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 int
  56 ia32_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
  63 int
  64 ia32_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
  72 static struct vm_operations_struct ia32_shared_page_vm_ops = {
  73         .fault = ia32_install_shared_page
  74 };
  75
  76 static struct vm_operations_struct ia32_gate_page_vm_ops = {
  77         .fault = ia32_install_gate_page
  78 };
  79
  80 void
  81 ia64_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
 200 int
 201 ia32_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
 217 static void
 218 elf32_set_personality (void)
 219 {
 220         set_personality(PER_LINUX32);
 221         current->thread.map_base  = IA32_PAGE_OFFSET/3;
 222 }
 223
 224 static unsigned long
 225 elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
 226 {
 227         unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
 228
 229         return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
 230                             eppnt->p_offset - pgoff);
 231 }
 232
 233 #define cpu_uses_ia32el()       (local_cpu_data->family > 0x1f)
 234
 235 static int __init check_elf32_binfmt(void)
 236 {
 237         if (cpu_uses_ia32el()) {
 238                 printk("Please use IA-32 EL for executing IA-32 binaries\n");
 239                 unregister_binfmt(&elf_format);
 240         }
 241         return 0;
 242 }
 243
 244 module_init(check_elf32_binfmt)