LXR linux/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 */
  45static 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 */
  61static 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 */
  93enum or1k_regset {
  94        REGSET_GENERAL,
  95};
  96
  97static 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
 108static 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
 115const 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 */
 131void 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
 139long 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 */
 157asmlinkage 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
 176asmlinkage 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}
 186