1 /* 2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 3 * Licensed under the GPL 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 if (stack == NULL) { 29 stack = (unsigned long *) mm_idp->stack + 2; 30 *stack = 0; 31 } 32 return stack; 33 } 34 35 static unsigned long syscall_regs[MAX_REG_NR]; 36 37 static 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 return 0; 44 } 45 46 __initcall(init_syscall_regs); 47 48 static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr) 49 { 50 int n, i; 51 long ret, offset; 52 unsigned long * data; 53 unsigned long * syscall; 54 int err, pid = mm_idp->u.pid; 55 56 n = ptrace_setregs(pid, syscall_regs); 57 if (n < 0) { 58 printk(UM_KERN_ERR "Registers - \n"); 59 for (i = 0; i < MAX_REG_NR; i++) 60 printk(UM_KERN_ERR "\t%d\t0x%lx\n", i, syscall_regs[i]); 61 panic("do_syscall_stub : PTRACE_SETREGS failed, errno = %d\n", 62 -n); 63 } 64 65 err = ptrace(PTRACE_CONT, pid, 0, 0); 66 if (err) 67 panic("Failed to continue stub, pid = %d, errno = %d\n", pid, 68 errno); 69 70 wait_stub_done(pid); 71 72 /* 73 * When the stub stops, we find the following values on the 74 * beginning of the stack: 75 * (long )return_value 76 * (long )offset to failed sycall-data (0, if no error) 77 */ 78 ret = *((unsigned long *) mm_idp->stack); 79 offset = *((unsigned long *) mm_idp->stack + 1); 80 if (offset) { 81 data = (unsigned long *)(mm_idp->stack + offset - STUB_DATA); 82 printk(UM_KERN_ERR "do_syscall_stub : ret = %ld, offset = %ld, " 83 "data = %p\n", ret, offset, data); 84 syscall = (unsigned long *)((unsigned long)data + data[0]); 85 printk(UM_KERN_ERR "do_syscall_stub: syscall %ld failed, " 86 "return value = 0x%lx, expected return value = 0x%lx\n", 87 syscall[0], ret, syscall[7]); 88 printk(UM_KERN_ERR " syscall parameters: " 89 "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 " 95 "data:"); 96 if (n % 4 == 1) 97 printk("\n" UM_KERN_ERR " "); 98 printk(" 0x%lx", data[n]); 99 } 100 if (n > 1) 101 printk("\n"); 102 } 103 else ret = 0; 104 105 *addr = check_init_stack(mm_idp, NULL); 106 107 return ret; 108 } 109 110 long run_syscall_stub(struct mm_id * mm_idp, int syscall, 111 unsigned long *args, long expected, void **addr, 112 int done) 113 { 114 unsigned long *stack = check_init_stack(mm_idp, *addr); 115 116 *stack += sizeof(long); 117 stack += *stack / sizeof(long); 118 119 *stack++ = syscall; 120 *stack++ = args[0]; 121 *stack++ = args[1]; 122 *stack++ = args[2]; 123 *stack++ = args[3]; 124 *stack++ = args[4]; 125 *stack++ = args[5]; 126 *stack++ = expected; 127 *stack = 0; 128 129 if (!done && ((((unsigned long) stack) & ~UM_KERN_PAGE_MASK) < 130 UM_KERN_PAGE_SIZE - 10 * sizeof(long))) { 131 *addr = stack; 132 return 0; 133 } 134 135 return do_syscall_stub(mm_idp, addr); 136 } 137 138 long syscall_stub_data(struct mm_id * mm_idp, 139 unsigned long *data, int data_count, 140 void **addr, void **stub_addr) 141 { 142 unsigned long *stack; 143 int ret = 0; 144 145 /* 146 * If *addr still is uninitialized, it *must* contain NULL. 147 * Thus in this case do_syscall_stub correctly won't be called. 148 */ 149 if ((((unsigned long) *addr) & ~UM_KERN_PAGE_MASK) >= 150 UM_KERN_PAGE_SIZE - (10 + data_count) * sizeof(long)) { 151 ret = do_syscall_stub(mm_idp, addr); 152 /* in case of error, don't overwrite data on stack */ 153 if (ret) 154 return ret; 155 } 156 157 stack = check_init_stack(mm_idp, *addr); 158 *addr = stack; 159 160 *stack = data_count * sizeof(long); 161 162 memcpy(stack + 1, data, data_count * sizeof(long)); 163 164 *stub_addr = (void *)(((unsigned long)(stack + 1) & 165 ~UM_KERN_PAGE_MASK) + STUB_DATA); 166 167 return 0; 168 } 169 170 int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len, int prot, 171 int phys_fd, unsigned long long offset, int done, void **data) 172 { 173 int ret; 174 unsigned long args[] = { virt, len, prot, 175 MAP_SHARED | MAP_FIXED, phys_fd, 176 MMAP_OFFSET(offset) }; 177 178 ret = run_syscall_stub(mm_idp, STUB_MMAP_NR, args, virt, 179 data, done); 180 181 return ret; 182 } 183 184 int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len, 185 int done, void **data) 186 { 187 int ret; 188 unsigned long args[] = { (unsigned long) addr, len, 0, 0, 0, 189 0 }; 190 191 ret = run_syscall_stub(mm_idp, __NR_munmap, args, 0, 192 data, done); 193 194 return ret; 195 } 196 197 int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len, 198 unsigned int prot, int done, void **data) 199 { 200 int ret; 201 unsigned long args[] = { addr, len, prot, 0, 0, 0 }; 202 203 ret = run_syscall_stub(mm_idp, __NR_mprotect, args, 0, 204 data, done); 205 206 return ret; 207 } 208