325d6f5593
Iff the parent has TIF_DEBUG set, _and_ clone_flags includes CLONE_PTRACE we should set the TIF_DEBUG flag for the child and increment the ocd refcount. Otherwise, the TIF_DEBUG flag must be unset. Currently, the child inherits TIF_DEBUG from the parent before copy_thread is called, so TIF_DEBUG may be already be set before we determine whether the child is supposed to inherit debugging capabilities from the parent or not. This means that ocd_enable() won't increment the refcount, because TIF_DEBUG is already set, and that TIF_DEBUG will be set for processes that aren't being debugged. This leads to a refcounting asymmetry, which may show up as ------------[ cut here ]------------ Badness at arch/avr32/kernel/ocd.c:73 PC is at ocd_disable+0x34/0x60 LR is at put_lock_stats+0xa/0x20 as reported by David Brownell. Happens when strace'ing a process that forks a new child process, e.g. "strace mount -tjffs2 mtd1 /mnt", and subsequently killing the child process (e.g. "umount /mnt".) Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
445 lines
11 KiB
C
445 lines
11 KiB
C
/*
|
|
* Copyright (C) 2004-2006 Atmel Corporation
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#include <linux/sched.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kallsyms.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/tick.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/unistd.h>
|
|
|
|
#include <asm/sysreg.h>
|
|
#include <asm/ocd.h>
|
|
|
|
void (*pm_power_off)(void) = NULL;
|
|
EXPORT_SYMBOL(pm_power_off);
|
|
|
|
extern void cpu_idle_sleep(void);
|
|
|
|
/*
|
|
* This file handles the architecture-dependent parts of process handling..
|
|
*/
|
|
|
|
void cpu_idle(void)
|
|
{
|
|
/* endless idle loop with no priority at all */
|
|
while (1) {
|
|
tick_nohz_stop_sched_tick();
|
|
while (!need_resched())
|
|
cpu_idle_sleep();
|
|
tick_nohz_restart_sched_tick();
|
|
preempt_enable_no_resched();
|
|
schedule();
|
|
preempt_disable();
|
|
}
|
|
}
|
|
|
|
void machine_halt(void)
|
|
{
|
|
/*
|
|
* Enter Stop mode. The 32 kHz oscillator will keep running so
|
|
* the RTC will keep the time properly and the system will
|
|
* boot quickly.
|
|
*/
|
|
asm volatile("sleep 3\n\t"
|
|
"sub pc, -2");
|
|
}
|
|
|
|
void machine_power_off(void)
|
|
{
|
|
}
|
|
|
|
void machine_restart(char *cmd)
|
|
{
|
|
ocd_write(DC, (1 << OCD_DC_DBE_BIT));
|
|
ocd_write(DC, (1 << OCD_DC_RES_BIT));
|
|
while (1) ;
|
|
}
|
|
|
|
/*
|
|
* PC is actually discarded when returning from a system call -- the
|
|
* return address must be stored in LR. This function will make sure
|
|
* LR points to do_exit before starting the thread.
|
|
*
|
|
* Also, when returning from fork(), r12 is 0, so we must copy the
|
|
* argument as well.
|
|
*
|
|
* r0 : The argument to the main thread function
|
|
* r1 : The address of do_exit
|
|
* r2 : The address of the main thread function
|
|
*/
|
|
asmlinkage extern void kernel_thread_helper(void);
|
|
__asm__(" .type kernel_thread_helper, @function\n"
|
|
"kernel_thread_helper:\n"
|
|
" mov r12, r0\n"
|
|
" mov lr, r2\n"
|
|
" mov pc, r1\n"
|
|
" .size kernel_thread_helper, . - kernel_thread_helper");
|
|
|
|
int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
|
|
{
|
|
struct pt_regs regs;
|
|
|
|
memset(®s, 0, sizeof(regs));
|
|
|
|
regs.r0 = (unsigned long)arg;
|
|
regs.r1 = (unsigned long)fn;
|
|
regs.r2 = (unsigned long)do_exit;
|
|
regs.lr = (unsigned long)kernel_thread_helper;
|
|
regs.pc = (unsigned long)kernel_thread_helper;
|
|
regs.sr = MODE_SUPERVISOR;
|
|
|
|
return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
|
|
0, ®s, 0, NULL, NULL);
|
|
}
|
|
EXPORT_SYMBOL(kernel_thread);
|
|
|
|
/*
|
|
* Free current thread data structures etc
|
|
*/
|
|
void exit_thread(void)
|
|
{
|
|
ocd_disable(current);
|
|
}
|
|
|
|
void flush_thread(void)
|
|
{
|
|
/* nothing to do */
|
|
}
|
|
|
|
void release_thread(struct task_struct *dead_task)
|
|
{
|
|
/* do nothing */
|
|
}
|
|
|
|
static void dump_mem(const char *str, const char *log_lvl,
|
|
unsigned long bottom, unsigned long top)
|
|
{
|
|
unsigned long p;
|
|
int i;
|
|
|
|
printk("%s%s(0x%08lx to 0x%08lx)\n", log_lvl, str, bottom, top);
|
|
|
|
for (p = bottom & ~31; p < top; ) {
|
|
printk("%s%04lx: ", log_lvl, p & 0xffff);
|
|
|
|
for (i = 0; i < 8; i++, p += 4) {
|
|
unsigned int val;
|
|
|
|
if (p < bottom || p >= top)
|
|
printk(" ");
|
|
else {
|
|
if (__get_user(val, (unsigned int __user *)p)) {
|
|
printk("\n");
|
|
goto out;
|
|
}
|
|
printk("%08x ", val);
|
|
}
|
|
}
|
|
printk("\n");
|
|
}
|
|
|
|
out:
|
|
return;
|
|
}
|
|
|
|
static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
|
|
{
|
|
return (p > (unsigned long)tinfo)
|
|
&& (p < (unsigned long)tinfo + THREAD_SIZE - 3);
|
|
}
|
|
|
|
#ifdef CONFIG_FRAME_POINTER
|
|
static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
|
|
struct pt_regs *regs, const char *log_lvl)
|
|
{
|
|
unsigned long lr, fp;
|
|
struct thread_info *tinfo;
|
|
|
|
if (regs)
|
|
fp = regs->r7;
|
|
else if (tsk == current)
|
|
asm("mov %0, r7" : "=r"(fp));
|
|
else
|
|
fp = tsk->thread.cpu_context.r7;
|
|
|
|
/*
|
|
* Walk the stack as long as the frame pointer (a) is within
|
|
* the kernel stack of the task, and (b) it doesn't move
|
|
* downwards.
|
|
*/
|
|
tinfo = task_thread_info(tsk);
|
|
printk("%sCall trace:\n", log_lvl);
|
|
while (valid_stack_ptr(tinfo, fp)) {
|
|
unsigned long new_fp;
|
|
|
|
lr = *(unsigned long *)fp;
|
|
#ifdef CONFIG_KALLSYMS
|
|
printk("%s [<%08lx>] ", log_lvl, lr);
|
|
#else
|
|
printk(" [<%08lx>] ", lr);
|
|
#endif
|
|
print_symbol("%s\n", lr);
|
|
|
|
new_fp = *(unsigned long *)(fp + 4);
|
|
if (new_fp <= fp)
|
|
break;
|
|
fp = new_fp;
|
|
}
|
|
printk("\n");
|
|
}
|
|
#else
|
|
static void show_trace_log_lvl(struct task_struct *tsk, unsigned long *sp,
|
|
struct pt_regs *regs, const char *log_lvl)
|
|
{
|
|
unsigned long addr;
|
|
|
|
printk("%sCall trace:\n", log_lvl);
|
|
|
|
while (!kstack_end(sp)) {
|
|
addr = *sp++;
|
|
if (kernel_text_address(addr)) {
|
|
#ifdef CONFIG_KALLSYMS
|
|
printk("%s [<%08lx>] ", log_lvl, addr);
|
|
#else
|
|
printk(" [<%08lx>] ", addr);
|
|
#endif
|
|
print_symbol("%s\n", addr);
|
|
}
|
|
}
|
|
printk("\n");
|
|
}
|
|
#endif
|
|
|
|
void show_stack_log_lvl(struct task_struct *tsk, unsigned long sp,
|
|
struct pt_regs *regs, const char *log_lvl)
|
|
{
|
|
struct thread_info *tinfo;
|
|
|
|
if (sp == 0) {
|
|
if (tsk)
|
|
sp = tsk->thread.cpu_context.ksp;
|
|
else
|
|
sp = (unsigned long)&tinfo;
|
|
}
|
|
if (!tsk)
|
|
tsk = current;
|
|
|
|
tinfo = task_thread_info(tsk);
|
|
|
|
if (valid_stack_ptr(tinfo, sp)) {
|
|
dump_mem("Stack: ", log_lvl, sp,
|
|
THREAD_SIZE + (unsigned long)tinfo);
|
|
show_trace_log_lvl(tsk, (unsigned long *)sp, regs, log_lvl);
|
|
}
|
|
}
|
|
|
|
void show_stack(struct task_struct *tsk, unsigned long *stack)
|
|
{
|
|
show_stack_log_lvl(tsk, (unsigned long)stack, NULL, "");
|
|
}
|
|
|
|
void dump_stack(void)
|
|
{
|
|
unsigned long stack;
|
|
|
|
show_trace_log_lvl(current, &stack, NULL, "");
|
|
}
|
|
EXPORT_SYMBOL(dump_stack);
|
|
|
|
static const char *cpu_modes[] = {
|
|
"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
|
|
"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
|
|
};
|
|
|
|
void show_regs_log_lvl(struct pt_regs *regs, const char *log_lvl)
|
|
{
|
|
unsigned long sp = regs->sp;
|
|
unsigned long lr = regs->lr;
|
|
unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
|
|
|
|
if (!user_mode(regs)) {
|
|
sp = (unsigned long)regs + FRAME_SIZE_FULL;
|
|
|
|
printk("%s", log_lvl);
|
|
print_symbol("PC is at %s\n", instruction_pointer(regs));
|
|
printk("%s", log_lvl);
|
|
print_symbol("LR is at %s\n", lr);
|
|
}
|
|
|
|
printk("%spc : [<%08lx>] lr : [<%08lx>] %s\n"
|
|
"%ssp : %08lx r12: %08lx r11: %08lx\n",
|
|
log_lvl, instruction_pointer(regs), lr, print_tainted(),
|
|
log_lvl, sp, regs->r12, regs->r11);
|
|
printk("%sr10: %08lx r9 : %08lx r8 : %08lx\n",
|
|
log_lvl, regs->r10, regs->r9, regs->r8);
|
|
printk("%sr7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
|
|
log_lvl, regs->r7, regs->r6, regs->r5, regs->r4);
|
|
printk("%sr3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
|
|
log_lvl, regs->r3, regs->r2, regs->r1, regs->r0);
|
|
printk("%sFlags: %c%c%c%c%c\n", log_lvl,
|
|
regs->sr & SR_Q ? 'Q' : 'q',
|
|
regs->sr & SR_V ? 'V' : 'v',
|
|
regs->sr & SR_N ? 'N' : 'n',
|
|
regs->sr & SR_Z ? 'Z' : 'z',
|
|
regs->sr & SR_C ? 'C' : 'c');
|
|
printk("%sMode bits: %c%c%c%c%c%c%c%c%c%c\n", log_lvl,
|
|
regs->sr & SR_H ? 'H' : 'h',
|
|
regs->sr & SR_J ? 'J' : 'j',
|
|
regs->sr & SR_DM ? 'M' : 'm',
|
|
regs->sr & SR_D ? 'D' : 'd',
|
|
regs->sr & SR_EM ? 'E' : 'e',
|
|
regs->sr & SR_I3M ? '3' : '.',
|
|
regs->sr & SR_I2M ? '2' : '.',
|
|
regs->sr & SR_I1M ? '1' : '.',
|
|
regs->sr & SR_I0M ? '0' : '.',
|
|
regs->sr & SR_GM ? 'G' : 'g');
|
|
printk("%sCPU Mode: %s\n", log_lvl, cpu_modes[mode]);
|
|
printk("%sProcess: %s [%d] (task: %p thread: %p)\n",
|
|
log_lvl, current->comm, current->pid, current,
|
|
task_thread_info(current));
|
|
}
|
|
|
|
void show_regs(struct pt_regs *regs)
|
|
{
|
|
unsigned long sp = regs->sp;
|
|
|
|
if (!user_mode(regs))
|
|
sp = (unsigned long)regs + FRAME_SIZE_FULL;
|
|
|
|
show_regs_log_lvl(regs, "");
|
|
show_trace_log_lvl(current, (unsigned long *)sp, regs, "");
|
|
}
|
|
EXPORT_SYMBOL(show_regs);
|
|
|
|
/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
|
|
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
|
|
{
|
|
/* Not valid */
|
|
return 0;
|
|
}
|
|
|
|
asmlinkage void ret_from_fork(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 pt_regs *childregs;
|
|
|
|
childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)task_stack_page(p))) - 1;
|
|
*childregs = *regs;
|
|
|
|
if (user_mode(regs))
|
|
childregs->sp = usp;
|
|
else
|
|
childregs->sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
|
|
|
|
childregs->r12 = 0; /* Set return value for child */
|
|
|
|
p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
|
|
p->thread.cpu_context.ksp = (unsigned long)childregs;
|
|
p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
|
|
|
|
clear_tsk_thread_flag(p, TIF_DEBUG);
|
|
if ((clone_flags & CLONE_PTRACE) && test_thread_flag(TIF_DEBUG))
|
|
ocd_enable(p);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* r12-r8 are dummy parameters to force the compiler to use the stack */
|
|
asmlinkage int sys_fork(struct pt_regs *regs)
|
|
{
|
|
return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
|
|
}
|
|
|
|
asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
|
|
unsigned long parent_tidptr,
|
|
unsigned long child_tidptr, struct pt_regs *regs)
|
|
{
|
|
if (!newsp)
|
|
newsp = regs->sp;
|
|
return do_fork(clone_flags, newsp, regs, 0,
|
|
(int __user *)parent_tidptr,
|
|
(int __user *)child_tidptr);
|
|
}
|
|
|
|
asmlinkage int sys_vfork(struct pt_regs *regs)
|
|
{
|
|
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
|
|
0, NULL, NULL);
|
|
}
|
|
|
|
asmlinkage int sys_execve(char __user *ufilename, char __user *__user *uargv,
|
|
char __user *__user *uenvp, 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, regs);
|
|
if (error == 0)
|
|
current->ptrace &= ~PT_DTRACE;
|
|
putname(filename);
|
|
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
|
|
/*
|
|
* This function is supposed to answer the question "who called
|
|
* schedule()?"
|
|
*/
|
|
unsigned long get_wchan(struct task_struct *p)
|
|
{
|
|
unsigned long pc;
|
|
unsigned long stack_page;
|
|
|
|
if (!p || p == current || p->state == TASK_RUNNING)
|
|
return 0;
|
|
|
|
stack_page = (unsigned long)task_stack_page(p);
|
|
BUG_ON(!stack_page);
|
|
|
|
/*
|
|
* The stored value of PC is either the address right after
|
|
* the call to __switch_to() or ret_from_fork.
|
|
*/
|
|
pc = thread_saved_pc(p);
|
|
if (in_sched_functions(pc)) {
|
|
#ifdef CONFIG_FRAME_POINTER
|
|
unsigned long fp = p->thread.cpu_context.r7;
|
|
BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
|
|
pc = *(unsigned long *)fp;
|
|
#else
|
|
/*
|
|
* We depend on the frame size of schedule here, which
|
|
* is actually quite ugly. It might be possible to
|
|
* determine the frame size automatically at build
|
|
* time by doing this:
|
|
* - compile sched.c
|
|
* - disassemble the resulting sched.o
|
|
* - look for 'sub sp,??' shortly after '<schedule>:'
|
|
*/
|
|
unsigned long sp = p->thread.cpu_context.ksp + 16;
|
|
BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
|
|
pc = *(unsigned long *)sp;
|
|
#endif
|
|
}
|
|
|
|
return pc;
|
|
}
|