aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ia64/ia32/binfmt_elf32.c
blob: 4f0c30c38e994c1ea188f811232ecc27f7b81be1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
/*
 * IA-32 ELF support.
 *
 * Copyright (C) 1999 Arun Sharma <arun.sharma@intel.com>
 * Copyright (C) 2001 Hewlett-Packard Co
 *	David Mosberger-Tang <davidm@hpl.hp.com>
 *
 * 06/16/00	A. Mallick	initialize csd/ssd/tssd/cflg for ia32_load_state
 * 04/13/01	D. Mosberger	dropped saving tssd in ar.k1---it's not needed
 * 09/14/01	D. Mosberger	fixed memory management for gdt/tss page
 */

#include <linux/types.h>
#include <linux/mm.h>
#include <linux/security.h>

#include <asm/param.h>
#include <asm/signal.h>

#include "ia32priv.h"
#include "elfcore32.h"

/* Override some function names */
#undef start_thread
#define start_thread			ia32_start_thread
#define elf_format			elf32_format
#define init_elf_binfmt			init_elf32_binfmt
#define exit_elf_binfmt			exit_elf32_binfmt

#undef CLOCKS_PER_SEC
#define CLOCKS_PER_SEC	IA32_CLOCKS_PER_SEC

extern void ia64_elf32_init (struct pt_regs *regs);

static void elf32_set_personality (void);

static unsigned long __attribute ((unused))
randomize_stack_top(unsigned long stack_top);

#define setup_arg_pages(bprm,tos,exec)		ia32_setup_arg_pages(bprm,exec)
#define elf_map				elf32_map

#undef SET_PERSONALITY
#define SET_PERSONALITY(ex, ibcs2)	elf32_set_personality()

#define elf_read_implies_exec(ex, have_pt_gnu_stack)	(!(have_pt_gnu_stack))

/* Ugly but avoids duplication */
#include "../../../fs/binfmt_elf.c"

extern struct page *ia32_shared_page[];
extern unsigned long *ia32_gdt;
extern struct page *ia32_gate_page;

int
ia32_install_shared_page (struct vm_area_struct *vma, struct vm_fault *vmf)
{
	vmf->page = ia32_shared_page[smp_processor_id()];
	get_page(vmf->page);
	return 0;
}

int
ia32_install_gate_page (struct vm_area_struct *vma, struct vm_fault *vmf)
{
	vmf->page = ia32_gate_page;
	get_page(vmf->page);
	return 0;
}


static struct vm_operations_struct ia32_shared_page_vm_ops = {
	.fault = ia32_install_shared_page
};

static struct vm_operations_struct ia32_gate_page_vm_ops = {
	.fault = ia32_install_gate_page
};

void
ia64_elf32_init (struct pt_regs *regs)
{
	struct vm_area_struct *vma;

	/*
	 * Map GDT below 4GB, where the processor can find it.  We need to map
	 * it with privilege level 3 because the IVE uses non-privileged accesses to these
	 * tables.  IA-32 segmentation is used to protect against IA-32 accesses to them.
	 */
	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
	if (vma) {
		vma->vm_mm = current->mm;
		vma->vm_start = IA32_GDT_OFFSET;
		vma->vm_end = vma->vm_start + PAGE_SIZE;
		vma->vm_page_prot = PAGE_SHARED;
		vma->vm_flags = VM_READ|VM_MAYREAD|VM_RESERVED;
		vma->vm_ops = &ia32_shared_page_vm_ops;
		down_write(&current->mm->mmap_sem);
		{
			if (insert_vm_struct(current->mm, vma)) {
				kmem_cache_free(vm_area_cachep, vma);
				up_write(&current->mm->mmap_sem);
				BUG();
			}
		}
		up_write(&current->mm->mmap_sem);
	}

	/*
	 * When user stack is not executable, push sigreturn code to stack makes
	 * segmentation fault raised when returning to kernel. So now sigreturn
	 * code is locked in specific gate page, which is pointed by pretcode
	 * when setup_frame_ia32
	 */
	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
	if (vma) {
		vma->vm_mm = current->mm;
		vma->vm_start = IA32_GATE_OFFSET;
		vma->vm_end = vma->vm_start + PAGE_SIZE;
		vma->vm_page_prot = PAGE_COPY_EXEC;
		vma->vm_flags = VM_READ | VM_MAYREAD | VM_EXEC
				| VM_MAYEXEC | VM_RESERVED;
		vma->vm_ops = &ia32_gate_page_vm_ops;
		down_write(&current->mm->mmap_sem);
		{
			if (insert_vm_struct(current->mm, vma)) {
				kmem_cache_free(vm_area_cachep, vma);
				up_write(&current->mm->mmap_sem);
				BUG();
			}
		}
		up_write(&current->mm->mmap_sem);
	}

	/*
	 * Install LDT as anonymous memory.  This gives us all-zero segment descriptors
	 * until a task modifies them via modify_ldt().
	 */
	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
	if (vma) {
		vma->vm_mm = current->mm;
		vma->vm_start = IA32_LDT_OFFSET;
		vma->vm_end = vma->vm_start + PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
		vma->vm_page_prot = PAGE_SHARED;
		vma->vm_flags = VM_READ|VM_WRITE|VM_MAYREAD|VM_MAYWRITE;
		down_write(&current->mm->mmap_sem);
		{
			if (insert_vm_struct(current->mm, vma)) {
				kmem_cache_free(vm_area_cachep, vma);
				up_write(&current->mm->mmap_sem);
				BUG();
			}
		}
		up_write(&current->mm->mmap_sem);
	}

	ia64_psr(regs)->ac = 0;		/* turn off alignment checking */
	regs->loadrs = 0;
	/*
	 *  According to the ABI %edx points to an `atexit' handler.  Since we don't have
	 *  one we'll set it to 0 and initialize all the other registers just to make
	 *  things more deterministic, ala the i386 implementation.
	 */
	regs->r8 = 0;	/* %eax */
	regs->r11 = 0;	/* %ebx */
	regs->r9 = 0;	/* %ecx */
	regs->r10 = 0;	/* %edx */
	regs->r13 = 0;	/* %ebp */
	regs->r14 = 0;	/* %esi */
	regs->r15 = 0;	/* %edi */

	current->thread.eflag = IA32_EFLAG;
	current->thread.fsr = IA32_FSR_DEFAULT;
	current->thread.fcr = IA32_FCR_DEFAULT;
	current->thread.fir = 0;
	current->thread.fdr = 0;

	/*
	 * Setup GDTD.  Note: GDTD is the descrambled version of the pseudo-descriptor
	 * format defined by Figure 3-11 "Pseudo-Descriptor Format" in the IA-32
	 * architecture manual. Also note that the only fields that are not ignored are
	 * `base', `limit', 'G', `P' (must be 1) and `S' (must be 0).
	 */
	regs->r31 = IA32_SEG_UNSCRAMBLE(IA32_SEG_DESCRIPTOR(IA32_GDT_OFFSET, IA32_PAGE_SIZE - 1,
							    0, 0, 0, 1, 0, 0, 0));
	/* Setup the segment selectors */
	regs->r16 = (__USER_DS << 16) | __USER_DS; /* ES == DS, GS, FS are zero */
	regs->r17 = (__USER_DS << 16) | __USER_CS; /* SS, CS; ia32_load_state() sets TSS and LDT */

	ia32_load_segment_descriptors(current);
	ia32_load_state(current);
}

/*
 * Undo the override of setup_arg_pages() without this ia32_setup_arg_pages()
 * will suffer infinite self recursion.
 */
#undef setup_arg_pages

int
ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
{
	int ret;

	ret = setup_arg_pages(bprm, IA32_STACK_TOP, executable_stack);
	if (!ret) {
		/*
		 * Can't do it in ia64_elf32_init(). Needs to be done before
		 * calls to elf32_map()
		 */
		current->thread.ppl = ia32_init_pp_list();
	}

	return ret;
}

static void
elf32_set_personality (void)
{
	set_personality(PER_LINUX32);
	current->thread.map_base  = IA32_PAGE_OFFSET/3;
}

static unsigned long
elf32_map(struct file *filep, unsigned long addr, struct elf_phdr *eppnt,
		int prot, int type, unsigned long unused)
{
	unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;

	return ia32_do_mmap(filep, (addr & IA32_PAGE_MASK), eppnt->p_filesz + pgoff, prot, type,
			    eppnt->p_offset - pgoff);
}

#define cpu_uses_ia32el()	(local_cpu_data->family > 0x1f)

static int __init check_elf32_binfmt(void)
{
	if (cpu_uses_ia32el()) {
		printk("Please use IA-32 EL for executing IA-32 binaries\n");
		unregister_binfmt(&elf_format);
	}
	return 0;
}

module_init(check_elf32_binfmt)

Privacy Policy