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                          struct membuf to)
  34 {
  35         return membuf_write(&to, task_pt_regs(target),
  36                             sizeof(struct user_regs_struct));
  37 }
  38
  39 static int riscv_gpr_set(struct task_struct *target,
  40                          const struct user_regset *regset,
  41                          unsigned int pos, unsigned int count,
  42                          const void *kbuf, const void __user *ubuf)
  43 {
  44         int ret;
  45         struct pt_regs *regs;
  46
  47         regs = task_pt_regs(target);
  48         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
  49         return ret;
  50 }
  51
  52 #ifdef CONFIG_FPU
  53 static int riscv_fpr_get(struct task_struct *target,
  54                          const struct user_regset *regset,
  55                          struct membuf to)
  56 {
  57         struct __riscv_d_ext_state *fstate = &target->thread.fstate;
  58
  59         membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
  60         membuf_store(&to, fstate->fcsr);
  61         return membuf_zero(&to, 4);     // explicitly pad
  62 }
  63
  64 static int riscv_fpr_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         int ret;
  70         struct __riscv_d_ext_state *fstate = &target->thread.fstate;
  71
  72         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
  73                                  offsetof(struct __riscv_d_ext_state, fcsr));
  74         if (!ret) {
  75                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
  76                                          offsetof(struct __riscv_d_ext_state, fcsr) +
  77                                          sizeof(fstate->fcsr));
  78         }
  79
  80         return ret;
  81 }
  82 #endif
  83
  84 static const struct user_regset riscv_user_regset[] = {
  85         [REGSET_X] = {
  86                 .core_note_type = NT_PRSTATUS,
  87                 .n = ELF_NGREG,
  88                 .size = sizeof(elf_greg_t),
  89                 .align = sizeof(elf_greg_t),
  90                 .regset_get = riscv_gpr_get,
  91                 .set = riscv_gpr_set,
  92         },
  93 #ifdef CONFIG_FPU
  94         [REGSET_F] = {
  95                 .core_note_type = NT_PRFPREG,
  96                 .n = ELF_NFPREG,
  97                 .size = sizeof(elf_fpreg_t),
  98                 .align = sizeof(elf_fpreg_t),
  99                 .regset_get = riscv_fpr_get,
 100                 .set = riscv_fpr_set,
 101         },
 102 #endif
 103 };
 104
 105 static const struct user_regset_view riscv_user_native_view = {
 106         .name = "riscv",
 107         .e_machine = EM_RISCV,
 108         .regsets = riscv_user_regset,
 109         .n = ARRAY_SIZE(riscv_user_regset),
 110 };
 111
 112 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 113 {
 114         return &riscv_user_native_view;
 115 }
 116
 117 void ptrace_disable(struct task_struct *child)
 118 {
 119         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 120 }
 121
 122 long arch_ptrace(struct task_struct *child, long request,
 123                  unsigned long addr, unsigned long data)
 124 {
 125         long ret = -EIO;
 126
 127         switch (request) {
 128         default:
 129                 ret = ptrace_request(child, request, addr, data);
 130                 break;
 131         }
 132
 133         return ret;
 134 }
 135
 136 /*
 137  * Allows PTRACE_SYSCALL to work.  These are called from entry.S in
 138  * {handle,ret_from}_syscall.
 139  */
 140 __visible int do_syscall_trace_enter(struct pt_regs *regs)
 141 {
 142         if (test_thread_flag(TIF_SYSCALL_TRACE))
 143                 if (tracehook_report_syscall_entry(regs))
 144                         return -1;
 145
 146         /*
 147          * Do the secure computing after ptrace; failures should be fast.
 148          * If this fails we might have return value in a0 from seccomp
 149          * (via SECCOMP_RET_ERRNO/TRACE).
 150          */
 151         if (secure_computing() == -1)
 152                 return -1;
 153
 154 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 155         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 156                 trace_sys_enter(regs, syscall_get_nr(current, regs));
 157 #endif
 158
 159         audit_syscall_entry(regs->a7, regs->a0, regs->a1, regs->a2, regs->a3);
 160         return 0;
 161 }
 162
 163 __visible void do_syscall_trace_exit(struct pt_regs *regs)
 164 {
 165         audit_syscall_exit(regs);
 166
 167         if (test_thread_flag(TIF_SYSCALL_TRACE))
 168                 tracehook_report_syscall_exit(regs, 0);
 169
 170 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 171         if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
 172                 trace_sys_exit(regs, regs_return_value(regs));
 173 #endif
 174 }