MIPS: Enable heap randomization.
[sfrench/cifs-2.6.git] / arch / mips / kernel / syscall.c
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1995, 1996, 1997, 2000, 2001, 05 by Ralf Baechle
7  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8  * Copyright (C) 2001 MIPS Technologies, Inc.
9  */
10 #include <linux/capability.h>
11 #include <linux/errno.h>
12 #include <linux/linkage.h>
13 #include <linux/mm.h>
14 #include <linux/fs.h>
15 #include <linux/smp.h>
16 #include <linux/mman.h>
17 #include <linux/ptrace.h>
18 #include <linux/sched.h>
19 #include <linux/string.h>
20 #include <linux/syscalls.h>
21 #include <linux/file.h>
22 #include <linux/utsname.h>
23 #include <linux/unistd.h>
24 #include <linux/sem.h>
25 #include <linux/msg.h>
26 #include <linux/shm.h>
27 #include <linux/compiler.h>
28 #include <linux/module.h>
29 #include <linux/ipc.h>
30 #include <linux/uaccess.h>
31 #include <linux/slab.h>
32 #include <linux/random.h>
33 #include <linux/elf.h>
34
35 #include <asm/asm.h>
36 #include <asm/branch.h>
37 #include <asm/cachectl.h>
38 #include <asm/cacheflush.h>
39 #include <asm/asm-offsets.h>
40 #include <asm/signal.h>
41 #include <asm/sim.h>
42 #include <asm/shmparam.h>
43 #include <asm/sysmips.h>
44 #include <asm/uaccess.h>
45
46 /*
47  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
48  * convention.  It returns results in registers $v0 / $v1 which means there
49  * is no need for it to do verify the validity of a userspace pointer
50  * argument.  Historically that used to be expensive in Linux.  These days
51  * the performance advantage is negligible.
52  */
53 asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
54 {
55         int fd[2];
56         int error, res;
57
58         error = do_pipe_flags(fd, 0);
59         if (error) {
60                 res = error;
61                 goto out;
62         }
63         regs.regs[3] = fd[1];
64         res = fd[0];
65 out:
66         return res;
67 }
68
69 unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
70
71 EXPORT_SYMBOL(shm_align_mask);
72
73 #define COLOUR_ALIGN(addr,pgoff)                                \
74         ((((addr) + shm_align_mask) & ~shm_align_mask) +        \
75          (((pgoff) << PAGE_SHIFT) & shm_align_mask))
76
77 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
78         unsigned long len, unsigned long pgoff, unsigned long flags)
79 {
80         struct vm_area_struct * vmm;
81         int do_color_align;
82         unsigned long task_size;
83
84 #ifdef CONFIG_32BIT
85         task_size = TASK_SIZE;
86 #else /* Must be CONFIG_64BIT*/
87         task_size = test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE;
88 #endif
89
90         if (len > task_size)
91                 return -ENOMEM;
92
93         if (flags & MAP_FIXED) {
94                 /* Even MAP_FIXED mappings must reside within task_size.  */
95                 if (task_size - len < addr)
96                         return -EINVAL;
97
98                 /*
99                  * We do not accept a shared mapping if it would violate
100                  * cache aliasing constraints.
101                  */
102                 if ((flags & MAP_SHARED) &&
103                     ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
104                         return -EINVAL;
105                 return addr;
106         }
107
108         do_color_align = 0;
109         if (filp || (flags & MAP_SHARED))
110                 do_color_align = 1;
111         if (addr) {
112                 if (do_color_align)
113                         addr = COLOUR_ALIGN(addr, pgoff);
114                 else
115                         addr = PAGE_ALIGN(addr);
116                 vmm = find_vma(current->mm, addr);
117                 if (task_size - len >= addr &&
118                     (!vmm || addr + len <= vmm->vm_start))
119                         return addr;
120         }
121         addr = current->mm->mmap_base;
122         if (do_color_align)
123                 addr = COLOUR_ALIGN(addr, pgoff);
124         else
125                 addr = PAGE_ALIGN(addr);
126
127         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
128                 /* At this point:  (!vmm || addr < vmm->vm_end). */
129                 if (task_size - len < addr)
130                         return -ENOMEM;
131                 if (!vmm || addr + len <= vmm->vm_start)
132                         return addr;
133                 addr = vmm->vm_end;
134                 if (do_color_align)
135                         addr = COLOUR_ALIGN(addr, pgoff);
136         }
137 }
138
139 void arch_pick_mmap_layout(struct mm_struct *mm)
140 {
141         unsigned long random_factor = 0UL;
142
143         if (current->flags & PF_RANDOMIZE) {
144                 random_factor = get_random_int();
145                 random_factor = random_factor << PAGE_SHIFT;
146                 if (TASK_IS_32BIT_ADDR)
147                         random_factor &= 0xfffffful;
148                 else
149                         random_factor &= 0xffffffful;
150         }
151
152         mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
153         mm->get_unmapped_area = arch_get_unmapped_area;
154         mm->unmap_area = arch_unmap_area;
155 }
156
157 static inline unsigned long brk_rnd(void)
158 {
159         unsigned long rnd = get_random_int();
160
161         rnd = rnd << PAGE_SHIFT;
162         /* 8MB for 32bit, 256MB for 64bit */
163         if (TASK_IS_32BIT_ADDR)
164                 rnd = rnd & 0x7ffffful;
165         else
166                 rnd = rnd & 0xffffffful;
167
168         return rnd;
169 }
170
171 unsigned long arch_randomize_brk(struct mm_struct *mm)
172 {
173         unsigned long base = mm->brk;
174         unsigned long ret;
175
176         ret = PAGE_ALIGN(base + brk_rnd());
177
178         if (ret < mm->brk)
179                 return mm->brk;
180
181         return ret;
182 }
183
184 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
185         unsigned long, prot, unsigned long, flags, unsigned long,
186         fd, off_t, offset)
187 {
188         unsigned long result;
189
190         result = -EINVAL;
191         if (offset & ~PAGE_MASK)
192                 goto out;
193
194         result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
195
196 out:
197         return result;
198 }
199
200 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
201         unsigned long, prot, unsigned long, flags, unsigned long, fd,
202         unsigned long, pgoff)
203 {
204         if (pgoff & (~PAGE_MASK >> 12))
205                 return -EINVAL;
206
207         return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
208 }
209
210 save_static_function(sys_fork);
211 static int __used noinline
212 _sys_fork(nabi_no_regargs struct pt_regs regs)
213 {
214         return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
215 }
216
217 save_static_function(sys_clone);
218 static int __used noinline
219 _sys_clone(nabi_no_regargs struct pt_regs regs)
220 {
221         unsigned long clone_flags;
222         unsigned long newsp;
223         int __user *parent_tidptr, *child_tidptr;
224
225         clone_flags = regs.regs[4];
226         newsp = regs.regs[5];
227         if (!newsp)
228                 newsp = regs.regs[29];
229         parent_tidptr = (int __user *) regs.regs[6];
230 #ifdef CONFIG_32BIT
231         /* We need to fetch the fifth argument off the stack.  */
232         child_tidptr = NULL;
233         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
234                 int __user *__user *usp = (int __user *__user *) regs.regs[29];
235                 if (regs.regs[2] == __NR_syscall) {
236                         if (get_user (child_tidptr, &usp[5]))
237                                 return -EFAULT;
238                 }
239                 else if (get_user (child_tidptr, &usp[4]))
240                         return -EFAULT;
241         }
242 #else
243         child_tidptr = (int __user *) regs.regs[8];
244 #endif
245         return do_fork(clone_flags, newsp, &regs, 0,
246                        parent_tidptr, child_tidptr);
247 }
248
249 /*
250  * sys_execve() executes a new program.
251  */
252 asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
253 {
254         int error;
255         char * filename;
256
257         filename = getname((char __user *) (long)regs.regs[4]);
258         error = PTR_ERR(filename);
259         if (IS_ERR(filename))
260                 goto out;
261         error = do_execve(filename, (char __user *__user *) (long)regs.regs[5],
262                           (char __user *__user *) (long)regs.regs[6], &regs);
263         putname(filename);
264
265 out:
266         return error;
267 }
268
269 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
270 {
271         struct thread_info *ti = task_thread_info(current);
272
273         ti->tp_value = addr;
274         if (cpu_has_userlocal)
275                 write_c0_userlocal(addr);
276
277         return 0;
278 }
279
280 static inline int mips_atomic_set(struct pt_regs *regs,
281         unsigned long addr, unsigned long new)
282 {
283         unsigned long old, tmp;
284         unsigned int err;
285
286         if (unlikely(addr & 3))
287                 return -EINVAL;
288
289         if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
290                 return -EINVAL;
291
292         if (cpu_has_llsc && R10000_LLSC_WAR) {
293                 __asm__ __volatile__ (
294                 "       .set    mips3                                   \n"
295                 "       li      %[err], 0                               \n"
296                 "1:     ll      %[old], (%[addr])                       \n"
297                 "       move    %[tmp], %[new]                          \n"
298                 "2:     sc      %[tmp], (%[addr])                       \n"
299                 "       beqzl   %[tmp], 1b                              \n"
300                 "3:                                                     \n"
301                 "       .section .fixup,\"ax\"                          \n"
302                 "4:     li      %[err], %[efault]                       \n"
303                 "       j       3b                                      \n"
304                 "       .previous                                       \n"
305                 "       .section __ex_table,\"a\"                       \n"
306                 "       "STR(PTR)"      1b, 4b                          \n"
307                 "       "STR(PTR)"      2b, 4b                          \n"
308                 "       .previous                                       \n"
309                 "       .set    mips0                                   \n"
310                 : [old] "=&r" (old),
311                   [err] "=&r" (err),
312                   [tmp] "=&r" (tmp)
313                 : [addr] "r" (addr),
314                   [new] "r" (new),
315                   [efault] "i" (-EFAULT)
316                 : "memory");
317         } else if (cpu_has_llsc) {
318                 __asm__ __volatile__ (
319                 "       .set    mips3                                   \n"
320                 "       li      %[err], 0                               \n"
321                 "1:     ll      %[old], (%[addr])                       \n"
322                 "       move    %[tmp], %[new]                          \n"
323                 "2:     sc      %[tmp], (%[addr])                       \n"
324                 "       bnez    %[tmp], 4f                              \n"
325                 "3:                                                     \n"
326                 "       .subsection 2                                   \n"
327                 "4:     b       1b                                      \n"
328                 "       .previous                                       \n"
329                 "                                                       \n"
330                 "       .section .fixup,\"ax\"                          \n"
331                 "5:     li      %[err], %[efault]                       \n"
332                 "       j       3b                                      \n"
333                 "       .previous                                       \n"
334                 "       .section __ex_table,\"a\"                       \n"
335                 "       "STR(PTR)"      1b, 5b                          \n"
336                 "       "STR(PTR)"      2b, 5b                          \n"
337                 "       .previous                                       \n"
338                 "       .set    mips0                                   \n"
339                 : [old] "=&r" (old),
340                   [err] "=&r" (err),
341                   [tmp] "=&r" (tmp)
342                 : [addr] "r" (addr),
343                   [new] "r" (new),
344                   [efault] "i" (-EFAULT)
345                 : "memory");
346         } else {
347                 do {
348                         preempt_disable();
349                         ll_bit = 1;
350                         ll_task = current;
351                         preempt_enable();
352
353                         err = __get_user(old, (unsigned int *) addr);
354                         err |= __put_user(new, (unsigned int *) addr);
355                         if (err)
356                                 break;
357                         rmb();
358                 } while (!ll_bit);
359         }
360
361         if (unlikely(err))
362                 return err;
363
364         regs->regs[2] = old;
365         regs->regs[7] = 0;      /* No error */
366
367         /*
368          * Don't let your children do this ...
369          */
370         __asm__ __volatile__(
371         "       move    $29, %0                                         \n"
372         "       j       syscall_exit                                    \n"
373         : /* no outputs */
374         : "r" (regs));
375
376         /* unreached.  Honestly.  */
377         while (1);
378 }
379
380 save_static_function(sys_sysmips);
381 static int __used noinline
382 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
383 {
384         long cmd, arg1, arg2, arg3;
385
386         cmd = regs.regs[4];
387         arg1 = regs.regs[5];
388         arg2 = regs.regs[6];
389         arg3 = regs.regs[7];
390
391         switch (cmd) {
392         case MIPS_ATOMIC_SET:
393                 return mips_atomic_set(&regs, arg1, arg2);
394
395         case MIPS_FIXADE:
396                 if (arg1 & ~3)
397                         return -EINVAL;
398
399                 if (arg1 & 1)
400                         set_thread_flag(TIF_FIXADE);
401                 else
402                         clear_thread_flag(TIF_FIXADE);
403                 if (arg1 & 2)
404                         set_thread_flag(TIF_LOGADE);
405                 else
406                         clear_thread_flag(TIF_FIXADE);
407
408                 return 0;
409
410         case FLUSH_CACHE:
411                 __flush_cache_all();
412                 return 0;
413         }
414
415         return -EINVAL;
416 }
417
418 /*
419  * No implemented yet ...
420  */
421 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
422 {
423         return -ENOSYS;
424 }
425
426 /*
427  * If we ever come here the user sp is bad.  Zap the process right away.
428  * Due to the bad stack signaling wouldn't work.
429  */
430 asmlinkage void bad_stack(void)
431 {
432         do_exit(SIGSEGV);
433 }
434
435 /*
436  * Do a system call from kernel instead of calling sys_execve so we
437  * end up with proper pt_regs.
438  */
439 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
440 {
441         register unsigned long __a0 asm("$4") = (unsigned long) filename;
442         register unsigned long __a1 asm("$5") = (unsigned long) argv;
443         register unsigned long __a2 asm("$6") = (unsigned long) envp;
444         register unsigned long __a3 asm("$7");
445         unsigned long __v0;
446
447         __asm__ volatile ("                                     \n"
448         "       .set    noreorder                               \n"
449         "       li      $2, %5          # __NR_execve           \n"
450         "       syscall                                         \n"
451         "       move    %0, $2                                  \n"
452         "       .set    reorder                                 \n"
453         : "=&r" (__v0), "=r" (__a3)
454         : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
455         : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
456           "memory");
457
458         if (__a3 == 0)
459                 return __v0;
460
461         return -__v0;
462 }