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 #include <asm/cacheflush.h> 42 #include <asm/io.h> 43 44 /* Returns the address where the register at REG_OFFS in P is stashed away. */ 45 static microblaze_reg_t *reg_save_addr(unsigned reg_offs, 46 struct task_struct *t) 47 { 48 struct pt_regs *regs; 49 50 /* 51 * Three basic cases: 52 * 53 * (1) A register normally saved before calling the scheduler, is 54 * available in the kernel entry pt_regs structure at the top 55 * of the kernel stack. The kernel trap/irq exit path takes 56 * care to save/restore almost all registers for ptrace'd 57 * processes. 58 * 59 * (2) A call-clobbered register, where the process P entered the 60 * kernel via [syscall] trap, is not stored anywhere; that's 61 * OK, because such registers are not expected to be preserved 62 * when the trap returns anyway (so we don't actually bother to 63 * test for this case). 64 * 65 * (3) A few registers not used at all by the kernel, and so 66 * normally never saved except by context-switches, are in the 67 * context switch state. 68 */ 69 70 /* Register saved during kernel entry (or not available). */ 71 regs = task_pt_regs(t); 72 73 return (microblaze_reg_t *)((char *)regs + reg_offs); 74 } 75 76 long arch_ptrace(struct task_struct *child, long request, 77 unsigned long addr, unsigned long data) 78 { 79 int rval; 80 unsigned long val = 0; 81 82 switch (request) { 83 /* Read/write the word at location ADDR in the registers. */ 84 case PTRACE_PEEKUSR: 85 case PTRACE_POKEUSR: 86 pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr); 87 rval = 0; 88 if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) { 89 /* 90 * Special requests that don't actually correspond 91 * to offsets in struct pt_regs. 92 */ 93 if (addr == PT_TEXT_ADDR) { 94 val = child->mm->start_code; 95 } else if (addr == PT_DATA_ADDR) { 96 val = child->mm->start_data; 97 } else if (addr == PT_TEXT_LEN) { 98 val = child->mm->end_code 99 - child->mm->start_code; 100 } else { 101 rval = -EIO; 102 } 103 } else if (addr < PT_SIZE && (addr & 0x3) == 0) { 104 microblaze_reg_t *reg_addr = reg_save_addr(addr, child); 105 if (request == PTRACE_PEEKUSR) 106 val = *reg_addr; 107 else { 108 #if 1 109 *reg_addr = data; 110 #else 111 /* MS potential problem on WB system 112 * Be aware that reg_addr is virtual address 113 * virt_to_phys conversion is necessary. 114 * This could be sensible solution. 115 */ 116 u32 paddr = virt_to_phys((u32)reg_addr); 117 invalidate_icache_range(paddr, paddr + 4); 118 *reg_addr = data; 119 flush_dcache_range(paddr, paddr + 4); 120 #endif 121 } 122 } else 123 rval = -EIO; 124 125 if (rval == 0 && request == PTRACE_PEEKUSR) 126 rval = put_user(val, (unsigned long *)data); 127 break; 128 default: 129 rval = ptrace_request(child, request, addr, data); 130 } 131 return rval; 132 } 133 134 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 135 { 136 long ret = 0; 137 138 secure_computing(regs->r12); 139 140 if (test_thread_flag(TIF_SYSCALL_TRACE) && 141 tracehook_report_syscall_entry(regs)) 142 /* 143 * Tracing decided this syscall should not happen. 144 * We'll return a bogus call number to get an ENOSYS 145 * error, but leave the original number in regs->regs[0]. 146 */ 147 ret = -1L; 148 149 if (unlikely(current->audit_context)) 150 audit_syscall_entry(EM_XILINX_MICROBLAZE, regs->r12, 151 regs->r5, regs->r6, 152 regs->r7, regs->r8); 153 154 return ret ?: regs->r12; 155 } 156 157 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs) 158 { 159 int step; 160 161 if (unlikely(current->audit_context)) 162 audit_syscall_exit(AUDITSC_RESULT(regs->r3), regs->r3); 163 164 step = test_thread_flag(TIF_SINGLESTEP); 165 if (step || test_thread_flag(TIF_SYSCALL_TRACE)) 166 tracehook_report_syscall_exit(regs, step); 167 } 168 169 #if 0 170 static asmlinkage void syscall_trace(void) 171 { 172 if (!test_thread_flag(TIF_SYSCALL_TRACE)) 173 return; 174 if (!(current->ptrace & PT_PTRACED)) 175 return; 176 /* The 0x80 provides a way for the tracing parent to distinguish 177 between a syscall stop and SIGTRAP delivery */ 178 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) 179 ? 0x80 : 0)); 180 /* 181 * this isn't the same as continuing with a signal, but it will do 182 * for normal use. strace only continues with a signal if the 183 * stopping signal is not SIGTRAP. -brl 184 */ 185 if (current->exit_code) { 186 send_sig(current->exit_code, current, 1); 187 current->exit_code = 0; 188 } 189 } 190 #endif 191 192 void ptrace_disable(struct task_struct *child) 193 { 194 /* nothing to do */ 195 } 196