  42
  43#undef SET_PERSONALITY
  44#define SET_PERSONALITY(ex, ibcs2)      elf32_set_personality()
  45
  46#define elf_read_implies_exec(ex, have_pt_gnu_stack)    (!(have_pt_gnu_stack))
  47
  48/* Ugly but avoids duplication */
  49#include "../../../fs/binfmt_elf.c"
  50
  51extern struct page *ia32_shared_page[];
  52extern unsigned long *ia32_gdt;
  53extern struct page *ia32_gate_page;
  54
  55int
  56ia32_install_shared_page (struct vm_area_struct *vma, struct vm_fault *vmf)
  57{
  58        vmf->page = ia32_shared_page[smp_processor_id()];
  59        get_page(vmf->page);
  60        return 0;
  61}
  62
  63int
  64ia32_install_gate_page (struct vm_area_struct *vma, struct vm_fault *vmf)
  65{
  66        vmf->page = ia32_gate_page;
  67        get_page(vmf->page);
  68        return 0;
  69}
  70
  71
  72static struct vm_operations_struct ia32_shared_page_vm_ops = {
  73        .fault = ia32_install_shared_page
  74};
  75
  76static struct vm_operations_struct ia32_gate_page_vm_ops = {
  77        .fault = ia32_install_gate_page
  78};
  79
  80void
  81ia64_elf32_init (struct pt_regs *regs)
  82{
  83        struct vm_area_struct *vma;
  84
  85        /*
  86         * Map GDT below 4GB, where the processor can find it.  We need to map
  87         * it with privilege level 3 because the IVE uses non-privileged accesses to these
  88         * tables.  IA-32 segmentation is used to protect against IA-32 accesses to them.
  89         */
  90        vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
  91        if (vma) {
  92                vma->vm_mm = current->mm;
  93                vma->vm_start = IA32_GDT_OFFSET;
  94                vma->vm_end = vma->vm_start + PAGE_SIZE;
  95                vma->vm_page_prot = PAGE_SHARED;
  96                vma->vm_flags = VM_READ|VM_MAYREAD|VM_RESERVED;
  97                vma->vm_ops = &ia32_shared_page_vm_ops;
  98                down_write(&current->mm->mmap_sem);
  99                {
 100                        if (insert_vm_struct(current->mm, vma)) {
 101                                kmem_cache_free(vm_area_cachep, vma);
 102                                up_write(&current->mm->mmap_sem);
 103                                BUG();
 104                        }
 105                }
 106                up_write(&current->mm->mmap_sem);
 107        }
 108
 109        /*
 110         * When user stack is not executable, push sigreturn code to stack makes
 111         * segmentation fault raised when returning to kernel. So now sigreturn
 112         * code is locked in specific gate page, which is pointed by pretcode
 113         * when setup_frame_ia32
 114         */
 115        vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 116        if (vma) {
 117                vma->vm_mm = current->mm;
 118                vma->vm_start = IA32_GATE_OFFSET;
 119                vma->vm_end = vma->vm_start + PAGE_SIZE;
 120                vma->vm_page_prot = PAGE_COPY_EXEC;
 121                vma->vm_flags = VM_READ | VM_MAYREAD | VM_EXEC
 122                                | VM_MAYEXEC | VM_RESERVED;
 123                vma->vm_ops = &ia32_gate_page_vm_ops;
 124                down_write(&current->mm->mmap_sem);
 125                {
 126                        if (insert_vm_struct(current->mm, vma)) {
 127                                kmem_cache_free(vm_area_cachep, vma);
 128                                up_write(&current->mm->mmap_sem);
 129                                BUG();
 130                        }
 131                }
 132                up_write(&current->mm->mmap_sem);
 133        }
 134
 135        /*
 136         * Install LDT as anonymous memory.  This gives us all-zero segment descriptors
 137         * until a task modifies them via modify_ldt().
 138         */
 139        vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
 140        if (vma) {
 141                vma->vm_mm = current->mm;
 142                vma->vm_start = IA32_LDT_OFFSET;
 143                vma->vm_end = vma->vm_start + PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
 144                vma->vm_page_prot = PAGE_SHARED;
 145                vma->vm_flags = VM_READ|VM_WRITE|VM_MAYREAD|VM_MAYWRITE;
 146                down_write(&current->mm->mmap_sem);
 147                {
 148                        if (insert_vm_struct(current->mm, vma)) {
 149                                kmem_cache_free(vm_area_cachep, vma);
 150                                up_write(&current->mm->mmap_sem);
 151                                BUG();
 152                        }
 153                }
 154                up_write(&current->mm->mmap_sem);
 155        }
 156
 157        ia64_psr(regs)->ac = 0;         /* turn off alignment checking */
 158        regs->loadrs = 0;
 159        /*
 160         *  According to the ABI %edx points to an `atexit' handler.  Since we don't have
 161         *  one we'll set it to 0 and initialize all the other registers just to make
 162         *  things more deterministic, ala the i386 implementation.
 163         */
 164        regs->r8 = 0;   /* %eax */
 165        regs->r11 = 0;  /* %ebx */
 166        regs->r9 = 0;   /* %ecx */
 167        regs->r10 = 0;  /* %edx */
 168        regs->r13 = 0;  /* %ebp */
 169        regs->r14 = 0;  /* %esi */
 170        regs->r15 = 0;  /* %edi */
 171
 172        current->thread.eflag = IA32_EFLAG;
 173        current->thread.fsr = IA32_FSR_DEFAULT;
 174        current->thread.fcr = IA32_FCR_DEFAULT;
 175        current->thread.fir = 0;
 176        current->thread.fdr = 0;
 177
 178        /*
 179         * Setup GDTD.  Note: GDTD is the descrambled version of the pseudo-descriptor
 180         * format defined by Figure 3-11 "Pseudo-Descriptor Format" in the IA-32
 181         * architecture manual. Also note that the only fields that are not ignored are
 182         * `base', `limit', 'G', `P' (must be 1) and `S' (must be 0).
 183         */
 184        regs->r31 = IA32_SEG_UNSCRAMBLE(IA32_SEG_DESCRIPTOR(IA32_GDT_OFFSET, IA32_PAGE_SIZE - 1,
 185                                                            0, 0, 0, 1, 0, 0, 0));
 186        /* Setup the segment selectors */
 187        regs->r16 = (__USER_DS << 16) | __USER_DS; /* ES == DS, GS, FS are zero */
 188        regs->r17 = (__USER_DS << 16) | __USER_CS; /* SS, CS; ia32_load_state() sets TSS and LDT */
 189
 190        ia32_load_segment_descriptors(current);
 191        ia32_load_state(current);
 192}
 193
 194/*
 195 * Undo the override of setup_arg_pages() without this ia32_setup_arg_pages()
 196 * will suffer infinite self recursion.
 197 */
 198#undef setup_arg_pages
 199
 200int
 201ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
 202{
 203        int ret;
 204
 205        ret = setup_arg_pages(bprm, IA32_STACK_TOP, executable_stack);
 206        if (!ret) {
 207                /*
 208                 * Can't do it in ia64_elf32_init(). Needs to be done before
 209                 * calls to elf32_map()
 210                 */
 211                current->thread.ppl = ia32_init_pp_list();
 212        }
 213
 214        return ret;
 215}
 216
 217static void
 218elf32_set_personality (void)
 219{
 220        set_personality(PER_LINUX32);
 221        current->thread.map_base  = IA32_PAGE_OFFSET/3;
 222}
 223
 224static unsigned long
 225elf32_map(struct file *filep, unsigned long addr, struct elf_phdr *eppnt,
 226                int prot, int type, unsigned long unused)
 227{
 228        unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
 229
 230        return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
 231                            eppnt->p_offset - pgoff);
 232}
 233
 234#define cpu_uses_ia32el()       (local_cpu_data->family > 0x1f)
 235
 236static int __init check_elf32_binfmt(void)
 237{
 238        if (cpu_uses_ia32el()) {
 239                printk("Please use IA-32 EL for executing IA-32 binaries\n");
 240                unregister_binfmt(&elf_format);
 241        }
 242        return 0;
 243}
 244
 245module_init(check_elf32_binfmt)
 246