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-rw-r--r--arch/mips/kernel/process.c494
1 files changed, 494 insertions, 0 deletions
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
new file mode 100644
index 00000000..e9a5fd72
--- /dev/null
+++ b/arch/mips/kernel/process.c
@@ -0,0 +1,494 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * 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
+ */
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/tick.h>
+#include <linux/kernel.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/user.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/kallsyms.h>
+#include <linux/random.h>
+
+#include <asm/asm.h>
+#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/dsp.h>
+#include <asm/fpu.h>
+#include <asm/pgtable.h>
+#include <asm/mipsregs.h>
+#include <asm/processor.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/elf.h>
+#include <asm/isadep.h>
+#include <asm/inst.h>
+#include <asm/stacktrace.h>
+
+/*
+ * The idle thread. There's no useful work to be done, so just try to conserve
+ * power and have a low exit latency (ie sit in a loop waiting for somebody to
+ * say that they'd like to reschedule)
+ */
+void __noreturn cpu_idle(void)
+{
+ int cpu;
+
+ /* CPU is going idle. */
+ cpu = smp_processor_id();
+
+ /* endless idle loop with no priority at all */
+ while (1) {
+ tick_nohz_idle_enter();
+ rcu_idle_enter();
+ while (!need_resched() && cpu_online(cpu)) {
+#ifdef CONFIG_MIPS_MT_SMTC
+ extern void smtc_idle_loop_hook(void);
+
+ smtc_idle_loop_hook();
+#endif
+
+ if (cpu_wait) {
+ /* Don't trace irqs off for idle */
+ stop_critical_timings();
+ (*cpu_wait)();
+ start_critical_timings();
+ }
+ }
+#ifdef CONFIG_HOTPLUG_CPU
+ if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) &&
+ (system_state == SYSTEM_RUNNING ||
+ system_state == SYSTEM_BOOTING))
+ play_dead();
+#endif
+ rcu_idle_exit();
+ tick_nohz_idle_exit();
+ schedule_preempt_disabled();
+ }
+}
+
+asmlinkage void ret_from_fork(void);
+
+void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
+{
+ unsigned long status;
+
+ /* New thread loses kernel privileges. */
+ status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK);
+#ifdef CONFIG_64BIT
+ status |= test_thread_flag(TIF_32BIT_REGS) ? 0 : ST0_FR;
+#endif
+ status |= KU_USER;
+ regs->cp0_status = status;
+ clear_used_math();
+ clear_fpu_owner();
+ if (cpu_has_dsp)
+ __init_dsp();
+ regs->cp0_epc = pc;
+ regs->regs[29] = sp;
+}
+
+void exit_thread(void)
+{
+}
+
+void flush_thread(void)
+{
+}
+
+int copy_thread(unsigned long clone_flags, unsigned long usp,
+ unsigned long unused, struct task_struct *p, struct pt_regs *regs)
+{
+ struct thread_info *ti = task_thread_info(p);
+ struct pt_regs *childregs;
+ unsigned long childksp;
+ p->set_child_tid = p->clear_child_tid = NULL;
+
+ childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32;
+
+ preempt_disable();
+
+ if (is_fpu_owner())
+ save_fp(p);
+
+ if (cpu_has_dsp)
+ save_dsp(p);
+
+ preempt_enable();
+
+ /* set up new TSS. */
+ childregs = (struct pt_regs *) childksp - 1;
+ /* Put the stack after the struct pt_regs. */
+ childksp = (unsigned long) childregs;
+ *childregs = *regs;
+ childregs->regs[7] = 0; /* Clear error flag */
+
+ childregs->regs[2] = 0; /* Child gets zero as return value */
+
+ if (childregs->cp0_status & ST0_CU0) {
+ childregs->regs[28] = (unsigned long) ti;
+ childregs->regs[29] = childksp;
+ ti->addr_limit = KERNEL_DS;
+ } else {
+ childregs->regs[29] = usp;
+ ti->addr_limit = USER_DS;
+ }
+ p->thread.reg29 = (unsigned long) childregs;
+ p->thread.reg31 = (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.
+ */
+ p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
+ childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
+
+#ifdef CONFIG_MIPS_MT_SMTC
+ /*
+ * SMTC restores TCStatus after Status, and the CU bits
+ * are aliased there.
+ */
+ childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
+#endif
+ clear_tsk_thread_flag(p, TIF_USEDFPU);
+
+#ifdef CONFIG_MIPS_MT_FPAFF
+ clear_tsk_thread_flag(p, TIF_FPUBOUND);
+#endif /* CONFIG_MIPS_MT_FPAFF */
+
+ if (clone_flags & CLONE_SETTLS)
+ ti->tp_value = regs->regs[7];
+
+ return 0;
+}
+
+/* Fill in the fpu structure for a core dump.. */
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
+{
+ memcpy(r, &current->thread.fpu, sizeof(current->thread.fpu));
+
+ return 1;
+}
+
+void elf_dump_regs(elf_greg_t *gp, struct pt_regs *regs)
+{
+ int i;
+
+ for (i = 0; i < EF_R0; i++)
+ gp[i] = 0;
+ gp[EF_R0] = 0;
+ for (i = 1; i <= 31; i++)
+ gp[EF_R0 + i] = regs->regs[i];
+ gp[EF_R26] = 0;
+ gp[EF_R27] = 0;
+ gp[EF_LO] = regs->lo;
+ gp[EF_HI] = regs->hi;
+ gp[EF_CP0_EPC] = regs->cp0_epc;
+ gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
+ gp[EF_CP0_STATUS] = regs->cp0_status;
+ gp[EF_CP0_CAUSE] = regs->cp0_cause;
+#ifdef EF_UNUSED0
+ gp[EF_UNUSED0] = 0;
+#endif
+}
+
+int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
+{
+ elf_dump_regs(*regs, task_pt_regs(tsk));
+ return 1;
+}
+
+int dump_task_fpu(struct task_struct *t, elf_fpregset_t *fpr)
+{
+ memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
+
+ return 1;
+}
+
+/*
+ * Create a kernel thread
+ */
+static void __noreturn kernel_thread_helper(void *arg, int (*fn)(void *))
+{
+ do_exit(fn(arg));
+}
+
+long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
+{
+ struct pt_regs regs;
+
+ memset(&regs, 0, sizeof(regs));
+
+ regs.regs[4] = (unsigned long) arg;
+ regs.regs[5] = (unsigned long) fn;
+ regs.cp0_epc = (unsigned long) kernel_thread_helper;
+ regs.cp0_status = read_c0_status();
+#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
+ regs.cp0_status = (regs.cp0_status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) |
+ ((regs.cp0_status & (ST0_KUC | ST0_IEC)) << 2);
+#else
+ regs.cp0_status |= ST0_EXL;
+#endif
+
+ /* Ok, create the new process.. */
+ return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
+}
+
+/*
+ *
+ */
+struct mips_frame_info {
+ void *func;
+ unsigned long func_size;
+ int frame_size;
+ int pc_offset;
+};
+
+static inline int is_ra_save_ins(union mips_instruction *ip)
+{
+ /* sw / sd $ra, offset($sp) */
+ return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) &&
+ ip->i_format.rs == 29 &&
+ ip->i_format.rt == 31;
+}
+
+static inline int is_jal_jalr_jr_ins(union mips_instruction *ip)
+{
+ if (ip->j_format.opcode == jal_op)
+ return 1;
+ if (ip->r_format.opcode != spec_op)
+ return 0;
+ return ip->r_format.func == jalr_op || ip->r_format.func == jr_op;
+}
+
+static inline int is_sp_move_ins(union mips_instruction *ip)
+{
+ /* addiu/daddiu sp,sp,-imm */
+ if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
+ return 0;
+ if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
+ return 1;
+ return 0;
+}
+
+static int get_frame_info(struct mips_frame_info *info)
+{
+ union mips_instruction *ip = info->func;
+ unsigned max_insns = info->func_size / sizeof(union mips_instruction);
+ unsigned i;
+
+ info->pc_offset = -1;
+ info->frame_size = 0;
+
+ if (!ip)
+ goto err;
+
+ if (max_insns == 0)
+ max_insns = 128U; /* unknown function size */
+ max_insns = min(128U, max_insns);
+
+ for (i = 0; i < max_insns; i++, ip++) {
+
+ if (is_jal_jalr_jr_ins(ip))
+ break;
+ if (!info->frame_size) {
+ if (is_sp_move_ins(ip))
+ info->frame_size = - ip->i_format.simmediate;
+ continue;
+ }
+ if (info->pc_offset == -1 && is_ra_save_ins(ip)) {
+ info->pc_offset =
+ ip->i_format.simmediate / sizeof(long);
+ break;
+ }
+ }
+ if (info->frame_size && info->pc_offset >= 0) /* nested */
+ return 0;
+ if (info->pc_offset < 0) /* leaf */
+ return 1;
+ /* prologue seems boggus... */
+err:
+ return -1;
+}
+
+static struct mips_frame_info schedule_mfi __read_mostly;
+
+static int __init frame_info_init(void)
+{
+ unsigned long size = 0;
+#ifdef CONFIG_KALLSYMS
+ unsigned long ofs;
+
+ kallsyms_lookup_size_offset((unsigned long)schedule, &size, &ofs);
+#endif
+ schedule_mfi.func = schedule;
+ schedule_mfi.func_size = size;
+
+ get_frame_info(&schedule_mfi);
+
+ /*
+ * Without schedule() frame info, result given by
+ * thread_saved_pc() and get_wchan() are not reliable.
+ */
+ if (schedule_mfi.pc_offset < 0)
+ printk("Can't analyze schedule() prologue at %p\n", schedule);
+
+ return 0;
+}
+
+arch_initcall(frame_info_init);
+
+/*
+ * Return saved PC of a blocked thread.
+ */
+unsigned long thread_saved_pc(struct task_struct *tsk)
+{
+ struct thread_struct *t = &tsk->thread;
+
+ /* New born processes are a special case */
+ if (t->reg31 == (unsigned long) ret_from_fork)
+ return t->reg31;
+ if (schedule_mfi.pc_offset < 0)
+ return 0;
+ return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset];
+}
+
+
+#ifdef CONFIG_KALLSYMS
+/* generic stack unwinding function */
+unsigned long notrace unwind_stack_by_address(unsigned long stack_page,
+ unsigned long *sp,
+ unsigned long pc,
+ unsigned long *ra)
+{
+ struct mips_frame_info info;
+ unsigned long size, ofs;
+ int leaf;
+ extern void ret_from_irq(void);
+ extern void ret_from_exception(void);
+
+ if (!stack_page)
+ return 0;
+
+ /*
+ * If we reached the bottom of interrupt context,
+ * return saved pc in pt_regs.
+ */
+ if (pc == (unsigned long)ret_from_irq ||
+ pc == (unsigned long)ret_from_exception) {
+ struct pt_regs *regs;
+ if (*sp >= stack_page &&
+ *sp + sizeof(*regs) <= stack_page + THREAD_SIZE - 32) {
+ regs = (struct pt_regs *)*sp;
+ pc = regs->cp0_epc;
+ if (__kernel_text_address(pc)) {
+ *sp = regs->regs[29];
+ *ra = regs->regs[31];
+ return pc;
+ }
+ }
+ return 0;
+ }
+ if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
+ return 0;
+ /*
+ * Return ra if an exception occurred at the first instruction
+ */
+ if (unlikely(ofs == 0)) {
+ pc = *ra;
+ *ra = 0;
+ return pc;
+ }
+
+ info.func = (void *)(pc - ofs);
+ info.func_size = ofs; /* analyze from start to ofs */
+ leaf = get_frame_info(&info);
+ if (leaf < 0)
+ return 0;
+
+ if (*sp < stack_page ||
+ *sp + info.frame_size > stack_page + THREAD_SIZE - 32)
+ return 0;
+
+ if (leaf)
+ /*
+ * For some extreme cases, get_frame_info() can
+ * consider wrongly a nested function as a leaf
+ * one. In that cases avoid to return always the
+ * same value.
+ */
+ pc = pc != *ra ? *ra : 0;
+ else
+ pc = ((unsigned long *)(*sp))[info.pc_offset];
+
+ *sp += info.frame_size;
+ *ra = 0;
+ return __kernel_text_address(pc) ? pc : 0;
+}
+EXPORT_SYMBOL(unwind_stack_by_address);
+
+/* used by show_backtrace() */
+unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
+ unsigned long pc, unsigned long *ra)
+{
+ unsigned long stack_page = (unsigned long)task_stack_page(task);
+ return unwind_stack_by_address(stack_page, sp, pc, ra);
+}
+#endif
+
+/*
+ * get_wchan - a maintenance nightmare^W^Wpain in the ass ...
+ */
+unsigned long get_wchan(struct task_struct *task)
+{
+ unsigned long pc = 0;
+#ifdef CONFIG_KALLSYMS
+ unsigned long sp;
+ unsigned long ra = 0;
+#endif
+
+ if (!task || task == current || task->state == TASK_RUNNING)
+ goto out;
+ if (!task_stack_page(task))
+ goto out;
+
+ pc = thread_saved_pc(task);
+
+#ifdef CONFIG_KALLSYMS
+ sp = task->thread.reg29 + schedule_mfi.frame_size;
+
+ while (in_sched_functions(pc))
+ pc = unwind_stack(task, &sp, pc, &ra);
+#endif
+
+out:
+ return pc;
+}
+
+/*
+ * 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 & ALMASK;
+}
generated by cgit (git 2.34.1) at 2025-01-11 15:42:30 +0000