linux/arch/microblaze/kernel/traps.c
Dmitry Safonov 35f3968b49 microblaze: add show_stack_loglvl()
Currently, the log-level of show_stack() depends on a platform
realization.  It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on a platform or
user).

Furthermore, it forces the logic decision from user to an architecture
side.  In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.  And in
result it not only may print unwanted messages from other CPUs, but also
omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier
approach than introducing more printk buffers.  Also, it will consolidate
printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Simek <monstr@monstr.eu>
Link: http://lkml.kernel.org/r/20200418201944.482088-21-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:11 -07:00

85 lines
2.1 KiB
C

/*
* Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2007-2009 PetaLogix
* Copyright (C) 2006 Atmark Techno, Inc.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/kallsyms.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/debug_locks.h>
#include <asm/exceptions.h>
#include <asm/unwind.h>
void trap_init(void)
{
__enable_hw_exceptions();
}
static unsigned long kstack_depth_to_print; /* 0 == entire stack */
static int __init kstack_setup(char *s)
{
return !kstrtoul(s, 0, &kstack_depth_to_print);
}
__setup("kstack=", kstack_setup);
void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
const char *loglvl)
{
unsigned long words_to_show;
u32 fp = (u32) sp;
if (fp == 0) {
if (task) {
fp = ((struct thread_info *)
(task->stack))->cpu_context.r1;
} else {
/* Pick up caller of dump_stack() */
fp = (u32)&sp - 8;
}
}
words_to_show = (THREAD_SIZE - (fp & (THREAD_SIZE - 1))) >> 2;
if (kstack_depth_to_print && (words_to_show > kstack_depth_to_print))
words_to_show = kstack_depth_to_print;
printk("%sKernel Stack:\n", loglvl);
/*
* Make the first line an 'odd' size if necessary to get
* remaining lines to start at an address multiple of 0x10
*/
if (fp & 0xF) {
unsigned long line1_words = (0x10 - (fp & 0xF)) >> 2;
if (line1_words < words_to_show) {
print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32,
4, (void *)fp, line1_words << 2, 0);
fp += line1_words << 2;
words_to_show -= line1_words;
}
}
print_hex_dump(loglvl, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
words_to_show << 2, 0);
printk("%s\n\nCall Trace:\n", loglvl);
microblaze_unwind(task, NULL, loglvl);
printk("%s\n", loglvl);
if (!task)
task = current;
debug_show_held_locks(task);
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
show_stack_loglvl(task, sp, KERN_INFO);
}