1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * OpenRISC ptrace.c 4 * 5 * Linux architectural port borrowing liberally from similar works of 6 * others. All original copyrights apply as per the original source 7 * declaration. 8 * 9 * Modifications for the OpenRISC architecture: 10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> 11 * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com> 12 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> 13 */ 14 15 #include <linux/kernel.h> 16 #include <linux/sched.h> 17 #include <linux/sched/task_stack.h> 18 #include <linux/string.h> 19 20 #include <linux/mm.h> 21 #include <linux/errno.h> 22 #include <linux/ptrace.h> 23 #include <linux/audit.h> 24 #include <linux/regset.h> 25 #include <linux/elf.h> 26 27 #include <asm/thread_info.h> 28 #include <asm/page.h> 29 30 /* 31 * Copy the thread state to a regset that can be interpreted by userspace. 32 * 33 * It doesn't matter what our internal pt_regs structure looks like. The 34 * important thing is that we export a consistent view of the thread state 35 * to userspace. As such, we need to make sure that the regset remains 36 * ABI compatible as defined by the struct user_regs_struct: 37 * 38 * (Each item is a 32-bit word) 39 * r0 = 0 (exported for clarity) 40 * 31 GPRS r1-r31 41 * PC (Program counter) 42 * SR (Supervision register) 43 */ 44 static int genregs_get(struct task_struct *target, 45 const struct user_regset *regset, 46 struct membuf to) 47 { 48 const struct pt_regs *regs = task_pt_regs(target); 49 50 /* r0 */ 51 membuf_zero(&to, 4); 52 membuf_write(&to, regs->gpr + 1, 31 * 4); 53 membuf_store(&to, regs->pc); 54 return membuf_store(&to, regs->sr); 55 } 56 57 /* 58 * Set the thread state from a regset passed in via ptrace 59 */ 60 static int genregs_set(struct task_struct *target, 61 const struct user_regset *regset, 62 unsigned int pos, unsigned int count, 63 const void *kbuf, const void __user * ubuf) 64 { 65 struct pt_regs *regs = task_pt_regs(target); 66 int ret; 67 68 /* ignore r0 */ 69 user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4); 70 /* r1 - r31 */ 71 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, 72 regs->gpr+1, 4, 4*32); 73 /* PC */ 74 if (!ret) 75 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, 76 ®s->pc, 4*32, 4*33); 77 /* 78 * Skip SR and padding... userspace isn't allowed to changes bits in 79 * the Supervision register 80 */ 81 if (!ret) 82 user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 4*33, -1); 83 84 return ret; 85 } 86 87 /* 88 * As OpenRISC shares GPRs and floating point registers we don't need to export 89 * the floating point registers again. So here we only export the fpcsr special 90 * purpose register. 91 */ 92 static int fpregs_get(struct task_struct *target, 93 const struct user_regset *regset, 94 struct membuf to) 95 { 96 const struct pt_regs *regs = task_pt_regs(target); 97 98 return membuf_store(&to, regs->fpcsr); 99 } 100 101 static int fpregs_set(struct task_struct *target, 102 const struct user_regset *regset, 103 unsigned int pos, unsigned int count, 104 const void *kbuf, const void __user *ubuf) 105 { 106 struct pt_regs *regs = task_pt_regs(target); 107 int ret; 108 109 /* FPCSR */ 110 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, 111 ®s->fpcsr, 0, 4); 112 return ret; 113 } 114 115 /* 116 * Define the register sets available on OpenRISC under Linux 117 */ 118 enum or1k_regset { 119 REGSET_GENERAL, 120 REGSET_FPU, 121 }; 122 123 static const struct user_regset or1k_regsets[] = { 124 [REGSET_GENERAL] = { 125 .core_note_type = NT_PRSTATUS, 126 .n = ELF_NGREG, 127 .size = sizeof(long), 128 .align = sizeof(long), 129 .regset_get = genregs_get, 130 .set = genregs_set, 131 }, 132 [REGSET_FPU] = { 133 .core_note_type = NT_PRFPREG, 134 .n = sizeof(struct __or1k_fpu_state) / sizeof(long), 135 .size = sizeof(long), 136 .align = sizeof(long), 137 .regset_get = fpregs_get, 138 .set = fpregs_set, 139 }, 140 }; 141 142 static const struct user_regset_view user_or1k_native_view = { 143 .name = "or1k", 144 .e_machine = EM_OPENRISC, 145 .regsets = or1k_regsets, 146 .n = ARRAY_SIZE(or1k_regsets), 147 }; 148 149 const struct user_regset_view *task_user_regset_view(struct task_struct *task) 150 { 151 return &user_or1k_native_view; 152 } 153 154 /* 155 * does not yet catch signals sent when the child dies. 156 * in exit.c or in signal.c. 157 */ 158 159 160 /* 161 * Called by kernel/ptrace.c when detaching.. 162 * 163 * Make sure the single step bit is not set. 164 */ 165 void ptrace_disable(struct task_struct *child) 166 { 167 pr_debug("ptrace_disable(): TODO\n"); 168 169 user_disable_single_step(child); 170 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 171 } 172 173 long arch_ptrace(struct task_struct *child, long request, unsigned long addr, 174 unsigned long data) 175 { 176 int ret; 177 178 switch (request) { 179 default: 180 ret = ptrace_request(child, request, addr, data); 181 break; 182 } 183 184 return ret; 185 } 186 187 /* 188 * Notification of system call entry/exit 189 * - triggered by current->work.syscall_trace 190 */ 191 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 192 { 193 long ret = 0; 194 195 if (test_thread_flag(TIF_SYSCALL_TRACE) && 196 ptrace_report_syscall_entry(regs)) 197 /* 198 * Tracing decided this syscall should not happen. 199 * We'll return a bogus call number to get an ENOSYS 200 * error, but leave the original number in <something>. 201 */ 202 ret = -1L; 203 204 audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4], 205 regs->gpr[5], regs->gpr[6]); 206 207 return ret ? : regs->gpr[11]; 208 } 209 210 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs) 211 { 212 int step; 213 214 audit_syscall_exit(regs); 215 216 step = test_thread_flag(TIF_SINGLESTEP); 217 if (step || test_thread_flag(TIF_SYSCALL_TRACE)) 218 ptrace_report_syscall_exit(regs, step); 219 } 220