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 <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
  32 void 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! */
  80 int 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 }
 101 EXPORT_SYMBOL(kernel_thread);
 102
 103 void 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 }
 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 asmlinkage void ret_from_fork(void);
 160
 161 int 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
 246 asmlinkage 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
 259 asmlinkage 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  */
 282 asmlinkage 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  */
 294 asmlinkage 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         struct filename *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->name, uargv, uenvp, regs);
 309         putname(filename);
 310 out:
 311         return error;
 312 }
 313
 314 unsigned 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 }