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/mm.h>
  26 #include <linux/smp.h>
  27 #include <linux/errno.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/regset.h>
  30 #include <linux/user.h>
  31 #include <linux/elf.h>
  32
  33 #include <asm/user.h>
  34
  35 #if arch_has_single_step()
  36 /*  Both called from ptrace_resume  */
  37 void user_enable_single_step(struct task_struct *child)
  38 {
  39         pt_set_singlestep(task_pt_regs(child));
  40         set_tsk_thread_flag(child, TIF_SINGLESTEP);
  41 }
  42
  43 void user_disable_single_step(struct task_struct *child)
  44 {
  45         pt_clr_singlestep(task_pt_regs(child));
  46         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  47 }
  48 #endif
  49
  50 static int genregs_get(struct task_struct *target,
  51                    const struct user_regset *regset,
  52                    unsigned int pos, unsigned int count,
  53                    void *kbuf, void __user *ubuf)
  54 {
  55         int ret;
  56         unsigned int dummy;
  57         struct pt_regs *regs = task_pt_regs(target);
  58
  59
  60         if (!regs)
  61                 return -EIO;
  62
  63         /* The general idea here is that the copyout must happen in
  64          * exactly the same order in which the userspace expects these
  65          * regs. Now, the sequence in userspace does not match the
  66          * sequence in the kernel, so everything past the 32 gprs
  67          * happens one at a time.
  68          */
  69         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  70                                   &regs->r00, 0, 32*sizeof(unsigned long));
  71
  72 #define ONEXT(KPT_REG, USR_REG) \
  73         if (!ret) \
  74                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, \
  75                         KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
  76                         offsetof(struct user_regs_struct, USR_REG) + \
  77                                  sizeof(unsigned long));
  78
  79         /* Must be exactly same sequence as struct user_regs_struct */
  80         ONEXT(&regs->sa0, sa0);
  81         ONEXT(&regs->lc0, lc0);
  82         ONEXT(&regs->sa1, sa1);
  83         ONEXT(&regs->lc1, lc1);
  84         ONEXT(&regs->m0, m0);
  85         ONEXT(&regs->m1, m1);
  86         ONEXT(&regs->usr, usr);
  87         ONEXT(&regs->preds, p3_0);
  88         ONEXT(&regs->gp, gp);
  89         ONEXT(&regs->ugp, ugp);
  90         ONEXT(&pt_elr(regs), pc);
  91         dummy = pt_cause(regs);
  92         ONEXT(&dummy, cause);
  93         ONEXT(&pt_badva(regs), badva);
  94 #if CONFIG_HEXAGON_ARCH_VERSION >=4
  95         ONEXT(&regs->cs0, cs0);
  96         ONEXT(&regs->cs1, cs1);
  97 #endif
  98
  99         /* Pad the rest with zeros, if needed */
 100         if (!ret)
 101                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 102                                         offsetof(struct user_regs_struct, pad1), -1);
 103         return ret;
 104 }
 105
 106 static int genregs_set(struct task_struct *target,
 107                    const struct user_regset *regset,
 108                    unsigned int pos, unsigned int count,
 109                    const void *kbuf, const void __user *ubuf)
 110 {
 111         int ret;
 112         unsigned long bucket;
 113         struct pt_regs *regs = task_pt_regs(target);
 114
 115         if (!regs)
 116                 return -EIO;
 117
 118         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 119                                  &regs->r00, 0, 32*sizeof(unsigned long));
 120
 121 #define INEXT(KPT_REG, USR_REG) \
 122         if (!ret) \
 123                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
 124                         KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
 125                         offsetof(struct user_regs_struct, USR_REG) + \
 126                                 sizeof(unsigned long));
 127
 128         /* Must be exactly same sequence as struct user_regs_struct */
 129         INEXT(&regs->sa0, sa0);
 130         INEXT(&regs->lc0, lc0);
 131         INEXT(&regs->sa1, sa1);
 132         INEXT(&regs->lc1, lc1);
 133         INEXT(&regs->m0, m0);
 134         INEXT(&regs->m1, m1);
 135         INEXT(&regs->usr, usr);
 136         INEXT(&regs->preds, p3_0);
 137         INEXT(&regs->gp, gp);
 138         INEXT(&regs->ugp, ugp);
 139         INEXT(&pt_elr(regs), pc);
 140
 141         /* CAUSE and BADVA aren't writeable. */
 142         INEXT(&bucket, cause);
 143         INEXT(&bucket, badva);
 144
 145 #if CONFIG_HEXAGON_ARCH_VERSION >=4
 146         INEXT(&regs->cs0, cs0);
 147         INEXT(&regs->cs1, cs1);
 148 #endif
 149
 150         /* Ignore the rest, if needed */
 151         if (!ret)
 152                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 153                                         offsetof(struct user_regs_struct, pad1), -1);
 154
 155         if (ret)
 156                 return ret;
 157
 158         /*
 159          * This is special; SP is actually restored by the VM via the
 160          * special event record which is set by the special trap.
 161          */
 162         regs->hvmer.vmpsp = regs->r29;
 163         return 0;
 164 }
 165
 166 enum hexagon_regset {
 167         REGSET_GENERAL,
 168 };
 169
 170 static const struct user_regset hexagon_regsets[] = {
 171         [REGSET_GENERAL] = {
 172                 .core_note_type = NT_PRSTATUS,
 173                 .n = ELF_NGREG,
 174                 .size = sizeof(unsigned long),
 175                 .align = sizeof(unsigned long),
 176                 .get = genregs_get,
 177                 .set = genregs_set,
 178         },
 179 };
 180
 181 static const struct user_regset_view hexagon_user_view = {
 182         .name = UTS_MACHINE,
 183         .e_machine = ELF_ARCH,
 184         .ei_osabi = ELF_OSABI,
 185         .regsets = hexagon_regsets,
 186         .n = ARRAY_SIZE(hexagon_regsets)
 187 };
 188
 189 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 190 {
 191         return &hexagon_user_view;
 192 }
 193
 194 void ptrace_disable(struct task_struct *child)
 195 {
 196         /* Boilerplate - resolves to null inline if no HW single-step */
 197         user_disable_single_step(child);
 198 }
 199
 200 long arch_ptrace(struct task_struct *child, long request,
 201                  unsigned long addr, unsigned long data)
 202 {
 203         return ptrace_request(child, request, addr, data);
 204 }