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 30asmlinkage long do_syscall_trace_enter(struct pt_regs *regs); 31 32asmlinkage void do_syscall_trace_leave(struct pt_regs *regs); 33 34/* 35 * Copy the thread state to a regset that can be interpreted by userspace. 36 * 37 * It doesn't matter what our internal pt_regs structure looks like. The 38 * important thing is that we export a consistent view of the thread state 39 * to userspace. As such, we need to make sure that the regset remains 40 * ABI compatible as defined by the struct user_regs_struct: 41 * 42 * (Each item is a 32-bit word) 43 * r0 = 0 (exported for clarity) 44 * 31 GPRS r1-r31 45 * PC (Program counter) 46 * SR (Supervision register) 47 */ 48static int genregs_get(struct task_struct *target, 49 const struct user_regset *regset, 50 struct membuf to) 51{ 52 const struct pt_regs *regs = task_pt_regs(target); 53 54 /* r0 */ 55 membuf_zero(&to, 4); 56 membuf_write(&to, regs->gpr + 1, 31 * 4); 57 membuf_store(&to, regs->pc); 58 return membuf_store(&to, regs->sr); 59} 60 61/* 62 * Set the thread state from a regset passed in via ptrace 63 */ 64static int genregs_set(struct task_struct *target, 65 const struct user_regset *regset, 66 unsigned int pos, unsigned int count, 67 const void *kbuf, const void __user * ubuf) 68{ 69 struct pt_regs *regs = task_pt_regs(target); 70 int ret; 71 72 /* ignore r0 */ 73 user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4); 74 /* r1 - r31 */ 75 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, 76 regs->gpr+1, 4, 4*32); 77 /* PC */ 78 if (!ret) 79 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, 80 ®s->pc, 4*32, 4*33); 81 /* 82 * Skip SR and padding... userspace isn't allowed to changes bits in 83 * the Supervision register 84 */ 85 if (!ret) 86 user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 4*33, -1); 87 88 return ret; 89} 90 91/* 92 * As OpenRISC shares GPRs and floating point registers we don't need to export 93 * the floating point registers again. So here we only export the fpcsr special 94 * purpose register. 95 */ 96static int fpregs_get(struct task_struct *target, 97 const struct user_regset *regset, 98 struct membuf to) 99{ 100 const struct pt_regs *regs = task_pt_regs(target); 101 102 return membuf_store(&to, regs->fpcsr); 103} 104 105static int fpregs_set(struct task_struct *target, 106 const struct user_regset *regset, 107 unsigned int pos, unsigned int count, 108 const void *kbuf, const void __user *ubuf) 109{ 110 struct pt_regs *regs = task_pt_regs(target); 111 int ret; 112 113 /* FPCSR */ 114 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, 115 ®s->fpcsr, 0, 4); 116 return ret; 117} 118 119/* 120 * Define the register sets available on OpenRISC under Linux 121 */ 122enum or1k_regset { 123 REGSET_GENERAL, 124 REGSET_FPU, 125}; 126 127static const struct user_regset or1k_regsets[] = { 128 [REGSET_GENERAL] = { 129 .core_note_type = NT_PRSTATUS, 130 .n = ELF_NGREG, 131 .size = sizeof(long), 132 .align = sizeof(long), 133 .regset_get = genregs_get, 134 .set = genregs_set, 135 }, 136 [REGSET_FPU] = { 137 .core_note_type = NT_PRFPREG, 138 .n = sizeof(struct __or1k_fpu_state) / sizeof(long), 139 .size = sizeof(long), 140 .align = sizeof(long), 141 .regset_get = fpregs_get, 142 .set = fpregs_set, 143 }, 144}; 145 146static const struct user_regset_view user_or1k_native_view = { 147 .name = "or1k", 148 .e_machine = EM_OPENRISC, 149 .regsets = or1k_regsets, 150 .n = ARRAY_SIZE(or1k_regsets), 151}; 152 153const struct user_regset_view *task_user_regset_view(struct task_struct *task) 154{ 155 return &user_or1k_native_view; 156} 157 158/* 159 * does not yet catch signals sent when the child dies. 160 * in exit.c or in signal.c. 161 */ 162 163 164/* 165 * Called by kernel/ptrace.c when detaching.. 166 * 167 * Make sure the single step bit is not set. 168 */ 169void ptrace_disable(struct task_struct *child) 170{ 171 pr_debug("ptrace_disable(): TODO\n"); 172 173 user_disable_single_step(child); 174 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); 175} 176 177long arch_ptrace(struct task_struct *child, long request, unsigned long addr, 178 unsigned long data) 179{ 180 int ret; 181 182 switch (request) { 183 default: 184 ret = ptrace_request(child, request, addr, data); 185 break; 186 } 187 188 return ret; 189} 190 191/* 192 * Notification of system call entry/exit 193 * - triggered by current->work.syscall_trace 194 */ 195asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) 196{ 197 long ret = 0; 198 199 if (test_thread_flag(TIF_SYSCALL_TRACE) && 200 ptrace_report_syscall_entry(regs)) 201 /* 202 * Tracing decided this syscall should not happen. 203 * We'll return a bogus call number to get an ENOSYS 204 * error, but leave the original number in <something>. 205 */ 206 ret = -1L; 207 208 audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4], 209 regs->gpr[5], regs->gpr[6]); 210 211 return ret ? : regs->gpr[11]; 212} 213 214asmlinkage void do_syscall_trace_leave(struct pt_regs *regs) 215{ 216 int step; 217 218 audit_syscall_exit(regs); 219 220 step = test_thread_flag(TIF_SINGLESTEP); 221 if (step || test_thread_flag(TIF_SYSCALL_TRACE)) 222 ptrace_report_syscall_exit(regs, step); 223} 224