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Diffstat (limited to 'arch/loongarch/kernel/process.c')
| -rw-r--r-- | arch/loongarch/kernel/process.c | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c new file mode 100644 index 000000000000..54020223068f --- /dev/null +++ b/arch/loongarch/kernel/process.c @@ -0,0 +1,260 @@ +// 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 */ |