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