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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
34extern void ia64_elf32_init (struct pt_regs *regs);
35
36static void elf32_set_personality (void);
37
38#define setup_arg_pages(bprm,tos,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
49extern struct page *ia32_shared_page[];
50extern unsigned long *ia32_gdt;
51extern struct page *ia32_gate_page;
52
53struct page *
54ia32_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
63struct page *
64ia32_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
74static struct vm_operations_struct ia32_shared_page_vm_ops = {
75 .nopage = ia32_install_shared_page
76};
77
78static struct vm_operations_struct ia32_gate_page_vm_ops = {
79 .nopage = ia32_install_gate_page
80};
81
82void
83ia64_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 if (insert_vm_struct(current->mm, vma)) {
104 kmem_cache_free(vm_area_cachep, vma);
105 up_write(&current->mm->mmap_sem);
106 BUG();
107 }
108 }
109 up_write(&current->mm->mmap_sem);
110 }
111
112 /*
113 * When user stack is not executable, push sigreturn code to stack makes
114 * segmentation fault raised when returning to kernel. So now sigreturn
115 * code is locked in specific gate page, which is pointed by pretcode
116 * when setup_frame_ia32
117 */
118 vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
119 if (vma) {
120 memset(vma, 0, sizeof(*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_alloc(vm_area_cachep, SLAB_KERNEL);
144 if (vma) {
145 memset(vma, 0, sizeof(*vma));
146 vma->vm_mm = current->mm;
147 vma->vm_start = IA32_LDT_OFFSET;
148 vma->vm_end = vma->vm_start + PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
149 vma->vm_page_prot = PAGE_SHARED;
150 vma->vm_flags = VM_READ|VM_WRITE|VM_MAYREAD|VM_MAYWRITE;
151 down_write(&current->mm->mmap_sem);
152 {
153 if (insert_vm_struct(current->mm, vma)) {
154 kmem_cache_free(vm_area_cachep, vma);
155 up_write(&current->mm->mmap_sem);
156 BUG();
157 }
158 }
159 up_write(&current->mm->mmap_sem);
160 }
161
162 ia64_psr(regs)->ac = 0; /* turn off alignment checking */
163 regs->loadrs = 0;
164 /*
165 * According to the ABI %edx points to an `atexit' handler. Since we don't have
166 * one we'll set it to 0 and initialize all the other registers just to make
167 * things more deterministic, ala the i386 implementation.
168 */
169 regs->r8 = 0; /* %eax */
170 regs->r11 = 0; /* %ebx */
171 regs->r9 = 0; /* %ecx */
172 regs->r10 = 0; /* %edx */
173 regs->r13 = 0; /* %ebp */
174 regs->r14 = 0; /* %esi */
175 regs->r15 = 0; /* %edi */
176
177 current->thread.eflag = IA32_EFLAG;
178 current->thread.fsr = IA32_FSR_DEFAULT;
179 current->thread.fcr = IA32_FCR_DEFAULT;
180 current->thread.fir = 0;
181 current->thread.fdr = 0;
182
183 /*
184 * Setup GDTD. Note: GDTD is the descrambled version of the pseudo-descriptor
185 * format defined by Figure 3-11 "Pseudo-Descriptor Format" in the IA-32
186 * architecture manual. Also note that the only fields that are not ignored are
187 * `base', `limit', 'G', `P' (must be 1) and `S' (must be 0).
188 */
189 regs->r31 = IA32_SEG_UNSCRAMBLE(IA32_SEG_DESCRIPTOR(IA32_GDT_OFFSET, IA32_PAGE_SIZE - 1,
190 0, 0, 0, 1, 0, 0, 0));
191 /* Setup the segment selectors */
192 regs->r16 = (__USER_DS << 16) | __USER_DS; /* ES == DS, GS, FS are zero */
193 regs->r17 = (__USER_DS << 16) | __USER_CS; /* SS, CS; ia32_load_state() sets TSS and LDT */
194
195 ia32_load_segment_descriptors(current);
196 ia32_load_state(current);
197}
198
199int
200ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
201{
202 unsigned long stack_base;
203 struct vm_area_struct *mpnt;
204 struct mm_struct *mm = current->mm;
205 int i, ret;
206
207 stack_base = IA32_STACK_TOP - MAX_ARG_PAGES*PAGE_SIZE;
208 mm->arg_start = bprm->p + stack_base;
209
210 bprm->p += stack_base;
211 if (bprm->loader)
212 bprm->loader += stack_base;
213 bprm->exec += stack_base;
214
215 mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
216 if (!mpnt)
217 return -ENOMEM;
218
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 memset(mpnt, 0, sizeof(*mpnt));
220
221 down_write(&current->mm->mmap_sem);
222 {
223 mpnt->vm_mm = current->mm;
224 mpnt->vm_start = PAGE_MASK & (unsigned long) bprm->p;
225 mpnt->vm_end = IA32_STACK_TOP;
226 if (executable_stack == EXSTACK_ENABLE_X)
227 mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
228 else if (executable_stack == EXSTACK_DISABLE_X)
229 mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
230 else
231 mpnt->vm_flags = VM_STACK_FLAGS;
232 mpnt->vm_page_prot = (mpnt->vm_flags & VM_EXEC)?
233 PAGE_COPY_EXEC: PAGE_COPY;
234 if ((ret = insert_vm_struct(current->mm, mpnt))) {
235 up_write(&current->mm->mmap_sem);
236 kmem_cache_free(vm_area_cachep, mpnt);
237 return ret;
238 }
239 current->mm->stack_vm = current->mm->total_vm = vma_pages(mpnt);
240 }
241
242 for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
243 struct page *page = bprm->page[i];
244 if (page) {
245 bprm->page[i] = NULL;
246 install_arg_page(mpnt, page, stack_base);
247 }
248 stack_base += PAGE_SIZE;
249 }
250 up_write(&current->mm->mmap_sem);
251
252 /* Can't do it in ia64_elf32_init(). Needs to be done before calls to
253 elf32_map() */
254 current->thread.ppl = ia32_init_pp_list();
255
256 return 0;
257}
258
259static void
260elf32_set_personality (void)
261{
262 set_personality(PER_LINUX32);
263 current->thread.map_base = IA32_PAGE_OFFSET/3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264}
265
266static unsigned long
267elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
268{
269 unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
270
271 return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
272 eppnt->p_offset - pgoff);
273}
274
275#define cpu_uses_ia32el() (local_cpu_data->family > 0x1f)
276
277static int __init check_elf32_binfmt(void)
278{
279 if (cpu_uses_ia32el()) {
280 printk("Please use IA-32 EL for executing IA-32 binaries\n");
281 return unregister_binfmt(&elf_format);
282 }
283 return 0;
284}
285
286module_init(check_elf32_binfmt)