1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
  4 *  Chen Liqin <liqin.chen@sunplusct.com>
  5 *  Lennox Wu <lennox.wu@sunplusct.com>
  6 * Copyright (C) 2012 Regents of the University of California
  7 * Copyright (C) 2017 SiFive
  8 */
  9
 10#include <linux/cpu.h>
 11#include <linux/kernel.h>
 12#include <linux/sched.h>
 13#include <linux/sched/task_stack.h>
 14#include <linux/tick.h>
 15#include <linux/ptrace.h>
 16#include <linux/uaccess.h>
 17
 18#include <asm/unistd.h>
 19#include <asm/processor.h>
 20#include <asm/csr.h>
 21#include <asm/string.h>
 22#include <asm/switch_to.h>
 23#include <asm/thread_info.h>
 24
 25register unsigned long gp_in_global __asm__("gp");
 26
 27#ifdef CONFIG_STACKPROTECTOR
 28#include <linux/stackprotector.h>
 29unsigned long __stack_chk_guard __read_mostly;
 30EXPORT_SYMBOL(__stack_chk_guard);
 31#endif
 32
 33extern asmlinkage void ret_from_fork(void);
 34extern asmlinkage void ret_from_kernel_thread(void);
 35
 36void arch_cpu_idle(void)
 37{
 38	wait_for_interrupt();
 39	local_irq_enable();
 40}
 41
 42void show_regs(struct pt_regs *regs)
 43{
 44	show_regs_print_info(KERN_DEFAULT);
 45
 46	pr_cont("epc: " REG_FMT " ra : " REG_FMT " sp : " REG_FMT "\n",
 47		regs->epc, regs->ra, regs->sp);
 48	pr_cont(" gp : " REG_FMT " tp : " REG_FMT " t0 : " REG_FMT "\n",
 49		regs->gp, regs->tp, regs->t0);
 50	pr_cont(" t1 : " REG_FMT " t2 : " REG_FMT " s0 : " REG_FMT "\n",
 51		regs->t1, regs->t2, regs->s0);
 52	pr_cont(" s1 : " REG_FMT " a0 : " REG_FMT " a1 : " REG_FMT "\n",
 53		regs->s1, regs->a0, regs->a1);
 54	pr_cont(" a2 : " REG_FMT " a3 : " REG_FMT " a4 : " REG_FMT "\n",
 55		regs->a2, regs->a3, regs->a4);
 56	pr_cont(" a5 : " REG_FMT " a6 : " REG_FMT " a7 : " REG_FMT "\n",
 57		regs->a5, regs->a6, regs->a7);
 58	pr_cont(" s2 : " REG_FMT " s3 : " REG_FMT " s4 : " REG_FMT "\n",
 59		regs->s2, regs->s3, regs->s4);
 60	pr_cont(" s5 : " REG_FMT " s6 : " REG_FMT " s7 : " REG_FMT "\n",
 61		regs->s5, regs->s6, regs->s7);
 62	pr_cont(" s8 : " REG_FMT " s9 : " REG_FMT " s10: " REG_FMT "\n",
 63		regs->s8, regs->s9, regs->s10);
 64	pr_cont(" s11: " REG_FMT " t3 : " REG_FMT " t4 : " REG_FMT "\n",
 65		regs->s11, regs->t3, regs->t4);
 66	pr_cont(" t5 : " REG_FMT " t6 : " REG_FMT "\n",
 67		regs->t5, regs->t6);
 68
 69	pr_cont("status: " REG_FMT " badaddr: " REG_FMT " cause: " REG_FMT "\n",
 70		regs->status, regs->badaddr, regs->cause);
 71}
 72
 73void start_thread(struct pt_regs *regs, unsigned long pc,
 74	unsigned long sp)
 75{
 76	regs->status = SR_PIE;
 77	if (has_fpu) {
 78		regs->status |= SR_FS_INITIAL;
 79		/*
 80		 * Restore the initial value to the FP register
 81		 * before starting the user program.
 82		 */
 83		fstate_restore(current, regs);
 84	}
 85	regs->epc = pc;
 86	regs->sp = sp;
 87	set_fs(USER_DS);
 88}
 89
 90void flush_thread(void)
 91{
 92#ifdef CONFIG_FPU
 93	/*
 94	 * Reset FPU state and context
 95	 *	frm: round to nearest, ties to even (IEEE default)
 96	 *	fflags: accrued exceptions cleared
 97	 */
 98	fstate_off(current, task_pt_regs(current));
 99	memset(&current->thread.fstate, 0, sizeof(current->thread.fstate));
100#endif
101}
102
103int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
104{
105	fstate_save(src, task_pt_regs(src));
106	*dst = *src;
107	return 0;
108}
109
110int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
111		struct task_struct *p, unsigned long tls)
112{
113	struct pt_regs *childregs = task_pt_regs(p);
114
115	/* p->thread holds context to be restored by __switch_to() */
116	if (unlikely(p->flags & PF_KTHREAD)) {
117		/* Kernel thread */
118		memset(childregs, 0, sizeof(struct pt_regs));
119		childregs->gp = gp_in_global;
120		/* Supervisor/Machine, irqs on: */
121		childregs->status = SR_PP | SR_PIE;
122
123		p->thread.ra = (unsigned long)ret_from_kernel_thread;
124		p->thread.s[0] = usp; /* fn */
125		p->thread.s[1] = arg;
126	} else {
127		*childregs = *(current_pt_regs());
128		if (usp) /* User fork */
129			childregs->sp = usp;
130		if (clone_flags & CLONE_SETTLS)
131			childregs->tp = tls;
132		childregs->a0 = 0; /* Return value of fork() */
133		p->thread.ra = (unsigned long)ret_from_fork;
134	}
135	p->thread.sp = (unsigned long)childregs; /* kernel sp */
136	return 0;
137}