Commit eecac38b authored by Stafford Horne's avatar Stafford Horne
Browse files

openrisc: support framepointers and STACKTRACE_SUPPORT 



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: default avatarStafford Horne <shorne@gmail.com>
parent 306e5e50

arch/openrisc/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -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"

arch/openrisc/include/asm/unwinder.h

0 → 100644
+20 −0
Original line number Diff line number Diff line 
/*

 * 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 */

arch/openrisc/kernel/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -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

arch/openrisc/kernel/stacktrace.c

0 → 100644
+86 −0
Original line number Diff line number Diff line 
/*

 * 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);

arch/openrisc/kernel/traps.c

+7 −47
Original line number Diff line number Diff line
@@ -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;

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