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,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                         insert_vm_struct(current->mm, vma);
 104                 }
 105                 up_write(&current->mm->mmap_sem);
 106         }
 107
 108         /*
 109          * When user stack is not executable, push sigreturn code to stack makes
 110          * segmentation fault raised when returning to kernel. So now sigreturn
 111          * code is locked in specific gate page, which is pointed by pretcode
 112          * when setup_frame_ia32
 113          */
 114         vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 115         if (vma) {
 116                 memset(vma, 0, sizeof(*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                         insert_vm_struct(current->mm, vma);
 127                 }
 128                 up_write(&current->mm->mmap_sem);
 129         }
 130
 131         /*
 132          * Install LDT as anonymous memory.  This gives us all-zero segment descriptors
 133          * until a task modifies them via modify_ldt().
 134          */
 135         vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 136         if (vma) {
 137                 memset(vma, 0, sizeof(*vma));
 138                 vma->vm_mm = current->mm;
 139                 vma->vm_start = IA32_LDT_OFFSET;
 140                 vma->vm_end = vma->vm_start + PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
 141                 vma->vm_page_prot = PAGE_SHARED;
 142                 vma->vm_flags = VM_READ|VM_WRITE|VM_MAYREAD|VM_MAYWRITE;
 143                 down_write(&current->mm->mmap_sem);
 144                 {
 145                         insert_vm_struct(current->mm, vma);
 146                 }
 147                 up_write(&current->mm->mmap_sem);
 148         }
 149
 150         ia64_psr(regs)->ac = 0;         /* turn off alignment checking */
 151         regs->loadrs = 0;
 152         /*
 153          *  According to the ABI %edx points to an `atexit' handler.  Since we don't have
 154          *  one we'll set it to 0 and initialize all the other registers just to make
 155          *  things more deterministic, ala the i386 implementation.
 156          */
 157         regs->r8 = 0;   /* %eax */
 158         regs->r11 = 0;  /* %ebx */
 159         regs->r9 = 0;   /* %ecx */
 160         regs->r10 = 0;  /* %edx */
 161         regs->r13 = 0;  /* %ebp */
 162         regs->r14 = 0;  /* %esi */
 163         regs->r15 = 0;  /* %edi */
 164
 165         current->thread.eflag = IA32_EFLAG;
 166         current->thread.fsr = IA32_FSR_DEFAULT;
 167         current->thread.fcr = IA32_FCR_DEFAULT;
 168         current->thread.fir = 0;
 169         current->thread.fdr = 0;
 170
 171         /*
 172          * Setup GDTD.  Note: GDTD is the descrambled version of the pseudo-descriptor
 173          * format defined by Figure 3-11 "Pseudo-Descriptor Format" in the IA-32
 174          * architecture manual. Also note that the only fields that are not ignored are
 175          * `base', `limit', 'G', `P' (must be 1) and `S' (must be 0).
 176          */
 177         regs->r31 = IA32_SEG_UNSCRAMBLE(IA32_SEG_DESCRIPTOR(IA32_GDT_OFFSET, IA32_PAGE_SIZE - 1,
 178                                                             0, 0, 0, 1, 0, 0, 0));
 179         /* Setup the segment selectors */
 180         regs->r16 = (__USER_DS << 16) | __USER_DS; /* ES == DS, GS, FS are zero */
 181         regs->r17 = (__USER_DS << 16) | __USER_CS; /* SS, CS; ia32_load_state() sets TSS and LDT */
 182
 183         ia32_load_segment_descriptors(current);
 184         ia32_load_state(current);
 185 }
 186
 187 int
 188 ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
 189 {
 190         unsigned long stack_base;
 191         struct vm_area_struct *mpnt;
 192         struct mm_struct *mm = current->mm;
 193         int i;
 194
 195         stack_base = IA32_STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE;
 196         mm->arg_start = bprm->p + stack_base;
 197
 198         bprm->p += stack_base;
 199         if (bprm->loader)
 200                 bprm->loader += stack_base;
 201         bprm->exec += stack_base;
 202
 203         mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 204         if (!mpnt)
 205                 return -ENOMEM;
 206
 207         if (security_vm_enough_memory((IA32_STACK_TOP - (PAGE_MASK & (unsigned long) bprm->p))
 208                                       >> PAGE_SHIFT)) {
 209                 kmem_cache_free(vm_area_cachep, mpnt);
 210                 return -ENOMEM;
 211         }
 212
 213         memset(mpnt, 0, sizeof(*mpnt));
 214
 215         down_write(&current->mm->mmap_sem);
 216         {
 217                 mpnt->vm_mm = current->mm;
 218                 mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
 219                 mpnt->vm_end = IA32_STACK_TOP;
 220                 if (executable_stack == EXSTACK_ENABLE_X)
 221                         mpnt->vm_flags = VM_STACK_FLAGS |  VM_EXEC;
 222                 else if (executable_stack == EXSTACK_DISABLE_X)
 223                         mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
 224                 else
 225                         mpnt->vm_flags = VM_STACK_FLAGS;
 226                 mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC)?
 227                                         PAGE_COPY_EXEC: PAGE_COPY;
 228                 insert_vm_struct(current->mm, mpnt);
 229                 current->mm->stack_vm = current->mm->total_vm = vma_pages(mpnt);
 230         }
 231
 232         for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
 233                 struct page *page = bprm->page[i];
 234                 if (page) {
 235                         bprm->page[i] = NULL;
 236                         install_arg_page(mpnt, page, stack_base);
 237                 }
 238                 stack_base += PAGE_SIZE;
 239         }
 240         up_write(&current->mm->mmap_sem);
 241
 242         /* Can't do it in ia64_elf32_init(). Needs to be done before calls to
 243            elf32_map() */
 244         current->thread.ppl = ia32_init_pp_list();
 245
 246         return 0;
 247 }
 248
 249 static void
 250 elf32_set_personality (void)
 251 {
 252         set_personality(PER_LINUX32);
 253         current->thread.map_base  = IA32_PAGE_OFFSET/3;
 254         current->thread.task_size = IA32_PAGE_OFFSET;   /* use what Linux/x86 uses... */
 255         set_fs(USER_DS);                                /* set addr limit for new TASK_SIZE */
 256 }
 257
 258 static unsigned long
 259 elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
 260 {
 261         unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
 262
 263         return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
 264                             eppnt->p_offset - pgoff);
 265 }
 266
 267 #define cpu_uses_ia32el()       (local_cpu_data->family > 0x1f)
 268
 269 static int __init check_elf32_binfmt(void)
 270 {
 271         if (cpu_uses_ia32el()) {
 272                 printk("Please use IA-32 EL for executing IA-32 binaries\n");
 273                 return unregister_binfmt(&elf_format);
 274         }
 275         return 0;
 276 }
 277
 278 module_init(check_elf32_binfmt)