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>
21 #include <linux/hw_breakpoint.h>
23 #include <linux/stddef.h>
24 #include <linux/unistd.h>
25 #include <linux/export.h>
26 #include <linux/ptrace.h>
27 #include <linux/mman.h>
28 #include <linux/personality.h>
29 #include <linux/sys.h>
30 #include <linux/completion.h>
31 #include <linux/kallsyms.h>
32 #include <linux/random.h>
33 #include <linux/prctl.h>
34 #include <linux/nmi.h>
37 #include <asm/bootinfo.h>
44 #include <asm/irq_regs.h>
45 #include <asm/loongarch.h>
46 #include <asm/pgtable.h>
47 #include <asm/processor.h>
49 #include <asm/unwind.h>
52 #ifdef CONFIG_STACKPROTECTOR
53 #include <linux/stackprotector.h>
54 unsigned long __stack_chk_guard __read_mostly
;
55 EXPORT_SYMBOL(__stack_chk_guard
);
59 * Idle related variables and functions
62 unsigned long boot_option_idle_override
= IDLE_NO_OVERRIDE
;
63 EXPORT_SYMBOL(boot_option_idle_override
);
65 asmlinkage
void ret_from_fork(void);
66 asmlinkage
void ret_from_kernel_thread(void);
68 void start_thread(struct pt_regs
*regs
, unsigned long pc
, unsigned long sp
)
74 /* New thread loses kernel privileges. */
75 crmd
= regs
->csr_crmd
& ~(PLV_MASK
);
77 regs
->csr_crmd
= crmd
;
79 prmd
= regs
->csr_prmd
& ~(PLV_MASK
);
81 regs
->csr_prmd
= prmd
;
83 euen
= regs
->csr_euen
& ~(CSR_EUEN_FPEN
);
84 regs
->csr_euen
= euen
;
88 clear_thread_flag(TIF_LSX_CTX_LIVE
);
89 clear_thread_flag(TIF_LASX_CTX_LIVE
);
90 clear_thread_flag(TIF_LBT_CTX_LIVE
);
96 void flush_thread(void)
98 flush_ptrace_hw_breakpoint(current
);
101 void exit_thread(struct task_struct
*tsk
)
105 int arch_dup_task_struct(struct task_struct
*dst
, struct task_struct
*src
)
108 * Save any process state which is live in hardware registers to the
109 * parent context prior to duplication. This prevents the new child
110 * state becoming stale if the parent is preempted before copy_thread()
111 * gets a chance to save the parent's live hardware registers to the
116 if (is_fpu_owner()) {
117 if (is_lasx_enabled())
119 else if (is_lsx_enabled())
128 memcpy(dst
, src
, offsetof(struct task_struct
, thread
.fpu
.fpr
));
130 memcpy(dst
, src
, offsetof(struct task_struct
, thread
.lbt
.scr0
));
132 #ifdef CONFIG_CPU_HAS_LBT
133 memcpy(&dst
->thread
.lbt
, &src
->thread
.lbt
, sizeof(struct loongarch_lbt
));
140 * Copy architecture-specific thread state
142 int copy_thread(struct task_struct
*p
, const struct kernel_clone_args
*args
)
144 unsigned long childksp
;
145 unsigned long tls
= args
->tls
;
146 unsigned long usp
= args
->stack
;
147 unsigned long clone_flags
= args
->flags
;
148 struct pt_regs
*childregs
, *regs
= current_pt_regs();
150 childksp
= (unsigned long)task_stack_page(p
) + THREAD_SIZE
;
152 /* set up new TSS. */
153 childregs
= (struct pt_regs
*) childksp
- 1;
154 /* Put the stack after the struct pt_regs. */
155 childksp
= (unsigned long) childregs
;
156 p
->thread
.sched_cfa
= 0;
157 p
->thread
.csr_euen
= 0;
158 p
->thread
.csr_crmd
= csr_read32(LOONGARCH_CSR_CRMD
);
159 p
->thread
.csr_prmd
= csr_read32(LOONGARCH_CSR_PRMD
);
160 p
->thread
.csr_ecfg
= csr_read32(LOONGARCH_CSR_ECFG
);
161 if (unlikely(args
->fn
)) {
163 p
->thread
.reg03
= childksp
;
164 p
->thread
.reg23
= (unsigned long)args
->fn
;
165 p
->thread
.reg24
= (unsigned long)args
->fn_arg
;
166 p
->thread
.reg01
= (unsigned long)ret_from_kernel_thread
;
167 p
->thread
.sched_ra
= (unsigned long)ret_from_kernel_thread
;
168 memset(childregs
, 0, sizeof(struct pt_regs
));
169 childregs
->csr_euen
= p
->thread
.csr_euen
;
170 childregs
->csr_crmd
= p
->thread
.csr_crmd
;
171 childregs
->csr_prmd
= p
->thread
.csr_prmd
;
172 childregs
->csr_ecfg
= p
->thread
.csr_ecfg
;
178 childregs
->regs
[4] = 0; /* Child gets zero as return value */
180 childregs
->regs
[3] = usp
;
182 p
->thread
.reg03
= (unsigned long) childregs
;
183 p
->thread
.reg01
= (unsigned long) ret_from_fork
;
184 p
->thread
.sched_ra
= (unsigned long) ret_from_fork
;
187 * New tasks lose permission to use the fpu. This accelerates context
188 * switching for most programs since they don't use the fpu.
190 childregs
->csr_euen
= 0;
192 if (clone_flags
& CLONE_SETTLS
)
193 childregs
->regs
[2] = tls
;
196 ptrace_hw_copy_thread(p
);
197 clear_tsk_thread_flag(p
, TIF_USEDFPU
);
198 clear_tsk_thread_flag(p
, TIF_USEDSIMD
);
199 clear_tsk_thread_flag(p
, TIF_USEDLBT
);
200 clear_tsk_thread_flag(p
, TIF_LSX_CTX_LIVE
);
201 clear_tsk_thread_flag(p
, TIF_LASX_CTX_LIVE
);
202 clear_tsk_thread_flag(p
, TIF_LBT_CTX_LIVE
);
207 unsigned long __get_wchan(struct task_struct
*task
)
209 unsigned long pc
= 0;
210 struct unwind_state state
;
212 if (!try_get_task_stack(task
))
215 for (unwind_start(&state
, task
, NULL
);
216 !unwind_done(&state
); unwind_next_frame(&state
)) {
217 pc
= unwind_get_return_address(&state
);
220 if (in_sched_functions(pc
))
225 put_task_stack(task
);
230 bool in_irq_stack(unsigned long stack
, struct stack_info
*info
)
232 unsigned long nextsp
;
233 unsigned long begin
= (unsigned long)this_cpu_read(irq_stack
);
234 unsigned long end
= begin
+ IRQ_STACK_START
;
236 if (stack
< begin
|| stack
>= end
)
239 nextsp
= *(unsigned long *)end
;
240 if (nextsp
& (SZREG
- 1))
245 info
->next_sp
= nextsp
;
246 info
->type
= STACK_TYPE_IRQ
;
251 bool in_task_stack(unsigned long stack
, struct task_struct
*task
,
252 struct stack_info
*info
)
254 unsigned long begin
= (unsigned long)task_stack_page(task
);
255 unsigned long end
= begin
+ THREAD_SIZE
;
257 if (stack
< begin
|| stack
>= end
)
263 info
->type
= STACK_TYPE_TASK
;
268 int get_stack_info(unsigned long stack
, struct task_struct
*task
,
269 struct stack_info
*info
)
271 task
= task
? : current
;
273 if (!stack
|| stack
& (SZREG
- 1))
276 if (in_task_stack(stack
, task
, info
))
282 if (in_irq_stack(stack
, info
))
286 info
->type
= STACK_TYPE_UNKNOWN
;
290 unsigned long stack_top(void)
292 unsigned long top
= TASK_SIZE
& PAGE_MASK
;
294 /* Space for the VDSO & data page */
295 top
-= PAGE_ALIGN(current
->thread
.vdso
->size
);
298 /* Space to randomize the VDSO base */
299 if (current
->flags
& PF_RANDOMIZE
)
300 top
-= VDSO_RANDOMIZE_SIZE
;
306 * Don't forget that the stack pointer must be aligned on a 8 bytes
307 * boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
309 unsigned long arch_align_stack(unsigned long sp
)
311 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
312 sp
-= get_random_u32_below(PAGE_SIZE
);
314 return sp
& STACK_ALIGN
;
317 static DEFINE_PER_CPU(call_single_data_t
, backtrace_csd
);
318 static struct cpumask backtrace_csd_busy
;
320 static void handle_backtrace(void *info
)
322 nmi_cpu_backtrace(get_irq_regs());
323 cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy
);
326 static void raise_backtrace(cpumask_t
*mask
)
328 call_single_data_t
*csd
;
331 for_each_cpu(cpu
, mask
) {
333 * If we previously sent an IPI to the target CPU & it hasn't
334 * cleared its bit in the busy cpumask then it didn't handle
335 * our previous IPI & it's not safe for us to reuse the
336 * call_single_data_t.
338 if (cpumask_test_and_set_cpu(cpu
, &backtrace_csd_busy
)) {
339 pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",
344 csd
= &per_cpu(backtrace_csd
, cpu
);
345 csd
->func
= handle_backtrace
;
346 smp_call_function_single_async(cpu
, csd
);
350 void arch_trigger_cpumask_backtrace(const cpumask_t
*mask
, int exclude_cpu
)
352 nmi_trigger_cpumask_backtrace(mask
, exclude_cpu
, raise_backtrace
);
356 void loongarch_dump_regs64(u64
*uregs
, const struct pt_regs
*regs
)
360 for (i
= LOONGARCH_EF_R1
; i
<= LOONGARCH_EF_R31
; i
++) {
361 uregs
[i
] = regs
->regs
[i
- LOONGARCH_EF_R0
];
364 uregs
[LOONGARCH_EF_ORIG_A0
] = regs
->orig_a0
;
365 uregs
[LOONGARCH_EF_CSR_ERA
] = regs
->csr_era
;
366 uregs
[LOONGARCH_EF_CSR_BADV
] = regs
->csr_badvaddr
;
367 uregs
[LOONGARCH_EF_CSR_CRMD
] = regs
->csr_crmd
;
368 uregs
[LOONGARCH_EF_CSR_PRMD
] = regs
->csr_prmd
;
369 uregs
[LOONGARCH_EF_CSR_EUEN
] = regs
->csr_euen
;
370 uregs
[LOONGARCH_EF_CSR_ECFG
] = regs
->csr_ecfg
;
371 uregs
[LOONGARCH_EF_CSR_ESTAT
] = regs
->csr_estat
;
373 #endif /* CONFIG_64BIT */