arch/sh/kernel/process_32.c

   1 /*
   2  * arch/sh/kernel/process.c
   3  *
   4  * This file handles the architecture-dependent parts of process handling..
   5  *
   6  *  Copyright (C) 1995  Linus Torvalds
   7  *
   8  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
   9  *                   Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC
  10  *                   Copyright (C) 2002 - 2008  Paul Mundt
  11  *
  12  * This file is subject to the terms and conditions of the GNU General Public
  13  * License.  See the file "COPYING" in the main directory of this archive
  14  * for more details.
  15  */
  16 #include <linux/module.h>
  17 #include <linux/mm.h>
  18 #include <linux/slab.h>
  19 #include <linux/elfcore.h>
  20 #include <linux/kallsyms.h>
  21 #include <linux/fs.h>
  22 #include <linux/ftrace.h>
  23 #include <linux/hw_breakpoint.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/mmu_context.h>
  26 #include <asm/system.h>
  27 #include <asm/fpu.h>
  28 #include <asm/syscalls.h>
  29
  30 void show_regs(struct pt_regs * regs)
  31 {
  32         printk("\n");
  33         printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm);
  34         printk("CPU : %d        \t\t%s  (%s %.*s)\n\n",
  35                smp_processor_id(), print_tainted(), init_utsname()->release,
  36                (int)strcspn(init_utsname()->version, " "),
  37                init_utsname()->version);
  38
  39         print_symbol("PC is at %s\n", instruction_pointer(regs));
  40         print_symbol("PR is at %s\n", regs->pr);
  41
  42         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
  43                regs->pc, regs->regs[15], regs->sr);
  44 #ifdef CONFIG_MMU
  45         printk("TEA : %08x\n", __raw_readl(MMU_TEA));
  46 #else
  47         printk("\n");
  48 #endif
  49
  50         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
  51                regs->regs[0],regs->regs[1],
  52                regs->regs[2],regs->regs[3]);
  53         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
  54                regs->regs[4],regs->regs[5],
  55                regs->regs[6],regs->regs[7]);
  56         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
  57                regs->regs[8],regs->regs[9],
  58                regs->regs[10],regs->regs[11]);
  59         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
  60                regs->regs[12],regs->regs[13],
  61                regs->regs[14]);
  62         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
  63                regs->mach, regs->macl, regs->gbr, regs->pr);
  64
  65         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
  66         show_code(regs);
  67 }
  68
  69 /*
  70  * Create a kernel thread
  71  */
  72 ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
  73 {
  74         do_exit(fn(arg));
  75 }
  76
  77 /* Don't use this in BL=1(cli).  Or else, CPU resets! */
  78 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
  79 {
  80         struct pt_regs regs;
  81         int pid;
  82
  83         memset(&regs, 0, sizeof(regs));
  84         regs.regs[4] = (unsigned long)arg;
  85         regs.regs[5] = (unsigned long)fn;
  86
  87         regs.pc = (unsigned long)kernel_thread_helper;
  88         regs.sr = SR_MD;
  89 #if defined(CONFIG_SH_FPU)
  90         regs.sr |= SR_FD;
  91 #endif
  92
  93         /* Ok, create the new process.. */
  94         pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
  95                       &regs, 0, NULL, NULL);
  96
  97         return pid;
  98 }
  99 EXPORT_SYMBOL(kernel_thread);
 100
 101 void start_thread(struct pt_regs *regs, unsigned long new_pc,
 102                   unsigned long new_sp)
 103 {
 104         set_fs(USER_DS);
 105
 106         regs->pr = 0;
 107         regs->sr = SR_FD;
 108         regs->pc = new_pc;
 109         regs->regs[15] = new_sp;
 110
 111         free_thread_xstate(current);
 112 }
 113 EXPORT_SYMBOL(start_thread);
 114
 115 /*
 116  * Free current thread data structures etc..
 117  */
 118 void exit_thread(void)
 119 {
 120 }
 121
 122 void flush_thread(void)
 123 {
 124         struct task_struct *tsk = current;
 125
 126         flush_ptrace_hw_breakpoint(tsk);
 127
 128 #if defined(CONFIG_SH_FPU)
 129         /* Forget lazy FPU state */
 130         clear_fpu(tsk, task_pt_regs(tsk));
 131         clear_used_math();
 132 #endif
 133 }
 134
 135 void release_thread(struct task_struct *dead_task)
 136 {
 137         /* do nothing */
 138 }
 139
 140 /* Fill in the fpu structure for a core dump.. */
 141 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 142 {
 143         int fpvalid = 0;
 144
 145 #if defined(CONFIG_SH_FPU)
 146         struct task_struct *tsk = current;
 147
 148         fpvalid = !!tsk_used_math(tsk);
 149         if (fpvalid)
 150                 fpvalid = !fpregs_get(tsk, NULL, 0,
 151                                       sizeof(struct user_fpu_struct),
 152                                       fpu, NULL);
 153 #endif
 154
 155         return fpvalid;
 156 }
 157 EXPORT_SYMBOL(dump_fpu);
 158
 159 /*
 160  * This gets called before we allocate a new thread and copy
 161  * the current task into it.
 162  */
 163 void prepare_to_copy(struct task_struct *tsk)
 164 {
 165         unlazy_fpu(tsk, task_pt_regs(tsk));
 166 }
 167
 168 asmlinkage void ret_from_fork(void);
 169
 170 int copy_thread(unsigned long clone_flags, unsigned long usp,
 171                 unsigned long unused,
 172                 struct task_struct *p, struct pt_regs *regs)
 173 {
 174         struct thread_info *ti = task_thread_info(p);
 175         struct pt_regs *childregs;
 176
 177 #if defined(CONFIG_SH_DSP)
 178         struct task_struct *tsk = current;
 179
 180         if (is_dsp_enabled(tsk)) {
 181                 /* We can use the __save_dsp or just copy the struct:
 182                  * __save_dsp(p);
 183                  * p->thread.dsp_status.status |= SR_DSP
 184                  */
 185                 p->thread.dsp_status = tsk->thread.dsp_status;
 186         }
 187 #endif
 188
 189         childregs = task_pt_regs(p);
 190         *childregs = *regs;
 191
 192         if (user_mode(regs)) {
 193                 childregs->regs[15] = usp;
 194                 ti->addr_limit = USER_DS;
 195         } else {
 196                 childregs->regs[15] = (unsigned long)childregs;
 197                 ti->addr_limit = KERNEL_DS;
 198                 ti->status &= ~TS_USEDFPU;
 199                 p->fpu_counter = 0;
 200         }
 201
 202         if (clone_flags & CLONE_SETTLS)
 203                 childregs->gbr = childregs->regs[0];
 204
 205         childregs->regs[0] = 0; /* Set return value for child */
 206
 207         p->thread.sp = (unsigned long) childregs;
 208         p->thread.pc = (unsigned long) ret_from_fork;
 209
 210         memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 211
 212         return 0;
 213 }
 214
 215 /*
 216  *      switch_to(x,y) should switch tasks from x to y.
 217  *
 218  */
 219 __notrace_funcgraph struct task_struct *
 220 __switch_to(struct task_struct *prev, struct task_struct *next)
 221 {
 222         struct thread_struct *next_t = &next->thread;
 223
 224         unlazy_fpu(prev, task_pt_regs(prev));
 225
 226         /* we're going to use this soon, after a few expensive things */
 227         if (next->fpu_counter > 5)
 228                 prefetch(next_t->xstate);
 229
 230 #ifdef CONFIG_MMU
 231         /*
 232          * Restore the kernel mode register
 233          *      k7 (r7_bank1)
 234          */
 235         asm volatile("ldc       %0, r7_bank"
 236                      : /* no output */
 237                      : "r" (task_thread_info(next)));
 238 #endif
 239
 240         /*
 241          * If the task has used fpu the last 5 timeslices, just do a full
 242          * restore of the math state immediately to avoid the trap; the
 243          * chances of needing FPU soon are obviously high now
 244          */
 245         if (next->fpu_counter > 5)
 246                 __fpu_state_restore();
 247
 248         return prev;
 249 }
 250
 251 asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 252                         unsigned long r6, unsigned long r7,
 253                         struct pt_regs __regs)
 254 {
 255 #ifdef CONFIG_MMU
 256         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 257         return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 258 #else
 259         /* fork almost works, enough to trick you into looking elsewhere :-( */
 260         return -EINVAL;
 261 #endif
 262 }
 263
 264 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 265                          unsigned long parent_tidptr,
 266                          unsigned long child_tidptr,
 267                          struct pt_regs __regs)
 268 {
 269         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 270         if (!newsp)
 271                 newsp = regs->regs[15];
 272         return do_fork(clone_flags, newsp, regs, 0,
 273                         (int __user *)parent_tidptr,
 274                         (int __user *)child_tidptr);
 275 }
 276
 277 /*
 278  * This is trivial, and on the face of it looks like it
 279  * could equally well be done in user mode.
 280  *
 281  * Not so, for quite unobvious reasons - register pressure.
 282  * In user mode vfork() cannot have a stack frame, and if
 283  * done by calling the "clone()" system call directly, you
 284  * do not have enough call-clobbered registers to hold all
 285  * the information you need.
 286  */
 287 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 288                          unsigned long r6, unsigned long r7,
 289                          struct pt_regs __regs)
 290 {
 291         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 292         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 293                        0, NULL, NULL);
 294 }
 295
 296 /*
 297  * sys_execve() executes a new program.
 298  */
 299 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv,
 300                           char __user * __user *uenvp, unsigned long r7,
 301                           struct pt_regs __regs)
 302 {
 303         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 304         int error;
 305         char *filename;
 306
 307         filename = getname(ufilename);
 308         error = PTR_ERR(filename);
 309         if (IS_ERR(filename))
 310                 goto out;
 311
 312         error = do_execve(filename, uargv, uenvp, regs);
 313         putname(filename);
 314 out:
 315         return error;
 316 }
 317
 318 unsigned long get_wchan(struct task_struct *p)
 319 {
 320         unsigned long pc;
 321
 322         if (!p || p == current || p->state == TASK_RUNNING)
 323                 return 0;
 324
 325         /*
 326          * The same comment as on the Alpha applies here, too ...
 327          */
 328         pc = thread_saved_pc(p);
 329
 330 #ifdef CONFIG_FRAME_POINTER
 331         if (in_sched_functions(pc)) {
 332                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 333                 return ((unsigned long *)schedule_frame)[21];
 334         }
 335 #endif
 336
 337         return pc;
 338 }