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-rw-r--r--arch/loongarch/kernel/process.c375
1 files changed, 375 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c
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index 0000000000..f2ff8b5d59
--- /dev/null
+++ b/arch/loongarch/kernel/process.c
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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/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 */