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 <linux/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         show_regs_print_info(KERN_DEFAULT);
  36
  37         print_symbol("PC is at %s\n", instruction_pointer(regs));
  38         print_symbol("PR is at %s\n", regs->pr);
  39
  40         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
  41                regs->pc, regs->regs[15], regs->sr);
  42 #ifdef CONFIG_MMU
  43         printk("TEA : %08x\n", __raw_readl(MMU_TEA));
  44 #else
  45         printk("\n");
  46 #endif
  47
  48         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
  49                regs->regs[0],regs->regs[1],
  50                regs->regs[2],regs->regs[3]);
  51         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
  52                regs->regs[4],regs->regs[5],
  53                regs->regs[6],regs->regs[7]);
  54         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
  55                regs->regs[8],regs->regs[9],
  56                regs->regs[10],regs->regs[11]);
  57         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
  58                regs->regs[12],regs->regs[13],
  59                regs->regs[14]);
  60         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
  61                regs->mach, regs->macl, regs->gbr, regs->pr);
  62
  63         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
  64         show_code(regs);
  65 }
  66
  67 void start_thread(struct pt_regs *regs, unsigned long new_pc,
  68                   unsigned long new_sp)
  69 {
  70         regs->pr = 0;
  71         regs->sr = SR_FD;
  72         regs->pc = new_pc;
  73         regs->regs[15] = new_sp;
  74
  75         free_thread_xstate(current);
  76 }
  77 EXPORT_SYMBOL(start_thread);
  78
  79 void flush_thread(void)
  80 {
  81         struct task_struct *tsk = current;
  82
  83         flush_ptrace_hw_breakpoint(tsk);
  84
  85 #if defined(CONFIG_SH_FPU)
  86         /* Forget lazy FPU state */
  87         clear_fpu(tsk, task_pt_regs(tsk));
  88         clear_used_math();
  89 #endif
  90 }
  91
  92 void release_thread(struct task_struct *dead_task)
  93 {
  94         /* do nothing */
  95 }
  96
  97 /* Fill in the fpu structure for a core dump.. */
  98 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
  99 {
 100         int fpvalid = 0;
 101
 102 #if defined(CONFIG_SH_FPU)
 103         struct task_struct *tsk = current;
 104
 105         fpvalid = !!tsk_used_math(tsk);
 106         if (fpvalid)
 107                 fpvalid = !fpregs_get(tsk, NULL, 0,
 108                                       sizeof(struct user_fpu_struct),
 109                                       fpu, NULL);
 110 #endif
 111
 112         return fpvalid;
 113 }
 114 EXPORT_SYMBOL(dump_fpu);
 115
 116 asmlinkage void ret_from_fork(void);
 117 asmlinkage void ret_from_kernel_thread(void);
 118
 119 int copy_thread(unsigned long clone_flags, unsigned long usp,
 120                 unsigned long arg, struct task_struct *p)
 121 {
 122         struct thread_info *ti = task_thread_info(p);
 123         struct pt_regs *childregs;
 124
 125 #if defined(CONFIG_SH_DSP)
 126         struct task_struct *tsk = current;
 127
 128         if (is_dsp_enabled(tsk)) {
 129                 /* We can use the __save_dsp or just copy the struct:
 130                  * __save_dsp(p);
 131                  * p->thread.dsp_status.status |= SR_DSP
 132                  */
 133                 p->thread.dsp_status = tsk->thread.dsp_status;
 134         }
 135 #endif
 136
 137         memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 138
 139         childregs = task_pt_regs(p);
 140         p->thread.sp = (unsigned long) childregs;
 141         if (unlikely(p->flags & PF_KTHREAD)) {
 142                 memset(childregs, 0, sizeof(struct pt_regs));
 143                 p->thread.pc = (unsigned long) ret_from_kernel_thread;
 144                 childregs->regs[4] = arg;
 145                 childregs->regs[5] = usp;
 146                 childregs->sr = SR_MD;
 147 #if defined(CONFIG_SH_FPU)
 148                 childregs->sr |= SR_FD;
 149 #endif
 150                 ti->addr_limit = KERNEL_DS;
 151                 ti->status &= ~TS_USEDFPU;
 152                 p->thread.fpu_counter = 0;
 153                 return 0;
 154         }
 155         *childregs = *current_pt_regs();
 156
 157         if (usp)
 158                 childregs->regs[15] = usp;
 159         ti->addr_limit = USER_DS;
 160
 161         if (clone_flags & CLONE_SETTLS)
 162                 childregs->gbr = childregs->regs[0];
 163
 164         childregs->regs[0] = 0; /* Set return value for child */
 165         p->thread.pc = (unsigned long) ret_from_fork;
 166         return 0;
 167 }
 168
 169 /*
 170  *      switch_to(x,y) should switch tasks from x to y.
 171  *
 172  */
 173 __notrace_funcgraph struct task_struct *
 174 __switch_to(struct task_struct *prev, struct task_struct *next)
 175 {
 176         struct thread_struct *next_t = &next->thread;
 177
 178 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
 179         __stack_chk_guard = next->stack_canary;
 180 #endif
 181
 182         unlazy_fpu(prev, task_pt_regs(prev));
 183
 184         /* we're going to use this soon, after a few expensive things */
 185         if (next->thread.fpu_counter > 5)
 186                 prefetch(next_t->xstate);
 187
 188 #ifdef CONFIG_MMU
 189         /*
 190          * Restore the kernel mode register
 191          *      k7 (r7_bank1)
 192          */
 193         asm volatile("ldc       %0, r7_bank"
 194                      : /* no output */
 195                      : "r" (task_thread_info(next)));
 196 #endif
 197
 198         /*
 199          * If the task has used fpu the last 5 timeslices, just do a full
 200          * restore of the math state immediately to avoid the trap; the
 201          * chances of needing FPU soon are obviously high now
 202          */
 203         if (next->thread.fpu_counter > 5)
 204                 __fpu_state_restore();
 205
 206         return prev;
 207 }
 208
 209 unsigned long get_wchan(struct task_struct *p)
 210 {
 211         unsigned long pc;
 212
 213         if (!p || p == current || p->state == TASK_RUNNING)
 214                 return 0;
 215
 216         /*
 217          * The same comment as on the Alpha applies here, too ...
 218          */
 219         pc = thread_saved_pc(p);
 220
 221 #ifdef CONFIG_FRAME_POINTER
 222         if (in_sched_functions(pc)) {
 223                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 224                 return ((unsigned long *)schedule_frame)[21];
 225         }
 226 #endif
 227
 228         return pc;
 229 }