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/sched/task_stack.h> 31 #include <linux/ptrace.h> 32 #include <linux/signal.h> 33 #include <linux/elf.h> 34 #include <linux/audit.h> 35 #include <linux/seccomp.h> 36 #include <linux/tracehook.h> 37 38 #include <linux/errno.h> 39 #include <asm/processor.h> 40 #include <linux/uaccess.h> 41 #include <asm/asm-offsets.h> 42 #include <asm/cacheflush.h> 43 #include <asm/syscall.h> 44 #include <linux/io.h> 45 46 /* Returns the address where the register at REG_OFFS in P is stashed away. */ 47 static microblaze_reg_t *reg_save_addr(unsigned reg_offs, 48 struct task_struct *t) 49 { 50 struct pt_regs *regs; 51 52 /* 53 * Three basic cases: 54 * 55 * (1) A register normally saved before calling the scheduler, is 56 * available in the kernel entry pt_regs structure at the top 57 * of the kernel stack. The kernel trap/irq exit path takes 58 * care to save/restore almost all registers for ptrace'd 59 * processes. 60 * 61 * (2) A call-clobbered register, where the process P entered the 62 * kernel via [syscall] trap, is not stored anywhere; that's 63 * OK, because such registers are not expected to be preserved 64 * when the trap returns anyway (so we don't actually bother to 65 * test for this case). 66 * 67 * (3) A few registers not used at all by the kernel, and so 68 * normally never saved except by context-switches, are in the 69 * context switch state. 70 */ 71 72 /* Register saved during kernel entry (or not available). */ 73 regs = task_pt_regs(t); 74 75 return (microblaze_reg_t *)((char *)regs + reg_offs); 76 } 77 78 long arch_ptrace(struct task_struct *child, long request, 79 unsigned long addr, unsigned long data) 80 { 81 int rval; 82 unsigned long val = 0; 83 84 switch (request) { 85 /* Read/write the word at location ADDR in the registers. */ 86 case PTRACE_PEEKUSR: 87 case PTRACE_POKEUSR: 88 pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr); 89 rval = 0; 90 if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) { 91 /* 92 * Special requests that don't actually correspond 93 * to offsets in struct pt_regs. 94 */ 95 if (addr == PT_TEXT_ADDR) { 96 val = child->mm->start_code; 97 } else if (addr == PT_DATA_ADDR) { 98 val = child->mm->start_data; 99 } else if (addr == PT_TEXT_LEN) { 100 val = child->mm->end_code 101 - child->mm->start_code; 102 } else { 103 rval = -EIO; 104 } 105 } else if (addr < PT_SIZE && (addr & 0x3) == 0) { 106 microblaze_reg_t *reg_addr = reg_save_addr(addr, child); 107 if (request == PTRACE_PEEKUSR) 108 val = *reg_addr; 109 else { 110 #if 1 111 *reg_addr = data; 112 #else 113 /* MS potential problem on WB system 114 * Be aware that reg_addr is virtual address 115 * virt_to_phys conversion is necessary. 116 * This could be sensible solution. 117 */ 118 u32 paddr = virt_to_phys((u32)reg_addr); 119 invalidate_icache_range(paddr, paddr + 4); 120 *reg_addr = data; 121 flush_dcache_range(paddr, paddr + 4); 122 #endif 123 } 124 } else 125 rval = -EIO; 126 127 if (rval == 0 && request == PTRACE_PEEKUSR) 128 rval = put_user(val, (unsigned long __user *)data); 129 break; 130 default: 131 rval = ptrace_request(child, request, addr, data); 132 } 133 return rval; 134 } 135 136 asmlinkage unsigned long do_syscall_trace_enter(struct pt_regs *regs) 137 { 138 unsigned long ret = 0; 139 140 secure_computing_strict(regs->r12); 141 142 if (test_thread_flag(TIF_SYSCALL_TRACE) && 143 tracehook_report_syscall_entry(regs)) 144 /* 145 * Tracing decided this syscall should not happen. 146 * We'll return a bogus call number to get an ENOSYS 147 * error, but leave the original number in regs->regs[0]. 148 */ 149 ret = -1L; 150 151 audit_syscall_entry(regs->r12, regs->r5, regs->r6, regs->r7, regs->r8); 152 153 return ret ?: regs->r12; 154 } 155 156 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs) 157 { 158 int step; 159 160 audit_syscall_exit(regs); 161 162 step = test_thread_flag(TIF_SINGLESTEP); 163 if (step || test_thread_flag(TIF_SYSCALL_TRACE)) 164 tracehook_report_syscall_exit(regs, step); 165 } 166 167 void ptrace_disable(struct task_struct *child) 168 { 169 /* nothing to do */ 170 } 171