Pileus Git - ~andy/linux/blob - 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/elf.h>
  21 #include <asm/pgtable.h>
  22 #include <asm/pgalloc.h>
  23 #include <asm/sections.h>
  24 #include <arch/sim_def.h>
  25
  26 /* Notify a running simulator, if any, that an exec just occurred. */
  27 static void sim_notify_exec(const char *binary_name)
  28 {
  29         unsigned char c;
  30         do {
  31                 c = *binary_name++;
  32                 __insn_mtspr(SPR_SIM_CONTROL,
  33                              (SIM_CONTROL_OS_EXEC
  34                               | (c << _SIM_CONTROL_OPERATOR_BITS)));
  35
  36         } while (c);
  37 }
  38
  39 static int notify_exec(struct mm_struct *mm)
  40 {
  41         int retval = 0;  /* failure */
  42
  43         if (mm->exe_file) {
  44                 char *buf = (char *) __get_free_page(GFP_KERNEL);
  45                 if (buf) {
  46                         char *path = d_path(&mm->exe_file->f_path,
  47                                             buf, PAGE_SIZE);
  48                         if (!IS_ERR(path)) {
  49                                 sim_notify_exec(path);
  50                                 retval = 1;
  51                         }
  52                         free_page((unsigned long)buf);
  53                 }
  54         }
  55         return retval;
  56 }
  57
  58 /* Notify a running simulator, if any, that we loaded an interpreter. */
  59 static void sim_notify_interp(unsigned long load_addr)
  60 {
  61         size_t i;
  62         for (i = 0; i < sizeof(load_addr); i++) {
  63                 unsigned char c = load_addr >> (i * 8);
  64                 __insn_mtspr(SPR_SIM_CONTROL,
  65                              (SIM_CONTROL_OS_INTERP
  66                               | (c << _SIM_CONTROL_OPERATOR_BITS)));
  67         }
  68 }
  69
  70
  71 /* Kernel address of page used to map read-only kernel data into userspace. */
  72 static void *vdso_page;
  73
  74 /* One-entry array used for install_special_mapping. */
  75 static struct page *vdso_pages[1];
  76
  77 static int __init vdso_setup(void)
  78 {
  79         vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
  80         memcpy(vdso_page, __rt_sigreturn, __rt_sigreturn_end - __rt_sigreturn);
  81         vdso_pages[0] = virt_to_page(vdso_page);
  82         return 0;
  83 }
  84 device_initcall(vdso_setup);
  85
  86 const char *arch_vma_name(struct vm_area_struct *vma)
  87 {
  88         if (vma->vm_private_data == vdso_pages)
  89                 return "[vdso]";
  90 #ifndef __tilegx__
  91         if (vma->vm_start == MEM_USER_INTRPT)
  92                 return "[intrpt]";
  93 #endif
  94         return NULL;
  95 }
  96
  97 int arch_setup_additional_pages(struct linux_binprm *bprm,
  98                                 int executable_stack)
  99 {
 100         struct mm_struct *mm = current->mm;
 101         unsigned long vdso_base;
 102         int retval = 0;
 103
 104         down_write(&mm->mmap_sem);
 105
 106         /*
 107          * Notify the simulator that an exec just occurred.
 108          * If we can't find the filename of the mapping, just use
 109          * whatever was passed as the linux_binprm filename.
 110          */
 111         if (!notify_exec(mm))
 112                 sim_notify_exec(bprm->filename);
 113
 114         /*
 115          * MAYWRITE to allow gdb to COW and set breakpoints
 116          */
 117         vdso_base = VDSO_BASE;
 118         retval = install_special_mapping(mm, vdso_base, PAGE_SIZE,
 119                                          VM_READ|VM_EXEC|
 120                                          VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
 121                                          vdso_pages);
 122
 123 #ifndef __tilegx__
 124         /*
 125          * Set up a user-interrupt mapping here; the user can't
 126          * create one themselves since it is above TASK_SIZE.
 127          * We make it unwritable by default, so the model for adding
 128          * interrupt vectors always involves an mprotect.
 129          */
 130         if (!retval) {
 131                 unsigned long addr = MEM_USER_INTRPT;
 132                 addr = mmap_region(NULL, addr, INTRPT_SIZE,
 133                                    VM_READ|VM_EXEC|
 134                                    VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 0);
 135                 if (addr > (unsigned long) -PAGE_SIZE)
 136                         retval = (int) addr;
 137         }
 138 #endif
 139
 140         up_write(&mm->mmap_sem);
 141
 142         return retval;
 143 }
 144
 145
 146 void elf_plat_init(struct pt_regs *regs, unsigned long load_addr)
 147 {
 148         /* Zero all registers. */
 149         memset(regs, 0, sizeof(*regs));
 150
 151         /* Report the interpreter's load address. */
 152         sim_notify_interp(load_addr);
 153 }