1/*
2 * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
3 * these modifications are Copyright 2004-2010 Analog Devices Inc.
4 *
5 * Licensed under the GPL-2
6 */
7
8#include <linux/kernel.h>
9#include <linux/sched.h>
10#include <linux/mm.h>
11#include <linux/smp.h>
12#include <linux/elf.h>
13#include <linux/errno.h>
14#include <linux/ptrace.h>
15#include <linux/user.h>
16#include <linux/regset.h>
17#include <linux/signal.h>
18#include <linux/tracehook.h>
19#include <linux/uaccess.h>
20
21#include <asm/page.h>
22#include <asm/pgtable.h>
23#include <asm/processor.h>
24#include <asm/asm-offsets.h>
25#include <asm/dma.h>
26#include <asm/fixed_code.h>
27#include <asm/cacheflush.h>
28#include <asm/mem_map.h>
29#include <asm/mmu_context.h>
30
31/*
32 * does not yet catch signals sent when the child dies.
33 * in exit.c or in signal.c.
34 */
35
36/*
37 * Get contents of register REGNO in task TASK.
38 */
39static inline long
40get_reg(struct task_struct *task, unsigned long regno,
41	unsigned long __user *datap)
42{
43	long tmp;
44	struct pt_regs *regs = task_pt_regs(task);
45
46	if (regno & 3 || regno > PT_LAST_PSEUDO)
47		return -EIO;
48
49	switch (regno) {
50	case PT_TEXT_ADDR:
51		tmp = task->mm->start_code;
52		break;
53	case PT_TEXT_END_ADDR:
54		tmp = task->mm->end_code;
55		break;
56	case PT_DATA_ADDR:
57		tmp = task->mm->start_data;
58		break;
59	case PT_USP:
60		tmp = task->thread.usp;
61		break;
62	default:
63		if (regno < sizeof(*regs)) {
64			void *reg_ptr = regs;
65			tmp = *(long *)(reg_ptr + regno);
66		} else
67			return -EIO;
68	}
69
70	return put_user(tmp, datap);
71}
72
73/*
74 * Write contents of register REGNO in task TASK.
75 */
76static inline int
77put_reg(struct task_struct *task, unsigned long regno, unsigned long data)
78{
79	struct pt_regs *regs = task_pt_regs(task);
80
81	if (regno & 3 || regno > PT_LAST_PSEUDO)
82		return -EIO;
83
84	switch (regno) {
85	case PT_PC:
86		/*********************************************************************/
87		/* At this point the kernel is most likely in exception.             */
88		/* The RETX register will be used to populate the pc of the process. */
89		/*********************************************************************/
90		regs->retx = data;
91		regs->pc = data;
92		break;
93	case PT_RETX:
94		break;		/* regs->retx = data; break; */
95	case PT_USP:
96		regs->usp = data;
97		task->thread.usp = data;
98		break;
99	case PT_SYSCFG:	/* don't let userspace screw with this */
100		if ((data & ~1) != 0x6)
101			pr_warning("ptrace: ignore syscfg write of %#lx\n", data);
102		break;		/* regs->syscfg = data; break; */
103	default:
104		if (regno < sizeof(*regs)) {
105			void *reg_offset = regs;
106			*(long *)(reg_offset + regno) = data;
107		}
108		/* Ignore writes to pseudo registers */
109	}
110
111	return 0;
112}
113
114/*
115 * check that an address falls within the bounds of the target process's memory mappings
116 */
117int
118is_user_addr_valid(struct task_struct *child, unsigned long start, unsigned long len)
119{
120	bool valid;
121	struct vm_area_struct *vma;
122	struct sram_list_struct *sraml;
123
124	/* overflow */
125	if (start + len < start)
126		return -EIO;
127
128	down_read(&child->mm->mmap_sem);
129	vma = find_vma(child->mm, start);
130	valid = vma && start >= vma->vm_start && start + len <= vma->vm_end;
131	up_read(&child->mm->mmap_sem);
132	if (valid)
133		return 0;
134
135	for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
136		if (start >= (unsigned long)sraml->addr
137		    && start + len < (unsigned long)sraml->addr + sraml->length)
138			return 0;
139
140	if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
141		return 0;
142
143#ifdef CONFIG_APP_STACK_L1
144	if (child->mm->context.l1_stack_save)
145		if (start >= (unsigned long)l1_stack_base &&
146			start + len < (unsigned long)l1_stack_base + l1_stack_len)
147			return 0;
148#endif
149
150	return -EIO;
151}
152
153/*
154 * retrieve the contents of Blackfin userspace general registers
155 */
156static int genregs_get(struct task_struct *target,
157		       const struct user_regset *regset,
158		       unsigned int pos, unsigned int count,
159		       void *kbuf, void __user *ubuf)
160{
161	struct pt_regs *regs = task_pt_regs(target);
162	int ret;
163
164	/* This sucks ... */
165	regs->usp = target->thread.usp;
166
167	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
168				  regs, 0, sizeof(*regs));
169	if (ret < 0)
170		return ret;
171
172	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
173					sizeof(*regs), -1);
174}
175
176/*
177 * update the contents of the Blackfin userspace general registers
178 */
179static int genregs_set(struct task_struct *target,
180		       const struct user_regset *regset,
181		       unsigned int pos, unsigned int count,
182		       const void *kbuf, const void __user *ubuf)
183{
184	struct pt_regs *regs = task_pt_regs(target);
185	int ret;
186
187	/* Don't let people set SYSCFG (it's at the end of pt_regs) */
188	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
189				 regs, 0, PT_SYSCFG);
190	if (ret < 0)
191		return ret;
192
193	/* This sucks ... */
194	target->thread.usp = regs->usp;
195	/* regs->retx = regs->pc; */
196
197	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
198					PT_SYSCFG, -1);
199}
200
201/*
202 * Define the register sets available on the Blackfin under Linux
203 */
204enum bfin_regset {
205	REGSET_GENERAL,
206};
207
208static const struct user_regset bfin_regsets[] = {
209	[REGSET_GENERAL] = {
210		.core_note_type = NT_PRSTATUS,
211		.n              = sizeof(struct pt_regs) / sizeof(long),
212		.size           = sizeof(long),
213		.align          = sizeof(long),
214		.get            = genregs_get,
215		.set            = genregs_set,
216	},
217};
218
219static const struct user_regset_view user_bfin_native_view = {
220	.name      = "Blackfin",
221	.e_machine = EM_BLACKFIN,
222	.regsets   = bfin_regsets,
223	.n         = ARRAY_SIZE(bfin_regsets),
224};
225
226const struct user_regset_view *task_user_regset_view(struct task_struct *task)
227{
228	return &user_bfin_native_view;
229}
230
231void user_enable_single_step(struct task_struct *child)
232{
233	struct pt_regs *regs = task_pt_regs(child);
234	regs->syscfg |= SYSCFG_SSSTEP;
235
236	set_tsk_thread_flag(child, TIF_SINGLESTEP);
237}
238
239void user_disable_single_step(struct task_struct *child)
240{
241	struct pt_regs *regs = task_pt_regs(child);
242	regs->syscfg &= ~SYSCFG_SSSTEP;
243
244	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
245}
246
247long arch_ptrace(struct task_struct *child, long request,
248		 unsigned long addr, unsigned long data)
249{
250	int ret;
251	unsigned long __user *datap = (unsigned long __user *)data;
252	void *paddr = (void *)addr;
253
254	switch (request) {
255		/* when I and D space are separate, these will need to be fixed. */
256	case PTRACE_PEEKDATA:
257		pr_debug("ptrace: PEEKDATA\n");
258		/* fall through */
259	case PTRACE_PEEKTEXT:	/* read word at location addr. */
260		{
261			unsigned long tmp = 0;
262			int copied = 0, to_copy = sizeof(tmp);
263
264			ret = -EIO;
265			pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %i\n", addr, to_copy);
266			if (is_user_addr_valid(child, addr, to_copy) < 0)
267				break;
268			pr_debug("ptrace: user address is valid\n");
269
270			switch (bfin_mem_access_type(addr, to_copy)) {
271			case BFIN_MEM_ACCESS_CORE:
272			case BFIN_MEM_ACCESS_CORE_ONLY:
273				copied = access_process_vm(child, addr, &tmp,
274				                           to_copy, 0);
275				if (copied)
276					break;
277
278				/* hrm, why didn't that work ... maybe no mapping */
279				if (addr >= FIXED_CODE_START &&
280				    addr + to_copy <= FIXED_CODE_END) {
281					copy_from_user_page(0, 0, 0, &tmp, paddr, to_copy);
282					copied = to_copy;
283				} else if (addr >= BOOT_ROM_START) {
284					memcpy(&tmp, paddr, to_copy);
285					copied = to_copy;
286				}
287
288				break;
289			case BFIN_MEM_ACCESS_DMA:
290				if (safe_dma_memcpy(&tmp, paddr, to_copy))
291					copied = to_copy;
292				break;
293			case BFIN_MEM_ACCESS_ITEST:
294				if (isram_memcpy(&tmp, paddr, to_copy))
295					copied = to_copy;
296				break;
297			default:
298				copied = 0;
299				break;
300			}
301
302			pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
303			if (copied == to_copy)
304				ret = put_user(tmp, datap);
305			break;
306		}
307
308		/* when I and D space are separate, this will have to be fixed. */
309	case PTRACE_POKEDATA:
310		pr_debug("ptrace: PTRACE_PEEKDATA\n");
311		/* fall through */
312	case PTRACE_POKETEXT:	/* write the word at location addr. */
313		{
314			int copied = 0, to_copy = sizeof(data);
315
316			ret = -EIO;
317			pr_debug("ptrace: POKETEXT at addr 0x%08lx + %i bytes %lx\n",
318			         addr, to_copy, data);
319			if (is_user_addr_valid(child, addr, to_copy) < 0)
320				break;
321			pr_debug("ptrace: user address is valid\n");
322
323			switch (bfin_mem_access_type(addr, to_copy)) {
324			case BFIN_MEM_ACCESS_CORE:
325			case BFIN_MEM_ACCESS_CORE_ONLY:
326				copied = access_process_vm(child, addr, &data,
327				                           to_copy, 1);
328				break;
329			case BFIN_MEM_ACCESS_DMA:
330				if (safe_dma_memcpy(paddr, &data, to_copy))
331					copied = to_copy;
332				break;
333			case BFIN_MEM_ACCESS_ITEST:
334				if (isram_memcpy(paddr, &data, to_copy))
335					copied = to_copy;
336				break;
337			default:
338				copied = 0;
339				break;
340			}
341
342			pr_debug("ptrace: copied size %d\n", copied);
343			if (copied == to_copy)
344				ret = 0;
345			break;
346		}
347
348	case PTRACE_PEEKUSR:
349		switch (addr) {
350#ifdef CONFIG_BINFMT_ELF_FDPIC	/* backwards compat */
351		case PT_FDPIC_EXEC:
352			request = PTRACE_GETFDPIC;
353			addr = PTRACE_GETFDPIC_EXEC;
354			goto case_default;
355		case PT_FDPIC_INTERP:
356			request = PTRACE_GETFDPIC;
357			addr = PTRACE_GETFDPIC_INTERP;
358			goto case_default;
359#endif
360		default:
361			ret = get_reg(child, addr, datap);
362		}
363		pr_debug("ptrace: PEEKUSR reg %li with %#lx = %i\n", addr, data, ret);
364		break;
365
366	case PTRACE_POKEUSR:
367		ret = put_reg(child, addr, data);
368		pr_debug("ptrace: POKEUSR reg %li with %li = %i\n", addr, data, ret);
369		break;
370
371	case PTRACE_GETREGS:
372		pr_debug("ptrace: PTRACE_GETREGS\n");
373		return copy_regset_to_user(child, &user_bfin_native_view,
374					   REGSET_GENERAL,
375					   0, sizeof(struct pt_regs),
376					   datap);
377
378	case PTRACE_SETREGS:
379		pr_debug("ptrace: PTRACE_SETREGS\n");
380		return copy_regset_from_user(child, &user_bfin_native_view,
381					     REGSET_GENERAL,
382					     0, sizeof(struct pt_regs),
383					     datap);
384
385	case_default:
386	default:
387		ret = ptrace_request(child, request, addr, data);
388		break;
389	}
390
391	return ret;
392}
393
394asmlinkage int syscall_trace_enter(struct pt_regs *regs)
395{
396	int ret = 0;
397
398	if (test_thread_flag(TIF_SYSCALL_TRACE))
399		ret = tracehook_report_syscall_entry(regs);
400
401	return ret;
402}
403
404asmlinkage void syscall_trace_leave(struct pt_regs *regs)
405{
406	int step;
407
408	step = test_thread_flag(TIF_SINGLESTEP);
409	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
410		tracehook_report_syscall_exit(regs, step);
411}
412