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 <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
  31void 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! */
  79int 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}
 100EXPORT_SYMBOL(kernel_thread);
 101
 102void 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}
 112EXPORT_SYMBOL(start_thread);
 113
 114/*
 115 * Free current thread data structures etc..
 116 */
 117void exit_thread(void)
 118{
 119}
 120
 121void 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
 134void release_thread(struct task_struct *dead_task)
 135{
 136        /* do nothing */
 137}
 138
 139/* Fill in the fpu structure for a core dump.. */
 140int 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}
 156EXPORT_SYMBOL(dump_fpu);
 157
 158/*
 159 * This gets called before we allocate a new thread and copy
 160 * the current task into it.
 161 */
 162void prepare_to_copy(struct task_struct *tsk)
 163{
 164        unlazy_fpu(tsk, task_pt_regs(tsk));
 165}
 166
 167asmlinkage void ret_from_fork(void);
 168
 169int 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
 250asmlinkage 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
 263asmlinkage 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 */
 286asmlinkage 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 */
 298asmlinkage 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);
 314out:
 315        return error;
 316}
 317
 318unsigned 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}
 339