summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/process.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/mips/kernel/process.c')
-rw-r--r--arch/mips/kernel/process.c364
1 files changed, 364 insertions, 0 deletions
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
new file mode 100644
index 0000000..6e70c42
--- /dev/null
+++ b/arch/mips/kernel/process.c
@@ -0,0 +1,364 @@
+/*
+ * 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) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 2004 Thiemo Seufer
+ */
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/mman.h>
+#include <linux/personality.h>
+#include <linux/sys.h>
+#include <linux/user.h>
+#include <linux/a.out.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+
+#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/fpu.h>
+#include <asm/pgtable.h>
+#include <asm/system.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>
+
+/*
+ * We use this if we don't have any better idle routine..
+ * (This to kill: kernel/platform.c.
+ */
+void default_idle (void)
+{
+}
+
+/*
+ * 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)
+ */
+ATTRIB_NORET void cpu_idle(void)
+{
+ /* endless idle loop with no priority at all */
+ while (1) {
+ while (!need_resched())
+ if (cpu_wait)
+ (*cpu_wait)();
+ schedule();
+ }
+}
+
+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|KU_MASK);
+#ifdef CONFIG_MIPS64
+ status &= ~ST0_FR;
+ status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
+#endif
+ status |= KU_USER;
+ regs->cp0_status = status;
+ clear_used_math();
+ lose_fpu();
+ regs->cp0_epc = pc;
+ regs->regs[29] = sp;
+ current_thread_info()->addr_limit = USER_DS;
+}
+
+void exit_thread(void)
+{
+}
+
+void flush_thread(void)
+{
+}
+
+int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
+ unsigned long unused, struct task_struct *p, struct pt_regs *regs)
+{
+ struct thread_info *ti = p->thread_info;
+ struct pt_regs *childregs;
+ long childksp;
+
+ childksp = (unsigned long)ti + THREAD_SIZE - 32;
+
+ preempt_disable();
+
+ if (is_fpu_owner()) {
+ save_fp(p);
+ }
+
+ preempt_enable();
+
+ /* set up new TSS. */
+ childregs = (struct pt_regs *) childksp - 1;
+ *childregs = *regs;
+ childregs->regs[7] = 0; /* Clear error flag */
+
+#if defined(CONFIG_BINFMT_IRIX)
+ if (current->personality != PER_LINUX) {
+ /* Under IRIX things are a little different. */
+ childregs->regs[3] = 1;
+ regs->regs[3] = 0;
+ }
+#endif
+ childregs->regs[2] = 0; /* Child gets zero as return value */
+ regs->regs[2] = p->pid;
+
+ 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);
+ clear_tsk_thread_flag(p, TIF_USEDFPU);
+
+ 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 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_fpu (struct task_struct *t, elf_fpregset_t *fpr)
+{
+ memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
+
+ return 1;
+}
+
+/*
+ * Create a kernel thread
+ */
+ATTRIB_NORET void 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 &= ~(ST0_KUP | ST0_IEC);
+ regs.cp0_status |= ST0_IEP;
+#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 {
+ int frame_offset;
+ int pc_offset;
+};
+static struct mips_frame_info schedule_frame;
+static struct mips_frame_info schedule_timeout_frame;
+static struct mips_frame_info sleep_on_frame;
+static struct mips_frame_info sleep_on_timeout_frame;
+static struct mips_frame_info wait_for_completion_frame;
+static int mips_frame_info_initialized;
+static int __init get_frame_info(struct mips_frame_info *info, void *func)
+{
+ int i;
+ union mips_instruction *ip = (union mips_instruction *)func;
+ info->pc_offset = -1;
+ info->frame_offset = -1;
+ for (i = 0; i < 128; i++, ip++) {
+ /* if jal, jalr, jr, stop. */
+ if (ip->j_format.opcode == jal_op ||
+ (ip->r_format.opcode == spec_op &&
+ (ip->r_format.func == jalr_op ||
+ ip->r_format.func == jr_op)))
+ break;
+
+ if (
+#ifdef CONFIG_MIPS32
+ ip->i_format.opcode == sw_op &&
+#endif
+#ifdef CONFIG_MIPS64
+ ip->i_format.opcode == sd_op &&
+#endif
+ ip->i_format.rs == 29)
+ {
+ /* sw / sd $ra, offset($sp) */
+ if (ip->i_format.rt == 31) {
+ if (info->pc_offset != -1)
+ break;
+ info->pc_offset =
+ ip->i_format.simmediate / sizeof(long);
+ }
+ /* sw / sd $s8, offset($sp) */
+ if (ip->i_format.rt == 30) {
+ if (info->frame_offset != -1)
+ break;
+ info->frame_offset =
+ ip->i_format.simmediate / sizeof(long);
+ }
+ }
+ }
+ if (info->pc_offset == -1 || info->frame_offset == -1) {
+ printk("Can't analyze prologue code at %p\n", func);
+ info->pc_offset = -1;
+ info->frame_offset = -1;
+ return -1;
+ }
+
+ return 0;
+}
+
+static int __init frame_info_init(void)
+{
+ mips_frame_info_initialized =
+ !get_frame_info(&schedule_frame, schedule) &&
+ !get_frame_info(&schedule_timeout_frame, schedule_timeout) &&
+ !get_frame_info(&sleep_on_frame, sleep_on) &&
+ !get_frame_info(&sleep_on_timeout_frame, sleep_on_timeout) &&
+ !get_frame_info(&wait_for_completion_frame, wait_for_completion);
+
+ 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_frame.pc_offset < 0)
+ return 0;
+ return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
+}
+
+/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
+unsigned long get_wchan(struct task_struct *p)
+{
+ unsigned long frame, pc;
+
+ if (!p || p == current || p->state == TASK_RUNNING)
+ return 0;
+
+ if (!mips_frame_info_initialized)
+ return 0;
+ pc = thread_saved_pc(p);
+ if (!in_sched_functions(pc))
+ goto out;
+
+ if (pc >= (unsigned long) sleep_on_timeout)
+ goto schedule_timeout_caller;
+ if (pc >= (unsigned long) sleep_on)
+ goto schedule_caller;
+ if (pc >= (unsigned long) interruptible_sleep_on_timeout)
+ goto schedule_timeout_caller;
+ if (pc >= (unsigned long)interruptible_sleep_on)
+ goto schedule_caller;
+ if (pc >= (unsigned long)wait_for_completion)
+ goto schedule_caller;
+ goto schedule_timeout_caller;
+
+schedule_caller:
+ frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
+ if (pc >= (unsigned long) sleep_on)
+ pc = ((unsigned long *)frame)[sleep_on_frame.pc_offset];
+ else
+ pc = ((unsigned long *)frame)[wait_for_completion_frame.pc_offset];
+ goto out;
+
+schedule_timeout_caller:
+ /*
+ * The schedule_timeout frame
+ */
+ frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
+
+ /*
+ * frame now points to sleep_on_timeout's frame
+ */
+ pc = ((unsigned long *)frame)[schedule_timeout_frame.pc_offset];
+
+ if (in_sched_functions(pc)) {
+ /* schedule_timeout called by [interruptible_]sleep_on_timeout */
+ frame = ((unsigned long *)frame)[schedule_timeout_frame.frame_offset];
+ pc = ((unsigned long *)frame)[sleep_on_timeout_frame.pc_offset];
+ }
+
+out:
+
+#ifdef CONFIG_MIPS64
+ if (current->thread.mflags & MF_32BIT_REGS) /* Kludge for 32-bit ps */
+ pc &= 0xffffffffUL;
+#endif
+
+ return pc;
+}
+
+EXPORT_SYMBOL(get_wchan);
OpenPOWER on IntegriCloud