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 79 switch (request) { 80 /* Read/write the word at location ADDR in the registers. */ 81 case PTRACE_PEEKUSR: 82 case PTRACE_POKEUSR: 83 pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr); 84 rval = 0; 85 if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) { 86 /* 87 * Special requests that don't actually correspond 88 * to offsets in struct pt_regs. 89 */ 90 if (addr == PT_TEXT_ADDR) { 91 val = child->mm->start_code; 92 } else if (addr == PT_DATA_ADDR) { 93 val = child->mm->start_data; 94 } else if (addr == PT_TEXT_LEN) { 95 val = child->mm->end_code 96 - child->mm->start_code; 97 } else { 98 rval = -EIO; 99 } 100 } else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) { 101 microblaze_reg_t *reg_addr = reg_save_addr(addr, child); 102 if (request == PTRACE_PEEKUSR) 103 val = *reg_addr; 104 else 105 *reg_addr = data; 106 } else 107 rval = -EIO; 108 109 if (rval == 0 && request == PTRACE_PEEKUSR) 110 rval = put_user(val, (unsigned long *)data); 111 break; 112 default: 113 rval = ptrace_request(child, request, addr, data); 114 } 115 return rval; 116 } 117 118 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 119 { 120 long ret = 0; 121 122 secure_computing(regs->r12); 123 124 if (test_thread_flag(TIF_SYSCALL_TRACE) && 125 tracehook_report_syscall_entry(regs)) 126 /* 127 * Tracing decided this syscall should not happen. 128 * We'll return a bogus call number to get an ENOSYS 129 * error, but leave the original number in regs->regs[0]. 130 */ 131 ret = -1L; 132 133 if (unlikely(current->audit_context)) 134 audit_syscall_entry(EM_XILINX_MICROBLAZE, regs->r12, 135 regs->r5, regs->r6, 136 regs->r7, regs->r8); 137 138 return ret ?: regs->r12; 139 } 140 141 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs) 142 { 143 int step; 144 145 if (unlikely(current->audit_context)) 146 audit_syscall_exit(AUDITSC_RESULT(regs->r3), regs->r3); 147 148 step = test_thread_flag(TIF_SINGLESTEP); 149 if (step || test_thread_flag(TIF_SYSCALL_TRACE)) 150 tracehook_report_syscall_exit(regs, step); 151 } 152 153 #if 0 154 static asmlinkage void syscall_trace(void) 155 { 156 if (!test_thread_flag(TIF_SYSCALL_TRACE)) 157 return; 158 if (!(current->ptrace & PT_PTRACED)) 159 return; 160 /* The 0x80 provides a way for the tracing parent to distinguish 161 between a syscall stop and SIGTRAP delivery */ 162 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 163 ? 0x80 : 0)); 164 /* 165 * this isn't the same as continuing with a signal, but it will do 166 * for normal use. strace only continues with a signal if the 167 * stopping signal is not SIGTRAP. -brl 168 */ 169 if (current->exit_code) { 170 send_sig(current->exit_code, current, 1); 171 current->exit_code = 0; 172 } 173 } 174 #endif 175 176 void ptrace_disable(struct task_struct *child) 177 { 178 /* nothing to do */ 179 } 180