x86/arm: Add BUGFRAME_NR define and BUILD checks.

So that we have a nice mechansim to figure out the upper
bounds of bug.frames and also catch compiler errors in case
one tries to use a higher frame number.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <julien.grall@arm.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
Cc: Stefano Stabellini <stefano.stabellini@citrix.com>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v3: First time included.
v4: Add BUG_FRAME check also in the assembler version of the macro.
v5: Add Acks, make BUILD_BUG_ON checks look correct. Position the
    BUGFRAME_NR properly. Reposition the BUGFRAME_NR again.
---

diff --git a/xen/include/asm-arm/bug.h b/xen/include/asm-arm/bug.h
index ab9e811ab807fac5af3570a46cbe22a98f409656..68353e1748b98703cad590411c179a2a83581e91 100644 (file)
--- a/xen/include/asm-arm/bug.h
+++ b/xen/include/asm-arm/bug.h
@@ -32,6 +32,8 @@ struct bug_frame {
 #define BUGFRAME_bug    1
 #define BUGFRAME_assert 2
 
+#define BUGFRAME_NR     3
+
 /* Many versions of GCC doesn't support the asm %c parameter which would
  * be preferable to this unpleasantness. We use mergeable string
  * sections to avoid multiple copies of the string appearing in the
@@ -39,6 +41,7 @@ struct bug_frame {
  */
 #define BUG_FRAME(type, line, file, has_msg, msg) do {                      \
     BUILD_BUG_ON((line) >> 16);                                             \
+    BUILD_BUG_ON((type) >= BUGFRAME_NR);                                    \
     asm ("1:"BUG_INSTR"\n"                                                  \
          ".pushsection .rodata.str, \"aMS\", %progbits, 1\n"                \
          "2:\t.asciz " __stringify(file) "\n"                               \

diff --git a/xen/include/asm-x86/bug.h b/xen/include/asm-x86/bug.h
index e868e8533008f53c2ab192580277f943fdbecb3f..c5d2d4c8325f847f01cb86d3ac58f1e371accd88 100644 (file)
--- a/xen/include/asm-x86/bug.h
+++ b/xen/include/asm-x86/bug.h
@@ -10,6 +10,8 @@
 #define BUGFRAME_bug    2
 #define BUGFRAME_assert 3
 
+#define BUGFRAME_NR     4
+
 #ifndef __ASSEMBLY__
 
 struct bug_frame {
@@ -51,6 +53,7 @@ struct bug_frame {
 
 #define BUG_FRAME(type, line, ptr, second_frame, msg) do {                   \
     BUILD_BUG_ON((line) >> (BUG_LINE_LO_WIDTH + BUG_LINE_HI_WIDTH));         \
+    BUILD_BUG_ON((type) >= BUGFRAME_NR);                                     \
     asm volatile ( _ASM_BUGFRAME_TEXT(second_frame)                          \
                    :: _ASM_BUGFRAME_INFO(type, line, ptr, msg) );            \
 } while (0)
@@ -83,6 +86,11 @@ extern const struct bug_frame __start_bug_frames[],
  * in .rodata
  */
     .macro BUG_FRAME type, line, file_str, second_frame, msg
+
+    .if \type >= BUGFRAME_NR
+        .error "Invalid BUGFRAME index"
+    .endif
+
     .L\@ud: ud2a
 
     .pushsection .rodata.str1, "aMS", @progbits, 1