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openrisc: support framepointers and STACKTRACE_SUPPORT

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For lockdep support a reliable stack trace mechanism is needed.  This
patch adds support in OpenRISC for the stacktrace framework, implemented
by a simple unwinder api.  The unwinder api supports both framepointer
and basic stack tracing.

The unwinder is now used to replace the stack_dump() implementation as
well. The new traces are inline with other architectures trace format:

 Call trace:
 [<c0004448>] show_stack+0x3c/0x58
 [<c031c940>] dump_stack+0xa8/0xe4
 [<c0008104>] __cpu_up+0x64/0x130
 [<c000d268>] bringup_cpu+0x3c/0x178
 [<c000d038>] cpuhp_invoke_callback+0xa8/0x1fc
 [<c000d680>] cpuhp_up_callbacks+0x44/0x14c
 [<c000e400>] cpu_up+0x14c/0x1bc
 [<c041da60>] smp_init+0x104/0x15c
 [<c033843c>] ? kernel_init+0x0/0x140
 [<c0415e04>] kernel_init_freeable+0xbc/0x25c
 [<c033843c>] ? kernel_init+0x0/0x140
 [<c0338458>] kernel_init+0x1c/0x140
 [<c003a174>] ? schedule_tail+0x18/0xa0
 [<c0006b80>] ret_from_fork+0x1c/0x9c

Signed-off-by: Stafford Horne <shorne@gmail.com>
This commit is contained in:
Stafford Horne 2017-07-24 21:44:35 +09:00
parent 306e5e50a3
commit eecac38b04
6 changed files with 224 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/openrisc/Kconfig
View File

@ -33,6 +33,7 @@ config OPENRISC
select ARCH_USE_QUEUED_SPINLOCKS
select ARCH_USE_QUEUED_RWLOCKS
select OMPIC if SMP
select ARCH_WANT_FRAME_POINTERS
config CPU_BIG_ENDIAN
def_bool y
@ -60,6 +61,9 @@ config TRACE_IRQFLAGS_SUPPORT
config GENERIC_CSUM
def_bool y
config STACKTRACE_SUPPORT
def_bool y
source "init/Kconfig"
source "kernel/Kconfig.freezer"

20
arch/openrisc/include/asm/unwinder.h Normal file
View File

@ -0,0 +1,20 @@
/*
* OpenRISC unwinder.h
*
* Architecture API for unwinding stacks.
*
* Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#ifndef __ASM_OPENRISC_UNWINDER_H
#define __ASM_OPENRISC_UNWINDER_H
void unwind_stack(void *data, unsigned long *stack,
void (*trace)(void *data, unsigned long addr,
int reliable));
#endif /* __ASM_OPENRISC_UNWINDER_H */

3
arch/openrisc/kernel/Makefile
View File

@ -6,9 +6,10 @@ extra-y := head.o vmlinux.lds
obj-y := setup.o or32_ksyms.o process.o dma.o \
traps.o time.o irq.o entry.o ptrace.o signal.o \
sys_call_table.o
sys_call_table.o unwinder.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_OF) += prom.o

86
arch/openrisc/kernel/stacktrace.c Normal file
View File

@ -0,0 +1,86 @@
/*
* Stack trace utility for OpenRISC
*
* Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*
* Losely based on work from sh and powerpc.
*/
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/stacktrace.h>
#include <asm/processor.h>
#include <asm/unwinder.h>
/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
static void
save_stack_address(void *data, unsigned long addr, int reliable)
{
struct stack_trace *trace = data;
if (!reliable)
return;
if (trace->skip > 0) {
trace->skip--;
return;
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = addr;
}
void save_stack_trace(struct stack_trace *trace)
{
unwind_stack(trace, (unsigned long *) &trace, save_stack_address);
}
EXPORT_SYMBOL_GPL(save_stack_trace);
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;
}
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
unsigned long *sp = NULL;
if (tsk == current)
sp = (unsigned long *) &sp;
else
sp = (unsigned long *) KSTK_ESP(tsk);
unwind_stack(trace, sp, save_stack_address_nosched);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
void
save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
unwind_stack(trace, (unsigned long *) regs->sp,
save_stack_address_nosched);
}
EXPORT_SYMBOL_GPL(save_stack_trace_regs);

54
arch/openrisc/kernel/traps.c
View File

@ -38,6 +38,7 @@
#include <asm/segment.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/unwinder.h>
extern char _etext, _stext;
@ -45,61 +46,20 @@ int kstack_depth_to_print = 0x180;
int lwa_flag;
unsigned long __user *lwa_addr;
static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
void print_trace(void *data, unsigned long addr, int reliable)
{
return p > (void *)tinfo && p < (void *)tinfo + THREAD_SIZE - 3;
}
void show_trace(struct task_struct *task, unsigned long *stack)
{
struct thread_info *context;
unsigned long addr;
context = (struct thread_info *)
((unsigned long)stack & (~(THREAD_SIZE - 1)));
while (valid_stack_ptr(context, stack)) {
addr = *stack++;
if (__kernel_text_address(addr)) {
printk(" [<%08lx>]", addr);
print_symbol(" %s", addr);
printk("\n");
}
}
printk(" =======================\n");
pr_emerg("[<%p>] %s%pS\n", (void *) addr, reliable ? "" : "? ",
(void *) addr);
}
/* displays a short stack trace */
void show_stack(struct task_struct *task, unsigned long *esp)
{
unsigned long addr, *stack;
int i;
if (esp == NULL)
esp = (unsigned long *)&esp;
stack = esp;
printk("Stack dump [0x%08lx]:\n", (unsigned long)esp);
for (i = 0; i < kstack_depth_to_print; i++) {
if (kstack_end(stack))
break;
if (__get_user(addr, stack)) {
/* This message matches "failing address" marked
s390 in ksymoops, so lines containing it will
not be filtered out by ksymoops. */
printk("Failing address 0x%lx\n", (unsigned long)stack);
break;
}
stack++;
printk("sp + %02d: 0x%08lx\n", i * 4, addr);
}
printk("\n");
show_trace(task, esp);
return;
pr_emerg("Call trace:\n");
unwind_stack(NULL, esp, print_trace);
}
void show_trace_task(struct task_struct *tsk)
@ -115,7 +75,7 @@ void show_registers(struct pt_regs *regs)
int in_kernel = 1;
unsigned long esp;
esp = (unsigned long)(&regs->sp);
esp = (unsigned long)(regs->sp);
if (user_mode(regs))
in_kernel = 0;

105
arch/openrisc/kernel/unwinder.c Normal file
View File

@ -0,0 +1,105 @@
/*
* OpenRISC unwinder.c
*
* Reusable arch specific api for unwinding stacks.
*
* Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#include <linux/sched/task_stack.h>
#include <linux/kernel.h>
#include <asm/unwinder.h>
#ifdef CONFIG_FRAME_POINTER
struct or1k_frameinfo {
unsigned long *fp;
unsigned long ra;
unsigned long top;
};
/*
* Verify a frameinfo structure. The return address should be a valid text
* address. The frame pointer may be null if its the last frame, otherwise
* the frame pointer should point to a location in the stack after the the
* top of the next frame up.
*/
static inline int or1k_frameinfo_valid(struct or1k_frameinfo *frameinfo)
{
return (frameinfo->fp == NULL ||
(!kstack_end(frameinfo->fp) &&
frameinfo->fp > &frameinfo->top)) &&
__kernel_text_address(frameinfo->ra);
}
/*
* Create a stack trace doing scanning which is frame pointer aware. We can
* get reliable stack traces by matching the previously found frame
* pointer with the top of the stack address every time we find a valid
* or1k_frameinfo.
*
* Ideally the stack parameter will be passed as FP, but it can not be
* guaranteed. Therefore we scan each address looking for the first sign
* of a return address.
*
* The OpenRISC stack frame looks something like the following. The
* location SP is held in r1 and location FP is held in r2 when frame pointers
* enabled.
*
* SP -> (top of stack)
* - (callee saved registers)
* - (local variables)
* FP-8 -> previous FP \
* FP-4 -> return address |- or1k_frameinfo
* FP -> (previous top of stack) /
*/
void unwind_stack(void *data, unsigned long *stack,
void (*trace)(void *data, unsigned long addr, int reliable))
{
unsigned long *next_fp = NULL;
struct or1k_frameinfo *frameinfo = NULL;
int reliable = 0;
while (!kstack_end(stack)) {
frameinfo = container_of(stack,
struct or1k_frameinfo,
top);
if (__kernel_text_address(frameinfo->ra)) {
if (or1k_frameinfo_valid(frameinfo) &&
(next_fp == NULL ||
next_fp == &frameinfo->top)) {
reliable = 1;
next_fp = frameinfo->fp;
} else
reliable = 0;
trace(data, frameinfo->ra, reliable);
}
stack++;
}
}
#else /* CONFIG_FRAME_POINTER */
/*
* Create a stack trace by doing a simple scan treating all text addresses
* as return addresses.
*/
void unwind_stack(void *data, unsigned long *stack,
void (*trace)(void *data, unsigned long addr, int reliable))
{
unsigned long addr;
while (!kstack_end(stack)) {
addr = *stack++;
if (__kernel_text_address(addr))
trace(data, addr, 0);
}
}
#endif /* CONFIG_FRAME_POINTER */