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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * unaligned.c: Unaligned load/store trap handling with special
4 * cases for the kernel to do them more quickly.
5 *
6 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
7 * Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
8 */
9
10
11#include <linux/kernel.h>
12#include <linux/sched/signal.h>
13#include <linux/mm.h>
14#include <asm/ptrace.h>
15#include <asm/processor.h>
16#include <linux/uaccess.h>
17#include <linux/smp.h>
18#include <linux/perf_event.h>
19
20#include <asm/setup.h>
21
22#include "kernel.h"
23
24enum direction {
25 load, /* ld, ldd, ldh, ldsh */
26 store, /* st, std, sth, stsh */
27 both, /* Swap, ldstub, etc. */
28 fpload,
29 fpstore,
30 invalid,
31};
32
33static inline enum direction decode_direction(unsigned int insn)
34{
35 unsigned long tmp = (insn >> 21) & 1;
36
37 if(!tmp)
38 return load;
39 else {
40 if(((insn>>19)&0x3f) == 15)
41 return both;
42 else
43 return store;
44 }
45}
46
47/* 8 = double-word, 4 = word, 2 = half-word */
48static inline int decode_access_size(unsigned int insn)
49{
50 insn = (insn >> 19) & 3;
51
52 if(!insn)
53 return 4;
54 else if(insn == 3)
55 return 8;
56 else if(insn == 2)
57 return 2;
58 else {
59 printk("Impossible unaligned trap. insn=%08x\n", insn);
60 die_if_kernel("Byte sized unaligned access?!?!", current->thread.kregs);
61 return 4; /* just to keep gcc happy. */
62 }
63}
64
65/* 0x400000 = signed, 0 = unsigned */
66static inline int decode_signedness(unsigned int insn)
67{
68 return (insn & 0x400000);
69}
70
71static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
72 unsigned int rd)
73{
74 if(rs2 >= 16 || rs1 >= 16 || rd >= 16) {
75 /* Wheee... */
76 __asm__ __volatile__("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 "save %sp, -0x40, %sp\n\t"
81 "save %sp, -0x40, %sp\n\t"
82 "save %sp, -0x40, %sp\n\t"
83 "restore; restore; restore; restore;\n\t"
84 "restore; restore; restore;\n\t");
85 }
86}
87
88static inline int sign_extend_imm13(int imm)
89{
90 return imm << 19 >> 19;
91}
92
93static inline unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
94{
95 struct reg_window32 *win;
96
97 if(reg < 16)
98 return (!reg ? 0 : regs->u_regs[reg]);
99
100 /* Ho hum, the slightly complicated case. */
101 win = (struct reg_window32 *) regs->u_regs[UREG_FP];
102 return win->locals[reg - 16]; /* yes, I know what this does... */
103}
104
105static inline unsigned long safe_fetch_reg(unsigned int reg, struct pt_regs *regs)
106{
107 struct reg_window32 __user *win;
108 unsigned long ret;
109
110 if (reg < 16)
111 return (!reg ? 0 : regs->u_regs[reg]);
112
113 /* Ho hum, the slightly complicated case. */
114 win = (struct reg_window32 __user *) regs->u_regs[UREG_FP];
115
116 if ((unsigned long)win & 3)
117 return -1;
118
119 if (get_user(ret, &win->locals[reg - 16]))
120 return -1;
121
122 return ret;
123}
124
125static inline unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
126{
127 struct reg_window32 *win;
128
129 if(reg < 16)
130 return ®s->u_regs[reg];
131 win = (struct reg_window32 *) regs->u_regs[UREG_FP];
132 return &win->locals[reg - 16];
133}
134
135static unsigned long compute_effective_address(struct pt_regs *regs,
136 unsigned int insn)
137{
138 unsigned int rs1 = (insn >> 14) & 0x1f;
139 unsigned int rs2 = insn & 0x1f;
140 unsigned int rd = (insn >> 25) & 0x1f;
141
142 if(insn & 0x2000) {
143 maybe_flush_windows(rs1, 0, rd);
144 return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
145 } else {
146 maybe_flush_windows(rs1, rs2, rd);
147 return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
148 }
149}
150
151unsigned long safe_compute_effective_address(struct pt_regs *regs,
152 unsigned int insn)
153{
154 unsigned int rs1 = (insn >> 14) & 0x1f;
155 unsigned int rs2 = insn & 0x1f;
156 unsigned int rd = (insn >> 25) & 0x1f;
157
158 if(insn & 0x2000) {
159 maybe_flush_windows(rs1, 0, rd);
160 return (safe_fetch_reg(rs1, regs) + sign_extend_imm13(insn));
161 } else {
162 maybe_flush_windows(rs1, rs2, rd);
163 return (safe_fetch_reg(rs1, regs) + safe_fetch_reg(rs2, regs));
164 }
165}
166
167/* This is just to make gcc think panic does return... */
168static void unaligned_panic(char *str)
169{
170 panic("%s", str);
171}
172
173/* una_asm.S */
174extern int do_int_load(unsigned long *dest_reg, int size,
175 unsigned long *saddr, int is_signed);
176extern int __do_int_store(unsigned long *dst_addr, int size,
177 unsigned long *src_val);
178
179static int do_int_store(int reg_num, int size, unsigned long *dst_addr,
180 struct pt_regs *regs)
181{
182 unsigned long zero[2] = { 0, 0 };
183 unsigned long *src_val;
184
185 if (reg_num)
186 src_val = fetch_reg_addr(reg_num, regs);
187 else {
188 src_val = &zero[0];
189 if (size == 8)
190 zero[1] = fetch_reg(1, regs);
191 }
192 return __do_int_store(dst_addr, size, src_val);
193}
194
195extern void smp_capture(void);
196extern void smp_release(void);
197
198static inline void advance(struct pt_regs *regs)
199{
200 regs->pc = regs->npc;
201 regs->npc += 4;
202}
203
204static inline int floating_point_load_or_store_p(unsigned int insn)
205{
206 return (insn >> 24) & 1;
207}
208
209static inline int ok_for_kernel(unsigned int insn)
210{
211 return !floating_point_load_or_store_p(insn);
212}
213
214static void kernel_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
215{
216 unsigned long g2 = regs->u_regs [UREG_G2];
217 unsigned long fixup = search_extables_range(regs->pc, &g2);
218
219 if (!fixup) {
220 unsigned long address = compute_effective_address(regs, insn);
221 if(address < PAGE_SIZE) {
222 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference in mna handler");
223 } else
224 printk(KERN_ALERT "Unable to handle kernel paging request in mna handler");
225 printk(KERN_ALERT " at virtual address %08lx\n",address);
226 printk(KERN_ALERT "current->{mm,active_mm}->context = %08lx\n",
227 (current->mm ? current->mm->context :
228 current->active_mm->context));
229 printk(KERN_ALERT "current->{mm,active_mm}->pgd = %08lx\n",
230 (current->mm ? (unsigned long) current->mm->pgd :
231 (unsigned long) current->active_mm->pgd));
232 die_if_kernel("Oops", regs);
233 /* Not reached */
234 }
235 regs->pc = fixup;
236 regs->npc = regs->pc + 4;
237 regs->u_regs [UREG_G2] = g2;
238}
239
240asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)
241{
242 enum direction dir = decode_direction(insn);
243 int size = decode_access_size(insn);
244
245 if(!ok_for_kernel(insn) || dir == both) {
246 printk("Unsupported unaligned load/store trap for kernel at <%08lx>.\n",
247 regs->pc);
248 unaligned_panic("Wheee. Kernel does fpu/atomic unaligned load/store.");
249 } else {
250 unsigned long addr = compute_effective_address(regs, insn);
251 int err;
252
253 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
254 switch (dir) {
255 case load:
256 err = do_int_load(fetch_reg_addr(((insn>>25)&0x1f),
257 regs),
258 size, (unsigned long *) addr,
259 decode_signedness(insn));
260 break;
261
262 case store:
263 err = do_int_store(((insn>>25)&0x1f), size,
264 (unsigned long *) addr, regs);
265 break;
266 default:
267 panic("Impossible kernel unaligned trap.");
268 /* Not reached... */
269 }
270 if (err)
271 kernel_mna_trap_fault(regs, insn);
272 else
273 advance(regs);
274 }
275}
276
277static inline int ok_for_user(struct pt_regs *regs, unsigned int insn,
278 enum direction dir)
279{
280 unsigned int reg;
281 int check = (dir == load) ? VERIFY_READ : VERIFY_WRITE;
282 int size = ((insn >> 19) & 3) == 3 ? 8 : 4;
283
284 if ((regs->pc | regs->npc) & 3)
285 return 0;
286
287 /* Must access_ok() in all the necessary places. */
288#define WINREG_ADDR(regnum) \
289 ((void __user *)(((unsigned long *)regs->u_regs[UREG_FP])+(regnum)))
290
291 reg = (insn >> 25) & 0x1f;
292 if (reg >= 16) {
293 if (!access_ok(check, WINREG_ADDR(reg - 16), size))
294 return -EFAULT;
295 }
296 reg = (insn >> 14) & 0x1f;
297 if (reg >= 16) {
298 if (!access_ok(check, WINREG_ADDR(reg - 16), size))
299 return -EFAULT;
300 }
301 if (!(insn & 0x2000)) {
302 reg = (insn & 0x1f);
303 if (reg >= 16) {
304 if (!access_ok(check, WINREG_ADDR(reg - 16), size))
305 return -EFAULT;
306 }
307 }
308#undef WINREG_ADDR
309 return 0;
310}
311
312static void user_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
313{
314 siginfo_t info;
315
316 info.si_signo = SIGBUS;
317 info.si_errno = 0;
318 info.si_code = BUS_ADRALN;
319 info.si_addr = (void __user *)safe_compute_effective_address(regs, insn);
320 info.si_trapno = 0;
321 send_sig_info(SIGBUS, &info, current);
322}
323
324asmlinkage void user_unaligned_trap(struct pt_regs *regs, unsigned int insn)
325{
326 enum direction dir;
327
328 if(!(current->thread.flags & SPARC_FLAG_UNALIGNED) ||
329 (((insn >> 30) & 3) != 3))
330 goto kill_user;
331 dir = decode_direction(insn);
332 if(!ok_for_user(regs, insn, dir)) {
333 goto kill_user;
334 } else {
335 int err, size = decode_access_size(insn);
336 unsigned long addr;
337
338 if(floating_point_load_or_store_p(insn)) {
339 printk("User FPU load/store unaligned unsupported.\n");
340 goto kill_user;
341 }
342
343 addr = compute_effective_address(regs, insn);
344 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
345 switch(dir) {
346 case load:
347 err = do_int_load(fetch_reg_addr(((insn>>25)&0x1f),
348 regs),
349 size, (unsigned long *) addr,
350 decode_signedness(insn));
351 break;
352
353 case store:
354 err = do_int_store(((insn>>25)&0x1f), size,
355 (unsigned long *) addr, regs);
356 break;
357
358 case both:
359 /*
360 * This was supported in 2.4. However, we question
361 * the value of SWAP instruction across word boundaries.
362 */
363 printk("Unaligned SWAP unsupported.\n");
364 err = -EFAULT;
365 break;
366
367 default:
368 unaligned_panic("Impossible user unaligned trap.");
369 goto out;
370 }
371 if (err)
372 goto kill_user;
373 else
374 advance(regs);
375 goto out;
376 }
377
378kill_user:
379 user_mna_trap_fault(regs, insn);
380out:
381 ;
382}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * unaligned.c: Unaligned load/store trap handling with special
4 * cases for the kernel to do them more quickly.
5 *
6 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
7 * Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
8 */
9
10
11#include <linux/kernel.h>
12#include <linux/sched/signal.h>
13#include <linux/mm.h>
14#include <asm/ptrace.h>
15#include <asm/processor.h>
16#include <linux/uaccess.h>
17#include <linux/smp.h>
18#include <linux/perf_event.h>
19#include <linux/extable.h>
20
21#include <asm/setup.h>
22
23#include "kernel.h"
24
25enum direction {
26 load, /* ld, ldd, ldh, ldsh */
27 store, /* st, std, sth, stsh */
28 both, /* Swap, ldstub, etc. */
29 fpload,
30 fpstore,
31 invalid,
32};
33
34static inline enum direction decode_direction(unsigned int insn)
35{
36 unsigned long tmp = (insn >> 21) & 1;
37
38 if(!tmp)
39 return load;
40 else {
41 if(((insn>>19)&0x3f) == 15)
42 return both;
43 else
44 return store;
45 }
46}
47
48/* 8 = double-word, 4 = word, 2 = half-word */
49static inline int decode_access_size(unsigned int insn)
50{
51 insn = (insn >> 19) & 3;
52
53 if(!insn)
54 return 4;
55 else if(insn == 3)
56 return 8;
57 else if(insn == 2)
58 return 2;
59 else {
60 printk("Impossible unaligned trap. insn=%08x\n", insn);
61 die_if_kernel("Byte sized unaligned access?!?!", current->thread.kregs);
62 return 4; /* just to keep gcc happy. */
63 }
64}
65
66/* 0x400000 = signed, 0 = unsigned */
67static inline int decode_signedness(unsigned int insn)
68{
69 return (insn & 0x400000);
70}
71
72static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
73 unsigned int rd)
74{
75 if(rs2 >= 16 || rs1 >= 16 || rd >= 16) {
76 /* Wheee... */
77 __asm__ __volatile__("save %sp, -0x40, %sp\n\t"
78 "save %sp, -0x40, %sp\n\t"
79 "save %sp, -0x40, %sp\n\t"
80 "save %sp, -0x40, %sp\n\t"
81 "save %sp, -0x40, %sp\n\t"
82 "save %sp, -0x40, %sp\n\t"
83 "save %sp, -0x40, %sp\n\t"
84 "restore; restore; restore; restore;\n\t"
85 "restore; restore; restore;\n\t");
86 }
87}
88
89static inline int sign_extend_imm13(int imm)
90{
91 return imm << 19 >> 19;
92}
93
94static inline unsigned long fetch_reg(unsigned int reg, struct pt_regs *regs)
95{
96 struct reg_window32 *win;
97
98 if(reg < 16)
99 return (!reg ? 0 : regs->u_regs[reg]);
100
101 /* Ho hum, the slightly complicated case. */
102 win = (struct reg_window32 *) regs->u_regs[UREG_FP];
103 return win->locals[reg - 16]; /* yes, I know what this does... */
104}
105
106static inline unsigned long safe_fetch_reg(unsigned int reg, struct pt_regs *regs)
107{
108 struct reg_window32 __user *win;
109 unsigned long ret;
110
111 if (reg < 16)
112 return (!reg ? 0 : regs->u_regs[reg]);
113
114 /* Ho hum, the slightly complicated case. */
115 win = (struct reg_window32 __user *) regs->u_regs[UREG_FP];
116
117 if ((unsigned long)win & 3)
118 return -1;
119
120 if (get_user(ret, &win->locals[reg - 16]))
121 return -1;
122
123 return ret;
124}
125
126static inline unsigned long *fetch_reg_addr(unsigned int reg, struct pt_regs *regs)
127{
128 struct reg_window32 *win;
129
130 if(reg < 16)
131 return ®s->u_regs[reg];
132 win = (struct reg_window32 *) regs->u_regs[UREG_FP];
133 return &win->locals[reg - 16];
134}
135
136static unsigned long compute_effective_address(struct pt_regs *regs,
137 unsigned int insn)
138{
139 unsigned int rs1 = (insn >> 14) & 0x1f;
140 unsigned int rs2 = insn & 0x1f;
141 unsigned int rd = (insn >> 25) & 0x1f;
142
143 if(insn & 0x2000) {
144 maybe_flush_windows(rs1, 0, rd);
145 return (fetch_reg(rs1, regs) + sign_extend_imm13(insn));
146 } else {
147 maybe_flush_windows(rs1, rs2, rd);
148 return (fetch_reg(rs1, regs) + fetch_reg(rs2, regs));
149 }
150}
151
152unsigned long safe_compute_effective_address(struct pt_regs *regs,
153 unsigned int insn)
154{
155 unsigned int rs1 = (insn >> 14) & 0x1f;
156 unsigned int rs2 = insn & 0x1f;
157 unsigned int rd = (insn >> 25) & 0x1f;
158
159 if(insn & 0x2000) {
160 maybe_flush_windows(rs1, 0, rd);
161 return (safe_fetch_reg(rs1, regs) + sign_extend_imm13(insn));
162 } else {
163 maybe_flush_windows(rs1, rs2, rd);
164 return (safe_fetch_reg(rs1, regs) + safe_fetch_reg(rs2, regs));
165 }
166}
167
168/* This is just to make gcc think panic does return... */
169static void unaligned_panic(char *str)
170{
171 panic("%s", str);
172}
173
174/* una_asm.S */
175extern int do_int_load(unsigned long *dest_reg, int size,
176 unsigned long *saddr, int is_signed);
177extern int __do_int_store(unsigned long *dst_addr, int size,
178 unsigned long *src_val);
179
180static int do_int_store(int reg_num, int size, unsigned long *dst_addr,
181 struct pt_regs *regs)
182{
183 unsigned long zero[2] = { 0, 0 };
184 unsigned long *src_val;
185
186 if (reg_num)
187 src_val = fetch_reg_addr(reg_num, regs);
188 else {
189 src_val = &zero[0];
190 if (size == 8)
191 zero[1] = fetch_reg(1, regs);
192 }
193 return __do_int_store(dst_addr, size, src_val);
194}
195
196extern void smp_capture(void);
197extern void smp_release(void);
198
199static inline void advance(struct pt_regs *regs)
200{
201 regs->pc = regs->npc;
202 regs->npc += 4;
203}
204
205static inline int floating_point_load_or_store_p(unsigned int insn)
206{
207 return (insn >> 24) & 1;
208}
209
210static inline int ok_for_kernel(unsigned int insn)
211{
212 return !floating_point_load_or_store_p(insn);
213}
214
215static void kernel_mna_trap_fault(struct pt_regs *regs, unsigned int insn)
216{
217 const struct exception_table_entry *entry;
218
219 entry = search_exception_tables(regs->pc);
220 if (!entry) {
221 unsigned long address = compute_effective_address(regs, insn);
222 if(address < PAGE_SIZE) {
223 printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference in mna handler");
224 } else
225 printk(KERN_ALERT "Unable to handle kernel paging request in mna handler");
226 printk(KERN_ALERT " at virtual address %08lx\n",address);
227 printk(KERN_ALERT "current->{mm,active_mm}->context = %08lx\n",
228 (current->mm ? current->mm->context :
229 current->active_mm->context));
230 printk(KERN_ALERT "current->{mm,active_mm}->pgd = %08lx\n",
231 (current->mm ? (unsigned long) current->mm->pgd :
232 (unsigned long) current->active_mm->pgd));
233 die_if_kernel("Oops", regs);
234 /* Not reached */
235 }
236 regs->pc = entry->fixup;
237 regs->npc = regs->pc + 4;
238}
239
240asmlinkage void kernel_unaligned_trap(struct pt_regs *regs, unsigned int insn)
241{
242 enum direction dir = decode_direction(insn);
243 int size = decode_access_size(insn);
244
245 if(!ok_for_kernel(insn) || dir == both) {
246 printk("Unsupported unaligned load/store trap for kernel at <%08lx>.\n",
247 regs->pc);
248 unaligned_panic("Wheee. Kernel does fpu/atomic unaligned load/store.");
249 } else {
250 unsigned long addr = compute_effective_address(regs, insn);
251 int err;
252
253 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, addr);
254 switch (dir) {
255 case load:
256 err = do_int_load(fetch_reg_addr(((insn>>25)&0x1f),
257 regs),
258 size, (unsigned long *) addr,
259 decode_signedness(insn));
260 break;
261
262 case store:
263 err = do_int_store(((insn>>25)&0x1f), size,
264 (unsigned long *) addr, regs);
265 break;
266 default:
267 panic("Impossible kernel unaligned trap.");
268 /* Not reached... */
269 }
270 if (err)
271 kernel_mna_trap_fault(regs, insn);
272 else
273 advance(regs);
274 }
275}
276
277asmlinkage void user_unaligned_trap(struct pt_regs *regs, unsigned int insn)
278{
279 send_sig_fault(SIGBUS, BUS_ADRALN,
280 (void __user *)safe_compute_effective_address(regs, insn),
281 current);
282}