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