[PATCH] remove all kernel BUGs

This patch eliminates all kernel BUGs, trims about 35k off the typical
kernel, and makes the system slightly faster.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

20 files changed, 82 insertions, 7 deletions

diff --git a/include/asm-alpha/bug.h b/include/asm-alpha/bug.h
index ae1e0a5fa492..39a3e2a5017d 100644
--- a/include/asm-alpha/bug.h
+++ b/include/asm-alpha/bug.h
@@ -1,6 +1,7 @@
 #ifndef _ALPHA_BUG_H
 #define _ALPHA_BUG_H
 
+#ifdef CONFIG_BUG
 #include <asm/pal.h>
 
 /* ??? Would be nice to use .gprel32 here, but we can't be sure that the
@@ -10,6 +11,8 @@
 		       : : "i" (PAL_bugchk), "i"(__LINE__), "i"(__FILE__))
 
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-arm/bug.h b/include/asm-arm/bug.h
index 5e91b90a8181..24d11672eb60 100644
--- a/include/asm-arm/bug.h
+++ b/include/asm-arm/bug.h
@@ -3,6 +3,7 @@
 
 #include <linux/config.h>
 
+#ifdef CONFIG_BUG
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 extern volatile void __bug(const char *file, int line, void *data);
 
@@ -17,6 +18,8 @@ extern volatile void __bug(const char *file, int line, void *data);
 #endif
 
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-arm26/bug.h b/include/asm-arm26/bug.h
index 920b70533368..7177c7399967 100644
--- a/include/asm-arm26/bug.h
+++ b/include/asm-arm26/bug.h
@@ -3,6 +3,7 @@
 
 #include <linux/config.h>
 
+#ifdef CONFIG_BUG
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 extern volatile void __bug(const char *file, int line, void *data);
 /* give file/line information */
@@ -12,6 +13,8 @@ extern volatile void __bug(const char *file, int line, void *data);
 #endif
 
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-frv/bug.h b/include/asm-frv/bug.h
index 011860b28818..074c0d5770eb 100644
--- a/include/asm-frv/bug.h
+++ b/include/asm-frv/bug.h
@@ -13,6 +13,7 @@
 
 #include <linux/config.h>
 
+#ifdef CONFIG_BUG
 /*
  * Tell the user there is some problem.
  */
@@ -45,6 +46,7 @@ do {						\
 #define HAVE_ARCH_KGDB_BAD_PAGE
 #define kgdb_bad_page(page) do { kgdb_raise(SIGABRT); } while(0)
 #endif
+#endif
 
 #include <asm-generic/bug.h>
 
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index e5913c3b715a..6e5aaaa9a2fb 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -4,6 +4,7 @@
 #include <linux/compiler.h>
 #include <linux/config.h>
 
+#ifdef CONFIG_BUG
 #ifndef HAVE_ARCH_BUG
 #define BUG() do { \
 	printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \
@@ -31,4 +32,22 @@
 } while (0)
 #endif
 
+#else /* !CONFIG_BUG */
+#ifndef HAVE_ARCH_BUG
+#define BUG()
+#endif
+
+#ifndef HAVE_ARCH_PAGE_BUG
+#define PAGE_BUG(page) do { if (page) ; } 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) do { if (condition) ; } while(0)
+#endif
+#endif
+
 #endif
diff --git a/include/asm-i386/bug.h b/include/asm-i386/bug.h
index 706eb511c330..8f79de19eb94 100644
--- a/include/asm-i386/bug.h
+++ b/include/asm-i386/bug.h
@@ -9,6 +9,8 @@
  * undefined" opcode for parsing in the trap handler.
  */
 
+#ifdef CONFIG_BUG
+#define HAVE_ARCH_BUG
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 #define BUG()				\
  __asm__ __volatile__(	"ud2\n"		\
@@ -18,8 +20,7 @@
 #else
 #define BUG() __asm__ __volatile__("ud2\n")
 #endif
+#endif
 
-#define HAVE_ARCH_BUG
 #include <asm-generic/bug.h>
-
 #endif
diff --git a/include/asm-ia64/bug.h b/include/asm-ia64/bug.h
index 2c0cd51e8856..3aa0a0a5474b 100644
--- a/include/asm-ia64/bug.h
+++ b/include/asm-ia64/bug.h
@@ -1,6 +1,7 @@
 #ifndef _ASM_IA64_BUG_H
 #define _ASM_IA64_BUG_H
 
+#ifdef CONFIG_BUG
 #if (__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)
 # define ia64_abort()	__builtin_trap()
 #else
@@ -8,8 +9,10 @@
 #endif
 #define BUG() do { printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); ia64_abort(); } while (0)
 
-/* should this BUG should be made generic? */
+/* should this BUG be made generic? */
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-m68k/bug.h b/include/asm-m68k/bug.h
index 3e1d2266fa69..072ce274d537 100644
--- a/include/asm-m68k/bug.h
+++ b/include/asm-m68k/bug.h
@@ -3,6 +3,7 @@
 
 #include <linux/config.h>
 
+#ifdef CONFIG_BUG
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 #ifndef CONFIG_SUN3
 #define BUG() do { \
@@ -22,6 +23,8 @@
 #endif
 
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-mips/bug.h b/include/asm-mips/bug.h
index eb94bb96cfbc..3f594b440abc 100644
--- a/include/asm-mips/bug.h
+++ b/include/asm-mips/bug.h
@@ -3,12 +3,14 @@
 
 #include <asm/break.h>
 
+#ifdef CONFIG_BUG
+#define HAVE_ARCH_BUG
 #define BUG()								\
 do {									\
 	__asm__ __volatile__("break %0" : : "i" (BRK_BUG));		\
 } while (0)
+#endif
 
-#define HAVE_ARCH_BUG
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-parisc/bug.h b/include/asm-parisc/bug.h
index e72f6e2b4b9f..695588da41f8 100644
--- a/include/asm-parisc/bug.h
+++ b/include/asm-parisc/bug.h
@@ -1,12 +1,14 @@
 #ifndef _PARISC_BUG_H
 #define _PARISC_BUG_H
 
+#ifdef CONFIG_BUG
 #define HAVE_ARCH_BUG
 #define BUG() do { \
 	printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \
 	dump_stack(); \
 	panic("BUG!"); \
 } while (0)
+#endif
 
 #include <asm-generic/bug.h>
 #endif
diff --git a/include/asm-ppc/bug.h b/include/asm-ppc/bug.h
index e99c6cb9d618..8b34fd682b0d 100644
--- a/include/asm-ppc/bug.h
+++ b/include/asm-ppc/bug.h
@@ -14,6 +14,7 @@ struct bug_entry {
  */
 #define BUG_WARNING_TRAP	0x1000000
 
+#ifdef CONFIG_BUG
 #define BUG() do {							 \
 	__asm__ __volatile__(						 \
 		"1:	twi 31,0,0\n"					 \
@@ -50,6 +51,8 @@ struct bug_entry {
 #define HAVE_ARCH_BUG
 #define HAVE_ARCH_BUG_ON
 #define HAVE_ARCH_WARN_ON
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-ppc64/bug.h b/include/asm-ppc64/bug.h
index db31dd22233c..169868fa307d 100644
--- a/include/asm-ppc64/bug.h
+++ b/include/asm-ppc64/bug.h
@@ -26,6 +26,8 @@ struct bug_entry *find_bug(unsigned long bugaddr);
  */
 #define BUG_WARNING_TRAP	0x1000000
 
+#ifdef CONFIG_BUG
+
 #define BUG() do {							 \
 	__asm__ __volatile__(						 \
 		"1:	twi 31,0,0\n"					 \
@@ -55,11 +57,12 @@ struct bug_entry *find_bug(unsigned long bugaddr);
 		    "i" (__FILE__), "i" (__FUNCTION__));	\
 } while (0)
 
-#endif
-
 #define HAVE_ARCH_BUG
 #define HAVE_ARCH_BUG_ON
 #define HAVE_ARCH_WARN_ON
+#endif
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-s390/bug.h b/include/asm-s390/bug.h
index 2b8d6d4dffcf..a2e7430aafa6 100644
--- a/include/asm-s390/bug.h
+++ b/include/asm-s390/bug.h
@@ -3,12 +3,15 @@
 
 #include <linux/kernel.h>
 
+#ifdef CONFIG_BUG
 #define BUG() do { \
         printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); \
         __asm__ __volatile__(".long 0"); \
 } while (0)
 
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-sh/bug.h b/include/asm-sh/bug.h
index 70172217140f..70508a360cd6 100644
--- a/include/asm-sh/bug.h
+++ b/include/asm-sh/bug.h
@@ -3,6 +3,7 @@
 
 #include <linux/config.h>
 
+#ifdef CONFIG_BUG
 /*
  * Tell the user there is some problem.
  */
@@ -12,6 +13,8 @@
 } while (0)
 
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-sparc/bug.h b/include/asm-sparc/bug.h
index 0d30a67d87a3..04151208189f 100644
--- a/include/asm-sparc/bug.h
+++ b/include/asm-sparc/bug.h
@@ -1,6 +1,7 @@
 #ifndef _SPARC_BUG_H
 #define _SPARC_BUG_H
 
+#ifdef CONFIG_BUG
 /* Only use the inline asm until a gcc release that can handle __builtin_trap
  * -rob 2003-06-25
  *
@@ -26,6 +27,8 @@ extern void do_BUG(const char *file, int line);
 #endif
 
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-sparc64/bug.h b/include/asm-sparc64/bug.h
index 25c5b1dfe378..516bb27f3fc4 100644
--- a/include/asm-sparc64/bug.h
+++ b/include/asm-sparc64/bug.h
@@ -1,6 +1,7 @@
 #ifndef _SPARC64_BUG_H
 #define _SPARC64_BUG_H
 
+#ifdef CONFIG_BUG
 #include <linux/compiler.h>
 
 #ifdef CONFIG_DEBUG_BUGVERBOSE
@@ -14,6 +15,8 @@ extern void do_BUG(const char *file, int line);
 #endif
 
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif
diff --git a/include/asm-v850/bug.h b/include/asm-v850/bug.h
index c778916bf7f2..b0ed2d35f3e8 100644
--- a/include/asm-v850/bug.h
+++ b/include/asm-v850/bug.h
@@ -14,9 +14,12 @@
 #ifndef __V850_BUG_H__
 #define __V850_BUG_H__
 
+#ifdef CONFIG_BUG
 extern void __bug (void) __attribute__ ((noreturn));
 #define BUG()		__bug()
 #define HAVE_ARCH_BUG
+#endif
+
 #include <asm-generic/bug.h>
 
 #endif /* __V850_BUG_H__ */
diff --git a/include/asm-x86_64/bug.h b/include/asm-x86_64/bug.h
index 19aed6e78fec..bdbf66eab6ee 100644
--- a/include/asm-x86_64/bug.h
+++ b/include/asm-x86_64/bug.h
@@ -15,11 +15,13 @@ struct bug_frame {
 	unsigned short line;
 } __attribute__((packed));
 
+#ifdef CONFIG_BUG
 #define HAVE_ARCH_BUG
 #define BUG() \
 	asm volatile("ud2 ; .quad %c1 ; .short %c0" :: \
 		     "i"(__LINE__), "i" (__stringify(__FILE__)))
 void out_of_line_bug(void);
-#include <asm-generic/bug.h>
+#endif
 
+#include <asm-generic/bug.h>
 #endif
diff --git a/init/Kconfig b/init/Kconfig
index abe2682a6ca6..42dca393b94e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -275,6 +275,16 @@ config KALLSYMS_EXTRA_PASS
 	   reported.  KALLSYMS_EXTRA_PASS is only a temporary workaround while
 	   you wait for kallsyms to be fixed.
 
+config BUG
+	bool "BUG() support" if EMBEDDED
+	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 BASE_FULL
 	default y
 	bool "Enable full-sized data structures for core" if EMBEDDED
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 426a0cf7b11c..ac23847ce0e3 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -108,6 +108,7 @@ config DEBUG_HIGHMEM
 
 config DEBUG_BUGVERBOSE
 	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
+	depends on BUG
 	depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || (X86 && !X86_64) || FRV
 	default !EMBEDDED
 	help