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Diffstat (limited to 'arch/x86/vdso/vdso32-setup.c')
-rw-r--r--arch/x86/vdso/vdso32-setup.c301
1 files changed, 81 insertions, 220 deletions
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index d6bfb876cfb0..00348980a3a6 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -16,6 +16,7 @@
16#include <linux/mm.h> 16#include <linux/mm.h>
17#include <linux/err.h> 17#include <linux/err.h>
18#include <linux/module.h> 18#include <linux/module.h>
19#include <linux/slab.h>
19 20
20#include <asm/cpufeature.h> 21#include <asm/cpufeature.h>
21#include <asm/msr.h> 22#include <asm/msr.h>
@@ -25,17 +26,14 @@
25#include <asm/tlbflush.h> 26#include <asm/tlbflush.h>
26#include <asm/vdso.h> 27#include <asm/vdso.h>
27#include <asm/proto.h> 28#include <asm/proto.h>
28 29#include <asm/fixmap.h>
29enum { 30#include <asm/hpet.h>
30 VDSO_DISABLED = 0, 31#include <asm/vvar.h>
31 VDSO_ENABLED = 1,
32 VDSO_COMPAT = 2,
33};
34 32
35#ifdef CONFIG_COMPAT_VDSO 33#ifdef CONFIG_COMPAT_VDSO
36#define VDSO_DEFAULT VDSO_COMPAT 34#define VDSO_DEFAULT 0
37#else 35#else
38#define VDSO_DEFAULT VDSO_ENABLED 36#define VDSO_DEFAULT 1
39#endif 37#endif
40 38
41#ifdef CONFIG_X86_64 39#ifdef CONFIG_X86_64
@@ -44,13 +42,6 @@ enum {
44#endif 42#endif
45 43
46/* 44/*
47 * This is the difference between the prelinked addresses in the vDSO images
48 * and the VDSO_HIGH_BASE address where CONFIG_COMPAT_VDSO places the vDSO
49 * in the user address space.
50 */
51#define VDSO_ADDR_ADJUST (VDSO_HIGH_BASE - (unsigned long)VDSO32_PRELINK)
52
53/*
54 * Should the kernel map a VDSO page into processes and pass its 45 * Should the kernel map a VDSO page into processes and pass its
55 * address down to glibc upon exec()? 46 * address down to glibc upon exec()?
56 */ 47 */
@@ -60,6 +51,9 @@ static int __init vdso_setup(char *s)
60{ 51{
61 vdso_enabled = simple_strtoul(s, NULL, 0); 52 vdso_enabled = simple_strtoul(s, NULL, 0);
62 53
54 if (vdso_enabled > 1)
55 pr_warn("vdso32 values other than 0 and 1 are no longer allowed; vdso disabled\n");
56
63 return 1; 57 return 1;
64} 58}
65 59
@@ -76,124 +70,8 @@ __setup_param("vdso=", vdso32_setup, vdso_setup, 0);
76EXPORT_SYMBOL_GPL(vdso_enabled); 70EXPORT_SYMBOL_GPL(vdso_enabled);
77#endif 71#endif
78 72
79static __init void reloc_symtab(Elf32_Ehdr *ehdr, 73static struct page **vdso32_pages;
80 unsigned offset, unsigned size) 74static unsigned vdso32_size;
81{
82 Elf32_Sym *sym = (void *)ehdr + offset;
83 unsigned nsym = size / sizeof(*sym);
84 unsigned i;
85
86 for(i = 0; i < nsym; i++, sym++) {
87 if (sym->st_shndx == SHN_UNDEF ||
88 sym->st_shndx == SHN_ABS)
89 continue; /* skip */
90
91 if (sym->st_shndx > SHN_LORESERVE) {
92 printk(KERN_INFO "VDSO: unexpected st_shndx %x\n",
93 sym->st_shndx);
94 continue;
95 }
96
97 switch(ELF_ST_TYPE(sym->st_info)) {
98 case STT_OBJECT:
99 case STT_FUNC:
100 case STT_SECTION:
101 case STT_FILE:
102 sym->st_value += VDSO_ADDR_ADJUST;
103 }
104 }
105}
106
107static __init void reloc_dyn(Elf32_Ehdr *ehdr, unsigned offset)
108{
109 Elf32_Dyn *dyn = (void *)ehdr + offset;
110
111 for(; dyn->d_tag != DT_NULL; dyn++)
112 switch(dyn->d_tag) {
113 case DT_PLTGOT:
114 case DT_HASH:
115 case DT_STRTAB:
116 case DT_SYMTAB:
117 case DT_RELA:
118 case DT_INIT:
119 case DT_FINI:
120 case DT_REL:
121 case DT_DEBUG:
122 case DT_JMPREL:
123 case DT_VERSYM:
124 case DT_VERDEF:
125 case DT_VERNEED:
126 case DT_ADDRRNGLO ... DT_ADDRRNGHI:
127 /* definitely pointers needing relocation */
128 dyn->d_un.d_ptr += VDSO_ADDR_ADJUST;
129 break;
130
131 case DT_ENCODING ... OLD_DT_LOOS-1:
132 case DT_LOOS ... DT_HIOS-1:
133 /* Tags above DT_ENCODING are pointers if
134 they're even */
135 if (dyn->d_tag >= DT_ENCODING &&
136 (dyn->d_tag & 1) == 0)
137 dyn->d_un.d_ptr += VDSO_ADDR_ADJUST;
138 break;
139
140 case DT_VERDEFNUM:
141 case DT_VERNEEDNUM:
142 case DT_FLAGS_1:
143 case DT_RELACOUNT:
144 case DT_RELCOUNT:
145 case DT_VALRNGLO ... DT_VALRNGHI:
146 /* definitely not pointers */
147 break;
148
149 case OLD_DT_LOOS ... DT_LOOS-1:
150 case DT_HIOS ... DT_VALRNGLO-1:
151 default:
152 if (dyn->d_tag > DT_ENCODING)
153 printk(KERN_INFO "VDSO: unexpected DT_tag %x\n",
154 dyn->d_tag);
155 break;
156 }
157}
158
159static __init void relocate_vdso(Elf32_Ehdr *ehdr)
160{
161 Elf32_Phdr *phdr;
162 Elf32_Shdr *shdr;
163 int i;
164
165 BUG_ON(memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0 ||
166 !elf_check_arch_ia32(ehdr) ||
167 ehdr->e_type != ET_DYN);
168
169 ehdr->e_entry += VDSO_ADDR_ADJUST;
170
171 /* rebase phdrs */
172 phdr = (void *)ehdr + ehdr->e_phoff;
173 for (i = 0; i < ehdr->e_phnum; i++) {
174 phdr[i].p_vaddr += VDSO_ADDR_ADJUST;
175
176 /* relocate dynamic stuff */
177 if (phdr[i].p_type == PT_DYNAMIC)
178 reloc_dyn(ehdr, phdr[i].p_offset);
179 }
180
181 /* rebase sections */
182 shdr = (void *)ehdr + ehdr->e_shoff;
183 for(i = 0; i < ehdr->e_shnum; i++) {
184 if (!(shdr[i].sh_flags & SHF_ALLOC))
185 continue;
186
187 shdr[i].sh_addr += VDSO_ADDR_ADJUST;
188
189 if (shdr[i].sh_type == SHT_SYMTAB ||
190 shdr[i].sh_type == SHT_DYNSYM)
191 reloc_symtab(ehdr, shdr[i].sh_offset,
192 shdr[i].sh_size);
193 }
194}
195
196static struct page *vdso32_pages[1];
197 75
198#ifdef CONFIG_X86_64 76#ifdef CONFIG_X86_64
199 77
@@ -212,12 +90,6 @@ void syscall32_cpu_init(void)
212 wrmsrl(MSR_CSTAR, ia32_cstar_target); 90 wrmsrl(MSR_CSTAR, ia32_cstar_target);
213} 91}
214 92
215#define compat_uses_vma 1
216
217static inline void map_compat_vdso(int map)
218{
219}
220
221#else /* CONFIG_X86_32 */ 93#else /* CONFIG_X86_32 */
222 94
223#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SEP)) 95#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SEP))
@@ -241,64 +113,36 @@ void enable_sep_cpu(void)
241 put_cpu(); 113 put_cpu();
242} 114}
243 115
244static struct vm_area_struct gate_vma;
245
246static int __init gate_vma_init(void)
247{
248 gate_vma.vm_mm = NULL;
249 gate_vma.vm_start = FIXADDR_USER_START;
250 gate_vma.vm_end = FIXADDR_USER_END;
251 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
252 gate_vma.vm_page_prot = __P101;
253
254 return 0;
255}
256
257#define compat_uses_vma 0
258
259static void map_compat_vdso(int map)
260{
261 static int vdso_mapped;
262
263 if (map == vdso_mapped)
264 return;
265
266 vdso_mapped = map;
267
268 __set_fixmap(FIX_VDSO, page_to_pfn(vdso32_pages[0]) << PAGE_SHIFT,
269 map ? PAGE_READONLY_EXEC : PAGE_NONE);
270
271 /* flush stray tlbs */
272 flush_tlb_all();
273}
274
275#endif /* CONFIG_X86_64 */ 116#endif /* CONFIG_X86_64 */
276 117
277int __init sysenter_setup(void) 118int __init sysenter_setup(void)
278{ 119{
279 void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC); 120 char *vdso32_start, *vdso32_end;
280 const void *vsyscall; 121 int npages, i;
281 size_t vsyscall_len;
282
283 vdso32_pages[0] = virt_to_page(syscall_page);
284
285#ifdef CONFIG_X86_32
286 gate_vma_init();
287#endif
288 122
123#ifdef CONFIG_COMPAT
289 if (vdso32_syscall()) { 124 if (vdso32_syscall()) {
290 vsyscall = &vdso32_syscall_start; 125 vdso32_start = vdso32_syscall_start;
291 vsyscall_len = &vdso32_syscall_end - &vdso32_syscall_start; 126 vdso32_end = vdso32_syscall_end;
292 } else if (vdso32_sysenter()){ 127 vdso32_pages = vdso32_syscall_pages;
293 vsyscall = &vdso32_sysenter_start; 128 } else
294 vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start; 129#endif
130 if (vdso32_sysenter()) {
131 vdso32_start = vdso32_sysenter_start;
132 vdso32_end = vdso32_sysenter_end;
133 vdso32_pages = vdso32_sysenter_pages;
295 } else { 134 } else {
296 vsyscall = &vdso32_int80_start; 135 vdso32_start = vdso32_int80_start;
297 vsyscall_len = &vdso32_int80_end - &vdso32_int80_start; 136 vdso32_end = vdso32_int80_end;
137 vdso32_pages = vdso32_int80_pages;
298 } 138 }
299 139
300 memcpy(syscall_page, vsyscall, vsyscall_len); 140 npages = ((vdso32_end - vdso32_start) + PAGE_SIZE - 1) / PAGE_SIZE;
301 relocate_vdso(syscall_page); 141 vdso32_size = npages << PAGE_SHIFT;
142 for (i = 0; i < npages; i++)
143 vdso32_pages[i] = virt_to_page(vdso32_start + i*PAGE_SIZE);
144
145 patch_vdso32(vdso32_start, vdso32_size);
302 146
303 return 0; 147 return 0;
304} 148}
@@ -309,48 +153,73 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
309 struct mm_struct *mm = current->mm; 153 struct mm_struct *mm = current->mm;
310 unsigned long addr; 154 unsigned long addr;
311 int ret = 0; 155 int ret = 0;
312 bool compat; 156 struct vm_area_struct *vma;
313 157
314#ifdef CONFIG_X86_X32_ABI 158#ifdef CONFIG_X86_X32_ABI
315 if (test_thread_flag(TIF_X32)) 159 if (test_thread_flag(TIF_X32))
316 return x32_setup_additional_pages(bprm, uses_interp); 160 return x32_setup_additional_pages(bprm, uses_interp);
317#endif 161#endif
318 162
319 if (vdso_enabled == VDSO_DISABLED) 163 if (vdso_enabled != 1) /* Other values all mean "disabled" */
320 return 0; 164 return 0;
321 165
322 down_write(&mm->mmap_sem); 166 down_write(&mm->mmap_sem);
323 167
324 /* Test compat mode once here, in case someone 168 addr = get_unmapped_area(NULL, 0, vdso32_size + VDSO_OFFSET(VDSO_PREV_PAGES), 0, 0);
325 changes it via sysctl */ 169 if (IS_ERR_VALUE(addr)) {
326 compat = (vdso_enabled == VDSO_COMPAT); 170 ret = addr;
171 goto up_fail;
172 }
173
174 addr += VDSO_OFFSET(VDSO_PREV_PAGES);
327 175
328 map_compat_vdso(compat); 176 current->mm->context.vdso = (void *)addr;
329 177
330 if (compat) 178 /*
331 addr = VDSO_HIGH_BASE; 179 * MAYWRITE to allow gdb to COW and set breakpoints
332 else { 180 */
333 addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0); 181 ret = install_special_mapping(mm,
334 if (IS_ERR_VALUE(addr)) { 182 addr,
335 ret = addr; 183 vdso32_size,
336 goto up_fail; 184 VM_READ|VM_EXEC|
337 } 185 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
186 vdso32_pages);
187
188 if (ret)
189 goto up_fail;
190
191 vma = _install_special_mapping(mm,
192 addr - VDSO_OFFSET(VDSO_PREV_PAGES),
193 VDSO_OFFSET(VDSO_PREV_PAGES),
194 VM_READ,
195 NULL);
196
197 if (IS_ERR(vma)) {
198 ret = PTR_ERR(vma);
199 goto up_fail;
338 } 200 }
339 201
340 current->mm->context.vdso = (void *)addr; 202 ret = remap_pfn_range(vma,
203 addr - VDSO_OFFSET(VDSO_VVAR_PAGE),
204 __pa_symbol(&__vvar_page) >> PAGE_SHIFT,
205 PAGE_SIZE,
206 PAGE_READONLY);
207
208 if (ret)
209 goto up_fail;
341 210
342 if (compat_uses_vma || !compat) { 211#ifdef CONFIG_HPET_TIMER
343 /* 212 if (hpet_address) {
344 * MAYWRITE to allow gdb to COW and set breakpoints 213 ret = io_remap_pfn_range(vma,
345 */ 214 addr - VDSO_OFFSET(VDSO_HPET_PAGE),
346 ret = install_special_mapping(mm, addr, PAGE_SIZE, 215 hpet_address >> PAGE_SHIFT,
347 VM_READ|VM_EXEC| 216 PAGE_SIZE,
348 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 217 pgprot_noncached(PAGE_READONLY));
349 vdso32_pages);
350 218
351 if (ret) 219 if (ret)
352 goto up_fail; 220 goto up_fail;
353 } 221 }
222#endif
354 223
355 current_thread_info()->sysenter_return = 224 current_thread_info()->sysenter_return =
356 VDSO32_SYMBOL(addr, SYSENTER_RETURN); 225 VDSO32_SYMBOL(addr, SYSENTER_RETURN);
@@ -411,20 +280,12 @@ const char *arch_vma_name(struct vm_area_struct *vma)
411 280
412struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 281struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
413{ 282{
414 /*
415 * Check to see if the corresponding task was created in compat vdso
416 * mode.
417 */
418 if (mm && mm->context.vdso == (void *)VDSO_HIGH_BASE)
419 return &gate_vma;
420 return NULL; 283 return NULL;
421} 284}
422 285
423int in_gate_area(struct mm_struct *mm, unsigned long addr) 286int in_gate_area(struct mm_struct *mm, unsigned long addr)
424{ 287{
425 const struct vm_area_struct *vma = get_gate_vma(mm); 288 return 0;
426
427 return vma && addr >= vma->vm_start && addr < vma->vm_end;
428} 289}
429 290
430int in_gate_area_no_mm(unsigned long addr) 291int in_gate_area_no_mm(unsigned long addr)