arch/openrisc/kernel/ptrace.c

   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/tracehook.h>
  26 #include <linux/elf.h>
  27
  28 #include <asm/thread_info.h>
  29 #include <asm/page.h>
  30
  31 /*
  32  * Copy the thread state to a regset that can be interpreted by userspace.
  33  *
  34  * It doesn't matter what our internal pt_regs structure looks like.  The
  35  * important thing is that we export a consistent view of the thread state
  36  * to userspace.  As such, we need to make sure that the regset remains
  37  * ABI compatible as defined by the struct user_regs_struct:
  38  *
  39  * (Each item is a 32-bit word)
  40  * r0 = 0 (exported for clarity)
  41  * 31 GPRS r1-r31
  42  * PC (Program counter)
  43  * SR (Supervision register)
  44  */
  45 static int genregs_get(struct task_struct *target,
  46                        const struct user_regset *regset,
  47                        struct membuf to)
  48 {
  49         const struct pt_regs *regs = task_pt_regs(target);
  50
  51         /* r0 */
  52         membuf_zero(&to, 4);
  53         membuf_write(&to, regs->gpr + 1, 31 * 4);
  54         membuf_store(&to, regs->pc);
  55         return membuf_store(&to, regs->sr);
  56 }
  57
  58 /*
  59  * Set the thread state from a regset passed in via ptrace
  60  */
  61 static int genregs_set(struct task_struct *target,
  62                        const struct user_regset *regset,
  63                        unsigned int pos, unsigned int count,
  64                        const void *kbuf, const void __user * ubuf)
  65 {
  66         struct pt_regs *regs = task_pt_regs(target);
  67         int ret;
  68
  69         /* ignore r0 */
  70         ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
  71         /* r1 - r31 */
  72         if (!ret)
  73                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  74                                          regs->gpr+1, 4, 4*32);
  75         /* PC */
  76         if (!ret)
  77                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  78                                  &regs->pc, 4*32, 4*33);
  79         /*
  80          * Skip SR and padding... userspace isn't allowed to changes bits in
  81          * the Supervision register
  82          */
  83         if (!ret)
  84                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
  85                                                 4*33, -1);
  86
  87         return ret;
  88 }
  89
  90 /*
  91  * Define the register sets available on OpenRISC under Linux
  92  */
  93 enum or1k_regset {
  94         REGSET_GENERAL,
  95 };
  96
  97 static const struct user_regset or1k_regsets[] = {
  98         [REGSET_GENERAL] = {
  99                             .core_note_type = NT_PRSTATUS,
 100                             .n = ELF_NGREG,
 101                             .size = sizeof(long),
 102                             .align = sizeof(long),
 103                             .regset_get = genregs_get,
 104                             .set = genregs_set,
 105                             },
 106 };
 107
 108 static const struct user_regset_view user_or1k_native_view = {
 109         .name = "or1k",
 110         .e_machine = EM_OPENRISC,
 111         .regsets = or1k_regsets,
 112         .n = ARRAY_SIZE(or1k_regsets),
 113 };
 114
 115 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 116 {
 117         return &user_or1k_native_view;
 118 }
 119
 120 /*
 121  * does not yet catch signals sent when the child dies.
 122  * in exit.c or in signal.c.
 123  */
 124
 125
 126 /*
 127  * Called by kernel/ptrace.c when detaching..
 128  *
 129  * Make sure the single step bit is not set.
 130  */
 131 void ptrace_disable(struct task_struct *child)
 132 {
 133         pr_debug("ptrace_disable(): TODO\n");
 134
 135         user_disable_single_step(child);
 136         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 137 }
 138
 139 long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
 140                  unsigned long data)
 141 {
 142         int ret;
 143
 144         switch (request) {
 145         default:
 146                 ret = ptrace_request(child, request, addr, data);
 147                 break;
 148         }
 149
 150         return ret;
 151 }
 152
 153 /*
 154  * Notification of system call entry/exit
 155  * - triggered by current->work.syscall_trace
 156  */
 157 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 158 {
 159         long ret = 0;
 160
 161         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 162             tracehook_report_syscall_entry(regs))
 163                 /*
 164                  * Tracing decided this syscall should not happen.
 165                  * We'll return a bogus call number to get an ENOSYS
 166                  * error, but leave the original number in <something>.
 167                  */
 168                 ret = -1L;
 169
 170         audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4],
 171                             regs->gpr[5], regs->gpr[6]);
 172
 173         return ret ? : regs->gpr[11];
 174 }
 175
 176 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 177 {
 178         int step;
 179
 180         audit_syscall_exit(regs);
 181
 182         step = test_thread_flag(TIF_SINGLESTEP);
 183         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 184                 tracehook_report_syscall_exit(regs, step);
 185 }