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 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 syscall_regs[REGS_SP_INDEX] = STUB_DATA; 44 45 return 0; 46 } 47 48 __initcall(init_syscall_regs); 49 50 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 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 } 108 109 long 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 } 136 137 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 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 } 168 169 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 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 } 182 183 int 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 } 195 196 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 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