LXR linux/arch/sh/kernel/process

   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
  30void 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 */
  72ATTRIB_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! */
  78int 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}
  99EXPORT_SYMBOL(kernel_thread);
 100
 101void 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}
 113EXPORT_SYMBOL(start_thread);
 114
 115/*
 116 * Free current thread data structures etc..
 117 */
 118void exit_thread(void)
 119{
 120}
 121
 122void 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
 135void release_thread(struct task_struct *dead_task)
 136{
 137        /* do nothing */
 138}
 139
 140/* Fill in the fpu structure for a core dump.. */
 141int 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}
 157EXPORT_SYMBOL(dump_fpu);
 158
 159/*
 160 * This gets called before we allocate a new thread and copy
 161 * the current task into it.
 162 */
 163void prepare_to_copy(struct task_struct *tsk)
 164{
 165        unlazy_fpu(tsk, task_pt_regs(tsk));
 166}
 167
 168asmlinkage void ret_from_fork(void);
 169
 170int 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
 251asmlinkage 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
 264asmlinkage 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 */
 287asmlinkage 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 */
 299asmlinkage int sys_execve(const char __user *ufilename,
 300                          const char __user *const __user *uargv,
 301                          const char __user *const __user *uenvp,
 302                          unsigned long r7, struct pt_regs __regs)
 303{
 304        struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 305        int error;
 306        char *filename;
 307
 308        filename = getname(ufilename);
 309        error = PTR_ERR(filename);
 310        if (IS_ERR(filename))
 311                goto out;
 312
 313        error = do_execve(filename, uargv, uenvp, regs);
 314        putname(filename);
 315out:
 316        return error;
 317}
 318
 319unsigned long get_wchan(struct task_struct *p)
 320{
 321        unsigned long pc;
 322
 323        if (!p || p == current || p->state == TASK_RUNNING)
 324                return 0;
 325
 326        /*
 327         * The same comment as on the Alpha applies here, too ...
 328         */
 329        pc = thread_saved_pc(p);
 330
 331#ifdef CONFIG_FRAME_POINTER
 332        if (in_sched_functions(pc)) {
 333                unsigned long schedule_frame = (unsigned long)p->thread.sp;
 334                return ((unsigned long *)schedule_frame)[21];
 335        }
 336#endif
 337
 338        return pc;
 339}
 340