x86: unify BUG() & Co, reduce overhead on x86-64

Since it's only the string pointer representations that differ between
i386 and x86-64, abstract out those and make everything else shared.

While touching this code, also use
- proper instructions rather than a mixture of such and raw .byte/
  .long/.quad data emissions,
- PC-relative pointers on x86-64 to cut the amount of storage (and
  in particular cache space) needed for string references by half.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

1 files changed, 4 insertions, 27 deletions

diff --git a/xen/include/asm-x86/x86_64/bug.h b/xen/include/asm-x86/x86_64/bug.h
index 3fa5debfa7..ecae455b83 100644
--- a/xen/include/asm-x86/x86_64/bug.h
+++ b/xen/include/asm-x86/x86_64/bug.h
@@ -2,33 +2,10 @@
 #define __X86_64_BUG_H__
 
 struct bug_frame_str {
-    unsigned char mov[2];
-    unsigned long str;
+    unsigned char mov;
+    signed int str_disp;
 } __attribute__((packed));
-#define BUG_MOV_STR "\x48\xbc"
-
-#define dump_execution_state()                          \
-    asm volatile (                                      \
-        "ud2 ; ret $%c0"                                \
-        : : "i" (BUGFRAME_dump) )
-
-#define WARN()                                          \
-    asm volatile (                                      \
-        "ud2 ; ret $%c0 ; .byte 0x48,0xbc ; .quad %c1"  \
-        : : "i" (BUGFRAME_warn | (__LINE__<<2)),        \
-            "i" (__FILE__) )
-
-#define BUG()                                           \
-    asm volatile (                                      \
-        "ud2 ; ret $%c0 ; .byte 0x48,0xbc ; .quad %c1"  \
-        : : "i" (BUGFRAME_bug | (__LINE__<<2)),         \
-            "i" (__FILE__) )
-
-#define assert_failed(p)                                \
-    asm volatile (                                      \
-        "ud2 ; ret $%c0 ; .byte 0x48,0xbc ; .quad %c1"  \
-        " ; .byte 0x48,0xbc ; .quad %c2"                \
-        : : "i" (BUGFRAME_assert | (__LINE__<<2)),      \
-            "i" (__FILE__), "i" (#p) )
+#define bug_str(b, rip) ((const char *)(rip) + (b).str_disp)
+#define BUG_STR(n) "; movl %" #n " - ., %%esp"
 
 #endif /* __X86_64_BUG_H__ */