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/kallsyms.h>
  24 #include <linux/fs.h>
  25 #include <linux/ftrace.h>
  26 #include <linux/hw_breakpoint.h>
  27 #include <linux/prefetch.h>
  28 #include <linux/stackprotector.h>
  29 #include <linux/uaccess.h>
  30 #include <asm/mmu_context.h>
  31 #include <asm/fpu.h>
  32 #include <asm/syscalls.h>
  33 #include <asm/switch_to.h>
  34
  35 void show_regs(struct pt_regs * regs)
  36 {
  37         printk("\n");
  38         show_regs_print_info(KERN_DEFAULT);
  39
  40         print_symbol("PC is at %s\n", instruction_pointer(regs));
  41         print_symbol("PR is at %s\n", regs->pr);
  42
  43         printk("PC  : %08lx SP  : %08lx SR  : %08lx ",
  44                regs->pc, regs->regs[15], regs->sr);
  45 #ifdef CONFIG_MMU
  46         printk("TEA : %08x\n", __raw_readl(MMU_TEA));
  47 #else
  48         printk("\n");
  49 #endif
  50
  51         printk("R0  : %08lx R1  : %08lx R2  : %08lx R3  : %08lx\n",
  52                regs->regs[0],regs->regs[1],
  53                regs->regs[2],regs->regs[3]);
  54         printk("R4  : %08lx R5  : %08lx R6  : %08lx R7  : %08lx\n",
  55                regs->regs[4],regs->regs[5],
  56                regs->regs[6],regs->regs[7]);
  57         printk("R8  : %08lx R9  : %08lx R10 : %08lx R11 : %08lx\n",
  58                regs->regs[8],regs->regs[9],
  59                regs->regs[10],regs->regs[11]);
  60         printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
  61                regs->regs[12],regs->regs[13],
  62                regs->regs[14]);
  63         printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
  64                regs->mach, regs->macl, regs->gbr, regs->pr);
  65
  66         show_trace(NULL, (unsigned long *)regs->regs[15], regs);
  67         show_code(regs);
  68 }
  69
  70 void start_thread(struct pt_regs *regs, unsigned long new_pc,
  71                   unsigned long new_sp)
  72 {
  73         regs->pr = 0;
  74         regs->sr = SR_FD;
  75         regs->pc = new_pc;
  76         regs->regs[15] = new_sp;
  77
  78         free_thread_xstate(current);
  79 }
  80 EXPORT_SYMBOL(start_thread);
  81
  82 void flush_thread(void)
  83 {
  84         struct task_struct *tsk = current;
  85
  86         flush_ptrace_hw_breakpoint(tsk);
  87
  88 #if defined(CONFIG_SH_FPU)
  89         /* Forget lazy FPU state */
  90         clear_fpu(tsk, task_pt_regs(tsk));
  91         clear_used_math();
  92 #endif
  93 }
  94
  95 void release_thread(struct task_struct *dead_task)
  96 {
  97         /* do nothing */
  98 }
  99
 100 /* Fill in the fpu structure for a core dump.. */
 101 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 102 {
 103         int fpvalid = 0;
 104
 105 #if defined(CONFIG_SH_FPU)
 106         struct task_struct *tsk = current;
 107
 108         fpvalid = !!tsk_used_math(tsk);
 109         if (fpvalid)
 110                 fpvalid = !fpregs_get(tsk, NULL, 0,
 111                                       sizeof(struct user_fpu_struct),
 112                                       fpu, NULL);
 113 #endif
 114
 115         return fpvalid;
 116 }
 117 EXPORT_SYMBOL(dump_fpu);
 118
 119 asmlinkage void ret_from_fork(void);
 120 asmlinkage void ret_from_kernel_thread(void);
 121
 122 int copy_thread(unsigned long clone_flags, unsigned long usp,
 123                 unsigned long arg, struct task_struct *p)
 124 {
 125         struct thread_info *ti = task_thread_info(p);
 126         struct pt_regs *childregs;
 127
 128 #if defined(CONFIG_SH_DSP)
 129         struct task_struct *tsk = current;
 130
 131         if (is_dsp_enabled(tsk)) {
 132                 /* We can use the __save_dsp or just copy the struct:
 133                  * __save_dsp(p);
 134                  * p->thread.dsp_status.status |= SR_DSP
 135                  */
 136                 p->thread.dsp_status = tsk->thread.dsp_status;
 137         }
 138 #endif
 139
 140         memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
 141
 142         childregs = task_pt_regs(p);
 143         p->thread.sp = (unsigned long) childregs;
 144         if (unlikely(p->flags & PF_KTHREAD)) {
 145                 memset(childregs, 0, sizeof(struct pt_regs));
 146                 p->thread.pc = (unsigned long) ret_from_kernel_thread;
 147                 childregs->regs[4] = arg;
 148                 childregs->regs[5] = usp;
 149                 childregs->sr = SR_MD;
 150 #if defined(CONFIG_SH_FPU)
 151                 childregs->sr |= SR_FD;
 152 #endif
 153                 ti->addr_limit = KERNEL_DS;
 154                 ti->status &= ~TS_USEDFPU;
 155                 p->thread.fpu_counter = 0;
 156                 return 0;
 157         }
 158         *childregs = *current_pt_regs();
 159
 160         if (usp)
 161                 childregs->regs[15] = usp;
 162         ti->addr_limit = USER_DS;
 163
 164         if (clone_flags & CLONE_SETTLS)
 165                 childregs->gbr = childregs->regs[0];
 166
 167         childregs->regs[0] = 0; /* Set return value for child */
 168         p->thread.pc = (unsigned long) ret_from_fork;
 169         return 0;
 170 }
 171
 172 /*
 173  *      switch_to(x,y) should switch tasks from x to y.
 174  *
 175  */
 176 __notrace_funcgraph struct task_struct *
 177 __switch_to(struct task_struct *prev, struct task_struct *next)
 178 {
 179         struct thread_struct *next_t = &next->thread;
 180
 181 #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP)
 182         __stack_chk_guard = next->stack_canary;
 183 #endif
 184
 185         unlazy_fpu(prev, task_pt_regs(prev));
 186
 187         /* we're going to use this soon, after a few expensive things */
 188         if (next->thread.fpu_counter > 5)
 189                 prefetch(next_t->xstate);
 190
 191 #ifdef CONFIG_MMU
 192         /*
 193          * Restore the kernel mode register
 194          *      k7 (r7_bank1)
 195          */
 196         asm volatile("ldc       %0, r7_bank"
 197                      : /* no output */
 198                      : "r" (task_thread_info(next)));
 199 #endif
 200
 201         /*
 202          * If the task has used fpu the last 5 timeslices, just do a full
 203          * restore of the math state immediately to avoid the trap; the
 204          * chances of needing FPU soon are obviously high now
 205          */
 206         if (next->thread.fpu_counter > 5)
 207                 __fpu_state_restore();
 208
 209         return prev;
 210 }
 211
 212 unsigned long get_wchan(struct task_struct *p)
 213 {
 214         unsigned long pc;
 215
 216         if (!p || p == current || p->state == TASK_RUNNING)
 217                 return 0;
 218
 219         /*
 220          * The same comment as on the Alpha applies here, too ...
 221          */
 222         pc = thread_saved_pc(p);
 223
 224 #ifdef CONFIG_FRAME_POINTER
 225         if (in_sched_functions(pc)) {
 226                 unsigned long schedule_frame = (unsigned long)p->thread.sp;
 227                 return ((unsigned long *)schedule_frame)[21];
 228         }
 229 #endif
 230
 231         return pc;
 232 }