Commit 608e2619 authored by Heiko Carstens's avatar Heiko Carstens Committed by Linus Torvalds

generic bug: use show_regs() instead of dump_stack()

The current generic bug implementation has a call to dump_stack() in case a
WARN_ON(whatever) gets hit.  Since report_bug(), which calls dump_stack(),
gets called from an exception handler we can do better: just pass the
pt_regs structure to report_bug() and pass it to show_regs() in case of a
warning.  This will give more debug informations like register contents,
etc...  In addition this avoids some pointless lines that dump_stack()
emits, since it includes a stack backtrace of the exception handler which
is of no interest in case of a warning.  E.g.  on s390 the following lines
are currently always present in a stack backtrace if dump_stack() gets
called from report_bug():

 [<000000000001517a>] show_trace+0x92/0xe8)
 [<0000000000015270>] show_stack+0xa0/0xd0
 [<00000000000152ce>] dump_stack+0x2e/0x3c
 [<0000000000195450>] report_bug+0x98/0xf8
 [<0000000000016cc8>] illegal_op+0x1fc/0x21c
 [<00000000000227d6>] sysc_return+0x0/0x10
Acked-by: default avatarJeremy Fitzhardinge <jeremy@goop.org>
Acked-by: default avatarHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 94bed2a9
......@@ -184,7 +184,7 @@ asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) {
enum bug_trap_type type;
type = report_bug(regs->pc);
type = report_bug(regs->pc, regs);
switch (type) {
case BUG_TRAP_TYPE_NONE:
break;
......
......@@ -390,7 +390,7 @@ void die(const char * str, struct pt_regs * regs, long err)
unsigned long esp;
unsigned short ss;
report_bug(regs->eip);
report_bug(regs->eip, regs);
printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
#ifdef CONFIG_PREEMPT
......
......@@ -302,7 +302,7 @@ static void handle_break(struct pt_regs *regs)
if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) {
/* check if a BUG() or WARN() trapped here. */
enum bug_trap_type tt;
tt = report_bug(regs->iaoq[0] & ~3);
tt = report_bug(regs->iaoq[0] & ~3, regs);
if (tt == BUG_TRAP_TYPE_WARN) {
regs->iaoq[0] += 4;
regs->iaoq[1] += 4;
......
......@@ -777,7 +777,7 @@ void __kprobes program_check_exception(struct pt_regs *regs)
return;
if (!(regs->msr & MSR_PR) && /* not user-mode */
report_bug(regs->nip) == BUG_TRAP_TYPE_WARN) {
report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
regs->nip += 4;
return;
}
......
......@@ -619,7 +619,7 @@ void program_check_exception(struct pt_regs *regs)
return;
if (!(regs->msr & MSR_PR) && /* not user-mode */
report_bug(regs->nip) == BUG_TRAP_TYPE_WARN) {
report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
regs->nip += 4;
return;
}
......
......@@ -319,7 +319,7 @@ static void __kprobes inline do_trap(long interruption_code, int signr,
else {
enum bug_trap_type btt;
btt = report_bug(regs->psw.addr & PSW_ADDR_INSN);
btt = report_bug(regs->psw.addr & PSW_ADDR_INSN, regs);
if (btt == BUG_TRAP_TYPE_WARN)
return;
die(str, regs, interruption_code);
......
......@@ -874,7 +874,7 @@ void __init trap_init(void)
void handle_BUG(struct pt_regs *regs)
{
enum bug_trap_type tt;
tt = report_bug(regs->pc);
tt = report_bug(regs->pc, regs);
if (tt == BUG_TRAP_TYPE_WARN) {
regs->pc += 2;
return;
......
......@@ -531,7 +531,7 @@ void die(const char * str, struct pt_regs * regs, long err)
unsigned long flags = oops_begin();
if (!user_mode(regs))
report_bug(regs->rip);
report_bug(regs->rip, regs);
__die(str, regs, err);
oops_end(flags);
......
......@@ -10,6 +10,8 @@ enum bug_trap_type {
BUG_TRAP_TYPE_BUG = 2,
};
struct pt_regs;
#ifdef CONFIG_GENERIC_BUG
#include <asm-generic/bug.h>
......@@ -20,7 +22,7 @@ static inline int is_warning_bug(const struct bug_entry *bug)
const struct bug_entry *find_bug(unsigned long bugaddr);
enum bug_trap_type report_bug(unsigned long bug_addr);
enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
int module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *,
struct module *);
......@@ -31,7 +33,8 @@ int is_valid_bugaddr(unsigned long addr);
#else /* !CONFIG_GENERIC_BUG */
static inline enum bug_trap_type report_bug(unsigned long bug_addr)
static inline enum bug_trap_type report_bug(unsigned long bug_addr,
struct pt_regs *regs)
{
return BUG_TRAP_TYPE_BUG;
}
......
......@@ -38,6 +38,7 @@
#include <linux/list.h>
#include <linux/module.h>
#include <linux/bug.h>
#include <linux/sched.h>
extern const struct bug_entry __start___bug_table[], __stop___bug_table[];
......@@ -112,7 +113,7 @@ const struct bug_entry *find_bug(unsigned long bugaddr)
return module_find_bug(bugaddr);
}
enum bug_trap_type report_bug(unsigned long bugaddr)
enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
{
const struct bug_entry *bug;
const char *file;
......@@ -147,7 +148,7 @@ enum bug_trap_type report_bug(unsigned long bugaddr)
"[verbose debug info unavailable]\n",
(void *)bugaddr);
dump_stack();
show_regs(regs);
return BUG_TRAP_TYPE_WARN;
}
......
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