linux/arch/openrisc/kernel/ptrace.c
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   1/*
   2 * OpenRISC ptrace.c
   3 *
   4 * Linux architectural port borrowing liberally from similar works of
   5 * others.  All original copyrights apply as per the original source
   6 * declaration.
   7 *
   8 * Modifications for the OpenRISC architecture:
   9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  10 * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
  11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12 *
  13 *      This program is free software; you can redistribute it and/or
  14 *      modify it under the terms of the GNU General Public License
  15 *      as published by the Free Software Foundation; either version
  16 *      2 of the License, or (at your option) any later version.
  17 */
  18
  19#include <stddef.h>
  20#include <linux/kernel.h>
  21#include <linux/sched.h>
  22#include <linux/string.h>
  23
  24#include <linux/mm.h>
  25#include <linux/errno.h>
  26#include <linux/ptrace.h>
  27#include <linux/audit.h>
  28#include <linux/regset.h>
  29#include <linux/tracehook.h>
  30#include <linux/elf.h>
  31
  32#include <asm/thread_info.h>
  33#include <asm/segment.h>
  34#include <asm/page.h>
  35#include <asm/pgtable.h>
  36
  37/*
  38 * Copy the thread state to a regset that can be interpreted by userspace.
  39 *
  40 * It doesn't matter what our internal pt_regs structure looks like.  The
  41 * important thing is that we export a consistent view of the thread state
  42 * to userspace.  As such, we need to make sure that the regset remains
  43 * ABI compatible as defined by the struct user_regs_struct:
  44 *
  45 * (Each item is a 32-bit word)
  46 * r0 = 0 (exported for clarity)
  47 * 31 GPRS r1-r31
  48 * PC (Program counter)
  49 * SR (Supervision register)
  50 */
  51static int genregs_get(struct task_struct *target,
  52                       const struct user_regset *regset,
  53                       unsigned int pos, unsigned int count,
  54                       void *kbuf, void __user * ubuf)
  55{
  56        const struct pt_regs *regs = task_pt_regs(target);
  57        int ret;
  58
  59        /* r0 */
  60        ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, 0, 4);
  61
  62        if (!ret)
  63                ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  64                                          regs->gpr+1, 4, 4*32);
  65        if (!ret)
  66                ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  67                                  &regs->pc, 4*32, 4*33);
  68        if (!ret)
  69                ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  70                                          &regs->sr, 4*33, 4*34);
  71        if (!ret)
  72                ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
  73                                               4*34, -1);
  74
  75        return ret;
  76}
  77
  78/*
  79 * Set the thread state from a regset passed in via ptrace
  80 */
  81static int genregs_set(struct task_struct *target,
  82                       const struct user_regset *regset,
  83                       unsigned int pos, unsigned int count,
  84                       const void *kbuf, const void __user * ubuf)
  85{
  86        struct pt_regs *regs = task_pt_regs(target);
  87        int ret;
  88
  89        /* ignore r0 */
  90        ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
  91        /* r1 - r31 */
  92        if (!ret)
  93                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  94                                         regs->gpr+1, 4, 4*32);
  95        /* PC */
  96        if (!ret)
  97                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
  98                                 &regs->pc, 4*32, 4*33);
  99        /*
 100         * Skip SR and padding... userspace isn't allowed to changes bits in
 101         * the Supervision register
 102         */
 103        if (!ret)
 104                ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 105                                                4*33, -1);
 106
 107        return ret;
 108}
 109
 110/*
 111 * Define the register sets available on OpenRISC under Linux
 112 */
 113enum or1k_regset {
 114        REGSET_GENERAL,
 115};
 116
 117static const struct user_regset or1k_regsets[] = {
 118        [REGSET_GENERAL] = {
 119                            .core_note_type = NT_PRSTATUS,
 120                            .n = ELF_NGREG,
 121                            .size = sizeof(long),
 122                            .align = sizeof(long),
 123                            .get = genregs_get,
 124                            .set = genregs_set,
 125                            },
 126};
 127
 128static const struct user_regset_view user_or1k_native_view = {
 129        .name = "or1k",
 130        .e_machine = EM_OPENRISC,
 131        .regsets = or1k_regsets,
 132        .n = ARRAY_SIZE(or1k_regsets),
 133};
 134
 135const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 136{
 137        return &user_or1k_native_view;
 138}
 139
 140/*
 141 * does not yet catch signals sent when the child dies.
 142 * in exit.c or in signal.c.
 143 */
 144
 145
 146/*
 147 * Called by kernel/ptrace.c when detaching..
 148 *
 149 * Make sure the single step bit is not set.
 150 */
 151void ptrace_disable(struct task_struct *child)
 152{
 153        pr_debug("ptrace_disable(): TODO\n");
 154
 155        user_disable_single_step(child);
 156        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 157}
 158
 159long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
 160                 unsigned long data)
 161{
 162        int ret;
 163
 164        switch (request) {
 165        default:
 166                ret = ptrace_request(child, request, addr, data);
 167                break;
 168        }
 169
 170        return ret;
 171}
 172
 173/*
 174 * Notification of system call entry/exit
 175 * - triggered by current->work.syscall_trace
 176 */
 177asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 178{
 179        long ret = 0;
 180
 181        if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 182            tracehook_report_syscall_entry(regs))
 183                /*
 184                 * Tracing decided this syscall should not happen.
 185                 * We'll return a bogus call number to get an ENOSYS
 186                 * error, but leave the original number in <something>.
 187                 */
 188                ret = -1L;
 189
 190        audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4],
 191                            regs->gpr[5], regs->gpr[6]);
 192
 193        return ret ? : regs->gpr[11];
 194}
 195
 196asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 197{
 198        int step;
 199
 200        audit_syscall_exit(regs);
 201
 202        step = test_thread_flag(TIF_SINGLESTEP);
 203        if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 204                tracehook_report_syscall_exit(regs, step);
 205}
 206