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