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 #define setup_arg_pages(bprm,tos,exec)          ia32_setup_arg_pages(bprm,exec)
  39 #define elf_map                         elf32_map
  40
  41 #undef SET_PERSONALITY
  42 #define SET_PERSONALITY(ex, ibcs2)      elf32_set_personality()
  43
  44 #define elf_read_implies_exec(ex, have_pt_gnu_stack)    (!(have_pt_gnu_stack))
  45
  46 /* Ugly but avoids duplication */
  47 #include "../../../fs/binfmt_elf.c"
  48
  49 extern struct page *ia32_shared_page[];
  50 extern unsigned long *ia32_gdt;
  51 extern struct page *ia32_gate_page;
  52
  53 struct page *
  54 ia32_install_shared_page (struct vm_area_struct *vma, unsigned long address, int *type)
  55 {
  56         struct page *pg = ia32_shared_page[smp_processor_id()];
  57         get_page(pg);
  58         if (type)
  59                 *type = VM_FAULT_MINOR;
  60         return pg;
  61 }
  62
  63 struct page *
  64 ia32_install_gate_page (struct vm_area_struct *vma, unsigned long address, int *type)
  65 {
  66         struct page *pg = ia32_gate_page;
  67         get_page(pg);
  68         if (type)
  69                 *type = VM_FAULT_MINOR;
  70         return pg;
  71 }
  72
  73
  74 static struct vm_operations_struct ia32_shared_page_vm_ops = {
  75         .nopage = ia32_install_shared_page
  76 };
  77
  78 static struct vm_operations_struct ia32_gate_page_vm_ops = {
  79         .nopage = ia32_install_gate_page
  80 };
  81
  82 void
  83 ia64_elf32_init (struct pt_regs *regs)
  84 {
  85         struct vm_area_struct *vma;
  86
  87         /*
  88          * Map GDT below 4GB, where the processor can find it.  We need to map
  89          * it with privilege level 3 because the IVE uses non-privileged accesses to these
  90          * tables.  IA-32 segmentation is used to protect against IA-32 accesses to them.
  91          */
  92         vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
  93         if (vma) {
  94                 memset(vma, 0, sizeof(*vma));
  95                 vma->vm_mm = current->mm;
  96                 vma->vm_start = IA32_GDT_OFFSET;
  97                 vma->vm_end = vma->vm_start + PAGE_SIZE;
  98                 vma->vm_page_prot = PAGE_SHARED;
  99                 vma->vm_flags = VM_READ|VM_MAYREAD|VM_RESERVED;
 100                 vma->vm_ops = &ia32_shared_page_vm_ops;
 101                 down_write(&current->mm->mmap_sem);
 102                 {
 103                         if (insert_vm_struct(current->mm, vma)) {
 104                                 kmem_cache_free(vm_area_cachep, vma);
 105                                 up_write(&current->mm->mmap_sem);
 106                                 BUG();
 107                         }
 108                 }
 109                 up_write(&current->mm->mmap_sem);
 110         }
 111
 112         /*
 113          * When user stack is not executable, push sigreturn code to stack makes
 114          * segmentation fault raised when returning to kernel. So now sigreturn
 115          * code is locked in specific gate page, which is pointed by pretcode
 116          * when setup_frame_ia32
 117          */
 118         vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 119         if (vma) {
 120                 memset(vma, 0, sizeof(*vma));
 121                 vma->vm_mm = current->mm;
 122                 vma->vm_start = IA32_GATE_OFFSET;
 123                 vma->vm_end = vma->vm_start + PAGE_SIZE;
 124                 vma->vm_page_prot = PAGE_COPY_EXEC;
 125                 vma->vm_flags = VM_READ | VM_MAYREAD | VM_EXEC
 126                                 | VM_MAYEXEC | VM_RESERVED;
 127                 vma->vm_ops = &ia32_gate_page_vm_ops;
 128                 down_write(&current->mm->mmap_sem);
 129                 {
 130                         if (insert_vm_struct(current->mm, vma)) {
 131                                 kmem_cache_free(vm_area_cachep, vma);
 132                                 up_write(&current->mm->mmap_sem);
 133                                 BUG();
 134                         }
 135                 }
 136                 up_write(&current->mm->mmap_sem);
 137         }
 138
 139         /*
 140          * Install LDT as anonymous memory.  This gives us all-zero segment descriptors
 141          * until a task modifies them via modify_ldt().
 142          */
 143         vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 144         if (vma) {
 145                 memset(vma, 0, sizeof(*vma));
 146                 vma->vm_mm = current->mm;
 147                 vma->vm_start = IA32_LDT_OFFSET;
 148                 vma->vm_end = vma->vm_start + PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
 149                 vma->vm_page_prot = PAGE_SHARED;
 150                 vma->vm_flags = VM_READ|VM_WRITE|VM_MAYREAD|VM_MAYWRITE;
 151                 down_write(&current->mm->mmap_sem);
 152                 {
 153                         if (insert_vm_struct(current->mm, vma)) {
 154                                 kmem_cache_free(vm_area_cachep, vma);
 155                                 up_write(&current->mm->mmap_sem);
 156                                 BUG();
 157                         }
 158                 }
 159                 up_write(&current->mm->mmap_sem);
 160         }
 161
 162         ia64_psr(regs)->ac = 0;         /* turn off alignment checking */
 163         regs->loadrs = 0;
 164         /*
 165          *  According to the ABI %edx points to an `atexit' handler.  Since we don't have
 166          *  one we'll set it to 0 and initialize all the other registers just to make
 167          *  things more deterministic, ala the i386 implementation.
 168          */
 169         regs->r8 = 0;   /* %eax */
 170         regs->r11 = 0;  /* %ebx */
 171         regs->r9 = 0;   /* %ecx */
 172         regs->r10 = 0;  /* %edx */
 173         regs->r13 = 0;  /* %ebp */
 174         regs->r14 = 0;  /* %esi */
 175         regs->r15 = 0;  /* %edi */
 176
 177         current->thread.eflag = IA32_EFLAG;
 178         current->thread.fsr = IA32_FSR_DEFAULT;
 179         current->thread.fcr = IA32_FCR_DEFAULT;
 180         current->thread.fir = 0;
 181         current->thread.fdr = 0;
 182
 183         /*
 184          * Setup GDTD.  Note: GDTD is the descrambled version of the pseudo-descriptor
 185          * format defined by Figure 3-11 "Pseudo-Descriptor Format" in the IA-32
 186          * architecture manual. Also note that the only fields that are not ignored are
 187          * `base', `limit', 'G', `P' (must be 1) and `S' (must be 0).
 188          */
 189         regs->r31 = IA32_SEG_UNSCRAMBLE(IA32_SEG_DESCRIPTOR(IA32_GDT_OFFSET, IA32_PAGE_SIZE - 1,
 190                                                             0, 0, 0, 1, 0, 0, 0));
 191         /* Setup the segment selectors */
 192         regs->r16 = (__USER_DS << 16) | __USER_DS; /* ES == DS, GS, FS are zero */
 193         regs->r17 = (__USER_DS << 16) | __USER_CS; /* SS, CS; ia32_load_state() sets TSS and LDT */
 194
 195         ia32_load_segment_descriptors(current);
 196         ia32_load_state(current);
 197 }
 198
 199 int
 200 ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
 201 {
 202         unsigned long stack_base;
 203         struct vm_area_struct *mpnt;
 204         struct mm_struct *mm = current->mm;
 205         int i, ret;
 206
 207         stack_base = IA32_STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE;
 208         mm->arg_start = bprm->p + stack_base;
 209
 210         bprm->p += stack_base;
 211         if (bprm->loader)
 212                 bprm->loader += stack_base;
 213         bprm->exec += stack_base;
 214
 215         mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 216         if (!mpnt)
 217                 return -ENOMEM;
 218
 219         if (security_vm_enough_memory((IA32_STACK_TOP - (PAGE_MASK & (unsigned long) bprm->p))
 220                                       >> PAGE_SHIFT)) {
 221                 kmem_cache_free(vm_area_cachep, mpnt);
 222                 return -ENOMEM;
 223         }
 224
 225         memset(mpnt, 0, sizeof(*mpnt));
 226
 227         down_write(&current->mm->mmap_sem);
 228         {
 229                 mpnt->vm_mm = current->mm;
 230                 mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
 231                 mpnt->vm_end = IA32_STACK_TOP;
 232                 if (executable_stack == EXSTACK_ENABLE_X)
 233                         mpnt->vm_flags = VM_STACK_FLAGS |  VM_EXEC;
 234                 else if (executable_stack == EXSTACK_DISABLE_X)
 235                         mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
 236                 else
 237                         mpnt->vm_flags = VM_STACK_FLAGS;
 238                 mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC)?
 239                                         PAGE_COPY_EXEC: PAGE_COPY;
 240                 if ((ret = insert_vm_struct(current->mm, mpnt))) {
 241                         up_write(&current->mm->mmap_sem);
 242                         kmem_cache_free(vm_area_cachep, mpnt);
 243                         return ret;
 244                 }
 245                 current->mm->stack_vm = current->mm->total_vm = vma_pages(mpnt);
 246         }
 247
 248         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
 249                 struct page *page = bprm->page[i];
 250                 if (page) {
 251                         bprm->page[i] = NULL;
 252                         install_arg_page(mpnt, page, stack_base);
 253                 }
 254                 stack_base += PAGE_SIZE;
 255         }
 256         up_write(&current->mm->mmap_sem);
 257
 258         /* Can't do it in ia64_elf32_init(). Needs to be done before calls to
 259            elf32_map() */
 260         current->thread.ppl = ia32_init_pp_list();
 261
 262         return 0;
 263 }
 264
 265 static void
 266 elf32_set_personality (void)
 267 {
 268         set_personality(PER_LINUX32);
 269         current->thread.map_base  = IA32_PAGE_OFFSET/3;
 270         current->thread.task_size = IA32_PAGE_OFFSET;   /* use what Linux/x86 uses... */
 271         set_fs(USER_DS);                                /* set addr limit for new TASK_SIZE */
 272 }
 273
 274 static unsigned long
 275 elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
 276 {
 277         unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
 278
 279         return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
 280                             eppnt->p_offset - pgoff);
 281 }
 282
 283 #define cpu_uses_ia32el()       (local_cpu_data->family > 0x1f)
 284
 285 static int __init check_elf32_binfmt(void)
 286 {
 287         if (cpu_uses_ia32el()) {
 288                 printk("Please use IA-32 EL for executing IA-32 binaries\n");
 289                 return unregister_binfmt(&elf_format);
 290         }
 291         return 0;
 292 }
 293
 294 module_init(check_elf32_binfmt)