[PATCH v2] arch: configuration issue, random return value when disable 'CONFIG_BUG'

Chen Gang
2013-05-26T04:43:22Z

If user disable 'CONFIG_BUG' in menuconfig, many areas not only will
report compiling warnings, but also may return a random value from the
function when BUG().

In fact, most of architectures need always let 'CONFIG_BUG' enabled, so
'#ifdef CONFIG_BUG' is already not 'generic' enough in "include/asm-
generic/".

Also kernel has already provided the 'generic' implementation in
"include/asm-generic" when 'CONFIG_BUG' enabled. Even if we disable
'CONFIG_BUG', we also shall have to implement the BUG() in "include/asm-
generic", just like when 'CONFIG_BUG' enabled (at least, it is not the
minimal size implementation).

So need remove 'CONFIG_BUG', and let it always enabled everywhere, then
fix this issue.

The architectures which need their own architecture specific features
(e.g. minimal size implementation), can customize their own BUG() and
__WARN_TAINT() to give a better fix (e.g. use one inline asm code, then
followed by 'unreachable' function, or another more better fix ways).

Signed-off-by: Chen Gang <gang.chen@asianux.com>
---
arch/arm/Kconfig | 1 -
arch/avr32/Kconfig | 1 -
arch/blackfin/Kconfig | 1 -
arch/h8300/Kconfig | 1 -
arch/hexagon/Kconfig | 1 -
arch/parisc/Kconfig | 2 --
arch/powerpc/Kconfig | 1 -
arch/s390/Kconfig | 2 +-
arch/sh/Kconfig | 2 +-
arch/um/Kconfig.common | 1 -
arch/x86/Kconfig | 1 -
include/asm-generic/bug.h | 29 -----------------------------
init/Kconfig | 10 ----------
lib/Kconfig.debug | 2 +-
14 files changed, 3 insertions(+), 52 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a7fc5ea..ea4a146 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -265,7 +265,6 @@ config PHYS_OFFSET

config GENERIC_BUG
def_bool y
- depends on BUG

source "init/Kconfig"

diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index bdc3558..7c9005a 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -55,7 +55,6 @@ config GENERIC_CALIBRATE_DELAY

config GENERIC_BUG
def_bool y
- depends on BUG

source "init/Kconfig"

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index a117652..637dc42 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -47,7 +47,6 @@ config GENERIC_CSUM

config GENERIC_BUG
def_bool y
- depends on BUG

config ZONE_DMA
def_bool y
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index 303e4f9..88848da 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -56,7 +56,6 @@ config GENERIC_CALIBRATE_DELAY

config GENERIC_BUG
bool
- depends on BUG

config TIME_LOW_RES
bool
diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
index 33a9792..f50cc8f 100644
--- a/arch/hexagon/Kconfig
+++ b/arch/hexagon/Kconfig
@@ -84,7 +84,6 @@ config STACKTRACE_SUPPORT

config GENERIC_BUG
def_bool y
- depends on BUG

menu "Machine selection"

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 6507dab..5de1f8c 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -10,7 +10,6 @@ config PARISC
select RTC_CLASS
select RTC_DRV_GENERIC
select INIT_ALL_POSSIBLE
- select BUG
select HAVE_PERF_EVENTS
select GENERIC_ATOMIC64 if !64BIT
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
@@ -62,7 +61,6 @@ config ARCH_HAS_ILOG2_U64
config GENERIC_BUG
bool
default y
- depends on BUG

config GENERIC_HWEIGHT
bool
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c33e3ad..34f4ca9 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -187,7 +187,6 @@ config AUDIT_ARCH
config GENERIC_BUG
bool
default y
- depends on BUG

config SYS_SUPPORTS_APM_EMULATION
default y if PMAC_APM_EMU
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index da183c5..5d7b3db 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -29,7 +29,7 @@ config GENERIC_HWEIGHT
def_bool y

config GENERIC_BUG
- def_bool y if BUG
+ def_bool y

config GENERIC_BUG_RELATIVE_POINTERS
def_bool y
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 8c868cf..d555e7f 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -84,7 +84,7 @@ config RWSEM_XCHGADD_ALGORITHM

config GENERIC_BUG
def_bool y
- depends on BUG && SUPERH32
+ depends on SUPERH32

config GENERIC_CSUM
def_bool y
diff --git a/arch/um/Kconfig.common b/arch/um/Kconfig.common
index bceee66..7aae42a 100644
--- a/arch/um/Kconfig.common
+++ b/arch/um/Kconfig.common
@@ -53,7 +53,6 @@ config GENERIC_CALIBRATE_DELAY
config GENERIC_BUG
bool
default y
- depends on BUG

config HZ
int
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 723e42e..a36e1b4 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -166,7 +166,6 @@ config GENERIC_ISA_DMA

config GENERIC_BUG
def_bool y
- depends on BUG
select GENERIC_BUG_RELATIVE_POINTERS if X86_64

config GENERIC_BUG_RELATIVE_POINTERS
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 7d10f96..5d50903 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -12,8 +12,6 @@
#ifndef __ASSEMBLY__
#include <linux/kernel.h>

-#ifdef CONFIG_BUG
-
#ifdef CONFIG_GENERIC_BUG
struct bug_entry {
#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
@@ -106,33 +104,6 @@ extern void warn_slowpath_null(const char *file, const int line);
unlikely(__ret_warn_on); \
})

-#else /* !CONFIG_BUG */
-#ifndef HAVE_ARCH_BUG
-#define BUG() do {} while(0)
-#endif
-
-#ifndef HAVE_ARCH_BUG_ON
-#define BUG_ON(condition) do { if (condition) ; } while(0)
-#endif
-
-#ifndef HAVE_ARCH_WARN_ON
-#define WARN_ON(condition) ({ \
- int __ret_warn_on = !!(condition); \
- unlikely(__ret_warn_on); \
-})
-#endif
-
-#ifndef WARN
-#define WARN(condition, format...) ({ \
- int __ret_warn_on = !!(condition); \
- unlikely(__ret_warn_on); \
-})
-#endif
-
-#define WARN_TAINT(condition, taint, format...) WARN_ON(condition)
-
-#endif
-
#define WARN_ON_ONCE(condition) ({ \
static bool __section(.data.unlikely) __warned; \
int __ret_warn_once = !!(condition); \
diff --git a/init/Kconfig b/init/Kconfig
index 7fb26a6..bc1dd49 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1360,16 +1360,6 @@ config PRINTK
very difficult to diagnose system problems, saying N here is
strongly discouraged.

-config BUG
- bool "BUG() support" if EXPERT
- default y
- help
- Disabling this option eliminates support for BUG and WARN, reducing
- the size of your kernel image and potentially quietly ignoring
- numerous fatal conditions. You should only consider disabling this
- option for embedded systems with no facilities for reporting errors.
- Just say Y.
-
config ELF_CORE
depends on COREDUMP
default y
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 566cf2b..54b3251 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -700,7 +700,7 @@ config HAVE_DEBUG_BUGVERBOSE

config DEBUG_BUGVERBOSE
bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
- depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
+ depends on GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE
default y
help
Say Y here to make BUG() panics output the file name and line number
--
1.7.7.6