unsigned long get_wchan(struct task_struct *p)
{
unsigned long bp, sp, ip;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)task_stack_page(p);
sp = p->thread.sp;
if (!stack_page || sp < stack_page || sp > top_esp+stack_page)
return 0;
/* L4Linux has a different layout in switch_to(), but
* the only difference is that we push a return
* address after ebp. So we simply adjust the esp to
* reflect that. And we leave the different name for
* esp to catch direct usage of thread data. */
sp += 4;/* add 4 to remove return address */
/* include/asm-i386/system.h:switch_to() pushes bp last. */
bp = *(unsigned long *) sp;
do {
if (bp < stack_page || bp > top_ebp+stack_page)
return 0;
ip = *(unsigned long *) (bp+4);
if (!in_sched_functions(ip))
return ip;
bp = *(unsigned long *) bp;
} while (count++ < 16);
return 0;
}
static void save_context_stack(struct stack_trace *trace,
struct task_struct *tsk, struct pt_regs *regs, int savesched)
{
unsigned long sp = regs->regs[29];
#ifdef CONFIG_KALLSYMS
unsigned long ra = regs->regs[31];
unsigned long pc = regs->cp0_epc;
if (raw_show_trace || !__kernel_text_address(pc)) {
unsigned long stack_page =
(unsigned long)task_stack_page(tsk);
if (stack_page && sp >= stack_page &&
sp <= stack_page + THREAD_SIZE - 32)
save_raw_context_stack(trace, sp, savesched);
return;
}
do {
if (savesched || !in_sched_functions(pc)) {
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = pc;
if (trace->nr_entries >= trace->max_entries)
break;
}
pc = unwind_stack(tsk, &sp, pc, &ra);
} while (pc);
#else
save_raw_context_stack(trace, sp, savesched);
#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;
}
static int
kgdb_get_blocked_state(struct vcpu *p,
struct cpu_user_regs *regs,
struct unw_frame_info *unw)
#endif
{
unsigned long ip;
int count = 0;
#ifndef XEN
unw_init_from_blocked_task(unw, p);
#endif
ip = 0UL;
do {
if (unw_unwind(unw) < 0)
return -1;
unw_get_ip(unw, &ip);
#ifndef XEN
if (!in_sched_functions(ip))
break;
#else
dbg_printk("ip 0x%lx cr_iip 0x%lx\n", ip, regs->cr_iip);
if (ip == regs->cr_iip)
break;
#endif
} while (count++ < 16);
if (!ip)
return -1;
else
return 0;
}
/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
static void save_context_stack(struct stack_trace *trace, unsigned long sp,
struct task_struct *tsk, int savesched)
{
for (;;) {
unsigned long *stack = (unsigned long *) sp;
unsigned long newsp, ip;
if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
return;
newsp = stack[0];
ip = stack[STACK_FRAME_LR_SAVE];
if (savesched || !in_sched_functions(ip)) {
if (!trace->skip)
trace->entries[trace->nr_entries++] = ip;
else
trace->skip--;
}
if (trace->nr_entries >= trace->max_entries)
return;
sp = newsp;
}
}
static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr,
bool reliable)
{
if (in_sched_functions(addr))
return true;
return stack_trace_consume_entry(cookie, addr, reliable);
}
unsigned long get_wchan(struct task_struct *p)
{
#if 0
/* YURGH. TODO. */
unsigned long ebp, esp, eip;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)p;
esp = p->thread.esp;
if (!stack_page || esp < stack_page || esp > 8188+stack_page)
return 0;
/* include/asm-i386/system.h:switch_to() pushes ebp last. */
ebp = *(unsigned long *) esp;
do {
if (ebp < stack_page || ebp > 8184+stack_page)
return 0;
eip = *(unsigned long *) (ebp+4);
if (!in_sched_functions(eip))
return eip;
ebp = *(unsigned long *) ebp;
} while (count++ < 16);
#endif
return 0;
}
unsigned long get_wchan(struct task_struct *p)
{
#if 0
unsigned long ebp, esp, eip;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)p;
esp = p->thread.esp;
if (!stack_page || esp < stack_page || esp > 8188+stack_page)
return 0;
ebp = *(unsigned long *) esp;
do {
if (ebp < stack_page || ebp > 8184+stack_page)
return 0;
eip = *(unsigned long *) (ebp+4);
if (!in_sched_functions(eip))
return eip;
ebp = *(unsigned long *) ebp;
} while (count++ < 16);
#endif
return 0;
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, lr;
unsigned long stack_start, stack_end;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
if (IS_ENABLED(CONFIG_FRAME_POINTER)) {
stack_start = (unsigned long)end_of_stack(p);
stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;
fp = thread_saved_fp(p);
do {
if (fp < stack_start || fp > stack_end)
return 0;
lr = ((unsigned long *)fp)[0];
if (!in_sched_functions(lr))
return lr;
fp = *(unsigned long *)(fp + 4);
} while (count++ < 16);
}
return 0;
}
/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
unsigned long get_wchan(struct task_struct *p)
{
unsigned long stack_page;
unsigned long pc;
#ifdef CONFIG_KALLSYMS
unsigned long frame;
#endif
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)task_stack_page(p);
if (!stack_page || !mfinfo_num)
return 0;
pc = thread_saved_pc(p);
#ifdef CONFIG_KALLSYMS
if (!in_sched_functions(pc))
return pc;
frame = p->thread.reg29 + schedule_frame->frame_size;
do {
int i;
if (frame < stack_page || frame > stack_page + THREAD_SIZE - 32)
return 0;
for (i = mfinfo_num - 1; i >= 0; i--) {
if (pc >= (unsigned long) mfinfo[i].func)
break;
}
if (i < 0)
break;
if (mfinfo[i].pc_offset < 0)
break;
pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
if (!mfinfo[i].frame_size)
break;
frame += mfinfo[i].frame_size;
} while (in_sched_functions(pc));
#endif
return pc;
}
static bool save_wchan(unsigned long pc, void *arg)
{
if (!in_sched_functions(pc)) {
unsigned long *p = arg;
*p = pc;
return true;
}
return false;
}
/*
* Return saved PC from a blocked thread
*/
unsigned long thread_saved_pc(struct task_struct *tsk)
{
struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
/* Check whether the thread is blocked in resume() */
if (in_sched_functions(sw->retpc))
return ((unsigned long *)sw->a6)[1];
else
return sw->retpc;
}
/*
* Called from fs/proc with a reference on @p to find the function
* which called into schedule(). This needs to be done carefully
* because the task might wake up and we might look at a stack
* changing under us.
*/
unsigned long get_wchan(struct task_struct *p)
{
unsigned long start, bottom, top, sp, fp, ip, ret = 0;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
if (!try_get_task_stack(p))
return 0;
start = (unsigned long)task_stack_page(p);
if (!start)
goto out;
/*
* Layout of the stack page:
*
* ----------- topmax = start + THREAD_SIZE - sizeof(unsigned long)
* PADDING
* ----------- top = topmax - TOP_OF_KERNEL_STACK_PADDING
* stack
* ----------- bottom = start
*
* The tasks stack pointer points at the location where the
* framepointer is stored. The data on the stack is:
* ... IP FP ... IP FP
*
* We need to read FP and IP, so we need to adjust the upper
* bound by another unsigned long.
*/
top = start + THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;
top -= 2 * sizeof(unsigned long);
bottom = start;
sp = READ_ONCE(p->thread.sp);
if (sp < bottom || sp > top)
goto out;
fp = READ_ONCE_NOCHECK(((struct inactive_task_frame *)sp)->bp);
do {
if (fp < bottom || fp > top)
goto out;
ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long)));
if (!in_sched_functions(ip)) {
ret = ip;
goto out;
}
fp = READ_ONCE_NOCHECK(*(unsigned long *)fp);
} while (count++ < 16 && p->state != TASK_RUNNING);
out:
put_task_stack(p);
return ret;
}
/*
* Return saved PC of a blocked thread.
*/
unsigned long thread_saved_pc(struct task_struct *tsk)
{
struct cpu_context *ctx =
&(((struct thread_info *)(tsk->stack))->cpu_context);
/* Check whether the thread is blocked in resume() */
if (in_sched_functions(ctx->r15))
return (unsigned long)ctx->r15;
else
return ctx->r14;
}
/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
unsigned long get_wchan(struct task_struct *p)
{
unsigned long stack_page;
unsigned long frame, pc;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)p->thread_info;
if (!stack_page || !mips_frame_info_initialized)
return 0;
pc = thread_saved_pc(p);
if (!in_sched_functions(pc))
return pc;
frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
do {
int i;
if (frame < stack_page || frame > stack_page + THREAD_SIZE - 32)
return 0;
for (i = ARRAY_SIZE(mfinfo) - 1; i >= 0; i--) {
if (pc >= (unsigned long) mfinfo[i].func)
break;
}
if (i < 0)
break;
if (mfinfo[i].omit_fp)
break;
pc = ((unsigned long *)frame)[mfinfo[i].pc_offset];
frame = ((unsigned long *)frame)[mfinfo[i].frame_offset];
} while (in_sched_functions(pc));
return pc;
}
static bool __save_trace(unsigned long pc, void *arg, bool nosched)
{
struct stack_trace *trace = arg;
if (unlikely(nosched && in_sched_functions(pc)))
return false;
if (unlikely(trace->skip > 0)) {
trace->skip--;
return false;
}
trace->entries[trace->nr_entries++] = pc;
return (trace->nr_entries >= trace->max_entries);
}
static unsigned long save_context_stack(struct stack_trace *trace,
unsigned long sp,
unsigned long low,
unsigned long high,
int savesched)
{
struct stack_frame *sf;
struct pt_regs *regs;
unsigned long addr;
while(1) {
sp &= PSW_ADDR_INSN;
if (sp < low || sp > high)
return sp;
sf = (struct stack_frame *)sp;
while(1) {
addr = sf->gprs[8] & PSW_ADDR_INSN;
if (!trace->skip)
trace->entries[trace->nr_entries++] = addr;
else
trace->skip--;
if (trace->nr_entries >= trace->max_entries)
return sp;
low = sp;
sp = sf->back_chain & PSW_ADDR_INSN;
if (!sp)
break;
if (sp <= low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *)sp;
}
/* Zero backchain detected, check for interrupt frame. */
sp = (unsigned long)(sf + 1);
if (sp <= low || sp > high - sizeof(*regs))
return sp;
regs = (struct pt_regs *)sp;
addr = regs->psw.addr & PSW_ADDR_INSN;
if (savesched || !in_sched_functions(addr)) {
if (!trace->skip)
trace->entries[trace->nr_entries++] = addr;
else
trace->skip--;
}
if (trace->nr_entries >= trace->max_entries)
return sp;
low = sp;
sp = regs->gprs[15];
}
}
static int __save_address(void *data, unsigned long address, int nosched)
{
struct stack_trace *trace = data;
if (nosched && in_sched_functions(address))
return 0;
if (trace->skip > 0) {
trace->skip--;
return 0;
}
if (trace->nr_entries < trace->max_entries) {
trace->entries[trace->nr_entries++] = address;
return 0;
}
return 1;
}
static void
__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)
{
struct stack_trace *trace = data;
#ifdef CONFIG_FRAME_POINTER
if (!reliable)
return;
#endif
if (nosched && in_sched_functions(addr))
return;
if (trace->skip > 0) {
trace->skip--;
return;
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = addr;
}
static int save_trace(struct stackframe *frame, void *d)
{
struct stack_trace_data *data = d;
struct stack_trace *trace = data->trace;
unsigned long addr = frame->pc;
if (data->no_sched_functions && in_sched_functions(addr))
return 0;
if (data->skip) {
data->skip--;
return 0;
}
trace->entries[trace->nr_entries++] = addr;
return trace->nr_entries >= trace->max_entries;
}
static int save_stack_address(struct stack_trace *trace, unsigned long addr,
bool nosched)
{
if (nosched && in_sched_functions(addr))
return 0;
if (trace->skip > 0) {
trace->skip--;
return 0;
}
if (trace->nr_entries >= trace->max_entries)
return -1;
trace->entries[trace->nr_entries++] = addr;
return 0;
}
/*
* Save stack-backtrace addresses into a stack_trace buffer:
*/
static void save_raw_context_stack(struct stack_trace *trace,
unsigned long reg29, int savesched)
{
unsigned long *sp = (unsigned long *)reg29;
unsigned long addr;
while (!kstack_end(sp)) {
addr = *sp++;
if (__kernel_text_address(addr) &&
(savesched || !in_sched_functions(addr))) {
if (trace->skip > 0)
trace->skip--;
else
trace->entries[trace->nr_entries++] = addr;
if (trace->nr_entries >= trace->max_entries)
break;
}
}
}
static void
save_stack_address_nosched(void *data, unsigned long addr, int reliable)
{
struct stack_trace *trace = (struct stack_trace *)data;
if (!reliable)
return;
if (in_sched_functions(addr))
return;
if (trace->skip > 0) {
trace->skip--;
return;
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = addr;
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, lr;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = 4096 + (unsigned long)p;
fp = thread_saved_fp(p);
do {
if (fp < stack_page || fp > 4092+stack_page)
return 0;
lr = pc_pointer (((unsigned long *)fp)[-1]);
if (!in_sched_functions(lr))
return lr;
fp = *(unsigned long *) (fp - 12);
} while (count ++ < 16);
return 0;
}
unsigned long
get_wchan(struct task_struct *p)
{
struct unwind_frame_info info;
unsigned long ip;
int count = 0;
/*
* These bracket the sleeping functions..
*/
unwind_frame_init_from_blocked_task(&info, p);
do {
if (unwind_once(&info) < 0)
return 0;
ip = info.ip;
if (!in_sched_functions(ip))
return ip;
} while (count++ < 16);
return 0;
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)p;
fp = ((struct pt_regs *)p->thread.ksp)->er6;
do {
if (fp < stack_page+sizeof(struct thread_info) ||
fp >= 8184+stack_page)
return 0;
pc = ((unsigned long *)fp)[1];
if (!in_sched_functions(pc))
return pc;
fp = *(unsigned long *) fp;
} while (count++ < 16);
return 0;
}
/*
* The "wait channel" terminology is archaic, but what we want
* is an identification of the point at which the scheduler
* was invoked by a blocked thread.
*/
unsigned long get_wchan(struct task_struct *p)
{
unsigned long fp, pc;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)task_stack_page(p);
fp = ((struct hexagon_switch_stack *)p->thread.switch_sp)->fp;
do {
if (fp < (stack_page + sizeof(struct thread_info)) ||
fp >= (THREAD_SIZE - 8 + stack_page))
return 0;
pc = ((unsigned long *)fp)[1];
if (!in_sched_functions(pc))
return pc;
fp = *(unsigned long *) fp;
} while (count++ < 16);
return 0;
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long bp, sp, ip;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = (unsigned long)task_stack_page(p);
sp = p->thread.sp;
if (!stack_page || sp < stack_page || sp > top_esp+stack_page)
return 0;
/* include/asm-i386/system.h:switch_to() pushes bp last. */
bp = *(unsigned long *) sp;
do {
if (bp < stack_page || bp > top_ebp+stack_page)
return 0;
ip = *(unsigned long *) (bp+4);
if (!in_sched_functions(ip))
return ip;
bp = *(unsigned long *) bp;
} while (count++ < 16);
return 0;
}
static int save_trace(struct stackframe *frame, void *d)
{
struct stack_trace_data *data = d;
struct stack_trace *trace = data->trace;
struct pt_regs *regs;
unsigned long addr = frame->pc;
if (data->no_sched_functions && in_sched_functions(addr))
return 0;
if (data->skip) {
data->skip--;
return 0;
}
trace->entries[trace->nr_entries++] = addr;
if (trace->nr_entries >= trace->max_entries)
return 1;
/*
* in_exception_text() is designed to test if the PC is one of
* the functions which has an exception stack above it, but
* unfortunately what is in frame->pc is the return LR value,
* not the saved PC value. So, we need to track the previous
* frame PC value when doing this.
*/
addr = data->last_pc;
data->last_pc = frame->pc;
if (!in_exception_text(addr))
return 0;
regs = (struct pt_regs *)frame->sp;
trace->entries[trace->nr_entries++] = regs->ARM_pc;
return trace->nr_entries >= trace->max_entries;
}
unsigned long
get_wchan(struct task_struct *p)
{
unsigned long schedule_frame;
unsigned long pc;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
/*
* This one depends on the frame size of schedule(). Do a
* "disass schedule" in gdb to find the frame size. Also, the
* code assumes that sleep_on() follows immediately after
* interruptible_sleep_on() and that add_timer() follows
* immediately after interruptible_sleep(). Ugly, isn't it?
* Maybe adding a wchan field to task_struct would be better,
* after all...
*/
pc = thread_saved_pc(p);
if (in_sched_functions(pc)) {
schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6];
return ((unsigned long *)schedule_frame)[12];
}
return pc;
}