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. */ 45static 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 76long arch_ptrace(struct task_struct *child, long request, long addr, long data) 77{ 78 int rval; 79 unsigned long val = 0; 80 81 switch (request) { 82 /* Read/write the word at location ADDR in the registers. */ 83 case PTRACE_PEEKUSR: 84 case PTRACE_POKEUSR: 85 pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr); 86 rval = 0; 87 if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) { 88 /* 89 * Special requests that don't actually correspond 90 * to offsets in struct pt_regs. 91 */ 92 if (addr == PT_TEXT_ADDR) { 93 val = child->mm->start_code; 94 } else if (addr == PT_DATA_ADDR) { 95 val = child->mm->start_data; 96 } else if (addr == PT_TEXT_LEN) { 97 val = child->mm->end_code 98 - child->mm->start_code; 99 } else { 100 rval = -EIO; 101 } 102 } else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) { 103 microblaze_reg_t *reg_addr = reg_save_addr(addr, child); 104 if (request == PTRACE_PEEKUSR) 105 val = *reg_addr; 106 else { 107 *reg_addr = data; 108 } 109 } else 110 rval = -EIO; 111 112 if (rval == 0 && request == PTRACE_PEEKUSR) 113 rval = put_user(val, (unsigned long *)data); 114 break; 115 default: 116 rval = ptrace_request(child, request, addr, data); 117 } 118 return rval; 119} 120 121asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 122{ 123 long ret = 0; 124 125 secure_computing(regs->r12); 126 127 if (test_thread_flag(TIF_SYSCALL_TRACE) && 128 tracehook_report_syscall_entry(regs)) 129 /* 130 * Tracing decided this syscall should not happen. 131 * We'll return a bogus call number to get an ENOSYS 132 * error, but leave the original number in regs->regs[0]. 133 */ 134 ret = -1L; 135 136 if (unlikely(current->audit_context)) 137 audit_syscall_entry(EM_XILINX_MICROBLAZE, regs->r12, 138 regs->r5, regs->r6, 139 regs->r7, regs->r8); 140 141 return ret ?: regs->r12; 142} 143 144asmlinkage void do_syscall_trace_leave(struct pt_regs *regs) 145{ 146 int step; 147 148 if (unlikely(current->audit_context)) 149 audit_syscall_exit(AUDITSC_RESULT(regs->r3), regs->r3); 150 151 step = test_thread_flag(TIF_SINGLESTEP); 152 if (step || test_thread_flag(TIF_SYSCALL_TRACE)) 153 tracehook_report_syscall_exit(regs, step); 154} 155 156 157void ptrace_disable(struct task_struct *child) 158{ 159 /* nothing to do */ 160} 161