1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <stddef.h>
7#include <unistd.h>
8#include <errno.h>
9#include <string.h>
10#include <sys/mman.h>
11#include <init.h>
12#include <as-layout.h>
13#include <mm_id.h>
14#include <os.h>
15#include <ptrace_user.h>
16#include <registers.h>
17#include <skas.h>
18#include <sysdep/ptrace.h>
19#include <sysdep/stub.h>
20
21extern char batch_syscall_stub[], __syscall_stub_start[];
22
23extern void wait_stub_done(int pid);
24
25static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
26					      unsigned long *stack)
27{
28	if (stack == NULL) {
29		stack = (unsigned long *) mm_idp->stack + 2;
30		*stack = 0;
31	}
32	return stack;
33}
34
35static unsigned long syscall_regs[MAX_REG_NR];
36
37static int __init init_syscall_regs(void)
38{
39	get_safe_registers(syscall_regs, NULL);
40	syscall_regs[REGS_IP_INDEX] = STUB_CODE +
41		((unsigned long) batch_syscall_stub -
42		 (unsigned long) __syscall_stub_start);
43	syscall_regs[REGS_SP_INDEX] = STUB_DATA;
44
45	return 0;
46}
47
48__initcall(init_syscall_regs);
49
50static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
51{
52	int n, i;
53	long ret, offset;
54	unsigned long * data;
55	unsigned long * syscall;
56	int err, pid = mm_idp->u.pid;
57
58	n = ptrace_setregs(pid, syscall_regs);
59	if (n < 0) {
60		printk(UM_KERN_ERR "Registers - \n");
61		for (i = 0; i < MAX_REG_NR; i++)
62			printk(UM_KERN_ERR "\t%d\t0x%lx\n", i, syscall_regs[i]);
63		panic("%s : PTRACE_SETREGS failed, errno = %d\n",
64		      __func__, -n);
65	}
66
67	err = ptrace(PTRACE_CONT, pid, 0, 0);
68	if (err)
69		panic("Failed to continue stub, pid = %d, errno = %d\n", pid,
70		      errno);
71
72	wait_stub_done(pid);
73
74	/*
75	 * When the stub stops, we find the following values on the
76	 * beginning of the stack:
77	 * (long )return_value
78	 * (long )offset to failed sycall-data (0, if no error)
79	 */
80	ret = *((unsigned long *) mm_idp->stack);
81	offset = *((unsigned long *) mm_idp->stack + 1);
82	if (offset) {
83		data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA);
84		printk(UM_KERN_ERR "%s : ret = %ld, offset = %ld, data = %p\n",
85		       __func__, ret, offset, data);
86		syscall = (unsigned long *)((unsigned long)data + data[0]);
87		printk(UM_KERN_ERR "%s: syscall %ld failed, return value = 0x%lx, expected return value = 0x%lx\n",
88		       __func__, syscall[0], ret, syscall[7]);
89		printk(UM_KERN_ERR "    syscall parameters: 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
90		       syscall[1], syscall[2], syscall[3],
91		       syscall[4], syscall[5], syscall[6]);
92		for (n = 1; n < data[0]/sizeof(long); n++) {
93			if (n == 1)
94				printk(UM_KERN_ERR "    additional syscall data:");
95			if (n % 4 == 1)
96				printk("\n" UM_KERN_ERR "      ");
97			printk("  0x%lx", data[n]);
98		}
99		if (n > 1)
100			printk("\n");
101	}
102	else ret = 0;
103
104	*addr = check_init_stack(mm_idp, NULL);
105
106	return ret;
107}
108
109long run_syscall_stub(struct mm_id * mm_idp, int syscall,
110		      unsigned long *args, long expected, void **addr,
111		      int done)
112{
113	unsigned long *stack = check_init_stack(mm_idp, *addr);
114
115	*stack += sizeof(long);
116	stack += *stack / sizeof(long);
117
118	*stack++ = syscall;
119	*stack++ = args[0];
120	*stack++ = args[1];
121	*stack++ = args[2];
122	*stack++ = args[3];
123	*stack++ = args[4];
124	*stack++ = args[5];
125	*stack++ = expected;
126	*stack = 0;
127
128	if (!done && ((((unsigned long) stack) & ~UM_KERN_PAGE_MASK) <
129		     UM_KERN_PAGE_SIZE - 10 * sizeof(long))) {
130		*addr = stack;
131		return 0;
132	}
133
134	return do_syscall_stub(mm_idp, addr);
135}
136
137long syscall_stub_data(struct mm_id * mm_idp,
138		       unsigned long *data, int data_count,
139		       void **addr, void **stub_addr)
140{
141	unsigned long *stack;
142	int ret = 0;
143
144	/*
145	 * If *addr still is uninitialized, it *must* contain NULL.
146	 * Thus in this case do_syscall_stub correctly won't be called.
147	 */
148	if ((((unsigned long) *addr) & ~UM_KERN_PAGE_MASK) >=
149	   UM_KERN_PAGE_SIZE - (10 + data_count) * sizeof(long)) {
150		ret = do_syscall_stub(mm_idp, addr);
151		/* in case of error, don't overwrite data on stack */
152		if (ret)
153			return ret;
154	}
155
156	stack = check_init_stack(mm_idp, *addr);
157	*addr = stack;
158
159	*stack = data_count * sizeof(long);
160
161	memcpy(stack + 1, data, data_count * sizeof(long));
162
163	*stub_addr = (void *)(((unsigned long)(stack + 1) &
164			       ~UM_KERN_PAGE_MASK) + STUB_DATA);
165
166	return 0;
167}
168
169int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len, int prot,
170	int phys_fd, unsigned long long offset, int done, void **data)
171{
172	int ret;
173	unsigned long args[] = { virt, len, prot,
174				 MAP_SHARED | MAP_FIXED, phys_fd,
175				 MMAP_OFFSET(offset) };
176
177	ret = run_syscall_stub(mm_idp, STUB_MMAP_NR, args, virt,
178			       data, done);
179
180	return ret;
181}
182
183int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
184	  int done, void **data)
185{
186	int ret;
187	unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0,
188				 0 };
189
190	ret = run_syscall_stub(mm_idp, __NR_munmap, args, 0,
191			       data, done);
192
193	return ret;
194}
195
196int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
197	    unsigned int prot, int done, void **data)
198{
199	int ret;
200	unsigned long args[] = { addr, len, prot, 0, 0, 0 };
201
202	ret = run_syscall_stub(mm_idp, __NR_mprotect, args, 0,
203			       data, done);
204
205	return ret;
206}
207