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 void start_thread(struct pt_regs *regs, unsigned long new_pc,
  72                   unsigned long new_sp)
  73 {
  74         regs->pr = 0;
  75         regs->sr = SR_FD;
  76         regs->pc = new_pc;
  77         regs->regs[15] = new_sp;
  78
  79         free_thread_xstate(current);
  80 }
  81 EXPORT_SYMBOL(start_thread);
  82
  83 /*
  84  * Free current thread data structures etc..
  85  */
  86 void exit_thread(void)
  87 {
  88 }
  89
  90 void flush_thread(void)
  91 {
  92         struct task_struct *tsk = current;
  93
  94         flush_ptrace_hw_breakpoint(tsk);
  95
  96 #if defined(CONFIG_SH_FPU)
  97         /* Forget lazy FPU state */
  98         clear_fpu(tsk, task_pt_regs(tsk));
  99         clear_used_math();
 100 #endif
 101 }
 102
 103 void release_thread(struct task_struct *dead_task)
 104 {
 105         /* do nothing */
 106 }
 107
 108 /* Fill in the fpu structure for a core dump.. */
 109 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 110 {
 111         int fpvalid = 0;
 112
 113 #if defined(CONFIG_SH_FPU)
 114         struct task_struct *tsk = current;
 115
 116         fpvalid = !!tsk_used_math(tsk);
 117         if (fpvalid)
 118                 fpvalid = !fpregs_get(tsk, NULL, 0,
 119                                       sizeof(struct user_fpu_struct),
 120                                       fpu, NULL);
 121 #endif
 122
 123         return fpvalid;
 124 }
 125 EXPORT_SYMBOL(dump_fpu);
 126
 127 asmlinkage void ret_from_fork(void);
 128 asmlinkage void ret_from_kernel_thread(void);
 129
 130 int copy_thread(unsigned long clone_flags, unsigned long usp,
 131                 unsigned long arg,
 132                 struct task_struct *p, struct pt_regs *unused)
 133 {
 134         struct thread_info *ti = task_thread_info(p);
 135         struct pt_regs *childregs;
 136
 137 #if defined(CONFIG_SH_DSP)
 138         struct task_struct *tsk = current;
 139
 140         if (is_dsp_enabled(tsk)) {
 141                 /* We can use the __save_dsp or just copy the struct:
 142                  * __save_dsp(p);
 143                  * p->thread.dsp_status.status |= SR_DSP
 144                  */
 145                 p->thread.dsp_status = tsk->thread.dsp_status;
 146         }
 147 #endif
 148
 149         memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 150
 151         childregs = task_pt_regs(p);
 152         p->thread.sp = (unsigned long) childregs;
 153         if (unlikely(p->flags & PF_KTHREAD)) {
 154                 memset(childregs, 0, sizeof(struct pt_regs));
 155                 p->thread.pc = (unsigned long) ret_from_kernel_thread;
 156                 childregs->regs[4] = arg;
 157                 childregs->regs[5] = usp;
 158                 childregs->sr = SR_MD;
 159 #if defined(CONFIG_SH_FPU)
 160                 childregs->sr |= SR_FD;
 161 #endif
 162                 ti->addr_limit = KERNEL_DS;
 163                 ti->status &= ~TS_USEDFPU;
 164                 p->fpu_counter = 0;
 165                 return 0;
 166         }
 167         *childregs = *current_pt_regs();
 168
 169         if (usp)
 170                 childregs->regs[15] = usp;
 171         ti->addr_limit = USER_DS;
 172
 173         if (clone_flags & CLONE_SETTLS)
 174                 childregs->gbr = childregs->regs[0];
 175
 176         childregs->regs[0] = 0; /* Set return value for child */
 177         p->thread.pc = (unsigned long) ret_from_fork;
 178         return 0;
 179 }
 180
 181 /*
 182  *      switch_to(x,y) should switch tasks from x to y.
 183  *
 184  */
 185 __notrace_funcgraph struct task_struct *
 186 __switch_to(struct task_struct *prev, struct task_struct *next)
 187 {
 188         struct thread_struct *next_t = &next->thread;
 189
 190 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
 191         __stack_chk_guard = next->stack_canary;
 192 #endif
 193
 194         unlazy_fpu(prev, task_pt_regs(prev));
 195
 196         /* we're going to use this soon, after a few expensive things */
 197         if (next->fpu_counter > 5)
 198                 prefetch(next_t->xstate);
 199
 200 #ifdef CONFIG_MMU
 201         /*
 202          * Restore the kernel mode register
 203          *      k7 (r7_bank1)
 204          */
 205         asm volatile("ldc       %0, r7_bank"
 206                      : /* no output */
 207                      : "r" (task_thread_info(next)));
 208 #endif
 209
 210         /*
 211          * If the task has used fpu the last 5 timeslices, just do a full
 212          * restore of the math state immediately to avoid the trap; the
 213          * chances of needing FPU soon are obviously high now
 214          */
 215         if (next->fpu_counter > 5)
 216                 __fpu_state_restore();
 217
 218         return prev;
 219 }
 220
 221 unsigned long get_wchan(struct task_struct *p)
 222 {
 223         unsigned long pc;
 224
 225         if (!p || p == current || p->state == TASK_RUNNING)
 226                 return 0;
 227
 228         /*
 229          * The same comment as on the Alpha applies here, too ...
 230          */
 231         pc = thread_saved_pc(p);
 232
 233 #ifdef CONFIG_FRAME_POINTER
 234         if (in_sched_functions(pc)) {
 235                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 236                 return ((unsigned long *)schedule_frame)[21];
 237         }
 238 #endif
 239
 240         return pc;
 241 }