1 /* 2 * `ptrace' system call 3 * 4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> 5 * Copyright (C) 2007-2009 PetaLogix 6 * Copyright (C) 2004-2007 John Williams <john.williams@petalogix.com> 7 * 8 * derived from arch/v850/kernel/ptrace.c 9 * 10 * Copyright (C) 2002,03 NEC Electronics Corporation 11 * Copyright (C) 2002,03 Miles Bader <miles@gnu.org> 12 * 13 * Derived from arch/mips/kernel/ptrace.c: 14 * 15 * Copyright (C) 1992 Ross Biro 16 * Copyright (C) Linus Torvalds 17 * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle 18 * Copyright (C) 1996 David S. Miller 19 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com 20 * Copyright (C) 1999 MIPS Technologies, Inc. 21 * 22 * This file is subject to the terms and conditions of the GNU General 23 * Public License. See the file COPYING in the main directory of this 24 * archive for more details. 25 */ 26 27 #include <linux/kernel.h> 28 #include <linux/mm.h> 29 #include <linux/sched.h> 30 #include <linux/ptrace.h> 31 #include <linux/signal.h> 32 #include <linux/elf.h> 33 #include <linux/audit.h> 34 #include <linux/seccomp.h> 35 #include <linux/tracehook.h> 36 37 #include <linux/errno.h> 38 #include <asm/processor.h> 39 #include <linux/uaccess.h> 40 #include <asm/asm-offsets.h> 41 42 /* Returns the address where the register at REG_OFFS in P is stashed away. */ 43 static microblaze_reg_t *reg_save_addr(unsigned reg_offs, 44 struct task_struct *t) 45 { 46 struct pt_regs *regs; 47 48 /* 49 * Three basic cases: 50 * 51 * (1) A register normally saved before calling the scheduler, is 52 * available in the kernel entry pt_regs structure at the top 53 * of the kernel stack. The kernel trap/irq exit path takes 54 * care to save/restore almost all registers for ptrace'd 55 * processes. 56 * 57 * (2) A call-clobbered register, where the process P entered the 58 * kernel via [syscall] trap, is not stored anywhere; that's 59 * OK, because such registers are not expected to be preserved 60 * when the trap returns anyway (so we don't actually bother to 61 * test for this case). 62 * 63 * (3) A few registers not used at all by the kernel, and so 64 * normally never saved except by context-switches, are in the 65 * context switch state. 66 */ 67 68 /* Register saved during kernel entry (or not available). */ 69 regs = task_pt_regs(t); 70 71 return (microblaze_reg_t *)((char *)regs + reg_offs); 72 } 73 74 long arch_ptrace(struct task_struct *child, long request, long addr, long data) 75 { 76 int rval; 77 unsigned long val = 0; 78 unsigned long copied; 79 80 switch (request) { 81 case PTRACE_PEEKTEXT: /* read word at location addr. */ 82 case PTRACE_PEEKDATA: 83 pr_debug("PEEKTEXT/PEEKDATA at %08lX\n", addr); 84 copied = access_process_vm(child, addr, &val, sizeof(val), 0); 85 rval = -EIO; 86 if (copied != sizeof(val)) 87 break; 88 rval = put_user(val, (unsigned long *)data); 89 break; 90 91 case PTRACE_POKETEXT: /* write the word at location addr. */ 92 case PTRACE_POKEDATA: 93 pr_debug("POKETEXT/POKEDATA to %08lX\n", addr); 94 rval = 0; 95 if (access_process_vm(child, addr, &data, sizeof(data), 1) 96 == sizeof(data)) 97 break; 98 rval = -EIO; 99 break; 100 101 /* Read/write the word at location ADDR in the registers. */ 102 case PTRACE_PEEKUSR: 103 case PTRACE_POKEUSR: 104 pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr); 105 rval = 0; 106 if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) { 107 /* 108 * Special requests that don't actually correspond 109 * to offsets in struct pt_regs. 110 */ 111 if (addr == PT_TEXT_ADDR) { 112 val = child->mm->start_code; 113 } else if (addr == PT_DATA_ADDR) { 114 val = child->mm->start_data; 115 } else if (addr == PT_TEXT_LEN) { 116 val = child->mm->end_code 117 - child->mm->start_code; 118 } else { 119 rval = -EIO; 120 } 121 } else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) { 122 microblaze_reg_t *reg_addr = reg_save_addr(addr, child); 123 if (request == PTRACE_PEEKUSR) 124 val = *reg_addr; 125 else 126 *reg_addr = data; 127 } else 128 rval = -EIO; 129 130 if (rval == 0 && request == PTRACE_PEEKUSR) 131 rval = put_user(val, (unsigned long *)data); 132 break; 133 /* Continue and stop at next (return from) syscall */ 134 case PTRACE_SYSCALL: 135 pr_debug("PTRACE_SYSCALL\n"); 136 case PTRACE_SINGLESTEP: 137 pr_debug("PTRACE_SINGLESTEP\n"); 138 /* Restart after a signal. */ 139 case PTRACE_CONT: 140 pr_debug("PTRACE_CONT\n"); 141 rval = -EIO; 142 if (!valid_signal(data)) 143 break; 144 145 if (request == PTRACE_SYSCALL) 146 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 147 else 148 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 149 150 child->exit_code = data; 151 pr_debug("wakeup_process\n"); 152 wake_up_process(child); 153 rval = 0; 154 break; 155 156 /* 157 * make the child exit. Best I can do is send it a sigkill. 158 * perhaps it should be put in the status that it wants to 159 * exit. 160 */ 161 case PTRACE_KILL: 162 pr_debug("PTRACE_KILL\n"); 163 rval = 0; 164 if (child->exit_state == EXIT_ZOMBIE) /* already dead */ 165 break; 166 child->exit_code = SIGKILL; 167 wake_up_process(child); 168 break; 169 170 case PTRACE_DETACH: /* detach a process that was attached. */ 171 pr_debug("PTRACE_DETACH\n"); 172 rval = ptrace_detach(child, data); 173 break; 174 default: 175 /* rval = ptrace_request(child, request, addr, data); noMMU */ 176 rval = -EIO; 177 } 178 return rval; 179 } 180 181 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 182 { 183 long ret = 0; 184 185 secure_computing(regs->r12); 186 187 if (test_thread_flag(TIF_SYSCALL_TRACE) && 188 tracehook_report_syscall_entry(regs)) 189 /* 190 * Tracing decided this syscall should not happen. 191 * We'll return a bogus call number to get an ENOSYS 192 * error, but leave the original number in regs->regs[0]. 193 */ 194 ret = -1L; 195 196 if (unlikely(current->audit_context)) 197 audit_syscall_entry(EM_XILINX_MICROBLAZE, regs->r12, 198 regs->r5, regs->r6, 199 regs->r7, regs->r8); 200 201 return ret ?: regs->r12; 202 } 203 204 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs) 205 { 206 int step; 207 208 if (unlikely(current->audit_context)) 209 audit_syscall_exit(AUDITSC_RESULT(regs->r3), regs->r3); 210 211 step = test_thread_flag(TIF_SINGLESTEP); 212 if (step || test_thread_flag(TIF_SYSCALL_TRACE)) 213 tracehook_report_syscall_exit(regs, step); 214 } 215 216 #if 0 217 static asmlinkage void syscall_trace(void) 218 { 219 if (!test_thread_flag(TIF_SYSCALL_TRACE)) 220 return; 221 if (!(current->ptrace & PT_PTRACED)) 222 return; 223 /* The 0x80 provides a way for the tracing parent to distinguish 224 between a syscall stop and SIGTRAP delivery */ 225 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 226 ? 0x80 : 0)); 227 /* 228 * this isn't the same as continuing with a signal, but it will do 229 * for normal use. strace only continues with a signal if the 230 * stopping signal is not SIGTRAP. -brl 231 */ 232 if (current->exit_code) { 233 send_sig(current->exit_code, current, 1); 234 current->exit_code = 0; 235 } 236 } 237 #endif 238 239 void ptrace_disable(struct task_struct *child) 240 { 241 /* nothing to do */ 242 } 243