Line data Source code
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 :
21 : extern char batch_syscall_stub[], __syscall_stub_start[];
22 :
23 : extern void wait_stub_done(int pid);
24 :
25 : static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
26 : unsigned long *stack)
27 : {
28 0 : if (stack == NULL) {
29 0 : stack = (unsigned long *) mm_idp->stack + 2;
30 0 : *stack = 0;
31 : }
32 : return stack;
33 : }
34 :
35 : static unsigned long syscall_regs[MAX_REG_NR];
36 :
37 1 : static int __init init_syscall_regs(void)
38 : {
39 1 : get_safe_registers(syscall_regs, NULL);
40 3 : syscall_regs[REGS_IP_INDEX] = STUB_CODE +
41 1 : ((unsigned long) batch_syscall_stub -
42 1 : (unsigned long) __syscall_stub_start);
43 1 : syscall_regs[REGS_SP_INDEX] = STUB_DATA;
44 :
45 1 : return 0;
46 : }
47 :
48 : __initcall(init_syscall_regs);
49 :
50 0 : static 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 0 : int err, pid = mm_idp->u.pid;
57 :
58 0 : n = ptrace_setregs(pid, syscall_regs);
59 0 : if (n < 0) {
60 0 : printk(UM_KERN_ERR "Registers - \n");
61 0 : for (i = 0; i < MAX_REG_NR; i++)
62 0 : printk(UM_KERN_ERR "\t%d\t0x%lx\n", i, syscall_regs[i]);
63 0 : panic("%s : PTRACE_SETREGS failed, errno = %d\n",
64 : __func__, -n);
65 : }
66 :
67 0 : err = ptrace(PTRACE_CONT, pid, 0, 0);
68 0 : if (err)
69 0 : panic("Failed to continue stub, pid = %d, errno = %d\n", pid,
70 0 : errno);
71 :
72 0 : 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 0 : ret = *((unsigned long *) mm_idp->stack);
81 0 : offset = *((unsigned long *) mm_idp->stack + 1);
82 0 : if (offset) {
83 0 : data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA);
84 0 : printk(UM_KERN_ERR "%s : ret = %ld, offset = %ld, data = %p\n",
85 : __func__, ret, offset, data);
86 0 : syscall = (unsigned long *)((unsigned long)data + data[0]);
87 0 : 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 0 : 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 0 : for (n = 1; n < data[0]/sizeof(long); n++) {
93 0 : if (n == 1)
94 0 : printk(UM_KERN_ERR " additional syscall data:");
95 0 : if (n % 4 == 1)
96 0 : printk("\n" UM_KERN_ERR " ");
97 0 : printk(" 0x%lx", data[n]);
98 : }
99 0 : if (n > 1)
100 0 : printk("\n");
101 : }
102 : else ret = 0;
103 :
104 0 : *addr = check_init_stack(mm_idp, NULL);
105 :
106 0 : return ret;
107 : }
108 :
109 0 : long run_syscall_stub(struct mm_id * mm_idp, int syscall,
110 : unsigned long *args, long expected, void **addr,
111 : int done)
112 : {
113 0 : unsigned long *stack = check_init_stack(mm_idp, *addr);
114 :
115 0 : *stack += sizeof(long);
116 0 : stack += *stack / sizeof(long);
117 :
118 0 : *stack++ = syscall;
119 0 : *stack++ = args[0];
120 0 : *stack++ = args[1];
121 0 : *stack++ = args[2];
122 0 : *stack++ = args[3];
123 0 : *stack++ = args[4];
124 0 : *stack++ = args[5];
125 0 : *stack++ = expected;
126 0 : *stack = 0;
127 :
128 0 : if (!done && ((((unsigned long) stack) & ~UM_KERN_PAGE_MASK) <
129 : UM_KERN_PAGE_SIZE - 10 * sizeof(long))) {
130 0 : *addr = stack;
131 0 : return 0;
132 : }
133 :
134 0 : return do_syscall_stub(mm_idp, addr);
135 : }
136 :
137 0 : long 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 0 : 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 0 : if ((((unsigned long) *addr) & ~UM_KERN_PAGE_MASK) >=
149 0 : UM_KERN_PAGE_SIZE - (10 + data_count) * sizeof(long)) {
150 0 : ret = do_syscall_stub(mm_idp, addr);
151 : /* in case of error, don't overwrite data on stack */
152 0 : if (ret)
153 0 : return ret;
154 : }
155 :
156 0 : stack = check_init_stack(mm_idp, *addr);
157 0 : *addr = stack;
158 :
159 0 : *stack = data_count * sizeof(long);
160 :
161 0 : memcpy(stack + 1, data, data_count * sizeof(long));
162 :
163 0 : *stub_addr = (void *)(((unsigned long)(stack + 1) &
164 0 : ~UM_KERN_PAGE_MASK) + STUB_DATA);
165 :
166 0 : return 0;
167 : }
168 :
169 0 : int 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 0 : unsigned long args[] = { virt, len, prot,
174 : MAP_SHARED | MAP_FIXED, phys_fd,
175 : MMAP_OFFSET(offset) };
176 :
177 0 : ret = run_syscall_stub(mm_idp, STUB_MMAP_NR, args, virt,
178 : data, done);
179 :
180 0 : return ret;
181 : }
182 :
183 0 : int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
184 : int done, void **data)
185 : {
186 : int ret;
187 0 : unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0,
188 : 0 };
189 :
190 0 : ret = run_syscall_stub(mm_idp, __NR_munmap, args, 0,
191 : data, done);
192 :
193 0 : return ret;
194 : }
195 :
196 0 : int 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 0 : unsigned long args[] = { addr, len, prot, 0, 0, 0 };
201 :
202 0 : ret = run_syscall_stub(mm_idp, __NR_mprotect, args, 0,
203 : data, done);
204 :
205 0 : return ret;
206 : }
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