arch/hexagon/kernel/ptrace.c

   1 /*
   2  * Ptrace support for Hexagon
   3  *
   4  * Copyright (c) 2010-2011, 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 static int genregs_get(struct task_struct *target,
  36                    const struct user_regset *regset,
  37                    unsigned int pos, unsigned int count,
  38                    void *kbuf, void __user *ubuf)
  39 {
  40         int ret;
  41         unsigned int dummy;
  42         struct pt_regs *regs = task_pt_regs(target);
  43
  44
  45         if (!regs)
  46                 return -EIO;
  47
  48         /* The general idea here is that the copyout must happen in
  49          * exactly the same order in which the userspace expects these
  50          * regs. Now, the sequence in userspace does not match the
  51          * sequence in the kernel, so everything past the 32 gprs
  52          * happens one at a time.
  53          */
  54         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  55                                   &regs->r00, 0, 32*sizeof(unsigned long));
  56
  57 #define ONEXT(KPT_REG, USR_REG) \
  58         if (!ret) \
  59                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, \
  60                         KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
  61                         offsetof(struct user_regs_struct, USR_REG) + \
  62                                  sizeof(unsigned long));
  63
  64         /* Must be exactly same sequence as struct user_regs_struct */
  65         ONEXT(&regs->sa0, sa0);
  66         ONEXT(&regs->lc0, lc0);
  67         ONEXT(&regs->sa1, sa1);
  68         ONEXT(&regs->lc1, lc1);
  69         ONEXT(&regs->m0, m0);
  70         ONEXT(&regs->m1, m1);
  71         ONEXT(&regs->usr, usr);
  72         ONEXT(&regs->preds, p3_0);
  73         ONEXT(&regs->gp, gp);
  74         ONEXT(&regs->ugp, ugp);
  75         ONEXT(&pt_elr(regs), pc);
  76         dummy = pt_cause(regs);
  77         ONEXT(&dummy, cause);
  78         ONEXT(&pt_badva(regs), badva);
  79
  80         /* Pad the rest with zeros, if needed */
  81         if (!ret)
  82                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
  83                                         offsetof(struct user_regs_struct, pad1), -1);
  84         return ret;
  85 }
  86
  87 static int genregs_set(struct task_struct *target,
  88                    const struct user_regset *regset,
  89                    unsigned int pos, unsigned int count,
  90                    const void *kbuf, const void __user *ubuf)
  91 {
  92         int ret;
  93         unsigned long bucket;
  94         struct pt_regs *regs = task_pt_regs(target);
  95
  96         if (!regs)
  97                 return -EIO;
  98
  99         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 100                                  &regs->r00, 0, 32*sizeof(unsigned long));
 101
 102 #define INEXT(KPT_REG, USR_REG) \
 103         if (!ret) \
 104                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
 105                         KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
 106                         offsetof(struct user_regs_struct, USR_REG) + \
 107                                 sizeof(unsigned long));
 108
 109         /* Must be exactly same sequence as struct user_regs_struct */
 110         INEXT(&regs->sa0, sa0);
 111         INEXT(&regs->lc0, lc0);
 112         INEXT(&regs->sa1, sa1);
 113         INEXT(&regs->lc1, lc1);
 114         INEXT(&regs->m0, m0);
 115         INEXT(&regs->m1, m1);
 116         INEXT(&regs->usr, usr);
 117         INEXT(&regs->preds, p3_0);
 118         INEXT(&regs->gp, gp);
 119         INEXT(&regs->ugp, ugp);
 120         INEXT(&pt_elr(regs), pc);
 121
 122         /* CAUSE and BADVA aren't writeable. */
 123         INEXT(&bucket, cause);
 124         INEXT(&bucket, badva);
 125
 126         /* Ignore the rest, if needed */
 127         if (!ret)
 128                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 129                                         offsetof(struct user_regs_struct, pad1), -1);
 130
 131         if (ret)
 132                 return ret;
 133
 134         /*
 135          * This is special; SP is actually restored by the VM via the
 136          * special event record which is set by the special trap.
 137          */
 138         regs->hvmer.vmpsp = regs->r29;
 139         return 0;
 140 }
 141
 142 enum hexagon_regset {
 143         REGSET_GENERAL,
 144 };
 145
 146 static const struct user_regset hexagon_regsets[] = {
 147         [REGSET_GENERAL] = {
 148                 .core_note_type = NT_PRSTATUS,
 149                 .n = ELF_NGREG,
 150                 .size = sizeof(unsigned long),
 151                 .align = sizeof(unsigned long),
 152                 .get = genregs_get,
 153                 .set = genregs_set,
 154         },
 155 };
 156
 157 static const struct user_regset_view hexagon_user_view = {
 158         .name = UTS_MACHINE,
 159         .e_machine = ELF_ARCH,
 160         .ei_osabi = ELF_OSABI,
 161         .regsets = hexagon_regsets,
 162         .n = ARRAY_SIZE(hexagon_regsets)
 163 };
 164
 165 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 166 {
 167         return &hexagon_user_view;
 168 }
 169
 170 void ptrace_disable(struct task_struct *child)
 171 {
 172         /* Boilerplate - resolves to null inline if no HW single-step */
 173         user_disable_single_step(child);
 174 }
 175
 176 long arch_ptrace(struct task_struct *child, long request,
 177                  unsigned long addr, unsigned long data)
 178 {
 179         return ptrace_request(child, request, addr, data);
 180 }