1 // SPDX-License-Identifier: GPL-2.0
3 * Author: Huacai Chen <chenhuacai@loongson.cn>
4 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
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.
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>
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>
36 #include <asm/bootinfo.h>
42 #include <asm/irq_regs.h>
43 #include <asm/loongarch.h>
44 #include <asm/pgtable.h>
45 #include <asm/processor.h>
47 #include <asm/unwind.h>
50 #ifdef CONFIG_STACKPROTECTOR
51 #include <linux/stackprotector.h>
52 unsigned long __stack_chk_guard __read_mostly;
53 EXPORT_SYMBOL(__stack_chk_guard);
57 * Idle related variables and functions
60 unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
61 EXPORT_SYMBOL(boot_option_idle_override);
63 #ifdef CONFIG_HOTPLUG_CPU
64 void arch_cpu_idle_dead(void)
70 asmlinkage void ret_from_fork(void);
71 asmlinkage void ret_from_kernel_thread(void);
73 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
79 /* New thread loses kernel privileges. */
80 crmd = regs->csr_crmd & ~(PLV_MASK);
82 regs->csr_crmd = crmd;
84 prmd = regs->csr_prmd & ~(PLV_MASK);
86 regs->csr_prmd = prmd;
88 euen = regs->csr_euen & ~(CSR_EUEN_FPEN);
89 regs->csr_euen = euen;
92 clear_thread_flag(TIF_LSX_CTX_LIVE);
93 clear_thread_flag(TIF_LASX_CTX_LIVE);
99 void exit_thread(struct task_struct *tsk)
103 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
106 * Save any process state which is live in hardware registers to the
107 * parent context prior to duplication. This prevents the new child
108 * state becoming stale if the parent is preempted before copy_thread()
109 * gets a chance to save the parent's live hardware registers to the
120 memcpy(dst, src, sizeof(struct task_struct));
122 memcpy(dst, src, offsetof(struct task_struct, thread.fpu.fpr));
128 * Copy architecture-specific thread state
130 int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
132 unsigned long childksp;
133 unsigned long tls = args->tls;
134 unsigned long usp = args->stack;
135 unsigned long clone_flags = args->flags;
136 struct pt_regs *childregs, *regs = current_pt_regs();
138 childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
140 /* set up new TSS. */
141 childregs = (struct pt_regs *) childksp - 1;
142 /* Put the stack after the struct pt_regs. */
143 childksp = (unsigned long) childregs;
144 p->thread.sched_cfa = 0;
145 p->thread.csr_euen = 0;
146 p->thread.csr_crmd = csr_read32(LOONGARCH_CSR_CRMD);
147 p->thread.csr_prmd = csr_read32(LOONGARCH_CSR_PRMD);
148 p->thread.csr_ecfg = csr_read32(LOONGARCH_CSR_ECFG);
149 if (unlikely(args->fn)) {
151 p->thread.reg03 = childksp;
152 p->thread.reg23 = (unsigned long)args->fn;
153 p->thread.reg24 = (unsigned long)args->fn_arg;
154 p->thread.reg01 = (unsigned long)ret_from_kernel_thread;
155 p->thread.sched_ra = (unsigned long)ret_from_kernel_thread;
156 memset(childregs, 0, sizeof(struct pt_regs));
157 childregs->csr_euen = p->thread.csr_euen;
158 childregs->csr_crmd = p->thread.csr_crmd;
159 childregs->csr_prmd = p->thread.csr_prmd;
160 childregs->csr_ecfg = p->thread.csr_ecfg;
166 childregs->regs[4] = 0; /* Child gets zero as return value */
168 childregs->regs[3] = usp;
170 p->thread.reg03 = (unsigned long) childregs;
171 p->thread.reg01 = (unsigned long) ret_from_fork;
172 p->thread.sched_ra = (unsigned long) ret_from_fork;
175 * New tasks lose permission to use the fpu. This accelerates context
176 * switching for most programs since they don't use the fpu.
178 childregs->csr_euen = 0;
180 if (clone_flags & CLONE_SETTLS)
181 childregs->regs[2] = tls;
184 clear_tsk_thread_flag(p, TIF_USEDFPU);
185 clear_tsk_thread_flag(p, TIF_USEDSIMD);
186 clear_tsk_thread_flag(p, TIF_LSX_CTX_LIVE);
187 clear_tsk_thread_flag(p, TIF_LASX_CTX_LIVE);
192 unsigned long __get_wchan(struct task_struct *task)
195 struct unwind_state state;
197 if (!try_get_task_stack(task))
200 unwind_start(&state, task, NULL);
201 state.sp = thread_saved_fp(task);
202 get_stack_info(state.sp, state.task, &state.stack_info);
203 state.pc = thread_saved_ra(task);
204 #ifdef CONFIG_UNWINDER_PROLOGUE
205 state.type = UNWINDER_PROLOGUE;
207 for (; !unwind_done(&state); unwind_next_frame(&state)) {
208 pc = unwind_get_return_address(&state);
211 if (in_sched_functions(pc))
216 put_task_stack(task);
221 bool in_irq_stack(unsigned long stack, struct stack_info *info)
223 unsigned long nextsp;
224 unsigned long begin = (unsigned long)this_cpu_read(irq_stack);
225 unsigned long end = begin + IRQ_STACK_START;
227 if (stack < begin || stack >= end)
230 nextsp = *(unsigned long *)end;
231 if (nextsp & (SZREG - 1))
236 info->next_sp = nextsp;
237 info->type = STACK_TYPE_IRQ;
242 bool in_task_stack(unsigned long stack, struct task_struct *task,
243 struct stack_info *info)
245 unsigned long begin = (unsigned long)task_stack_page(task);
246 unsigned long end = begin + THREAD_SIZE;
248 if (stack < begin || stack >= end)
254 info->type = STACK_TYPE_TASK;
259 int get_stack_info(unsigned long stack, struct task_struct *task,
260 struct stack_info *info)
262 task = task ? : current;
264 if (!stack || stack & (SZREG - 1))
267 if (in_task_stack(stack, task, info))
273 if (in_irq_stack(stack, info))
277 info->type = STACK_TYPE_UNKNOWN;
281 unsigned long stack_top(void)
283 unsigned long top = TASK_SIZE & PAGE_MASK;
285 /* Space for the VDSO & data page */
286 top -= PAGE_ALIGN(current->thread.vdso->size);
289 /* Space to randomize the VDSO base */
290 if (current->flags & PF_RANDOMIZE)
291 top -= VDSO_RANDOMIZE_SIZE;
297 * Don't forget that the stack pointer must be aligned on a 8 bytes
298 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
300 unsigned long arch_align_stack(unsigned long sp)
302 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
303 sp -= get_random_u32_below(PAGE_SIZE);
305 return sp & STACK_ALIGN;
308 static DEFINE_PER_CPU(call_single_data_t, backtrace_csd);
309 static struct cpumask backtrace_csd_busy;
311 static void handle_backtrace(void *info)
313 nmi_cpu_backtrace(get_irq_regs());
314 cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy);
317 static void raise_backtrace(cpumask_t *mask)
319 call_single_data_t *csd;
322 for_each_cpu(cpu, mask) {
324 * If we previously sent an IPI to the target CPU & it hasn't
325 * cleared its bit in the busy cpumask then it didn't handle
326 * our previous IPI & it's not safe for us to reuse the
327 * call_single_data_t.
329 if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) {
330 pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",
335 csd = &per_cpu(backtrace_csd, cpu);
336 csd->func = handle_backtrace;
337 smp_call_function_single_async(cpu, csd);
341 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
343 nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace);
347 void loongarch_dump_regs64(u64 *uregs, const struct pt_regs *regs)
351 for (i = LOONGARCH_EF_R1; i <= LOONGARCH_EF_R31; i++) {
352 uregs[i] = regs->regs[i - LOONGARCH_EF_R0];
355 uregs[LOONGARCH_EF_ORIG_A0] = regs->orig_a0;
356 uregs[LOONGARCH_EF_CSR_ERA] = regs->csr_era;
357 uregs[LOONGARCH_EF_CSR_BADV] = regs->csr_badvaddr;
358 uregs[LOONGARCH_EF_CSR_CRMD] = regs->csr_crmd;
359 uregs[LOONGARCH_EF_CSR_PRMD] = regs->csr_prmd;
360 uregs[LOONGARCH_EF_CSR_EUEN] = regs->csr_euen;
361 uregs[LOONGARCH_EF_CSR_ECFG] = regs->csr_ecfg;
362 uregs[LOONGARCH_EF_CSR_ESTAT] = regs->csr_estat;
364 #endif /* CONFIG_64BIT */