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 <linux/stackprotector.h>
  26#include <asm/uaccess.h>
  27#include <asm/mmu_context.h>
  28#include <asm/fpu.h>
  29#include <asm/syscalls.h>
  30#include <asm/switch_to.h>
  31
  32void show_regs(struct pt_regs * regs)
  33{
  34        printk("\n");
  35        printk("Pid : %d, Comm: \t\t%s\n", task_pid_nr(current), current->comm);
  36        printk("CPU : %d        \t\t%s  (%s %.*s)\n\n",
  37               smp_processor_id(), print_tainted(), init_utsname()->release,
  38               (int)strcspn(init_utsname()->version, " "),
  39               init_utsname()->version);
  40
  41        print_symbol("PC is at %s\n", instruction_pointer(regs));
  42        print_symbol("PR is at %s\n", regs->pr);
  43
  44        printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
  45               regs->pc, regs->regs[15], regs->sr);
  46#ifdef CONFIG_MMU
  47        printk("TEA : %08x\n", __raw_readl(MMU_TEA));
  48#else
  49        printk("\n");
  50#endif
  51
  52        printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
  53               regs->regs[0],regs->regs[1],
  54               regs->regs[2],regs->regs[3]);
  55        printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
  56               regs->regs[4],regs->regs[5],
  57               regs->regs[6],regs->regs[7]);
  58        printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
  59               regs->regs[8],regs->regs[9],
  60               regs->regs[10],regs->regs[11]);
  61        printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
  62               regs->regs[12],regs->regs[13],
  63               regs->regs[14]);
  64        printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
  65               regs->mach, regs->macl, regs->gbr, regs->pr);
  66
  67        show_trace(NULL, (unsigned long *)regs->regs[15], regs);
  68        show_code(regs);
  69}
  70
  71/*
  72 * Create a kernel thread
  73 */
  74__noreturn void kernel_thread_helper(void *arg, int (*fn)(void *))
  75{
  76        do_exit(fn(arg));
  77}
  78
  79/* Don't use this in BL=1(cli).  Or else, CPU resets! */
  80int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
  81{
  82        struct pt_regs regs;
  83        int pid;
  84
  85        memset(&regs, 0, sizeof(regs));
  86        regs.regs[4] = (unsigned long)arg;
  87        regs.regs[5] = (unsigned long)fn;
  88
  89        regs.pc = (unsigned long)kernel_thread_helper;
  90        regs.sr = SR_MD;
  91#if defined(CONFIG_SH_FPU)
  92        regs.sr |= SR_FD;
  93#endif
  94
  95        /* Ok, create the new process.. */
  96        pid = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
  97                      &regs, 0, NULL, NULL);
  98
  99        return pid;
 100}
 101EXPORT_SYMBOL(kernel_thread);
 102
 103void start_thread(struct pt_regs *regs, unsigned long new_pc,
 104                  unsigned long new_sp)
 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
 159asmlinkage void ret_from_fork(void);
 160
 161int copy_thread(unsigned long clone_flags, unsigned long usp,
 162                unsigned long unused,
 163                struct task_struct *p, struct pt_regs *regs)
 164{
 165        struct thread_info *ti = task_thread_info(p);
 166        struct pt_regs *childregs;
 167
 168#if defined(CONFIG_SH_DSP)
 169        struct task_struct *tsk = current;
 170
 171        if (is_dsp_enabled(tsk)) {
 172                /* We can use the __save_dsp or just copy the struct:
 173                 * __save_dsp(p);
 174                 * p->thread.dsp_status.status |= SR_DSP
 175                 */
 176                p->thread.dsp_status = tsk->thread.dsp_status;
 177        }
 178#endif
 179
 180        childregs = task_pt_regs(p);
 181        *childregs = *regs;
 182
 183        if (user_mode(regs)) {
 184                childregs->regs[15] = usp;
 185                ti->addr_limit = USER_DS;
 186        } else {
 187                childregs->regs[15] = (unsigned long)childregs;
 188                ti->addr_limit = KERNEL_DS;
 189                ti->status &= ~TS_USEDFPU;
 190                p->fpu_counter = 0;
 191        }
 192
 193        if (clone_flags & CLONE_SETTLS)
 194                childregs->gbr = childregs->regs[0];
 195
 196        childregs->regs[0] = 0; /* Set return value for child */
 197
 198        p->thread.sp = (unsigned long) childregs;
 199        p->thread.pc = (unsigned long) ret_from_fork;
 200
 201        memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 202
 203        return 0;
 204}
 205
 206/*
 207 *      switch_to(x,y) should switch tasks from x to y.
 208 *
 209 */
 210__notrace_funcgraph struct task_struct *
 211__switch_to(struct task_struct *prev, struct task_struct *next)
 212{
 213        struct thread_struct *next_t = &next->thread;
 214
 215#if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
 216        __stack_chk_guard = next->stack_canary;
 217#endif
 218
 219        unlazy_fpu(prev, task_pt_regs(prev));
 220
 221        /* we're going to use this soon, after a few expensive things */
 222        if (next->fpu_counter > 5)
 223                prefetch(next_t->xstate);
 224
 225#ifdef CONFIG_MMU
 226        /*
 227         * Restore the kernel mode register
 228         *      k7 (r7_bank1)
 229         */
 230        asm volatile("ldc       %0, r7_bank"
 231                     : /* no output */
 232                     : "r" (task_thread_info(next)));
 233#endif
 234
 235        /*
 236         * If the task has used fpu the last 5 timeslices, just do a full
 237         * restore of the math state immediately to avoid the trap; the
 238         * chances of needing FPU soon are obviously high now
 239         */
 240        if (next->fpu_counter > 5)
 241                __fpu_state_restore();
 242
 243        return prev;
 244}
 245
 246asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
 247                        unsigned long r6, unsigned long r7,
 248                        struct pt_regs __regs)
 249{
 250#ifdef CONFIG_MMU
 251        struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 252        return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL);
 253#else
 254        /* fork almost works, enough to trick you into looking elsewhere :-( */
 255        return -EINVAL;
 256#endif
 257}
 258
 259asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
 260                         unsigned long parent_tidptr,
 261                         unsigned long child_tidptr,
 262                         struct pt_regs __regs)
 263{
 264        struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 265        if (!newsp)
 266                newsp = regs->regs[15];
 267        return do_fork(clone_flags, newsp, regs, 0,
 268                        (int __user *)parent_tidptr,
 269                        (int __user *)child_tidptr);
 270}
 271
 272/*
 273 * This is trivial, and on the face of it looks like it
 274 * could equally well be done in user mode.
 275 *
 276 * Not so, for quite unobvious reasons - register pressure.
 277 * In user mode vfork() cannot have a stack frame, and if
 278 * done by calling the "clone()" system call directly, you
 279 * do not have enough call-clobbered registers to hold all
 280 * the information you need.
 281 */
 282asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
 283                         unsigned long r6, unsigned long r7,
 284                         struct pt_regs __regs)
 285{
 286        struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 287        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs,
 288                       0, NULL, NULL);
 289}
 290
 291/*
 292 * sys_execve() executes a new program.
 293 */
 294asmlinkage int sys_execve(const char __user *ufilename,
 295                          const char __user *const __user *uargv,
 296                          const char __user *const __user *uenvp,
 297                          unsigned long r7, struct pt_regs __regs)
 298{
 299        struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 300        int error;
 301        char *filename;
 302
 303        filename = getname(ufilename);
 304        error = PTR_ERR(filename);
 305        if (IS_ERR(filename))
 306                goto out;
 307
 308        error = do_execve(filename, uargv, uenvp, regs);
 309        putname(filename);
 310out:
 311        return error;
 312}
 313
 314unsigned long get_wchan(struct task_struct *p)
 315{
 316        unsigned long pc;
 317
 318        if (!p || p == current || p->state == TASK_RUNNING)
 319                return 0;
 320
 321        /*
 322         * The same comment as on the Alpha applies here, too ...
 323         */
 324        pc = thread_saved_pc(p);
 325
 326#ifdef CONFIG_FRAME_POINTER
 327        if (in_sched_functions(pc)) {
 328                unsigned long schedule_frame = (unsigned long)p->thread.sp;
 329                return ((unsigned long *)schedule_frame)[21];
 330        }
 331#endif
 332
 333        return pc;
 334}
 335