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authorJan Beulich <jbeulich@novell.com>2008-12-16 11:40:27 +0000
committerIngo Molnar <mingo@elte.hu>2008-12-16 18:40:32 +0100
commitb93a531e315e97ef00367099e6b5f19651936e20 (patch)
tree231e6d626fbf85dd80d7cbac49a9c9a14282f898 /lib
parent85072bd55219231b8ca5d9d3fa3492eb4fa6635f (diff)
downloadlinux-b93a531e315e97ef00367099e6b5f19651936e20.tar.gz
allow bug table entries to use relative pointers (and use it on x86-64)
Impact: reduce bug table size

This allows reducing the bug table size by half. Perhaps there are
other 64-bit architectures that could also make use of this.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'lib')
-rw-r--r--lib/bug.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/lib/bug.c b/lib/bug.c
index bfeafd60ee9f..300e41afbf97 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -5,6 +5,8 @@
 
   CONFIG_BUG - emit BUG traps.  Nothing happens without this.
   CONFIG_GENERIC_BUG - enable this code.
+  CONFIG_GENERIC_BUG_RELATIVE_POINTERS - use 32-bit pointers relative to
+	the containing struct bug_entry for bug_addr and file.
   CONFIG_DEBUG_BUGVERBOSE - emit full file+line information for each BUG
 
   CONFIG_BUG and CONFIG_DEBUG_BUGVERBOSE are potentially user-settable
@@ -43,6 +45,15 @@
 
 extern const struct bug_entry __start___bug_table[], __stop___bug_table[];
 
+static inline unsigned long bug_addr(const struct bug_entry *bug)
+{
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
+	return bug->bug_addr;
+#else
+	return (unsigned long)bug + bug->bug_addr_disp;
+#endif
+}
+
 #ifdef CONFIG_MODULES
 static LIST_HEAD(module_bug_list);
 
@@ -55,7 +66,7 @@ static const struct bug_entry *module_find_bug(unsigned long bugaddr)
 		unsigned i;
 
 		for (i = 0; i < mod->num_bugs; ++i, ++bug)
-			if (bugaddr == bug->bug_addr)
+			if (bugaddr == bug_addr(bug))
 				return bug;
 	}
 	return NULL;
@@ -108,7 +119,7 @@ const struct bug_entry *find_bug(unsigned long bugaddr)
 	const struct bug_entry *bug;
 
 	for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
-		if (bugaddr == bug->bug_addr)
+		if (bugaddr == bug_addr(bug))
 			return bug;
 
 	return module_find_bug(bugaddr);
@@ -133,7 +144,11 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 
 	if (bug) {
 #ifdef CONFIG_DEBUG_BUGVERBOSE
+#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
 		file = bug->file;
+#else
+		file = (const char *)bug + bug->file_disp;
+#endif
 		line = bug->line;
 #endif
 		warning = (bug->flags & BUGFLAG_WARNING) != 0;