arch/hexagon/kernel/ptrace.c

   1 /*
   2  * Ptrace support for Hexagon
   3  *
   4  * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 and
   8  * only version 2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA.
  19  */
  20
  21 #include <generated/compile.h>
  22
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/sched/task_stack.h>
  26 #include <linux/mm.h>
  27 #include <linux/smp.h>
  28 #include <linux/errno.h>
  29 #include <linux/ptrace.h>
  30 #include <linux/regset.h>
  31 #include <linux/user.h>
  32 #include <linux/elf.h>
  33
  34 #include <asm/user.h>
  35
  36 #if arch_has_single_step()
  37 /*  Both called from ptrace_resume  */
  38 void user_enable_single_step(struct task_struct *child)
  39 {
  40         pt_set_singlestep(task_pt_regs(child));
  41         set_tsk_thread_flag(child, TIF_SINGLESTEP);
  42 }
  43
  44 void user_disable_single_step(struct task_struct *child)
  45 {
  46         pt_clr_singlestep(task_pt_regs(child));
  47         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  48 }
  49 #endif
  50
  51 static 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         int ret;
  57         unsigned int dummy;
  58         struct pt_regs *regs = task_pt_regs(target);
  59
  60
  61         if (!regs)
  62                 return -EIO;
  63
  64         /* The general idea here is that the copyout must happen in
  65          * exactly the same order in which the userspace expects these
  66          * regs. Now, the sequence in userspace does not match the
  67          * sequence in the kernel, so everything past the 32 gprs
  68          * happens one at a time.
  69          */
  70         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  71                                   &regs->r00, 0, 32*sizeof(unsigned long));
  72
  73 #define ONEXT(KPT_REG, USR_REG) \
  74         if (!ret) \
  75                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, \
  76                         KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
  77                         offsetof(struct user_regs_struct, USR_REG) + \
  78                                  sizeof(unsigned long));
  79
  80         /* Must be exactly same sequence as struct user_regs_struct */
  81         ONEXT(&regs->sa0, sa0);
  82         ONEXT(&regs->lc0, lc0);
  83         ONEXT(&regs->sa1, sa1);
  84         ONEXT(&regs->lc1, lc1);
  85         ONEXT(&regs->m0, m0);
  86         ONEXT(&regs->m1, m1);
  87         ONEXT(&regs->usr, usr);
  88         ONEXT(&regs->preds, p3_0);
  89         ONEXT(&regs->gp, gp);
  90         ONEXT(&regs->ugp, ugp);
  91         ONEXT(&pt_elr(regs), pc);
  92         dummy = pt_cause(regs);
  93         ONEXT(&dummy, cause);
  94         ONEXT(&pt_badva(regs), badva);
  95 #if CONFIG_HEXAGON_ARCH_VERSION >=4
  96         ONEXT(&regs->cs0, cs0);
  97         ONEXT(&regs->cs1, cs1);
  98 #endif
  99
 100         /* Pad the rest with zeros, if needed */
 101         if (!ret)
 102                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 103                                         offsetof(struct user_regs_struct, pad1), -1);
 104         return ret;
 105 }
 106
 107 static int genregs_set(struct task_struct *target,
 108                    const struct user_regset *regset,
 109                    unsigned int pos, unsigned int count,
 110                    const void *kbuf, const void __user *ubuf)
 111 {
 112         int ret;
 113         unsigned long bucket;
 114         struct pt_regs *regs = task_pt_regs(target);
 115
 116         if (!regs)
 117                 return -EIO;
 118
 119         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 120                                  &regs->r00, 0, 32*sizeof(unsigned long));
 121
 122 #define INEXT(KPT_REG, USR_REG) \
 123         if (!ret) \
 124                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
 125                         KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
 126                         offsetof(struct user_regs_struct, USR_REG) + \
 127                                 sizeof(unsigned long));
 128
 129         /* Must be exactly same sequence as struct user_regs_struct */
 130         INEXT(&regs->sa0, sa0);
 131         INEXT(&regs->lc0, lc0);
 132         INEXT(&regs->sa1, sa1);
 133         INEXT(&regs->lc1, lc1);
 134         INEXT(&regs->m0, m0);
 135         INEXT(&regs->m1, m1);
 136         INEXT(&regs->usr, usr);
 137         INEXT(&regs->preds, p3_0);
 138         INEXT(&regs->gp, gp);
 139         INEXT(&regs->ugp, ugp);
 140         INEXT(&pt_elr(regs), pc);
 141
 142         /* CAUSE and BADVA aren't writeable. */
 143         INEXT(&bucket, cause);
 144         INEXT(&bucket, badva);
 145
 146 #if CONFIG_HEXAGON_ARCH_VERSION >=4
 147         INEXT(&regs->cs0, cs0);
 148         INEXT(&regs->cs1, cs1);
 149 #endif
 150
 151         /* Ignore the rest, if needed */
 152         if (!ret)
 153                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 154                                         offsetof(struct user_regs_struct, pad1), -1);
 155
 156         if (ret)
 157                 return ret;
 158
 159         /*
 160          * This is special; SP is actually restored by the VM via the
 161          * special event record which is set by the special trap.
 162          */
 163         regs->hvmer.vmpsp = regs->r29;
 164         return 0;
 165 }
 166
 167 enum hexagon_regset {
 168         REGSET_GENERAL,
 169 };
 170
 171 static const struct user_regset hexagon_regsets[] = {
 172         [REGSET_GENERAL] = {
 173                 .core_note_type = NT_PRSTATUS,
 174                 .n = ELF_NGREG,
 175                 .size = sizeof(unsigned long),
 176                 .align = sizeof(unsigned long),
 177                 .get = genregs_get,
 178                 .set = genregs_set,
 179         },
 180 };
 181
 182 static const struct user_regset_view hexagon_user_view = {
 183         .name = UTS_MACHINE,
 184         .e_machine = ELF_ARCH,
 185         .ei_osabi = ELF_OSABI,
 186         .regsets = hexagon_regsets,
 187         .e_flags = ELF_CORE_EFLAGS,
 188         .n = ARRAY_SIZE(hexagon_regsets)
 189 };
 190
 191 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 192 {
 193         return &hexagon_user_view;
 194 }
 195
 196 void ptrace_disable(struct task_struct *child)
 197 {
 198         /* Boilerplate - resolves to null inline if no HW single-step */
 199         user_disable_single_step(child);
 200 }
 201
 202 long arch_ptrace(struct task_struct *child, long request,
 203                  unsigned long addr, unsigned long data)
 204 {
 205         return ptrace_request(child, request, addr, data);
 206 }