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// SPDX-License-Identifier: GPL-2.0
/*
* Author: Huacai Chen <chenhuacai@loongson.cn>
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*
* Derived from MIPS:
* Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others.
* Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org)
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2004 Thiemo Seufer
* Copyright (C) 2013 Imagination Technologies Ltd.
*/
#include <linux/cpu.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/export.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/personality.h>
#include <linux/sys.h>
#include <linux/completion.h>
#include <linux/kallsyms.h>
#include <linux/random.h>
#include <linux/prctl.h>
#include <linux/nmi.h>
#include <asm/asm.h>
#include <asm/bootinfo.h>
#include <asm/cpu.h>
#include <asm/elf.h>
#include <asm/fpu.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <asm/loongarch.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/reg.h>
#include <asm/vdso.h>
/*
* Idle related variables and functions
*/
unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
EXPORT_SYMBOL(boot_option_idle_override);
asmlinkage void ret_from_fork(void);
asmlinkage void ret_from_kernel_thread(void);
void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
{
unsigned long crmd;
unsigned long prmd;
unsigned long euen;
/* New thread loses kernel privileges. */
crmd = regs->csr_crmd & ~(PLV_MASK);
crmd |= PLV_USER;
regs->csr_crmd = crmd;
prmd = regs->csr_prmd & ~(PLV_MASK);
prmd |= PLV_USER;
regs->csr_prmd = prmd;
euen = regs->csr_euen & ~(CSR_EUEN_FPEN);
regs->csr_euen = euen;
lose_fpu(0);
clear_thread_flag(TIF_LSX_CTX_LIVE);
clear_thread_flag(TIF_LASX_CTX_LIVE);
clear_used_math();
regs->csr_era = pc;
regs->regs[3] = sp;
}
void exit_thread(struct task_struct *tsk)
{
}
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
/*
* Save any process state which is live in hardware registers to the
* parent context prior to duplication. This prevents the new child
* state becoming stale if the parent is preempted before copy_thread()
* gets a chance to save the parent's live hardware registers to the
* child context.
*/
preempt_disable();
if (is_fpu_owner())
save_fp(current);
preempt_enable();
if (used_math())
memcpy(dst, src, sizeof(struct task_struct));
else
memcpy(dst, src, offsetof(struct task_struct, thread.fpu.fpr));
return 0;
}
/*
* Copy architecture-specific thread state
*/
int copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long kthread_arg, struct task_struct *p, unsigned long tls)
{
unsigned long childksp;
struct pt_regs *childregs, *regs = current_pt_regs();
childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
/* set up new TSS. */
childregs = (struct pt_regs *) childksp - 1;
/* Put the stack after the struct pt_regs. */
childksp = (unsigned long) childregs;
p->thread.csr_euen = 0;
p->thread.csr_crmd = csr_read32(LOONGARCH_CSR_CRMD);
p->thread.csr_prmd = csr_read32(LOONGARCH_CSR_PRMD);
p->thread.csr_ecfg = csr_read32(LOONGARCH_CSR_ECFG);
if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
/* kernel thread */
p->thread.reg23 = usp; /* fn */
p->thread.reg24 = kthread_arg;
p->thread.reg03 = childksp;
p->thread.reg01 = (unsigned long) ret_from_kernel_thread;
memset(childregs, 0, sizeof(struct pt_regs));
childregs->csr_euen = p->thread.csr_euen;
childregs->csr_crmd = p->thread.csr_crmd;
childregs->csr_prmd = p->thread.csr_prmd;
childregs->csr_ecfg = p->thread.csr_ecfg;
return 0;
}
/* user thread */
*childregs = *regs;
childregs->regs[4] = 0; /* Child gets zero as return value */
if (usp)
childregs->regs[3] = usp;
p->thread.reg03 = (unsigned long) childregs;
p->thread.reg01 = (unsigned long) ret_from_fork;
/*
* New tasks lose permission to use the fpu. This accelerates context
* switching for most programs since they don't use the fpu.
*/
childregs->csr_euen = 0;
clear_tsk_thread_flag(p, TIF_USEDFPU);
clear_tsk_thread_flag(p, TIF_USEDSIMD);
clear_tsk_thread_flag(p, TIF_LSX_CTX_LIVE);
clear_tsk_thread_flag(p, TIF_LASX_CTX_LIVE);
if (clone_flags & CLONE_SETTLS)
childregs->regs[2] = tls;
return 0;
}
unsigned long __get_wchan(struct task_struct *task)
{
return 0;
}
unsigned long stack_top(void)
{
unsigned long top = TASK_SIZE & PAGE_MASK;
/* Space for the VDSO & data page */
top -= PAGE_ALIGN(current->thread.vdso->size);
top -= PAGE_SIZE;
/* Space to randomize the VDSO base */
if (current->flags & PF_RANDOMIZE)
top -= VDSO_RANDOMIZE_SIZE;
return top;
}
/*
* Don't forget that the stack pointer must be aligned on a 8 bytes
* boundary for 32-bits ABI and 16 bytes for 64-bits ABI.
*/
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
sp -= get_random_int() & ~PAGE_MASK;
return sp & STACK_ALIGN;
}
static DEFINE_PER_CPU(call_single_data_t, backtrace_csd);
static struct cpumask backtrace_csd_busy;
static void handle_backtrace(void *info)
{
nmi_cpu_backtrace(get_irq_regs());
cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy);
}
static void raise_backtrace(cpumask_t *mask)
{
call_single_data_t *csd;
int cpu;
for_each_cpu(cpu, mask) {
/*
* If we previously sent an IPI to the target CPU & it hasn't
* cleared its bit in the busy cpumask then it didn't handle
* our previous IPI & it's not safe for us to reuse the
* call_single_data_t.
*/
if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) {
pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",
cpu);
continue;
}
csd = &per_cpu(backtrace_csd, cpu);
csd->func = handle_backtrace;
smp_call_function_single_async(cpu, csd);
}
}
void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
{
nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace);
}
#ifdef CONFIG_64BIT
void loongarch_dump_regs64(u64 *uregs, const struct pt_regs *regs)
{
unsigned int i;
for (i = LOONGARCH_EF_R1; i <= LOONGARCH_EF_R31; i++) {
uregs[i] = regs->regs[i - LOONGARCH_EF_R0];
}
uregs[LOONGARCH_EF_ORIG_A0] = regs->orig_a0;
uregs[LOONGARCH_EF_CSR_ERA] = regs->csr_era;
uregs[LOONGARCH_EF_CSR_BADV] = regs->csr_badvaddr;
uregs[LOONGARCH_EF_CSR_CRMD] = regs->csr_crmd;
uregs[LOONGARCH_EF_CSR_PRMD] = regs->csr_prmd;
uregs[LOONGARCH_EF_CSR_EUEN] = regs->csr_euen;
uregs[LOONGARCH_EF_CSR_ECFG] = regs->csr_ecfg;
uregs[LOONGARCH_EF_CSR_ESTAT] = regs->csr_estat;
}
#endif /* CONFIG_64BIT */
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