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/sched/debug.h>
  19 #include <linux/sched/task.h>
  20 #include <linux/sched/task_stack.h>
  21 #include <linux/slab.h>
  22 #include <linux/elfcore.h>
  23 #include <linux/fs.h>
  24 #include <linux/ftrace.h>
  25 #include <linux/hw_breakpoint.h>
  26 #include <linux/prefetch.h>
  27 #include <linux/stackprotector.h>
  28 #include <linux/uaccess.h>
  29 #include <asm/mmu_context.h>
  30 #include <asm/fpu.h>
  31 #include <asm/syscalls.h>
  32 #include <asm/switch_to.h>
  33
  34 void show_regs(struct pt_regs * regs)
  35 {
  36         printk("\n");
  37         show_regs_print_info(KERN_DEFAULT);
  38
  39         printk("PC is at %pS\n", (void *)instruction_pointer(regs));
  40         printk("PR is at %pS\n", (void *)regs->pr);
  41
  42         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
  43                regs->pc, regs->regs[15], regs->sr);
  44 #ifdef CONFIG_MMU
  45         printk("TEA : %08x\n", __raw_readl(MMU_TEA));
  46 #else
  47         printk("\n");
  48 #endif
  49
  50         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
  51                regs->regs[0],regs->regs[1],
  52                regs->regs[2],regs->regs[3]);
  53         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
  54                regs->regs[4],regs->regs[5],
  55                regs->regs[6],regs->regs[7]);
  56         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
  57                regs->regs[8],regs->regs[9],
  58                regs->regs[10],regs->regs[11]);
  59         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
  60                regs->regs[12],regs->regs[13],
  61                regs->regs[14]);
  62         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
  63                regs->mach, regs->macl, regs->gbr, regs->pr);
  64
  65         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
  66         show_code(regs);
  67 }
  68
  69 void start_thread(struct pt_regs *regs, unsigned long new_pc,
  70                   unsigned long new_sp)
  71 {
  72         regs->pr = 0;
  73         regs->sr = SR_FD;
  74         regs->pc = new_pc;
  75         regs->regs[15] = new_sp;
  76
  77         free_thread_xstate(current);
  78 }
  79 EXPORT_SYMBOL(start_thread);
  80
  81 void flush_thread(void)
  82 {
  83         struct task_struct *tsk = current;
  84
  85         flush_ptrace_hw_breakpoint(tsk);
  86
  87 #if defined(CONFIG_SH_FPU)
  88         /* Forget lazy FPU state */
  89         clear_fpu(tsk, task_pt_regs(tsk));
  90         clear_used_math();
  91 #endif
  92 }
  93
  94 void release_thread(struct task_struct *dead_task)
  95 {
  96         /* do nothing */
  97 }
  98
  99 /* Fill in the fpu structure for a core dump.. */
 100 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 101 {
 102         int fpvalid = 0;
 103
 104 #if defined(CONFIG_SH_FPU)
 105         struct task_struct *tsk = current;
 106
 107         fpvalid = !!tsk_used_math(tsk);
 108         if (fpvalid)
 109                 fpvalid = !fpregs_get(tsk, NULL, 0,
 110                                       sizeof(struct user_fpu_struct),
 111                                       fpu, NULL);
 112 #endif
 113
 114         return fpvalid;
 115 }
 116 EXPORT_SYMBOL(dump_fpu);
 117
 118 asmlinkage void ret_from_fork(void);
 119 asmlinkage void ret_from_kernel_thread(void);
 120
 121 int copy_thread(unsigned long clone_flags, unsigned long usp,
 122                 unsigned long arg, struct task_struct *p)
 123 {
 124         struct thread_info *ti = task_thread_info(p);
 125         struct pt_regs *childregs;
 126
 127 #if defined(CONFIG_SH_DSP)
 128         struct task_struct *tsk = current;
 129
 130         if (is_dsp_enabled(tsk)) {
 131                 /* We can use the __save_dsp or just copy the struct:
 132                  * __save_dsp(p);
 133                  * p->thread.dsp_status.status |= SR_DSP
 134                  */
 135                 p->thread.dsp_status = tsk->thread.dsp_status;
 136         }
 137 #endif
 138
 139         memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 140
 141         childregs = task_pt_regs(p);
 142         p->thread.sp = (unsigned long) childregs;
 143         if (unlikely(p->flags & PF_KTHREAD)) {
 144                 memset(childregs, 0, sizeof(struct pt_regs));
 145                 p->thread.pc = (unsigned long) ret_from_kernel_thread;
 146                 childregs->regs[4] = arg;
 147                 childregs->regs[5] = usp;
 148                 childregs->sr = SR_MD;
 149 #if defined(CONFIG_SH_FPU)
 150                 childregs->sr |= SR_FD;
 151 #endif
 152                 ti->addr_limit = KERNEL_DS;
 153                 ti->status &= ~TS_USEDFPU;
 154                 p->thread.fpu_counter = 0;
 155                 return 0;
 156         }
 157         *childregs = *current_pt_regs();
 158
 159         if (usp)
 160                 childregs->regs[15] = usp;
 161         ti->addr_limit = USER_DS;
 162
 163         if (clone_flags & CLONE_SETTLS)
 164                 childregs->gbr = childregs->regs[0];
 165
 166         childregs->regs[0] = 0; /* Set return value for child */
 167         p->thread.pc = (unsigned long) ret_from_fork;
 168         return 0;
 169 }
 170
 171 /*
 172  *      switch_to(x,y) should switch tasks from x to y.
 173  *
 174  */
 175 __notrace_funcgraph struct task_struct *
 176 __switch_to(struct task_struct *prev, struct task_struct *next)
 177 {
 178         struct thread_struct *next_t = &next->thread;
 179
 180 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP)
 181         __stack_chk_guard = next->stack_canary;
 182 #endif
 183
 184         unlazy_fpu(prev, task_pt_regs(prev));
 185
 186         /* we're going to use this soon, after a few expensive things */
 187         if (next->thread.fpu_counter > 5)
 188                 prefetch(next_t->xstate);
 189
 190 #ifdef CONFIG_MMU
 191         /*
 192          * Restore the kernel mode register
 193          *      k7 (r7_bank1)
 194          */
 195         asm volatile("ldc       %0, r7_bank"
 196                      : /* no output */
 197                      : "r" (task_thread_info(next)));
 198 #endif
 199
 200         /*
 201          * If the task has used fpu the last 5 timeslices, just do a full
 202          * restore of the math state immediately to avoid the trap; the
 203          * chances of needing FPU soon are obviously high now
 204          */
 205         if (next->thread.fpu_counter > 5)
 206                 __fpu_state_restore();
 207
 208         return prev;
 209 }
 210
 211 unsigned long get_wchan(struct task_struct *p)
 212 {
 213         unsigned long pc;
 214
 215         if (!p || p == current || p->state == TASK_RUNNING)
 216                 return 0;
 217
 218         /*
 219          * The same comment as on the Alpha applies here, too ...
 220          */
 221         pc = thread_saved_pc(p);
 222
 223 #ifdef CONFIG_FRAME_POINTER
 224         if (in_sched_functions(pc)) {
 225                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 226                 return ((unsigned long *)schedule_frame)[21];
 227         }
 228 #endif
 229
 230         return pc;
 231 }