arch/tile/mm/elf.c

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  */
  14
  15 #include <linux/mm.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/binfmts.h>
  18 #include <linux/compat.h>
  19 #include <linux/mman.h>
  20 #include <linux/file.h>
  21 #include <linux/elf.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/pgalloc.h>
  24 #include <asm/sections.h>
  25 #include <asm/vdso.h>
  26 #include <arch/sim.h>
  27
  28 /* Notify a running simulator, if any, that an exec just occurred. */
  29 static void sim_notify_exec(const char *binary_name)
  30 {
  31         unsigned char c;
  32         do {
  33                 c = *binary_name++;
  34                 __insn_mtspr(SPR_SIM_CONTROL,
  35                              (SIM_CONTROL_OS_EXEC
  36                               | (c << _SIM_CONTROL_OPERATOR_BITS)));
  37
  38         } while (c);
  39 }
  40
  41 static int notify_exec(struct mm_struct *mm)
  42 {
  43         int ret = 0;
  44         char *buf, *path;
  45         struct vm_area_struct *vma;
  46         struct file *exe_file;
  47
  48         if (!sim_is_simulator())
  49                 return 1;
  50
  51         buf = (char *) __get_free_page(GFP_KERNEL);
  52         if (buf == NULL)
  53                 return 0;
  54
  55         exe_file = get_mm_exe_file(mm);
  56         if (exe_file == NULL)
  57                 goto done_free;
  58
  59         path = file_path(exe_file, buf, PAGE_SIZE);
  60         if (IS_ERR(path))
  61                 goto done_put;
  62
  63         down_read(&mm->mmap_sem);
  64         for (vma = current->mm->mmap; ; vma = vma->vm_next) {
  65                 if (vma == NULL) {
  66                         up_read(&mm->mmap_sem);
  67                         goto done_put;
  68                 }
  69                 if (vma->vm_file == exe_file)
  70                         break;
  71         }
  72
  73         /*
  74          * Notify simulator of an ET_DYN object so we know the load address.
  75          * The somewhat cryptic overuse of SIM_CONTROL_DLOPEN allows us
  76          * to be backward-compatible with older simulator releases.
  77          */
  78         if (vma->vm_start == (ELF_ET_DYN_BASE & PAGE_MASK)) {
  79                 char buf[64];
  80                 int i;
  81
  82                 snprintf(buf, sizeof(buf), "0x%lx:@", vma->vm_start);
  83                 for (i = 0; ; ++i) {
  84                         char c = buf[i];
  85                         __insn_mtspr(SPR_SIM_CONTROL,
  86                                      (SIM_CONTROL_DLOPEN
  87                                       | (c << _SIM_CONTROL_OPERATOR_BITS)));
  88                         if (c == '\0') {
  89                                 ret = 1; /* success */
  90                                 break;
  91                         }
  92                 }
  93         }
  94         up_read(&mm->mmap_sem);
  95
  96         sim_notify_exec(path);
  97 done_put:
  98         fput(exe_file);
  99 done_free:
 100         free_page((unsigned long)buf);
 101         return ret;
 102 }
 103
 104 /* Notify a running simulator, if any, that we loaded an interpreter. */
 105 static void sim_notify_interp(unsigned long load_addr)
 106 {
 107         size_t i;
 108         for (i = 0; i < sizeof(load_addr); i++) {
 109                 unsigned char c = load_addr >> (i * 8);
 110                 __insn_mtspr(SPR_SIM_CONTROL,
 111                              (SIM_CONTROL_OS_INTERP
 112                               | (c << _SIM_CONTROL_OPERATOR_BITS)));
 113         }
 114 }
 115
 116
 117 int arch_setup_additional_pages(struct linux_binprm *bprm,
 118                                 int executable_stack)
 119 {
 120         struct mm_struct *mm = current->mm;
 121         int retval = 0;
 122
 123         /*
 124          * Notify the simulator that an exec just occurred.
 125          * If we can't find the filename of the mapping, just use
 126          * whatever was passed as the linux_binprm filename.
 127          */
 128         if (!notify_exec(mm))
 129                 sim_notify_exec(bprm->filename);
 130
 131         down_write(&mm->mmap_sem);
 132
 133         retval = setup_vdso_pages();
 134
 135 #ifndef __tilegx__
 136         /*
 137          * Set up a user-interrupt mapping here; the user can't
 138          * create one themselves since it is above TASK_SIZE.
 139          * We make it unwritable by default, so the model for adding
 140          * interrupt vectors always involves an mprotect.
 141          */
 142         if (!retval) {
 143                 unsigned long addr = MEM_USER_INTRPT;
 144                 addr = mmap_region(NULL, addr, INTRPT_SIZE,
 145                                    VM_READ|VM_EXEC|
 146                                    VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 0);
 147                 if (addr > (unsigned long) -PAGE_SIZE)
 148                         retval = (int) addr;
 149         }
 150 #endif
 151
 152         up_write(&mm->mmap_sem);
 153
 154         return retval;
 155 }
 156
 157
 158 void elf_plat_init(struct pt_regs *regs, unsigned long load_addr)
 159 {
 160         /* Zero all registers. */
 161         memset(regs, 0, sizeof(*regs));
 162
 163         /* Report the interpreter's load address. */
 164         sim_notify_interp(load_addr);
 165 }