mm: variable length argument support
[linux-2.6.git] / 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 struct page *
56 ia32_install_shared_page (struct vm_area_struct *vma, unsigned long address, int *type)
57 {
58         struct page *pg = ia32_shared_page[smp_processor_id()];
59         get_page(pg);
60         if (type)
61                 *type = VM_FAULT_MINOR;
62         return pg;
63 }
64
65 struct page *
66 ia32_install_gate_page (struct vm_area_struct *vma, unsigned long address, int *type)
67 {
68         struct page *pg = ia32_gate_page;
69         get_page(pg);
70         if (type)
71                 *type = VM_FAULT_MINOR;
72         return pg;
73 }
74
75
76 static struct vm_operations_struct ia32_shared_page_vm_ops = {
77         .nopage = ia32_install_shared_page
78 };
79
80 static struct vm_operations_struct ia32_gate_page_vm_ops = {
81         .nopage = ia32_install_gate_page
82 };
83
84 void
85 ia64_elf32_init (struct pt_regs *regs)
86 {
87         struct vm_area_struct *vma;
88
89         /*
90          * Map GDT below 4GB, where the processor can find it.  We need to map
91          * it with privilege level 3 because the IVE uses non-privileged accesses to these
92          * tables.  IA-32 segmentation is used to protect against IA-32 accesses to them.
93          */
94         vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
95         if (vma) {
96                 vma->vm_mm = current->mm;
97                 vma->vm_start = IA32_GDT_OFFSET;
98                 vma->vm_end = vma->vm_start + PAGE_SIZE;
99                 vma->vm_page_prot = PAGE_SHARED;
100                 vma->vm_flags = VM_READ|VM_MAYREAD|VM_RESERVED;
101                 vma->vm_ops = &ia32_shared_page_vm_ops;
102                 down_write(&current->mm->mmap_sem);
103                 {
104                         if (insert_vm_struct(current->mm, vma)) {
105                                 kmem_cache_free(vm_area_cachep, vma);
106                                 up_write(&current->mm->mmap_sem);
107                                 BUG();
108                         }
109                 }
110                 up_write(&current->mm->mmap_sem);
111         }
112
113         /*
114          * When user stack is not executable, push sigreturn code to stack makes
115          * segmentation fault raised when returning to kernel. So now sigreturn
116          * code is locked in specific gate page, which is pointed by pretcode
117          * when setup_frame_ia32
118          */
119         vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
120         if (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_zalloc(vm_area_cachep, GFP_KERNEL);
144         if (vma) {
145                 vma->vm_mm = current->mm;
146                 vma->vm_start = IA32_LDT_OFFSET;
147                 vma->vm_end = vma->vm_start + PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
148                 vma->vm_page_prot = PAGE_SHARED;
149                 vma->vm_flags = VM_READ|VM_WRITE|VM_MAYREAD|VM_MAYWRITE;
150                 down_write(&current->mm->mmap_sem);
151                 {
152                         if (insert_vm_struct(current->mm, vma)) {
153                                 kmem_cache_free(vm_area_cachep, vma);
154                                 up_write(&current->mm->mmap_sem);
155                                 BUG();
156                         }
157                 }
158                 up_write(&current->mm->mmap_sem);
159         }
160
161         ia64_psr(regs)->ac = 0;         /* turn off alignment checking */
162         regs->loadrs = 0;
163         /*
164          *  According to the ABI %edx points to an `atexit' handler.  Since we don't have
165          *  one we'll set it to 0 and initialize all the other registers just to make
166          *  things more deterministic, ala the i386 implementation.
167          */
168         regs->r8 = 0;   /* %eax */
169         regs->r11 = 0;  /* %ebx */
170         regs->r9 = 0;   /* %ecx */
171         regs->r10 = 0;  /* %edx */
172         regs->r13 = 0;  /* %ebp */
173         regs->r14 = 0;  /* %esi */
174         regs->r15 = 0;  /* %edi */
175
176         current->thread.eflag = IA32_EFLAG;
177         current->thread.fsr = IA32_FSR_DEFAULT;
178         current->thread.fcr = IA32_FCR_DEFAULT;
179         current->thread.fir = 0;
180         current->thread.fdr = 0;
181
182         /*
183          * Setup GDTD.  Note: GDTD is the descrambled version of the pseudo-descriptor
184          * format defined by Figure 3-11 "Pseudo-Descriptor Format" in the IA-32
185          * architecture manual. Also note that the only fields that are not ignored are
186          * `base', `limit', 'G', `P' (must be 1) and `S' (must be 0).
187          */
188         regs->r31 = IA32_SEG_UNSCRAMBLE(IA32_SEG_DESCRIPTOR(IA32_GDT_OFFSET, IA32_PAGE_SIZE - 1,
189                                                             0, 0, 0, 1, 0, 0, 0));
190         /* Setup the segment selectors */
191         regs->r16 = (__USER_DS << 16) | __USER_DS; /* ES == DS, GS, FS are zero */
192         regs->r17 = (__USER_DS << 16) | __USER_CS; /* SS, CS; ia32_load_state() sets TSS and LDT */
193
194         ia32_load_segment_descriptors(current);
195         ia32_load_state(current);
196 }
197
198 /*
199  * Undo the override of setup_arg_pages() without this ia32_setup_arg_pages()
200  * will suffer infinite self recursion.
201  */
202 #undef setup_arg_pages
203
204 int
205 ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
206 {
207         int ret;
208
209         ret = setup_arg_pages(bprm, IA32_STACK_TOP, executable_stack);
210         if (!ret) {
211                 /*
212                  * Can't do it in ia64_elf32_init(). Needs to be done before
213                  * calls to elf32_map()
214                  */
215                 current->thread.ppl = ia32_init_pp_list();
216         }
217
218         return ret;
219 }
220
221 static void
222 elf32_set_personality (void)
223 {
224         set_personality(PER_LINUX32);
225         current->thread.map_base  = IA32_PAGE_OFFSET/3;
226 }
227
228 static unsigned long
229 elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type, unsigned long unused)
230 {
231         unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
232
233         return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
234                             eppnt->p_offset - pgoff);
235 }
236
237 #define cpu_uses_ia32el()       (local_cpu_data->family > 0x1f)
238
239 static int __init check_elf32_binfmt(void)
240 {
241         if (cpu_uses_ia32el()) {
242                 printk("Please use IA-32 EL for executing IA-32 binaries\n");
243                 return unregister_binfmt(&elf_format);
244         }
245         return 0;
246 }
247
248 module_init(check_elf32_binfmt)