diff options
Diffstat (limited to 'arch/loongarch/kernel/process.c')
| -rw-r--r-- | arch/loongarch/kernel/process.c | 375 |
1 files changed, 375 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c new file mode 100644 index 0000000000..f2ff8b5d59 --- /dev/null +++ b/arch/loongarch/kernel/process.c @@ -0,0 +1,375 @@ +// 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/hw_breakpoint.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/exec.h> +#include <asm/fpu.h> +#include <asm/lbt.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/unwind.h> +#include <asm/vdso.h> + +#ifdef CONFIG_STACKPROTECTOR +#include <linux/stackprotector.h> +unsigned long __stack_chk_guard __read_mostly; +EXPORT_SYMBOL(__stack_chk_guard); +#endif + +/* + * 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); + lose_lbt(0); + current->thread.fpu.fcsr = boot_cpu_data.fpu_csr0; + + clear_thread_flag(TIF_LSX_CTX_LIVE); + clear_thread_flag(TIF_LASX_CTX_LIVE); + clear_thread_flag(TIF_LBT_CTX_LIVE); + clear_used_math(); + regs->csr_era = pc; + regs->regs[3] = sp; +} + +void flush_thread(void) +{ + flush_ptrace_hw_breakpoint(current); +} + +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()) { + if (is_lasx_enabled()) + save_lasx(current); + else if (is_lsx_enabled()) + save_lsx(current); + else + save_fp(current); + } + + preempt_enable(); + + if (!used_math()) + memcpy(dst, src, offsetof(struct task_struct, thread.fpu.fpr)); + else + memcpy(dst, src, offsetof(struct task_struct, thread.lbt.scr0)); + +#ifdef CONFIG_CPU_HAS_LBT + memcpy(&dst->thread.lbt, &src->thread.lbt, sizeof(struct loongarch_lbt)); +#endif + + return 0; +} + +/* + * Copy architecture-specific thread state + */ +int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) +{ + unsigned long childksp; + unsigned long tls = args->tls; + unsigned long usp = args->stack; + unsigned long clone_flags = args->flags; + struct pt_regs *childregs, *regs = current_pt_regs(); + + childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE; + + /* set up new TSS. */ + childregs = (struct pt_regs *) childksp - 1; + /* Put the stack after the struct pt_regs. */ + childksp = (unsigned long) childregs; + p->thread.sched_cfa = 0; + 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(args->fn)) { + /* kernel thread */ + p->thread.reg03 = childksp; + p->thread.reg23 = (unsigned long)args->fn; + p->thread.reg24 = (unsigned long)args->fn_arg; + p->thread.reg01 = (unsigned long)ret_from_kernel_thread; + p->thread.sched_ra = (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; + goto out; + } + + /* 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; + p->thread.sched_ra = (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; + + if (clone_flags & CLONE_SETTLS) + childregs->regs[2] = tls; + +out: + ptrace_hw_copy_thread(p); + clear_tsk_thread_flag(p, TIF_USEDFPU); + clear_tsk_thread_flag(p, TIF_USEDSIMD); + clear_tsk_thread_flag(p, TIF_USEDLBT); + clear_tsk_thread_flag(p, TIF_LSX_CTX_LIVE); + clear_tsk_thread_flag(p, TIF_LASX_CTX_LIVE); + clear_tsk_thread_flag(p, TIF_LBT_CTX_LIVE); + + return 0; +} + +unsigned long __get_wchan(struct task_struct *task) +{ + unsigned long pc = 0; + struct unwind_state state; + + if (!try_get_task_stack(task)) + return 0; + + for (unwind_start(&state, task, NULL); + !unwind_done(&state); unwind_next_frame(&state)) { + pc = unwind_get_return_address(&state); + if (!pc) + break; + if (in_sched_functions(pc)) + continue; + break; + } + + put_task_stack(task); + + return pc; +} + +bool in_irq_stack(unsigned long stack, struct stack_info *info) +{ + unsigned long nextsp; + unsigned long begin = (unsigned long)this_cpu_read(irq_stack); + unsigned long end = begin + IRQ_STACK_START; + + if (stack < begin || stack >= end) + return false; + + nextsp = *(unsigned long *)end; + if (nextsp & (SZREG - 1)) + return false; + + info->begin = begin; + info->end = end; + info->next_sp = nextsp; + info->type = STACK_TYPE_IRQ; + + return true; +} + +bool in_task_stack(unsigned long stack, struct task_struct *task, + struct stack_info *info) +{ + unsigned long begin = (unsigned long)task_stack_page(task); + unsigned long end = begin + THREAD_SIZE; + + if (stack < begin || stack >= end) + return false; + + info->begin = begin; + info->end = end; + info->next_sp = 0; + info->type = STACK_TYPE_TASK; + + return true; +} + +int get_stack_info(unsigned long stack, struct task_struct *task, + struct stack_info *info) +{ + task = task ? : current; + + if (!stack || stack & (SZREG - 1)) + goto unknown; + + if (in_task_stack(stack, task, info)) + return 0; + + if (task != current) + goto unknown; + + if (in_irq_stack(stack, info)) + return 0; + +unknown: + info->type = STACK_TYPE_UNKNOWN; + return -EINVAL; +} + +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 -= VVAR_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_u32_below(PAGE_SIZE); + + 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, int exclude_cpu) +{ + nmi_trigger_cpumask_backtrace(mask, exclude_cpu, 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 */ |