1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * arch/sh/kernel/process.c 4 * 5 * This file handles the architecture-dependent parts of process handling.. 6 * 7 * Copyright (C) 1995 Linus Torvalds 8 * 9 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 10 * Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC 11 * Copyright (C) 2002 - 2008 Paul Mundt 12 */ 13 #include <linux/module.h> 14 #include <linux/mm.h> 15 #include <linux/sched/debug.h> 16 #include <linux/sched/task.h> 17 #include <linux/sched/task_stack.h> 18 #include <linux/slab.h> 19 #include <linux/elfcore.h> 20 #include <linux/fs.h> 21 #include <linux/ftrace.h> 22 #include <linux/hw_breakpoint.h> 23 #include <linux/prefetch.h> 24 #include <linux/stackprotector.h> 25 #include <linux/uaccess.h> 26 #include <asm/mmu_context.h> 27 #include <asm/fpu.h> 28 #include <asm/syscalls.h> 29 #include <asm/switch_to.h> 30 31 void show_regs(struct pt_regs * regs) 32 { 33 pr_info("\n"); 34 show_regs_print_info(KERN_DEFAULT); 35 36 pr_info("PC is at %pS\n", (void *)instruction_pointer(regs)); 37 pr_info("PR is at %pS\n", (void *)regs->pr); 38 39 pr_info("PC : %08lx SP : %08lx SR : %08lx ", regs->pc, 40 regs->regs[15], regs->sr); 41 #ifdef CONFIG_MMU 42 pr_cont("TEA : %08x\n", __raw_readl(MMU_TEA)); 43 #else 44 pr_cont("\n"); 45 #endif 46 47 pr_info("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 48 regs->regs[0], regs->regs[1], regs->regs[2], regs->regs[3]); 49 pr_info("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 50 regs->regs[4], regs->regs[5], regs->regs[6], regs->regs[7]); 51 pr_info("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 52 regs->regs[8], regs->regs[9], regs->regs[10], regs->regs[11]); 53 pr_info("R12 : %08lx R13 : %08lx R14 : %08lx\n", 54 regs->regs[12], regs->regs[13], regs->regs[14]); 55 pr_info("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 56 regs->mach, regs->macl, regs->gbr, regs->pr); 57 58 show_trace(NULL, (unsigned long *)regs->regs[15], regs, KERN_DEFAULT); 59 show_code(regs); 60 } 61 62 void start_thread(struct pt_regs *regs, unsigned long new_pc, 63 unsigned long new_sp) 64 { 65 regs->pr = 0; 66 regs->sr = SR_FD; 67 regs->pc = new_pc; 68 regs->regs[15] = new_sp; 69 70 free_thread_xstate(current); 71 } 72 EXPORT_SYMBOL(start_thread); 73 74 void flush_thread(void) 75 { 76 struct task_struct *tsk = current; 77 78 flush_ptrace_hw_breakpoint(tsk); 79 80 #if defined(CONFIG_SH_FPU) 81 /* Forget lazy FPU state */ 82 clear_fpu(tsk, task_pt_regs(tsk)); 83 clear_used_math(); 84 #endif 85 } 86 87 void release_thread(struct task_struct *dead_task) 88 { 89 /* do nothing */ 90 } 91 92 /* Fill in the fpu structure for a core dump.. */ 93 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 94 { 95 int fpvalid = 0; 96 97 #if defined(CONFIG_SH_FPU) 98 struct task_struct *tsk = current; 99 100 fpvalid = !!tsk_used_math(tsk); 101 if (fpvalid) 102 fpvalid = !fpregs_get(tsk, NULL, 0, 103 sizeof(struct user_fpu_struct), 104 fpu, NULL); 105 #endif 106 107 return fpvalid; 108 } 109 EXPORT_SYMBOL(dump_fpu); 110 111 asmlinkage void ret_from_fork(void); 112 asmlinkage void ret_from_kernel_thread(void); 113 114 int copy_thread(unsigned long clone_flags, unsigned long usp, 115 unsigned long arg, struct task_struct *p) 116 { 117 struct thread_info *ti = task_thread_info(p); 118 struct pt_regs *childregs; 119 120 #if defined(CONFIG_SH_DSP) 121 struct task_struct *tsk = current; 122 123 if (is_dsp_enabled(tsk)) { 124 /* We can use the __save_dsp or just copy the struct: 125 * __save_dsp(p); 126 * p->thread.dsp_status.status |= SR_DSP 127 */ 128 p->thread.dsp_status = tsk->thread.dsp_status; 129 } 130 #endif 131 132 memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps)); 133 134 childregs = task_pt_regs(p); 135 p->thread.sp = (unsigned long) childregs; 136 if (unlikely(p->flags & PF_KTHREAD)) { 137 memset(childregs, 0, sizeof(struct pt_regs)); 138 p->thread.pc = (unsigned long) ret_from_kernel_thread; 139 childregs->regs[4] = arg; 140 childregs->regs[5] = usp; 141 childregs->sr = SR_MD; 142 #if defined(CONFIG_SH_FPU) 143 childregs->sr |= SR_FD; 144 #endif 145 ti->addr_limit = KERNEL_DS; 146 ti->status &= ~TS_USEDFPU; 147 p->thread.fpu_counter = 0; 148 return 0; 149 } 150 *childregs = *current_pt_regs(); 151 152 if (usp) 153 childregs->regs[15] = usp; 154 ti->addr_limit = USER_DS; 155 156 if (clone_flags & CLONE_SETTLS) 157 childregs->gbr = childregs->regs[0]; 158 159 childregs->regs[0] = 0; /* Set return value for child */ 160 p->thread.pc = (unsigned long) ret_from_fork; 161 return 0; 162 } 163 164 /* 165 * switch_to(x,y) should switch tasks from x to y. 166 * 167 */ 168 __notrace_funcgraph struct task_struct * 169 __switch_to(struct task_struct *prev, struct task_struct *next) 170 { 171 struct thread_struct *next_t = &next->thread; 172 173 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP) 174 __stack_chk_guard = next->stack_canary; 175 #endif 176 177 unlazy_fpu(prev, task_pt_regs(prev)); 178 179 /* we're going to use this soon, after a few expensive things */ 180 if (next->thread.fpu_counter > 5) 181 prefetch(next_t->xstate); 182 183 #ifdef CONFIG_MMU 184 /* 185 * Restore the kernel mode register 186 * k7 (r7_bank1) 187 */ 188 asm volatile("ldc %0, r7_bank" 189 : /* no output */ 190 : "r" (task_thread_info(next))); 191 #endif 192 193 /* 194 * If the task has used fpu the last 5 timeslices, just do a full 195 * restore of the math state immediately to avoid the trap; the 196 * chances of needing FPU soon are obviously high now 197 */ 198 if (next->thread.fpu_counter > 5) 199 __fpu_state_restore(); 200 201 return prev; 202 } 203 204 unsigned long get_wchan(struct task_struct *p) 205 { 206 unsigned long pc; 207 208 if (!p || p == current || p->state == TASK_RUNNING) 209 return 0; 210 211 /* 212 * The same comment as on the Alpha applies here, too ... 213 */ 214 pc = thread_saved_pc(p); 215 216 #ifdef CONFIG_FRAME_POINTER 217 if (in_sched_functions(pc)) { 218 unsigned long schedule_frame = (unsigned long)p->thread.sp; 219 return ((unsigned long *)schedule_frame)[21]; 220 } 221 #endif 222 223 return pc; 224 } 225