perf: Remove the nmi parameter from the swevent and overflow interface
[linux-2.6.git] / arch / sparc / kernel / unaligned_32.c
1 /*
2  * unaligned.c: Unaligned load/store trap handling with special
3  *              cases for the kernel to do them more quickly.
4  *
5  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
6  * Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
7  */
8
9
10 #include <linux/kernel.h>
11 #include <linux/sched.h>
12 #include <linux/mm.h>
13 #include <linux/module.h>
14 #include <asm/ptrace.h>
15 #include <asm/processor.h>
16 #include <asm/system.h>
17 #include <asm/uaccess.h>
18 #include <linux/smp.h>
19 #include <linux/perf_event.h>
20
21 enum direction {
22         load,    /* ld, ldd, ldh, ldsh */
23         store,   /* st, std, sth, stsh */
24         both,    /* Swap, ldstub, etc. */
25         fpload,
26         fpstore,
27         invalid,
28 };
29
30 static inline enum direction decode_direction(unsigned int insn)
31 {
32         unsigned long tmp = (insn >> 21) & 1;
33
34         if(!tmp)
35                 return load;
36         else {
37                 if(((insn>>19)&0x3f) == 15)
38                         return both;
39                 else
40                         return store;
41         }
42 }
43
44 /* 8 = double-word, 4 = word, 2 = half-word */
45 static inline int decode_access_size(unsigned int insn)
46 {
47         insn = (insn >> 19) & 3;
48
49         if(!insn)
50                 return 4;
51         else if(insn == 3)
52                 return 8;
53         else if(insn == 2)
54                 return 2;
55         else {
56                 printk("Impossible unaligned trap. insn=%08x\n", insn);
57                 die_if_kernel("Byte sized unaligned access?!?!", current->thread.kregs);
58                 return 4; /* just to keep gcc happy. */
59         }
60 }
61
62 /* 0x400000 = signed, 0 = unsigned */
63 static inline int decode_signedness(unsigned int insn)
64 {
65         return (insn & 0x400000);
66 }
67
68 static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
69                                        unsigned int rd)
70 {
71         if(rs2 >= 16 || rs1 >= 16 || rd >= 16) {
72                 /* Wheee... */
73                 __asm__ __volatile__("save %sp, -0x40, %sp\n\t"
74                                      "save %sp, -0x40, %sp\n\t"
75                                      "save %sp, -0x40, %sp\n\t"
76                                      "save %sp, -0x40, %sp\n\t"
77                                      "save %sp, -0x40, %sp\n\t"
78                                      "save %sp, -0x40, %sp\n\t"
79                                      "save %sp, -0x40, %sp\n\t"
80                                      "restore; restore; restore; restore;\n\t"
81                                      "restore; restore; restore;\n\t");
82         }
83 }
84
85 static inline int sign_extend_imm13(int imm)
86 {
87         return imm << 19 >> 19;
88 }
89
90 static inline unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
91 {
92         struct reg_window32 *win;
93
94         if(reg < 16)
95                 return (!reg ? 0 : regs->u_regs[reg]);
96
97         /* Ho hum, the slightly complicated case. */
98         win = (struct reg_window32 *) regs->u_regs[UREG_FP];
99         return win->locals[reg - 16]; /* yes, I know what this does... */
100 }
101
102 static inline unsigned long safe_fetch_reg(unsigned int reg, struct pt_regs *regs)
103 {
104         struct reg_window32 __user *win;
105         unsigned long ret;
106
107         if (reg < 16)
108                 return (!reg ? 0 : regs->u_regs[reg]);
109
110         /* Ho hum, the slightly complicated case. */
111         win = (struct reg_window32 __user *) regs->u_regs[UREG_FP];
112
113         if ((unsigned long)win & 3)
114                 return -1;
115
116         if (get_user(ret, &win->locals[reg - 16]))
117                 return -1;
118
119         return ret;
120 }
121
122 static inline unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
123 {
124         struct reg_window32 *win;
125
126         if(reg < 16)
127                 return &regs->u_regs[reg];
128         win = (struct reg_window32 *) regs->u_regs[UREG_FP];
129         return &win->locals[reg - 16];
130 }
131
132 static unsigned long compute_effective_address(struct pt_regs *regs,
133                                                unsigned int insn)
134 {
135         unsigned int rs1 = (insn >> 14) & 0x1f;
136         unsigned int rs2 = insn & 0x1f;
137         unsigned int rd = (insn >> 25) & 0x1f;
138
139         if(insn & 0x2000) {
140                 maybe_flush_windows(rs1, 0, rd);
141                 return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
142         } else {
143                 maybe_flush_windows(rs1, rs2, rd);
144                 return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
145         }
146 }
147
148 unsigned long safe_compute_effective_address(struct pt_regs *regs,
149                                              unsigned int insn)
150 {
151         unsigned int rs1 = (insn >> 14) & 0x1f;
152         unsigned int rs2 = insn & 0x1f;
153         unsigned int rd = (insn >> 25) & 0x1f;
154
155         if(insn & 0x2000) {
156                 maybe_flush_windows(rs1, 0, rd);
157                 return (safe_fetch_reg(rs1, regs) + sign_extend_imm13(insn));
158         } else {
159                 maybe_flush_windows(rs1, rs2, rd);
160                 return (safe_fetch_reg(rs1, regs) + safe_fetch_reg(rs2, regs));
161         }
162 }
163
164 /* This is just to make gcc think panic does return... */
165 static void unaligned_panic(char *str)
166 {
167         panic(str);
168 }
169
170 /* una_asm.S */
171 extern int do_int_load(unsigned long *dest_reg, int size,
172                        unsigned long *saddr, int is_signed);
173 extern int __do_int_store(unsigned long *dst_addr, int size,
174                           unsigned long *src_val);
175
176 static int do_int_store(int reg_num, int size, unsigned long *dst_addr,
177                         struct pt_regs *regs)
178 {
179         unsigned long zero[2] = { 0, 0 };
180         unsigned long *src_val;
181
182         if (reg_num)
183                 src_val = fetch_reg_addr(reg_num, regs);
184         else {
185                 src_val = &zero[0];
186                 if (size == 8)
187                         zero[1] = fetch_reg(1, regs);
188         }
189         return __do_int_store(dst_addr, size, src_val);
190 }
191
192 extern void smp_capture(void);
193 extern void smp_release(void);
194
195 static inline void advance(struct pt_regs *regs)
196 {
197         regs->pc   = regs->npc;
198         regs->npc += 4;
199 }
200
201 static inline int floating_point_load_or_store_p(unsigned int insn)
202 {
203         return (insn >> 24) & 1;
204 }
205
206 static inline int ok_for_kernel(unsigned int insn)
207 {
208         return !floating_point_load_or_store_p(insn);
209 }
210
211 static void kernel_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
212 {
213         unsigned long g2 = regs->u_regs [UREG_G2];
214         unsigned long fixup = search_extables_range(regs->pc, &g2);
215
216         if (!fixup) {
217                 unsigned long address = compute_effective_address(regs, insn);
218                 if(address < PAGE_SIZE) {
219                         printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference in mna handler");
220                 } else
221                         printk(KERN_ALERT "Unable to handle kernel paging request in mna handler");
222                 printk(KERN_ALERT " at virtual address %08lx\n",address);
223                 printk(KERN_ALERT "current->{mm,active_mm}->context = %08lx\n",
224                         (current->mm ? current->mm->context :
225                         current->active_mm->context));
226                 printk(KERN_ALERT "current->{mm,active_mm}->pgd = %08lx\n",
227                         (current->mm ? (unsigned long) current->mm->pgd :
228                         (unsigned long) current->active_mm->pgd));
229                 die_if_kernel("Oops", regs);
230                 /* Not reached */
231         }
232         regs->pc = fixup;
233         regs->npc = regs->pc + 4;
234         regs->u_regs [UREG_G2] = g2;
235 }
236
237 asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)
238 {
239         enum direction dir = decode_direction(insn);
240         int size = decode_access_size(insn);
241
242         if(!ok_for_kernel(insn) || dir == both) {
243                 printk("Unsupported unaligned load/store trap for kernel at <%08lx>.\n",
244                        regs->pc);
245                 unaligned_panic("Wheee. Kernel does fpu/atomic unaligned load/store.");
246         } else {
247                 unsigned long addr = compute_effective_address(regs, insn);
248                 int err;
249
250                 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
251                 switch (dir) {
252                 case load:
253                         err = do_int_load(fetch_reg_addr(((insn>>25)&0x1f),
254                                                          regs),
255                                           size, (unsigned long *) addr,
256                                           decode_signedness(insn));
257                         break;
258
259                 case store:
260                         err = do_int_store(((insn>>25)&0x1f), size,
261                                            (unsigned long *) addr, regs);
262                         break;
263                 default:
264                         panic("Impossible kernel unaligned trap.");
265                         /* Not reached... */
266                 }
267                 if (err)
268                         kernel_mna_trap_fault(regs, insn);
269                 else
270                         advance(regs);
271         }
272 }
273
274 static inline int ok_for_user(struct pt_regs *regs, unsigned int insn,
275                               enum direction dir)
276 {
277         unsigned int reg;
278         int check = (dir == load) ? VERIFY_READ : VERIFY_WRITE;
279         int size = ((insn >> 19) & 3) == 3 ? 8 : 4;
280
281         if ((regs->pc | regs->npc) & 3)
282                 return 0;
283
284         /* Must access_ok() in all the necessary places. */
285 #define WINREG_ADDR(regnum) \
286         ((void __user *)(((unsigned long *)regs->u_regs[UREG_FP])+(regnum)))
287
288         reg = (insn >> 25) & 0x1f;
289         if (reg >= 16) {
290                 if (!access_ok(check, WINREG_ADDR(reg - 16), size))
291                         return -EFAULT;
292         }
293         reg = (insn >> 14) & 0x1f;
294         if (reg >= 16) {
295                 if (!access_ok(check, WINREG_ADDR(reg - 16), size))
296                         return -EFAULT;
297         }
298         if (!(insn & 0x2000)) {
299                 reg = (insn & 0x1f);
300                 if (reg >= 16) {
301                         if (!access_ok(check, WINREG_ADDR(reg - 16), size))
302                                 return -EFAULT;
303                 }
304         }
305 #undef WINREG_ADDR
306         return 0;
307 }
308
309 static void user_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
310 {
311         siginfo_t info;
312
313         info.si_signo = SIGBUS;
314         info.si_errno = 0;
315         info.si_code = BUS_ADRALN;
316         info.si_addr = (void __user *)safe_compute_effective_address(regs, insn);
317         info.si_trapno = 0;
318         send_sig_info(SIGBUS, &info, current);
319 }
320
321 asmlinkage void user_unaligned_trap(struct pt_regs *regs, unsigned int insn)
322 {
323         enum direction dir;
324
325         if(!(current->thread.flags & SPARC_FLAG_UNALIGNED) ||
326            (((insn >> 30) & 3) != 3))
327                 goto kill_user;
328         dir = decode_direction(insn);
329         if(!ok_for_user(regs, insn, dir)) {
330                 goto kill_user;
331         } else {
332                 int err, size = decode_access_size(insn);
333                 unsigned long addr;
334
335                 if(floating_point_load_or_store_p(insn)) {
336                         printk("User FPU load/store unaligned unsupported.\n");
337                         goto kill_user;
338                 }
339
340                 addr = compute_effective_address(regs, insn);
341                 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
342                 switch(dir) {
343                 case load:
344                         err = do_int_load(fetch_reg_addr(((insn>>25)&0x1f),
345                                                          regs),
346                                           size, (unsigned long *) addr,
347                                           decode_signedness(insn));
348                         break;
349
350                 case store:
351                         err = do_int_store(((insn>>25)&0x1f), size,
352                                            (unsigned long *) addr, regs);
353                         break;
354
355                 case both:
356                         /*
357                          * This was supported in 2.4. However, we question
358                          * the value of SWAP instruction across word boundaries.
359                          */
360                         printk("Unaligned SWAP unsupported.\n");
361                         err = -EFAULT;
362                         break;
363
364                 default:
365                         unaligned_panic("Impossible user unaligned trap.");
366                         goto out;
367                 }
368                 if (err)
369                         goto kill_user;
370                 else
371                         advance(regs);
372                 goto out;
373         }
374
375 kill_user:
376         user_mna_trap_fault(regs, insn);
377 out:
378         ;
379 }