process.c (7063B)
1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Author: Huacai Chen <chenhuacai@loongson.cn> 4 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 5 * 6 * Derived from MIPS: 7 * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others. 8 * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org) 9 * Copyright (C) 1999, 2000 Silicon Graphics, Inc. 10 * Copyright (C) 2004 Thiemo Seufer 11 * Copyright (C) 2013 Imagination Technologies Ltd. 12 */ 13#include <linux/cpu.h> 14#include <linux/init.h> 15#include <linux/kernel.h> 16#include <linux/errno.h> 17#include <linux/sched.h> 18#include <linux/sched/debug.h> 19#include <linux/sched/task.h> 20#include <linux/sched/task_stack.h> 21#include <linux/mm.h> 22#include <linux/stddef.h> 23#include <linux/unistd.h> 24#include <linux/export.h> 25#include <linux/ptrace.h> 26#include <linux/mman.h> 27#include <linux/personality.h> 28#include <linux/sys.h> 29#include <linux/completion.h> 30#include <linux/kallsyms.h> 31#include <linux/random.h> 32#include <linux/prctl.h> 33#include <linux/nmi.h> 34 35#include <asm/asm.h> 36#include <asm/bootinfo.h> 37#include <asm/cpu.h> 38#include <asm/elf.h> 39#include <asm/fpu.h> 40#include <asm/io.h> 41#include <asm/irq.h> 42#include <asm/irq_regs.h> 43#include <asm/loongarch.h> 44#include <asm/pgtable.h> 45#include <asm/processor.h> 46#include <asm/reg.h> 47#include <asm/vdso.h> 48 49/* 50 * Idle related variables and functions 51 */ 52 53unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE; 54EXPORT_SYMBOL(boot_option_idle_override); 55 56#ifdef CONFIG_HOTPLUG_CPU 57void arch_cpu_idle_dead(void) 58{ 59 play_dead(); 60} 61#endif 62 63asmlinkage void ret_from_fork(void); 64asmlinkage void ret_from_kernel_thread(void); 65 66void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) 67{ 68 unsigned long crmd; 69 unsigned long prmd; 70 unsigned long euen; 71 72 /* New thread loses kernel privileges. */ 73 crmd = regs->csr_crmd & ~(PLV_MASK); 74 crmd |= PLV_USER; 75 regs->csr_crmd = crmd; 76 77 prmd = regs->csr_prmd & ~(PLV_MASK); 78 prmd |= PLV_USER; 79 regs->csr_prmd = prmd; 80 81 euen = regs->csr_euen & ~(CSR_EUEN_FPEN); 82 regs->csr_euen = euen; 83 lose_fpu(0); 84 85 clear_thread_flag(TIF_LSX_CTX_LIVE); 86 clear_thread_flag(TIF_LASX_CTX_LIVE); 87 clear_used_math(); 88 regs->csr_era = pc; 89 regs->regs[3] = sp; 90} 91 92void exit_thread(struct task_struct *tsk) 93{ 94} 95 96int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 97{ 98 /* 99 * Save any process state which is live in hardware registers to the 100 * parent context prior to duplication. This prevents the new child 101 * state becoming stale if the parent is preempted before copy_thread() 102 * gets a chance to save the parent's live hardware registers to the 103 * child context. 104 */ 105 preempt_disable(); 106 107 if (is_fpu_owner()) 108 save_fp(current); 109 110 preempt_enable(); 111 112 if (used_math()) 113 memcpy(dst, src, sizeof(struct task_struct)); 114 else 115 memcpy(dst, src, offsetof(struct task_struct, thread.fpu.fpr)); 116 117 return 0; 118} 119 120/* 121 * Copy architecture-specific thread state 122 */ 123int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 124{ 125 unsigned long childksp; 126 unsigned long tls = args->tls; 127 unsigned long usp = args->stack; 128 unsigned long clone_flags = args->flags; 129 struct pt_regs *childregs, *regs = current_pt_regs(); 130 131 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; 132 133 /* set up new TSS. */ 134 childregs = (struct pt_regs *) childksp - 1; 135 /* Put the stack after the struct pt_regs. */ 136 childksp = (unsigned long) childregs; 137 p->thread.csr_euen = 0; 138 p->thread.csr_crmd = csr_read32(LOONGARCH_CSR_CRMD); 139 p->thread.csr_prmd = csr_read32(LOONGARCH_CSR_PRMD); 140 p->thread.csr_ecfg = csr_read32(LOONGARCH_CSR_ECFG); 141 if (unlikely(args->fn)) { 142 /* kernel thread */ 143 p->thread.reg03 = childksp; 144 p->thread.reg23 = (unsigned long)args->fn; 145 p->thread.reg24 = (unsigned long)args->fn_arg; 146 p->thread.reg01 = (unsigned long)ret_from_kernel_thread; 147 memset(childregs, 0, sizeof(struct pt_regs)); 148 childregs->csr_euen = p->thread.csr_euen; 149 childregs->csr_crmd = p->thread.csr_crmd; 150 childregs->csr_prmd = p->thread.csr_prmd; 151 childregs->csr_ecfg = p->thread.csr_ecfg; 152 return 0; 153 } 154 155 /* user thread */ 156 *childregs = *regs; 157 childregs->regs[4] = 0; /* Child gets zero as return value */ 158 if (usp) 159 childregs->regs[3] = usp; 160 161 p->thread.reg03 = (unsigned long) childregs; 162 p->thread.reg01 = (unsigned long) ret_from_fork; 163 164 /* 165 * New tasks lose permission to use the fpu. This accelerates context 166 * switching for most programs since they don't use the fpu. 167 */ 168 childregs->csr_euen = 0; 169 170 clear_tsk_thread_flag(p, TIF_USEDFPU); 171 clear_tsk_thread_flag(p, TIF_USEDSIMD); 172 clear_tsk_thread_flag(p, TIF_LSX_CTX_LIVE); 173 clear_tsk_thread_flag(p, TIF_LASX_CTX_LIVE); 174 175 if (clone_flags & CLONE_SETTLS) 176 childregs->regs[2] = tls; 177 178 return 0; 179} 180 181unsigned long __get_wchan(struct task_struct *task) 182{ 183 return 0; 184} 185 186unsigned long stack_top(void) 187{ 188 unsigned long top = TASK_SIZE & PAGE_MASK; 189 190 /* Space for the VDSO & data page */ 191 top -= PAGE_ALIGN(current->thread.vdso->size); 192 top -= PAGE_SIZE; 193 194 /* Space to randomize the VDSO base */ 195 if (current->flags & PF_RANDOMIZE) 196 top -= VDSO_RANDOMIZE_SIZE; 197 198 return top; 199} 200 201/* 202 * Don't forget that the stack pointer must be aligned on a 8 bytes 203 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. 204 */ 205unsigned long arch_align_stack(unsigned long sp) 206{ 207 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) 208 sp -= get_random_int() & ~PAGE_MASK; 209 210 return sp & STACK_ALIGN; 211} 212 213static DEFINE_PER_CPU(call_single_data_t, backtrace_csd); 214static struct cpumask backtrace_csd_busy; 215 216static void handle_backtrace(void *info) 217{ 218 nmi_cpu_backtrace(get_irq_regs()); 219 cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy); 220} 221 222static void raise_backtrace(cpumask_t *mask) 223{ 224 call_single_data_t *csd; 225 int cpu; 226 227 for_each_cpu(cpu, mask) { 228 /* 229 * If we previously sent an IPI to the target CPU & it hasn't 230 * cleared its bit in the busy cpumask then it didn't handle 231 * our previous IPI & it's not safe for us to reuse the 232 * call_single_data_t. 233 */ 234 if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) { 235 pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n", 236 cpu); 237 continue; 238 } 239 240 csd = &per_cpu(backtrace_csd, cpu); 241 csd->func = handle_backtrace; 242 smp_call_function_single_async(cpu, csd); 243 } 244} 245 246void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) 247{ 248 nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace); 249} 250 251#ifdef CONFIG_64BIT 252void loongarch_dump_regs64(u64 *uregs, const struct pt_regs *regs) 253{ 254 unsigned int i; 255 256 for (i = LOONGARCH_EF_R1; i <= LOONGARCH_EF_R31; i++) { 257 uregs[i] = regs->regs[i - LOONGARCH_EF_R0]; 258 } 259 260 uregs[LOONGARCH_EF_ORIG_A0] = regs->orig_a0; 261 uregs[LOONGARCH_EF_CSR_ERA] = regs->csr_era; 262 uregs[LOONGARCH_EF_CSR_BADV] = regs->csr_badvaddr; 263 uregs[LOONGARCH_EF_CSR_CRMD] = regs->csr_crmd; 264 uregs[LOONGARCH_EF_CSR_PRMD] = regs->csr_prmd; 265 uregs[LOONGARCH_EF_CSR_EUEN] = regs->csr_euen; 266 uregs[LOONGARCH_EF_CSR_ECFG] = regs->csr_ecfg; 267 uregs[LOONGARCH_EF_CSR_ESTAT] = regs->csr_estat; 268} 269#endif /* CONFIG_64BIT */