xref: /openbmc/linux/arch/mips/kernel/ptrace32.c (revision b9b77222)
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) 1992 Ross Biro
7  * Copyright (C) Linus Torvalds
8  * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
9  * Copyright (C) 1996 David S. Miller
10  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
11  * Copyright (C) 1999 MIPS Technologies, Inc.
12  * Copyright (C) 2000 Ulf Carlsson
13  *
14  * At this time Linux/MIPS64 only supports syscall tracing, even for 32-bit
15  * binaries.
16  */
17 #include <linux/compiler.h>
18 #include <linux/compat.h>
19 #include <linux/kernel.h>
20 #include <linux/sched.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/mm.h>
23 #include <linux/errno.h>
24 #include <linux/ptrace.h>
25 #include <linux/smp.h>
26 #include <linux/security.h>
27 
28 #include <asm/cpu.h>
29 #include <asm/dsp.h>
30 #include <asm/fpu.h>
31 #include <asm/mipsregs.h>
32 #include <asm/mipsmtregs.h>
33 #include <asm/pgtable.h>
34 #include <asm/page.h>
35 #include <asm/reg.h>
36 #include <asm/syscall.h>
37 #include <linux/uaccess.h>
38 #include <asm/bootinfo.h>
39 
40 /*
41  * Tracing a 32-bit process with a 64-bit strace and vice versa will not
42  * work.  I don't know how to fix this.
43  */
44 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
45 			compat_ulong_t caddr, compat_ulong_t cdata)
46 {
47 	int addr = caddr;
48 	int data = cdata;
49 	int ret;
50 
51 	switch (request) {
52 
53 	/*
54 	 * Read 4 bytes of the other process' storage
55 	 *  data is a pointer specifying where the user wants the
56 	 *	4 bytes copied into
57 	 *  addr is a pointer in the user's storage that contains an 8 byte
58 	 *	address in the other process of the 4 bytes that is to be read
59 	 * (this is run in a 32-bit process looking at a 64-bit process)
60 	 * when I and D space are separate, these will need to be fixed.
61 	 */
62 	case PTRACE_PEEKTEXT_3264:
63 	case PTRACE_PEEKDATA_3264: {
64 		u32 tmp;
65 		int copied;
66 		u32 __user * addrOthers;
67 
68 		ret = -EIO;
69 
70 		/* Get the addr in the other process that we want to read */
71 		if (get_user(addrOthers, (u32 __user * __user *) (unsigned long) addr) != 0)
72 			break;
73 
74 		copied = ptrace_access_vm(child, (u64)addrOthers, &tmp,
75 				sizeof(tmp), FOLL_FORCE);
76 		if (copied != sizeof(tmp))
77 			break;
78 		ret = put_user(tmp, (u32 __user *) (unsigned long) data);
79 		break;
80 	}
81 
82 	/* Read the word at location addr in the USER area. */
83 	case PTRACE_PEEKUSR: {
84 		struct pt_regs *regs;
85 		union fpureg *fregs;
86 		unsigned int tmp;
87 
88 		regs = task_pt_regs(child);
89 		ret = 0;  /* Default return value. */
90 
91 		switch (addr) {
92 		case 0 ... 31:
93 			tmp = regs->regs[addr];
94 			break;
95 		case FPR_BASE ... FPR_BASE + 31:
96 			if (!tsk_used_math(child)) {
97 				/* FP not yet used */
98 				tmp = -1;
99 				break;
100 			}
101 			fregs = get_fpu_regs(child);
102 			if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) {
103 				/*
104 				 * The odd registers are actually the high
105 				 * order bits of the values stored in the even
106 				 * registers.
107 				 */
108 				tmp = get_fpr32(&fregs[(addr & ~1) - FPR_BASE],
109 						addr & 1);
110 				break;
111 			}
112 			tmp = get_fpr64(&fregs[addr - FPR_BASE], 0);
113 			break;
114 		case PC:
115 			tmp = regs->cp0_epc;
116 			break;
117 		case CAUSE:
118 			tmp = regs->cp0_cause;
119 			break;
120 		case BADVADDR:
121 			tmp = regs->cp0_badvaddr;
122 			break;
123 		case MMHI:
124 			tmp = regs->hi;
125 			break;
126 		case MMLO:
127 			tmp = regs->lo;
128 			break;
129 		case FPC_CSR:
130 			tmp = child->thread.fpu.fcr31;
131 			break;
132 		case FPC_EIR:
133 			/* implementation / version register */
134 			tmp = boot_cpu_data.fpu_id;
135 			break;
136 		case DSP_BASE ... DSP_BASE + 5: {
137 			dspreg_t *dregs;
138 
139 			if (!cpu_has_dsp) {
140 				tmp = 0;
141 				ret = -EIO;
142 				goto out;
143 			}
144 			dregs = __get_dsp_regs(child);
145 			tmp = (unsigned long) (dregs[addr - DSP_BASE]);
146 			break;
147 		}
148 		case DSP_CONTROL:
149 			if (!cpu_has_dsp) {
150 				tmp = 0;
151 				ret = -EIO;
152 				goto out;
153 			}
154 			tmp = child->thread.dsp.dspcontrol;
155 			break;
156 		default:
157 			tmp = 0;
158 			ret = -EIO;
159 			goto out;
160 		}
161 		ret = put_user(tmp, (unsigned __user *) (unsigned long) data);
162 		break;
163 	}
164 
165 	/*
166 	 * Write 4 bytes into the other process' storage
167 	 *  data is the 4 bytes that the user wants written
168 	 *  addr is a pointer in the user's storage that contains an
169 	 *	8 byte address in the other process where the 4 bytes
170 	 *	that is to be written
171 	 * (this is run in a 32-bit process looking at a 64-bit process)
172 	 * when I and D space are separate, these will need to be fixed.
173 	 */
174 	case PTRACE_POKETEXT_3264:
175 	case PTRACE_POKEDATA_3264: {
176 		u32 __user * addrOthers;
177 
178 		/* Get the addr in the other process that we want to write into */
179 		ret = -EIO;
180 		if (get_user(addrOthers, (u32 __user * __user *) (unsigned long) addr) != 0)
181 			break;
182 		ret = 0;
183 		if (ptrace_access_vm(child, (u64)addrOthers, &data,
184 					sizeof(data),
185 					FOLL_FORCE | FOLL_WRITE) == sizeof(data))
186 			break;
187 		ret = -EIO;
188 		break;
189 	}
190 
191 	case PTRACE_POKEUSR: {
192 		struct pt_regs *regs;
193 		ret = 0;
194 		regs = task_pt_regs(child);
195 
196 		switch (addr) {
197 		case 0 ... 31:
198 			regs->regs[addr] = data;
199 			/* System call number may have been changed */
200 			if (addr == 2)
201 				mips_syscall_update_nr(child, regs);
202 			else if (addr == 4 &&
203 				 mips_syscall_is_indirect(child, regs))
204 				mips_syscall_update_nr(child, regs);
205 			break;
206 		case FPR_BASE ... FPR_BASE + 31: {
207 			union fpureg *fregs = get_fpu_regs(child);
208 
209 			if (!tsk_used_math(child)) {
210 				/* FP not yet used  */
211 				memset(&child->thread.fpu, ~0,
212 				       sizeof(child->thread.fpu));
213 				child->thread.fpu.fcr31 = 0;
214 			}
215 			if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) {
216 				/*
217 				 * The odd registers are actually the high
218 				 * order bits of the values stored in the even
219 				 * registers.
220 				 */
221 				set_fpr32(&fregs[(addr & ~1) - FPR_BASE],
222 					  addr & 1, data);
223 				break;
224 			}
225 			set_fpr64(&fregs[addr - FPR_BASE], 0, data);
226 			break;
227 		}
228 		case PC:
229 			regs->cp0_epc = data;
230 			break;
231 		case MMHI:
232 			regs->hi = data;
233 			break;
234 		case MMLO:
235 			regs->lo = data;
236 			break;
237 		case FPC_CSR:
238 			child->thread.fpu.fcr31 = data;
239 			break;
240 		case DSP_BASE ... DSP_BASE + 5: {
241 			dspreg_t *dregs;
242 
243 			if (!cpu_has_dsp) {
244 				ret = -EIO;
245 				break;
246 			}
247 
248 			dregs = __get_dsp_regs(child);
249 			dregs[addr - DSP_BASE] = data;
250 			break;
251 		}
252 		case DSP_CONTROL:
253 			if (!cpu_has_dsp) {
254 				ret = -EIO;
255 				break;
256 			}
257 			child->thread.dsp.dspcontrol = data;
258 			break;
259 		default:
260 			/* The rest are not allowed. */
261 			ret = -EIO;
262 			break;
263 		}
264 		break;
265 		}
266 
267 	case PTRACE_GETREGS:
268 		ret = ptrace_getregs(child,
269 				(struct user_pt_regs __user *) (__u64) data);
270 		break;
271 
272 	case PTRACE_SETREGS:
273 		ret = ptrace_setregs(child,
274 				(struct user_pt_regs __user *) (__u64) data);
275 		break;
276 
277 	case PTRACE_GETFPREGS:
278 		ret = ptrace_getfpregs(child, (__u32 __user *) (__u64) data);
279 		break;
280 
281 	case PTRACE_SETFPREGS:
282 		ret = ptrace_setfpregs(child, (__u32 __user *) (__u64) data);
283 		break;
284 
285 	case PTRACE_GET_THREAD_AREA:
286 		ret = put_user(task_thread_info(child)->tp_value,
287 				(unsigned int __user *) (unsigned long) data);
288 		break;
289 
290 	case PTRACE_GET_THREAD_AREA_3264:
291 		ret = put_user(task_thread_info(child)->tp_value,
292 				(unsigned long __user *) (unsigned long) data);
293 		break;
294 
295 	case PTRACE_GET_WATCH_REGS:
296 		ret = ptrace_get_watch_regs(child,
297 			(struct pt_watch_regs __user *) (unsigned long) addr);
298 		break;
299 
300 	case PTRACE_SET_WATCH_REGS:
301 		ret = ptrace_set_watch_regs(child,
302 			(struct pt_watch_regs __user *) (unsigned long) addr);
303 		break;
304 
305 	default:
306 		ret = compat_ptrace_request(child, request, addr, data);
307 		break;
308 	}
309 out:
310 	return ret;
311 }
312