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/elf.h>
  26
  27 #include <asm/thread_info.h>
  28 #include <asm/page.h>
  29
  30 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs);
  31
  32 asmlinkage 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  */
  48 static 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  */
  64 static 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                                  &regs->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 #ifdef CONFIG_FPU
  92 /*
  93  * As OpenRISC shares GPRs and floating point registers we don't need to export
  94  * the floating point registers again.  So here we only export the fpcsr special
  95  * purpose register.
  96  */
  97 static int fpregs_get(struct task_struct *target,
  98                        const struct user_regset *regset,
  99                        struct membuf to)
 100 {
 101         return membuf_store(&to, target->thread.fpcsr);
 102 }
 103
 104 static int fpregs_set(struct task_struct *target,
 105                        const struct user_regset *regset,
 106                        unsigned int pos, unsigned int count,
 107                        const void *kbuf, const void __user *ubuf)
 108 {
 109         /* FPCSR */
 110         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 111                                   &target->thread.fpcsr, 0, 4);
 112 }
 113 #endif
 114
 115 /*
 116  * Define the register sets available on OpenRISC under Linux
 117  */
 118 enum or1k_regset {
 119         REGSET_GENERAL,
 120 #ifdef CONFIG_FPU
 121         REGSET_FPU,
 122 #endif
 123 };
 124
 125 static const struct user_regset or1k_regsets[] = {
 126         [REGSET_GENERAL] = {
 127                             .core_note_type = NT_PRSTATUS,
 128                             .n = ELF_NGREG,
 129                             .size = sizeof(long),
 130                             .align = sizeof(long),
 131                             .regset_get = genregs_get,
 132                             .set = genregs_set,
 133                             },
 134 #ifdef CONFIG_FPU
 135         [REGSET_FPU] = {
 136                             .core_note_type = NT_PRFPREG,
 137                             .n = sizeof(struct __or1k_fpu_state) / sizeof(long),
 138                             .size = sizeof(long),
 139                             .align = sizeof(long),
 140                             .regset_get = fpregs_get,
 141                             .set = fpregs_set,
 142                             },
 143 #endif
 144 };
 145
 146 static 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
 153 const 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  */
 169 void 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
 177 long 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  */
 195 asmlinkage 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
 214 asmlinkage 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 }