48ae077cfc
In the old times, the whole idle task was considered as an RCU quiescent state. But as RCU became more and more successful overtime, some RCU read side critical section have been added even in the code of some architectures idle tasks, for tracing for example. So nowadays, rcu_idle_enter() and rcu_idle_exit() must be called by the architecture to tell RCU about the part in the idle loop that doesn't make use of rcu read side critical sections, typically the part that puts the CPU in low power mode. This is necessary for RCU to find the quiescent states in idle in order to complete grace periods. Add this missing pair of calls in the m32r's idle loop. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: <stable@vger.kernel.org> # 3.3+ Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
323 lines
7.5 KiB
C
323 lines
7.5 KiB
C
/*
|
|
* linux/arch/m32r/kernel/process.c
|
|
*
|
|
* Copyright (c) 2001, 2002 Hiroyuki Kondo, Hirokazu Takata,
|
|
* Hitoshi Yamamoto
|
|
* Taken from sh version.
|
|
* Copyright (C) 1995 Linus Torvalds
|
|
* SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
|
|
*/
|
|
|
|
#undef DEBUG_PROCESS
|
|
#ifdef DEBUG_PROCESS
|
|
#define DPRINTK(fmt, args...) printk("%s:%d:%s: " fmt, __FILE__, __LINE__, \
|
|
__func__, ##args)
|
|
#else
|
|
#define DPRINTK(fmt, args...)
|
|
#endif
|
|
|
|
/*
|
|
* This file handles the architecture-dependent parts of process handling..
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/module.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/unistd.h>
|
|
#include <linux/hardirq.h>
|
|
#include <linux/rcupdate.h>
|
|
|
|
#include <asm/io.h>
|
|
#include <asm/uaccess.h>
|
|
#include <asm/mmu_context.h>
|
|
#include <asm/elf.h>
|
|
#include <asm/m32r.h>
|
|
|
|
#include <linux/err.h>
|
|
|
|
/*
|
|
* Return saved PC of a blocked thread.
|
|
*/
|
|
unsigned long thread_saved_pc(struct task_struct *tsk)
|
|
{
|
|
return tsk->thread.lr;
|
|
}
|
|
|
|
/*
|
|
* Powermanagement idle function, if any..
|
|
*/
|
|
static void (*pm_idle)(void) = NULL;
|
|
|
|
void (*pm_power_off)(void) = NULL;
|
|
EXPORT_SYMBOL(pm_power_off);
|
|
|
|
/*
|
|
* We use this is we don't have any better
|
|
* idle routine..
|
|
*/
|
|
static void default_idle(void)
|
|
{
|
|
/* M32R_FIXME: Please use "cpu_sleep" mode. */
|
|
cpu_relax();
|
|
}
|
|
|
|
/*
|
|
* On SMP it's slightly faster (but much more power-consuming!)
|
|
* to poll the ->work.need_resched flag instead of waiting for the
|
|
* cross-CPU IPI to arrive. Use this option with caution.
|
|
*/
|
|
static void poll_idle (void)
|
|
{
|
|
/* M32R_FIXME */
|
|
cpu_relax();
|
|
}
|
|
|
|
/*
|
|
* 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 cpu_idle (void)
|
|
{
|
|
/* endless idle loop with no priority at all */
|
|
while (1) {
|
|
rcu_idle_enter();
|
|
while (!need_resched()) {
|
|
void (*idle)(void) = pm_idle;
|
|
|
|
if (!idle)
|
|
idle = default_idle;
|
|
|
|
idle();
|
|
}
|
|
rcu_idle_exit();
|
|
schedule_preempt_disabled();
|
|
}
|
|
}
|
|
|
|
void machine_restart(char *__unused)
|
|
{
|
|
#if defined(CONFIG_PLAT_MAPPI3)
|
|
outw(1, (unsigned long)PLD_REBOOT);
|
|
#endif
|
|
|
|
printk("Please push reset button!\n");
|
|
while (1)
|
|
cpu_relax();
|
|
}
|
|
|
|
void machine_halt(void)
|
|
{
|
|
printk("Please push reset button!\n");
|
|
while (1)
|
|
cpu_relax();
|
|
}
|
|
|
|
void machine_power_off(void)
|
|
{
|
|
/* M32R_FIXME */
|
|
}
|
|
|
|
static int __init idle_setup (char *str)
|
|
{
|
|
if (!strncmp(str, "poll", 4)) {
|
|
printk("using poll in idle threads.\n");
|
|
pm_idle = poll_idle;
|
|
} else if (!strncmp(str, "sleep", 4)) {
|
|
printk("using sleep in idle threads.\n");
|
|
pm_idle = default_idle;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
__setup("idle=", idle_setup);
|
|
|
|
void show_regs(struct pt_regs * regs)
|
|
{
|
|
printk("\n");
|
|
printk("BPC[%08lx]:PSW[%08lx]:LR [%08lx]:FP [%08lx]\n", \
|
|
regs->bpc, regs->psw, regs->lr, regs->fp);
|
|
printk("BBPC[%08lx]:BBPSW[%08lx]:SPU[%08lx]:SPI[%08lx]\n", \
|
|
regs->bbpc, regs->bbpsw, regs->spu, regs->spi);
|
|
printk("R0 [%08lx]:R1 [%08lx]:R2 [%08lx]:R3 [%08lx]\n", \
|
|
regs->r0, regs->r1, regs->r2, regs->r3);
|
|
printk("R4 [%08lx]:R5 [%08lx]:R6 [%08lx]:R7 [%08lx]\n", \
|
|
regs->r4, regs->r5, regs->r6, regs->r7);
|
|
printk("R8 [%08lx]:R9 [%08lx]:R10[%08lx]:R11[%08lx]\n", \
|
|
regs->r8, regs->r9, regs->r10, regs->r11);
|
|
printk("R12[%08lx]\n", \
|
|
regs->r12);
|
|
|
|
#if defined(CONFIG_ISA_M32R2) && defined(CONFIG_ISA_DSP_LEVEL2)
|
|
printk("ACC0H[%08lx]:ACC0L[%08lx]\n", \
|
|
regs->acc0h, regs->acc0l);
|
|
printk("ACC1H[%08lx]:ACC1L[%08lx]\n", \
|
|
regs->acc1h, regs->acc1l);
|
|
#elif defined(CONFIG_ISA_M32R2) || defined(CONFIG_ISA_M32R)
|
|
printk("ACCH[%08lx]:ACCL[%08lx]\n", \
|
|
regs->acc0h, regs->acc0l);
|
|
#else
|
|
#error unknown isa configuration
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Create a kernel thread
|
|
*/
|
|
|
|
/*
|
|
* This is the mechanism for creating a new kernel thread.
|
|
*
|
|
* NOTE! Only a kernel-only process(ie the swapper or direct descendants
|
|
* who haven't done an "execve()") should use this: it will work within
|
|
* a system call from a "real" process, but the process memory space will
|
|
* not be free'd until both the parent and the child have exited.
|
|
*/
|
|
static void kernel_thread_helper(void *nouse, int (*fn)(void *), void *arg)
|
|
{
|
|
fn(arg);
|
|
do_exit(-1);
|
|
}
|
|
|
|
int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
|
|
{
|
|
struct pt_regs regs;
|
|
|
|
memset(®s, 0, sizeof (regs));
|
|
regs.r1 = (unsigned long)fn;
|
|
regs.r2 = (unsigned long)arg;
|
|
|
|
regs.bpc = (unsigned long)kernel_thread_helper;
|
|
|
|
regs.psw = M32R_PSW_BIE;
|
|
|
|
/* Ok, create the new process. */
|
|
return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL,
|
|
NULL);
|
|
}
|
|
|
|
/*
|
|
* Free current thread data structures etc..
|
|
*/
|
|
void exit_thread(void)
|
|
{
|
|
/* Nothing to do. */
|
|
DPRINTK("pid = %d\n", current->pid);
|
|
}
|
|
|
|
void flush_thread(void)
|
|
{
|
|
DPRINTK("pid = %d\n", current->pid);
|
|
memset(¤t->thread.debug_trap, 0, sizeof(struct debug_trap));
|
|
}
|
|
|
|
void release_thread(struct task_struct *dead_task)
|
|
{
|
|
/* do nothing */
|
|
DPRINTK("pid = %d\n", dead_task->pid);
|
|
}
|
|
|
|
/* Fill in the fpu structure for a core dump.. */
|
|
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
|
|
{
|
|
return 0; /* Task didn't use the fpu at all. */
|
|
}
|
|
|
|
int copy_thread(unsigned long clone_flags, unsigned long spu,
|
|
unsigned long unused, struct task_struct *tsk, struct pt_regs *regs)
|
|
{
|
|
struct pt_regs *childregs = task_pt_regs(tsk);
|
|
extern void ret_from_fork(void);
|
|
|
|
/* Copy registers */
|
|
*childregs = *regs;
|
|
|
|
childregs->spu = spu;
|
|
childregs->r0 = 0; /* Child gets zero as return value */
|
|
regs->r0 = tsk->pid;
|
|
tsk->thread.sp = (unsigned long)childregs;
|
|
tsk->thread.lr = (unsigned long)ret_from_fork;
|
|
|
|
return 0;
|
|
}
|
|
|
|
asmlinkage int sys_fork(unsigned long r0, unsigned long r1, unsigned long r2,
|
|
unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6,
|
|
struct pt_regs regs)
|
|
{
|
|
#ifdef CONFIG_MMU
|
|
return do_fork(SIGCHLD, regs.spu, ®s, 0, NULL, NULL);
|
|
#else
|
|
return -EINVAL;
|
|
#endif /* CONFIG_MMU */
|
|
}
|
|
|
|
asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
|
|
unsigned long parent_tidptr,
|
|
unsigned long child_tidptr,
|
|
unsigned long r4, unsigned long r5, unsigned long r6,
|
|
struct pt_regs regs)
|
|
{
|
|
if (!newsp)
|
|
newsp = regs.spu;
|
|
|
|
return do_fork(clone_flags, newsp, ®s, 0,
|
|
(int __user *)parent_tidptr, (int __user *)child_tidptr);
|
|
}
|
|
|
|
/*
|
|
* This is trivial, and on the face of it looks like it
|
|
* could equally well be done in user mode.
|
|
*
|
|
* Not so, for quite unobvious reasons - register pressure.
|
|
* In user mode vfork() cannot have a stack frame, and if
|
|
* done by calling the "clone()" system call directly, you
|
|
* do not have enough call-clobbered registers to hold all
|
|
* the information you need.
|
|
*/
|
|
asmlinkage int sys_vfork(unsigned long r0, unsigned long r1, unsigned long r2,
|
|
unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6,
|
|
struct pt_regs regs)
|
|
{
|
|
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.spu, ®s, 0,
|
|
NULL, NULL);
|
|
}
|
|
|
|
/*
|
|
* sys_execve() executes a new program.
|
|
*/
|
|
asmlinkage int sys_execve(const char __user *ufilename,
|
|
const char __user *const __user *uargv,
|
|
const char __user *const __user *uenvp,
|
|
unsigned long r3, unsigned long r4, unsigned long r5,
|
|
unsigned long r6, struct pt_regs regs)
|
|
{
|
|
int error;
|
|
char *filename;
|
|
|
|
filename = getname(ufilename);
|
|
error = PTR_ERR(filename);
|
|
if (IS_ERR(filename))
|
|
goto out;
|
|
|
|
error = do_execve(filename, uargv, uenvp, ®s);
|
|
putname(filename);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* These bracket the sleeping functions..
|
|
*/
|
|
#define first_sched ((unsigned long) scheduling_functions_start_here)
|
|
#define last_sched ((unsigned long) scheduling_functions_end_here)
|
|
|
|
unsigned long get_wchan(struct task_struct *p)
|
|
{
|
|
/* M32R_FIXME */
|
|
return (0);
|
|
}
|