arch/ia64/ia32/binfmt_elf32.c

   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 #include <linux/config.h>
  13
  14 #include <linux/types.h>
  15 #include <linux/mm.h>
  16 #include <linux/security.h>
  17
  18 #include <asm/param.h>
  19 #include <asm/signal.h>
  20
  21 #include "ia32priv.h"
  22 #include "elfcore32.h"
  23
  24 /* Override some function names */
  25 #undef start_thread
  26 #define start_thread                    ia32_start_thread
  27 #define elf_format                      elf32_format
  28 #define init_elf_binfmt                 init_elf32_binfmt
  29 #define exit_elf_binfmt                 exit_elf32_binfmt
  30
  31 #undef CLOCKS_PER_SEC
  32 #define CLOCKS_PER_SEC  IA32_CLOCKS_PER_SEC
  33
  34 extern void ia64_elf32_init (struct pt_regs *regs);
  35
  36 static void elf32_set_personality (void);
  37
  38 static unsigned long __attribute ((unused))
  39 randomize_stack_top(unsigned long stack_top);
  40
  41 #define setup_arg_pages(bprm,tos,exec)          ia32_setup_arg_pages(bprm,exec)
  42 #define elf_map                         elf32_map
  43
  44 #undef SET_PERSONALITY
  45 #define SET_PERSONALITY(ex, ibcs2)      elf32_set_personality()
  46
  47 #define elf_read_implies_exec(ex, have_pt_gnu_stack)    (!(have_pt_gnu_stack))
  48
  49 /* Ugly but avoids duplication */
  50 #include "../../../fs/binfmt_elf.c"
  51
  52 extern struct page *ia32_shared_page[];
  53 extern unsigned long *ia32_gdt;
  54 extern struct page *ia32_gate_page;
  55
  56 struct page *
  57 ia32_install_shared_page (struct vm_area_struct *vma, unsigned long address, int *type)
  58 {
  59         struct page *pg = ia32_shared_page[smp_processor_id()];
  60         get_page(pg);
  61         if (type)
  62                 *type = VM_FAULT_MINOR;
  63         return pg;
  64 }
  65
  66 struct page *
  67 ia32_install_gate_page (struct vm_area_struct *vma, unsigned long address, int *type)
  68 {
  69         struct page *pg = ia32_gate_page;
  70         get_page(pg);
  71         if (type)
  72                 *type = VM_FAULT_MINOR;
  73         return pg;
  74 }
  75
  76
  77 static struct vm_operations_struct ia32_shared_page_vm_ops = {
  78         .nopage = ia32_install_shared_page
  79 };
  80
  81 static struct vm_operations_struct ia32_gate_page_vm_ops = {
  82         .nopage = ia32_install_gate_page
  83 };
  84
  85 void
  86 ia64_elf32_init (struct pt_regs *regs)
  87 {
  88         struct vm_area_struct *vma;
  89
  90         /*
  91          * Map GDT below 4GB, where the processor can find it.  We need to map
  92          * it with privilege level 3 because the IVE uses non-privileged accesses to these
  93          * tables.  IA-32 segmentation is used to protect against IA-32 accesses to them.
  94          */
  95         vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
  96         if (vma) {
  97                 memset(vma, 0, sizeof(*vma));
  98                 vma->vm_mm = current->mm;
  99                 vma->vm_start = IA32_GDT_OFFSET;
 100                 vma->vm_end = vma->vm_start + PAGE_SIZE;
 101                 vma->vm_page_prot = PAGE_SHARED;
 102                 vma->vm_flags = VM_READ|VM_MAYREAD|VM_RESERVED;
 103                 vma->vm_ops = &ia32_shared_page_vm_ops;
 104                 down_write(&current->mm->mmap_sem);
 105                 {
 106                         if (insert_vm_struct(current->mm, vma)) {
 107                                 kmem_cache_free(vm_area_cachep, vma);
 108                                 up_write(&current->mm->mmap_sem);
 109                                 BUG();
 110                         }
 111                 }
 112                 up_write(&current->mm->mmap_sem);
 113         }
 114
 115         /*
 116          * When user stack is not executable, push sigreturn code to stack makes
 117          * segmentation fault raised when returning to kernel. So now sigreturn
 118          * code is locked in specific gate page, which is pointed by pretcode
 119          * when setup_frame_ia32
 120          */
 121         vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 122         if (vma) {
 123                 memset(vma, 0, sizeof(*vma));
 124                 vma->vm_mm = current->mm;
 125                 vma->vm_start = IA32_GATE_OFFSET;
 126                 vma->vm_end = vma->vm_start + PAGE_SIZE;
 127                 vma->vm_page_prot = PAGE_COPY_EXEC;
 128                 vma->vm_flags = VM_READ | VM_MAYREAD | VM_EXEC
 129                                 | VM_MAYEXEC | VM_RESERVED;
 130                 vma->vm_ops = &ia32_gate_page_vm_ops;
 131                 down_write(&current->mm->mmap_sem);
 132                 {
 133                         if (insert_vm_struct(current->mm, vma)) {
 134                                 kmem_cache_free(vm_area_cachep, vma);
 135                                 up_write(&current->mm->mmap_sem);
 136                                 BUG();
 137                         }
 138                 }
 139                 up_write(&current->mm->mmap_sem);
 140         }
 141
 142         /*
 143          * Install LDT as anonymous memory.  This gives us all-zero segment descriptors
 144          * until a task modifies them via modify_ldt().
 145          */
 146         vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 147         if (vma) {
 148                 memset(vma, 0, sizeof(*vma));
 149                 vma->vm_mm = current->mm;
 150                 vma->vm_start = IA32_LDT_OFFSET;
 151                 vma->vm_end = vma->vm_start + PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
 152                 vma->vm_page_prot = PAGE_SHARED;
 153                 vma->vm_flags = VM_READ|VM_WRITE|VM_MAYREAD|VM_MAYWRITE;
 154                 down_write(&current->mm->mmap_sem);
 155                 {
 156                         if (insert_vm_struct(current->mm, vma)) {
 157                                 kmem_cache_free(vm_area_cachep, vma);
 158                                 up_write(&current->mm->mmap_sem);
 159                                 BUG();
 160                         }
 161                 }
 162                 up_write(&current->mm->mmap_sem);
 163         }
 164
 165         ia64_psr(regs)->ac = 0;         /* turn off alignment checking */
 166         regs->loadrs = 0;
 167         /*
 168          *  According to the ABI %edx points to an `atexit' handler.  Since we don't have
 169          *  one we'll set it to 0 and initialize all the other registers just to make
 170          *  things more deterministic, ala the i386 implementation.
 171          */
 172         regs->r8 = 0;   /* %eax */
 173         regs->r11 = 0;  /* %ebx */
 174         regs->r9 = 0;   /* %ecx */
 175         regs->r10 = 0;  /* %edx */
 176         regs->r13 = 0;  /* %ebp */
 177         regs->r14 = 0;  /* %esi */
 178         regs->r15 = 0;  /* %edi */
 179
 180         current->thread.eflag = IA32_EFLAG;
 181         current->thread.fsr = IA32_FSR_DEFAULT;
 182         current->thread.fcr = IA32_FCR_DEFAULT;
 183         current->thread.fir = 0;
 184         current->thread.fdr = 0;
 185
 186         /*
 187          * Setup GDTD.  Note: GDTD is the descrambled version of the pseudo-descriptor
 188          * format defined by Figure 3-11 "Pseudo-Descriptor Format" in the IA-32
 189          * architecture manual. Also note that the only fields that are not ignored are
 190          * `base', `limit', 'G', `P' (must be 1) and `S' (must be 0).
 191          */
 192         regs->r31 = IA32_SEG_UNSCRAMBLE(IA32_SEG_DESCRIPTOR(IA32_GDT_OFFSET, IA32_PAGE_SIZE - 1,
 193                                                             0, 0, 0, 1, 0, 0, 0));
 194         /* Setup the segment selectors */
 195         regs->r16 = (__USER_DS << 16) | __USER_DS; /* ES == DS, GS, FS are zero */
 196         regs->r17 = (__USER_DS << 16) | __USER_CS; /* SS, CS; ia32_load_state() sets TSS and LDT */
 197
 198         ia32_load_segment_descriptors(current);
 199         ia32_load_state(current);
 200 }
 201
 202 int
 203 ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
 204 {
 205         unsigned long stack_base;
 206         struct vm_area_struct *mpnt;
 207         struct mm_struct *mm = current->mm;
 208         int i, ret;
 209
 210         stack_base = IA32_STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE;
 211         mm->arg_start = bprm->p + stack_base;
 212
 213         bprm->p += stack_base;
 214         if (bprm->loader)
 215                 bprm->loader += stack_base;
 216         bprm->exec += stack_base;
 217
 218         mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 219         if (!mpnt)
 220                 return -ENOMEM;
 221
 222         memset(mpnt, 0, sizeof(*mpnt));
 223
 224         down_write(&current->mm->mmap_sem);
 225         {
 226                 mpnt->vm_mm = current->mm;
 227                 mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
 228                 mpnt->vm_end = IA32_STACK_TOP;
 229                 if (executable_stack == EXSTACK_ENABLE_X)
 230                         mpnt->vm_flags = VM_STACK_FLAGS |  VM_EXEC;
 231                 else if (executable_stack == EXSTACK_DISABLE_X)
 232                         mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
 233                 else
 234                         mpnt->vm_flags = VM_STACK_FLAGS;
 235                 mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC)?
 236                                         PAGE_COPY_EXEC: PAGE_COPY;
 237                 if ((ret = insert_vm_struct(current->mm, mpnt))) {
 238                         up_write(&current->mm->mmap_sem);
 239                         kmem_cache_free(vm_area_cachep, mpnt);
 240                         return ret;
 241                 }
 242                 current->mm->stack_vm = current->mm->total_vm = vma_pages(mpnt);
 243         }
 244
 245         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
 246                 struct page *page = bprm->page[i];
 247                 if (page) {
 248                         bprm->page[i] = NULL;
 249                         install_arg_page(mpnt, page, stack_base);
 250                 }
 251                 stack_base += PAGE_SIZE;
 252         }
 253         up_write(&current->mm->mmap_sem);
 254
 255         /* Can't do it in ia64_elf32_init(). Needs to be done before calls to
 256            elf32_map() */
 257         current->thread.ppl = ia32_init_pp_list();
 258
 259         return 0;
 260 }
 261
 262 static void
 263 elf32_set_personality (void)
 264 {
 265         set_personality(PER_LINUX32);
 266         current->thread.map_base  = IA32_PAGE_OFFSET/3;
 267 }
 268
 269 static unsigned long
 270 elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
 271 {
 272         unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
 273
 274         return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
 275                             eppnt->p_offset - pgoff);
 276 }
 277
 278 #define cpu_uses_ia32el()       (local_cpu_data->family > 0x1f)
 279
 280 static int __init check_elf32_binfmt(void)
 281 {
 282         if (cpu_uses_ia32el()) {
 283                 printk("Please use IA-32 EL for executing IA-32 binaries\n");
 284                 return unregister_binfmt(&elf_format);
 285         }
 286         return 0;
 287 }
 288
 289 module_init(check_elf32_binfmt)