arch/riscv/kernel/ptrace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   4  * Copyright 2015 Regents of the University of California
   5  * Copyright 2017 SiFive
   6  *
   7  * Copied from arch/tile/kernel/ptrace.c
   8  */
   9
  10 #include <asm/ptrace.h>
  11 #include <asm/syscall.h>
  12 #include <asm/thread_info.h>
  13 #include <linux/audit.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/elf.h>
  16 #include <linux/regset.h>
  17 #include <linux/sched.h>
  18 #include <linux/sched/task_stack.h>
  19 #include <linux/tracehook.h>
  20
  21 #define CREATE_TRACE_POINTS
  22 #include <trace/events/syscalls.h>
  23
  24 enum riscv_regset {
  25         REGSET_X,
  26 #ifdef CONFIG_FPU
  27         REGSET_F,
  28 #endif
  29 };
  30
  31 static int riscv_gpr_get(struct task_struct *target,
  32                          const struct user_regset *regset,
  33                          unsigned int pos, unsigned int count,
  34                          void *kbuf, void __user *ubuf)
  35 {
  36         struct pt_regs *regs;
  37
  38         regs = task_pt_regs(target);
  39         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
  40 }
  41
  42 static int riscv_gpr_set(struct task_struct *target,
  43                          const struct user_regset *regset,
  44                          unsigned int pos, unsigned int count,
  45                          const void *kbuf, const void __user *ubuf)
  46 {
  47         int ret;
  48         struct pt_regs *regs;
  49
  50         regs = task_pt_regs(target);
  51         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
  52         return ret;
  53 }
  54
  55 #ifdef CONFIG_FPU
  56 static int riscv_fpr_get(struct task_struct *target,
  57                          const struct user_regset *regset,
  58                          unsigned int pos, unsigned int count,
  59                          void *kbuf, void __user *ubuf)
  60 {
  61         int ret;
  62         struct __riscv_d_ext_state *fstate = &target->thread.fstate;
  63
  64         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, fstate, 0,
  65                                   offsetof(struct __riscv_d_ext_state, fcsr));
  66         if (!ret) {
  67                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, fstate, 0,
  68                                           offsetof(struct __riscv_d_ext_state, fcsr) +
  69                                           sizeof(fstate->fcsr));
  70         }
  71
  72         return ret;
  73 }
  74
  75 static int riscv_fpr_set(struct task_struct *target,
  76                          const struct user_regset *regset,
  77                          unsigned int pos, unsigned int count,
  78                          const void *kbuf, const void __user *ubuf)
  79 {
  80         int ret;
  81         struct __riscv_d_ext_state *fstate = &target->thread.fstate;
  82
  83         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
  84                                  offsetof(struct __riscv_d_ext_state, fcsr));
  85         if (!ret) {
  86                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
  87                                          offsetof(struct __riscv_d_ext_state, fcsr) +
  88                                          sizeof(fstate->fcsr));
  89         }
  90
  91         return ret;
  92 }
  93 #endif
  94
  95 static const struct user_regset riscv_user_regset[] = {
  96         [REGSET_X] = {
  97                 .core_note_type = NT_PRSTATUS,
  98                 .n = ELF_NGREG,
  99                 .size = sizeof(elf_greg_t),
 100                 .align = sizeof(elf_greg_t),
 101                 .get = &riscv_gpr_get,
 102                 .set = &riscv_gpr_set,
 103         },
 104 #ifdef CONFIG_FPU
 105         [REGSET_F] = {
 106                 .core_note_type = NT_PRFPREG,
 107                 .n = ELF_NFPREG,
 108                 .size = sizeof(elf_fpreg_t),
 109                 .align = sizeof(elf_fpreg_t),
 110                 .get = &riscv_fpr_get,
 111                 .set = &riscv_fpr_set,
 112         },
 113 #endif
 114 };
 115
 116 static const struct user_regset_view riscv_user_native_view = {
 117         .name = "riscv",
 118         .e_machine = EM_RISCV,
 119         .regsets = riscv_user_regset,
 120         .n = ARRAY_SIZE(riscv_user_regset),
 121 };
 122
 123 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 124 {
 125         return &riscv_user_native_view;
 126 }
 127
 128 void ptrace_disable(struct task_struct *child)
 129 {
 130         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 131 }
 132
 133 long arch_ptrace(struct task_struct *child, long request,
 134                  unsigned long addr, unsigned long data)
 135 {
 136         long ret = -EIO;
 137
 138         switch (request) {
 139         default:
 140                 ret = ptrace_request(child, request, addr, data);
 141                 break;
 142         }
 143
 144         return ret;
 145 }
 146
 147 /*
 148  * Allows PTRACE_SYSCALL to work.  These are called from entry.S in
 149  * {handle,ret_from}_syscall.
 150  */
 151 __visible int do_syscall_trace_enter(struct pt_regs *regs)
 152 {
 153         if (test_thread_flag(TIF_SYSCALL_TRACE))
 154                 if (tracehook_report_syscall_entry(regs))
 155                         return -1;
 156
 157         /*
 158          * Do the secure computing after ptrace; failures should be fast.
 159          * If this fails we might have return value in a0 from seccomp
 160          * (via SECCOMP_RET_ERRNO/TRACE).
 161          */
 162         if (secure_computing() == -1)
 163                 return -1;
 164
 165 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 166         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 167                 trace_sys_enter(regs, syscall_get_nr(current, regs));
 168 #endif
 169
 170         audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
 171         return 0;
 172 }
 173
 174 __visible void do_syscall_trace_exit(struct pt_regs *regs)
 175 {
 176         audit_syscall_exit(regs);
 177
 178         if (test_thread_flag(TIF_SYSCALL_TRACE))
 179                 tracehook_report_syscall_exit(regs, 0);
 180
 181 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 182         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 183                 trace_sys_exit(regs, regs_return_value(regs));
 184 #endif
 185 }