misra: modify deviations for empty and generated headers

This patch modifies deviations for Directive 4.10:
"Precautions shall be taken in order to prevent the contents of
a header file being included more than once"

This patch avoids the file-based deviation for empty headers, and
replaces it with a comment-based one using the format specified in
docs/misra/safe.json.

Generated headers are not generally safe against multi-inclusions,
whether a header is safe depends on the nature of the generated code
in the header. For that reason, this patch drops the deviation for
generated headers.

Signed-off-by: Simone Ballarin <simone.ballarin@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Alessandro Zucchelli <alessandro.zucchelli@bugseng.com>
Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>

automation/eclair_analysis/ECLAIR/deviations.ecl

@@ -72,13 +72,6 @@ they are not instances of commented-out code."
 -config=MC3R1.D4.3,reports+={deliberate, "any_area(any_loc(file(arm64_bitops))&&context(name(int_clear_mask16)))"}
 -doc_end
 
--doc_begin="This header file is autogenerated or empty, therefore it poses no
-risk if included more than once."
--file_tag+={empty_header, "^xen/arch/arm/efi/runtime\\.h$"}
--file_tag+={autogen_headers, "^xen/include/xen/compile\\.h$||^xen/include/generated/autoconf.h$||^xen/include/xen/hypercall-defs.h$"}
--config=MC3R1.D4.10,reports+={safe, "all_area(all_loc(file(empty_header||autogen_headers)))"}
--doc_end
-
 -doc_begin="Files that are intended to be included more than once do not need to
 conform to the directive."
 -config=MC3R1.D4.10,reports+={safe, "first_area(text(^/\\* This file is legitimately included multiple times\\. \\*/$, begin-4))"}

docs/misra/safe.json

@@ -76,6 +76,14 @@
         },
         {
             "id": "SAF-9-safe",
+            "analyser": {
+                "eclair": "MC3R1.D4.10"
+            },
+            "name": "Dir 4.10: empty headers",
+            "text": "Empty headers pose no risk if included more than once."
+        },
+        {
+            "id": "SAF-10-safe",
             "analyser": {},
             "name": "Sentinel",
             "text": "Next ID to be used"

xen/arch/arm/efi/runtime.h

@@ -1 +1,2 @@
 /* Placeholder for ARM-specific runtime include/declarations */
+/* SAF-9-safe empty header */

xen/include/Makefile

@@ -53,7 +53,7 @@ cmd_compat_h = \
     mv -f $@.new $@
 
 quiet_cmd_stub_h = GEN     $@
-cmd_stub_h = echo '/* empty */' >$@
+cmd_stub_h = echo '/* SAF-9-safe empty header */' >$@
 
 quiet_cmd_compat_i = CPP     $@
 cmd_compat_i = $(CPP) $(filter-out -Wa$(comma)% -include %/include/xen/config.h,$(XEN_CFLAGS)) $(cppflags-y) -o $@ $<