[PATCH] Generic BUG for i386

This makes i386 use the generic BUG machinery.  There are no functional
changes from the old i386 implementation.

The main advantage in using the generic BUG machinery for i386 is that the
inlined overhead of BUG is just the ud2a instruction; the file+line(+function)
information are no longer inlined into the instruction stream.  This reduces
cache pollution, and makes disassembly work properly.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index ea70359b02d09660147fb5066684452c6f9c1698..c2362c7ba74926580b9614eb19a69252ac504a82 100644 (file)
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -49,6 +49,11 @@ config GENERIC_IOMAP
        bool
        default y
 
+config GENERIC_BUG
+       bool
+       default y
+       depends on BUG
+
 config GENERIC_HWEIGHT
        bool
        default y

diff --git a/arch/i386/kernel/module.c b/arch/i386/kernel/module.c
index d7d9c8b23f72782f7798340678a41536b7dd64e6..3db0a5442eb1bab48d9bbdfa93a0a9ccd5b74fa0 100644 (file)
--- a/arch/i386/kernel/module.c
+++ b/arch/i386/kernel/module.c
@@ -21,6 +21,7 @@
 #include <linux/fs.h>
 #include <linux/string.h>
 #include <linux/kernel.h>
+#include <linux/bug.h>
 
 #if 0
 #define DEBUGP printk
@@ -141,10 +142,11 @@ int module_finalize(const Elf_Ehdr *hdr,
                apply_paravirt(pseg, pseg + para->sh_size);
        }
 
-       return 0;
+       return module_bug_finalize(hdr, sechdrs, me);
 }
 
 void module_arch_cleanup(struct module *mod)
 {
        alternatives_smp_module_del(mod);
+       module_bug_cleanup(mod);
 }

diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 68de48e498ca910804e6d71bf2f61bc01caed126..2b30dbf8d1170167283d57a7cbe3b0099231c788 100644 (file)
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -30,6 +30,7 @@
 #include <linux/unwind.h>
 #include <linux/uaccess.h>
 #include <linux/nmi.h>
+#include <linux/bug.h>
 
 #ifdef CONFIG_EISA
 #include <linux/ioport.h>
@@ -420,43 +421,22 @@ void show_registers(struct pt_regs *regs)
        printk("\n");
 }      
 
-static void handle_BUG(struct pt_regs *regs)
+int is_valid_bugaddr(unsigned long eip)
 {
-       unsigned long eip = regs->eip;
        unsigned short ud2;
 
        if (eip < PAGE_OFFSET)
-               return;
+               return 0;
        if (probe_kernel_address((unsigned short *)eip, ud2))
-               return;
-       if (ud2 != 0x0b0f)
-               return;
-
-       printk(KERN_EMERG "------------[ cut here ]------------\n");
-
-#ifdef CONFIG_DEBUG_BUGVERBOSE
-       do {
-               unsigned short line;
-               char *file;
-               char c;
-
-               if (probe_kernel_address((unsigned short *)(eip + 2), line))
-                       break;
-               if (probe_kernel_address((char **)(eip + 4), file) ||
-                   (unsigned long)file < PAGE_OFFSET ||
-                       probe_kernel_address(file, c))
-                       file = "<bad filename>";
+               return 0;
 
-               printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
-               return;
-       } while (0);
-#endif
-       printk(KERN_EMERG "Kernel BUG at [verbose debug info unavailable]\n");
+       return ud2 == 0x0b0f;
 }
 
-/* This is gone through when something in the kernel
- * has done something bad and is about to be terminated.
-*/
+/*
+ * This is gone through when something in the kernel has done something bad and
+ * is about to be terminated.
+ */
 void die(const char * str, struct pt_regs * regs, long err)
 {
        static struct {
@@ -488,7 +468,8 @@ void die(const char * str, struct pt_regs * regs, long err)
                unsigned long esp;
                unsigned short ss;
 
-               handle_BUG(regs);
+               report_bug(regs->eip);
+
                printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
 #ifdef CONFIG_PREEMPT
                printk(KERN_EMERG "PREEMPT ");

diff --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S
index 56e6ad5cb04556380ddbe2a0e386c4c34db03761..16d3c7133ad79364a9c1a805a84e3fa9abf20ade 100644 (file)
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -57,6 +57,8 @@ SECTIONS
 
   RODATA
 
+  BUG_TABLE
+
   . = ALIGN(4);
   .tracedata : AT(ADDR(.tracedata) - LOAD_OFFSET) {
        __tracedata_start = .;

diff --git a/include/asm-i386/bug.h b/include/asm-i386/bug.h
index 8062cdbf2587f9213a2f0e35c8b536fc92572dec..b0fd78ca2619908a84d0eca0fcfb7d81b6e3f377 100644 (file)
--- a/include/asm-i386/bug.h
+++ b/include/asm-i386/bug.h
@@ -4,20 +4,32 @@
 
 /*
  * Tell the user there is some problem.
- * The offending file and line are encoded after the "officially
- * undefined" opcode for parsing in the trap handler.
+ * The offending file and line are encoded encoded in the __bug_table section.
  */
 
 #ifdef CONFIG_BUG
 #define HAVE_ARCH_BUG
+
 #ifdef CONFIG_DEBUG_BUGVERBOSE
-#define BUG()                          \
- __asm__ __volatile__( "ud2\n"         \
-                       "\t.word %c0\n" \
-                       "\t.long %c1\n" \
-                        : : "i" (__LINE__), "i" (__FILE__))
+#define BUG()                                                          \
+       do {                                                            \
+               asm volatile("1:\tud2\n"                                \
+                            ".pushsection __bug_table,\"a\"\n"         \
+                            "2:\t.long 1b, %c0\n"                      \
+                            "\t.word %c1, 0\n"                         \
+                            "\t.org 2b+%c2\n"                          \
+                            ".popsection"                              \
+                            : : "i" (__FILE__), "i" (__LINE__),        \
+                            "i" (sizeof(struct bug_entry)));           \
+               for(;;) ;                                               \
+       } while(0)
+
 #else
-#define BUG() __asm__ __volatile__("ud2\n")
+#define BUG()                                                          \
+       do {                                                            \
+               asm volatile("ud2");                                    \
+               for(;;) ;                                               \
+       } while(0)
 #endif
 #endif
 

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ee46fb335d243b33e99f9d3dbd8a5e8ba5476eb3..2c133c098607668b7887ae8ecbce814a4f204a16 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -285,7 +285,7 @@ config DEBUG_HIGHMEM
 config DEBUG_BUGVERBOSE
        bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
        depends on BUG
-       depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV || SUPERH || GENERIC_BUG
+       depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG
        default !EMBEDDED
        help
          Say Y here to make BUG() panics output the file name and line number