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