9824a829f61d7ae76ac8cdb945fdc4fe623973bc
[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
34 #include <asm/asm.h>
35 #include <asm/branch.h>
36 #include <asm/cachectl.h>
37 #include <asm/cacheflush.h>
38 #include <asm/asm-offsets.h>
39 #include <asm/signal.h>
40 #include <asm/sim.h>
41 #include <asm/shmparam.h>
42 #include <asm/sysmips.h>
43 #include <asm/uaccess.h>
44
45 /*
46  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
47  * convention.  It returns results in registers $v0 / $v1 which means there
48  * is no need for it to do verify the validity of a userspace pointer
49  * argument.  Historically that used to be expensive in Linux.  These days
50  * the performance advantage is negligible.
51  */
52 asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
53 {
54         int fd[2];
55         int error, res;
56
57         error = do_pipe_flags(fd, 0);
58         if (error) {
59                 res = error;
60                 goto out;
61         }
62         regs.regs[3] = fd[1];
63         res = fd[0];
64 out:
65         return res;
66 }
67
68 unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane caches */
69
70 EXPORT_SYMBOL(shm_align_mask);
71
72 #define COLOUR_ALIGN(addr,pgoff)                                \
73         ((((addr) + shm_align_mask) & ~shm_align_mask) +        \
74          (((pgoff) << PAGE_SHIFT) & shm_align_mask))
75
76 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
77         unsigned long len, unsigned long pgoff, unsigned long flags)
78 {
79         struct vm_area_struct * vmm;
80         int do_color_align;
81         unsigned long task_size;
82
83 #ifdef CONFIG_32BIT
84         task_size = TASK_SIZE;
85 #else /* Must be CONFIG_64BIT*/
86         task_size = test_thread_flag(TIF_32BIT_ADDR) ? TASK_SIZE32 : TASK_SIZE;
87 #endif
88
89         if (len > task_size)
90                 return -ENOMEM;
91
92         if (flags & MAP_FIXED) {
93                 /* Even MAP_FIXED mappings must reside within task_size.  */
94                 if (task_size - len < addr)
95                         return -EINVAL;
96
97                 /*
98                  * We do not accept a shared mapping if it would violate
99                  * cache aliasing constraints.
100                  */
101                 if ((flags & MAP_SHARED) &&
102                     ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
103                         return -EINVAL;
104                 return addr;
105         }
106
107         do_color_align = 0;
108         if (filp || (flags & MAP_SHARED))
109                 do_color_align = 1;
110         if (addr) {
111                 if (do_color_align)
112                         addr = COLOUR_ALIGN(addr, pgoff);
113                 else
114                         addr = PAGE_ALIGN(addr);
115                 vmm = find_vma(current->mm, addr);
116                 if (task_size - len >= addr &&
117                     (!vmm || addr + len <= vmm->vm_start))
118                         return addr;
119         }
120         addr = current->mm->mmap_base;
121         if (do_color_align)
122                 addr = COLOUR_ALIGN(addr, pgoff);
123         else
124                 addr = PAGE_ALIGN(addr);
125
126         for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
127                 /* At this point:  (!vmm || addr < vmm->vm_end). */
128                 if (task_size - len < addr)
129                         return -ENOMEM;
130                 if (!vmm || addr + len <= vmm->vm_start)
131                         return addr;
132                 addr = vmm->vm_end;
133                 if (do_color_align)
134                         addr = COLOUR_ALIGN(addr, pgoff);
135         }
136 }
137
138 void arch_pick_mmap_layout(struct mm_struct *mm)
139 {
140         unsigned long random_factor = 0UL;
141
142         if (current->flags & PF_RANDOMIZE) {
143                 random_factor = get_random_int();
144                 random_factor = random_factor << PAGE_SHIFT;
145                 if (TASK_IS_32BIT_ADDR)
146                         random_factor &= 0xfffffful;
147                 else
148                         random_factor &= 0xffffffful;
149         }
150
151         mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
152         mm->get_unmapped_area = arch_get_unmapped_area;
153         mm->unmap_area = arch_unmap_area;
154 }
155
156 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
157         unsigned long, prot, unsigned long, flags, unsigned long,
158         fd, off_t, offset)
159 {
160         unsigned long result;
161
162         result = -EINVAL;
163         if (offset & ~PAGE_MASK)
164                 goto out;
165
166         result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
167
168 out:
169         return result;
170 }
171
172 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
173         unsigned long, prot, unsigned long, flags, unsigned long, fd,
174         unsigned long, pgoff)
175 {
176         if (pgoff & (~PAGE_MASK >> 12))
177                 return -EINVAL;
178
179         return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
180 }
181
182 save_static_function(sys_fork);
183 static int __used noinline
184 _sys_fork(nabi_no_regargs struct pt_regs regs)
185 {
186         return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
187 }
188
189 save_static_function(sys_clone);
190 static int __used noinline
191 _sys_clone(nabi_no_regargs struct pt_regs regs)
192 {
193         unsigned long clone_flags;
194         unsigned long newsp;
195         int __user *parent_tidptr, *child_tidptr;
196
197         clone_flags = regs.regs[4];
198         newsp = regs.regs[5];
199         if (!newsp)
200                 newsp = regs.regs[29];
201         parent_tidptr = (int __user *) regs.regs[6];
202 #ifdef CONFIG_32BIT
203         /* We need to fetch the fifth argument off the stack.  */
204         child_tidptr = NULL;
205         if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
206                 int __user *__user *usp = (int __user *__user *) regs.regs[29];
207                 if (regs.regs[2] == __NR_syscall) {
208                         if (get_user (child_tidptr, &usp[5]))
209                                 return -EFAULT;
210                 }
211                 else if (get_user (child_tidptr, &usp[4]))
212                         return -EFAULT;
213         }
214 #else
215         child_tidptr = (int __user *) regs.regs[8];
216 #endif
217         return do_fork(clone_flags, newsp, &regs, 0,
218                        parent_tidptr, child_tidptr);
219 }
220
221 /*
222  * sys_execve() executes a new program.
223  */
224 asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
225 {
226         int error;
227         char * filename;
228
229         filename = getname((char __user *) (long)regs.regs[4]);
230         error = PTR_ERR(filename);
231         if (IS_ERR(filename))
232                 goto out;
233         error = do_execve(filename, (char __user *__user *) (long)regs.regs[5],
234                           (char __user *__user *) (long)regs.regs[6], &regs);
235         putname(filename);
236
237 out:
238         return error;
239 }
240
241 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
242 {
243         struct thread_info *ti = task_thread_info(current);
244
245         ti->tp_value = addr;
246         if (cpu_has_userlocal)
247                 write_c0_userlocal(addr);
248
249         return 0;
250 }
251
252 static inline int mips_atomic_set(struct pt_regs *regs,
253         unsigned long addr, unsigned long new)
254 {
255         unsigned long old, tmp;
256         unsigned int err;
257
258         if (unlikely(addr & 3))
259                 return -EINVAL;
260
261         if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
262                 return -EINVAL;
263
264         if (cpu_has_llsc && R10000_LLSC_WAR) {
265                 __asm__ __volatile__ (
266                 "       .set    mips3                                   \n"
267                 "       li      %[err], 0                               \n"
268                 "1:     ll      %[old], (%[addr])                       \n"
269                 "       move    %[tmp], %[new]                          \n"
270                 "2:     sc      %[tmp], (%[addr])                       \n"
271                 "       beqzl   %[tmp], 1b                              \n"
272                 "3:                                                     \n"
273                 "       .section .fixup,\"ax\"                          \n"
274                 "4:     li      %[err], %[efault]                       \n"
275                 "       j       3b                                      \n"
276                 "       .previous                                       \n"
277                 "       .section __ex_table,\"a\"                       \n"
278                 "       "STR(PTR)"      1b, 4b                          \n"
279                 "       "STR(PTR)"      2b, 4b                          \n"
280                 "       .previous                                       \n"
281                 "       .set    mips0                                   \n"
282                 : [old] "=&r" (old),
283                   [err] "=&r" (err),
284                   [tmp] "=&r" (tmp)
285                 : [addr] "r" (addr),
286                   [new] "r" (new),
287                   [efault] "i" (-EFAULT)
288                 : "memory");
289         } else if (cpu_has_llsc) {
290                 __asm__ __volatile__ (
291                 "       .set    mips3                                   \n"
292                 "       li      %[err], 0                               \n"
293                 "1:     ll      %[old], (%[addr])                       \n"
294                 "       move    %[tmp], %[new]                          \n"
295                 "2:     sc      %[tmp], (%[addr])                       \n"
296                 "       bnez    %[tmp], 4f                              \n"
297                 "3:                                                     \n"
298                 "       .subsection 2                                   \n"
299                 "4:     b       1b                                      \n"
300                 "       .previous                                       \n"
301                 "                                                       \n"
302                 "       .section .fixup,\"ax\"                          \n"
303                 "5:     li      %[err], %[efault]                       \n"
304                 "       j       3b                                      \n"
305                 "       .previous                                       \n"
306                 "       .section __ex_table,\"a\"                       \n"
307                 "       "STR(PTR)"      1b, 5b                          \n"
308                 "       "STR(PTR)"      2b, 5b                          \n"
309                 "       .previous                                       \n"
310                 "       .set    mips0                                   \n"
311                 : [old] "=&r" (old),
312                   [err] "=&r" (err),
313                   [tmp] "=&r" (tmp)
314                 : [addr] "r" (addr),
315                   [new] "r" (new),
316                   [efault] "i" (-EFAULT)
317                 : "memory");
318         } else {
319                 do {
320                         preempt_disable();
321                         ll_bit = 1;
322                         ll_task = current;
323                         preempt_enable();
324
325                         err = __get_user(old, (unsigned int *) addr);
326                         err |= __put_user(new, (unsigned int *) addr);
327                         if (err)
328                                 break;
329                         rmb();
330                 } while (!ll_bit);
331         }
332
333         if (unlikely(err))
334                 return err;
335
336         regs->regs[2] = old;
337         regs->regs[7] = 0;      /* No error */
338
339         /*
340          * Don't let your children do this ...
341          */
342         __asm__ __volatile__(
343         "       move    $29, %0                                         \n"
344         "       j       syscall_exit                                    \n"
345         : /* no outputs */
346         : "r" (regs));
347
348         /* unreached.  Honestly.  */
349         while (1);
350 }
351
352 save_static_function(sys_sysmips);
353 static int __used noinline
354 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
355 {
356         long cmd, arg1, arg2, arg3;
357
358         cmd = regs.regs[4];
359         arg1 = regs.regs[5];
360         arg2 = regs.regs[6];
361         arg3 = regs.regs[7];
362
363         switch (cmd) {
364         case MIPS_ATOMIC_SET:
365                 return mips_atomic_set(&regs, arg1, arg2);
366
367         case MIPS_FIXADE:
368                 if (arg1 & ~3)
369                         return -EINVAL;
370
371                 if (arg1 & 1)
372                         set_thread_flag(TIF_FIXADE);
373                 else
374                         clear_thread_flag(TIF_FIXADE);
375                 if (arg1 & 2)
376                         set_thread_flag(TIF_LOGADE);
377                 else
378                         clear_thread_flag(TIF_FIXADE);
379
380                 return 0;
381
382         case FLUSH_CACHE:
383                 __flush_cache_all();
384                 return 0;
385         }
386
387         return -EINVAL;
388 }
389
390 /*
391  * No implemented yet ...
392  */
393 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
394 {
395         return -ENOSYS;
396 }
397
398 /*
399  * If we ever come here the user sp is bad.  Zap the process right away.
400  * Due to the bad stack signaling wouldn't work.
401  */
402 asmlinkage void bad_stack(void)
403 {
404         do_exit(SIGSEGV);
405 }
406
407 /*
408  * Do a system call from kernel instead of calling sys_execve so we
409  * end up with proper pt_regs.
410  */
411 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
412 {
413         register unsigned long __a0 asm("$4") = (unsigned long) filename;
414         register unsigned long __a1 asm("$5") = (unsigned long) argv;
415         register unsigned long __a2 asm("$6") = (unsigned long) envp;
416         register unsigned long __a3 asm("$7");
417         unsigned long __v0;
418
419         __asm__ volatile ("                                     \n"
420         "       .set    noreorder                               \n"
421         "       li      $2, %5          # __NR_execve           \n"
422         "       syscall                                         \n"
423         "       move    %0, $2                                  \n"
424         "       .set    reorder                                 \n"
425         : "=&r" (__v0), "=r" (__a3)
426         : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
427         : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
428           "memory");
429
430         if (__a3 == 0)
431                 return __v0;
432
433         return -__v0;
434 }