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) 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
ia32_install_shared_page(struct vm_area_struct * vma,struct vm_fault * vmf)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
ia32_install_gate_page(struct vm_area_struct * vma,struct vm_fault * vmf)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
ia64_elf32_init(struct pt_regs * regs)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(¤t->mm->mmap_sem);
99 {
100 if (insert_vm_struct(current->mm, vma)) {
101 kmem_cache_free(vm_area_cachep, vma);
102 up_write(¤t->mm->mmap_sem);
103 BUG();
104 }
105 }
106 up_write(¤t->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(¤t->mm->mmap_sem);
125 {
126 if (insert_vm_struct(current->mm, vma)) {
127 kmem_cache_free(vm_area_cachep, vma);
128 up_write(¤t->mm->mmap_sem);
129 BUG();
130 }
131 }
132 up_write(¤t->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(¤t->mm->mmap_sem);
147 {
148 if (insert_vm_struct(current->mm, vma)) {
149 kmem_cache_free(vm_area_cachep, vma);
150 up_write(¤t->mm->mmap_sem);
151 BUG();
152 }
153 }
154 up_write(¤t->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
ia32_setup_arg_pages(struct linux_binprm * bprm,int executable_stack)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
elf32_set_personality(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
elf32_map(struct file * filep,unsigned long addr,struct elf_phdr * eppnt,int prot,int type,unsigned long unused)225 elf32_map(struct file *filep, unsigned long addr, struct elf_phdr *eppnt,
226 int prot, int type, unsigned long unused)
227 {
228 unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
229
230 return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
231 eppnt->p_offset - pgoff);
232 }
233
234 #define cpu_uses_ia32el() (local_cpu_data->family > 0x1f)
235
check_elf32_binfmt(void)236 static int __init check_elf32_binfmt(void)
237 {
238 if (cpu_uses_ia32el()) {
239 printk("Please use IA-32 EL for executing IA-32 binaries\n");
240 unregister_binfmt(&elf_format);
241 }
242 return 0;
243 }
244
245 module_init(check_elf32_binfmt)
246