linux_dsm_epyc7002/arch/x86/include/asm/stacktrace.h
Dmitry Safonov d46b3df78a x86: add missing const qualifiers for log_lvl
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.

Keep log_lvl const show_trace_log_lvl() and printk_stack_address() as the
new generic show_stack_loglvl() wants to have a proper const qualifier.

And gcc rightfully produces warnings in case it's not keept:
arch/x86/kernel/dumpstack.c: In function `show_stack':
arch/x86/kernel/dumpstack.c:294:37: warning: passing argument 4 of `show_trace_log_lv ' discards `const' qualifier from pointer target type [-Wdiscarded-qualifiers]
  294 |  show_trace_log_lvl(task, NULL, sp, loglvl);
      |                                     ^~~~~~
arch/x86/kernel/dumpstack.c:163:32: note: expected `char *' but argument is of type `const char *'
  163 |    unsigned long *stack, char *log_lvl)
      |                          ~~~~~~^~~~~~~

[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: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200418201944.482088-41-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:12 -07:00

106 lines
2.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
*/
#ifndef _ASM_X86_STACKTRACE_H
#define _ASM_X86_STACKTRACE_H
#include <linux/uaccess.h>
#include <linux/ptrace.h>
#include <asm/cpu_entry_area.h>
#include <asm/switch_to.h>
enum stack_type {
STACK_TYPE_UNKNOWN,
STACK_TYPE_TASK,
STACK_TYPE_IRQ,
STACK_TYPE_SOFTIRQ,
STACK_TYPE_ENTRY,
STACK_TYPE_EXCEPTION,
STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1,
};
struct stack_info {
enum stack_type type;
unsigned long *begin, *end, *next_sp;
};
bool in_task_stack(unsigned long *stack, struct task_struct *task,
struct stack_info *info);
bool in_entry_stack(unsigned long *stack, struct stack_info *info);
int get_stack_info(unsigned long *stack, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask);
const char *stack_type_name(enum stack_type type);
static inline bool on_stack(struct stack_info *info, void *addr, size_t len)
{
void *begin = info->begin;
void *end = info->end;
return (info->type != STACK_TYPE_UNKNOWN &&
addr >= begin && addr < end &&
addr + len > begin && addr + len <= end);
}
#ifdef CONFIG_X86_32
#define STACKSLOTS_PER_LINE 8
#else
#define STACKSLOTS_PER_LINE 4
#endif
#ifdef CONFIG_FRAME_POINTER
static inline unsigned long *
get_frame_pointer(struct task_struct *task, struct pt_regs *regs)
{
if (regs)
return (unsigned long *)regs->bp;
if (task == current)
return __builtin_frame_address(0);
return &((struct inactive_task_frame *)task->thread.sp)->bp;
}
#else
static inline unsigned long *
get_frame_pointer(struct task_struct *task, struct pt_regs *regs)
{
return NULL;
}
#endif /* CONFIG_FRAME_POINTER */
static inline unsigned long *
get_stack_pointer(struct task_struct *task, struct pt_regs *regs)
{
if (regs)
return (unsigned long *)regs->sp;
if (task == current)
return __builtin_frame_address(0);
return (unsigned long *)task->thread.sp;
}
void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, const char *log_lvl);
/* The form of the top of the frame on the stack */
struct stack_frame {
struct stack_frame *next_frame;
unsigned long return_address;
};
struct stack_frame_ia32 {
u32 next_frame;
u32 return_address;
};
void show_opcodes(struct pt_regs *regs, const char *loglvl);
void show_ip(struct pt_regs *regs, const char *loglvl);
#endif /* _ASM_X86_STACKTRACE_H */