[PATCH 02/17] misra: modify deviations for empty and generated headers

[Alessandro Zucchelli <alessandro.zucchelli@xxxxxxxxxxx>]

From: Simone Ballarin <simone.ballarin@xxxxxxxxxxx>

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@xxxxxxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
Signed-off-by: Alessandro Zucchelli <alessandro.zucchelli@xxxxxxxxxxx>

---
Changes in v4:
- rebased against current staging tree

Changes in v2:
- use the format introduced with doc/misra/safe.json instead of
  a file-based deviation for empty headers
- remove deviation for generated headers

The reason of moving the comment-based deviation in "runtime.h" is that
it should appear immediatly before the violation and, for files with no
tokens, the location is the the last line of the file.
---
 automation/eclair_analysis/ECLAIR/deviations.ecl | 7 -------
 docs/misra/safe.json                             | 8 ++++++++
 xen/arch/arm/efi/runtime.h                       | 1 +
 xen/include/Makefile                             | 2 +-
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/automation/eclair_analysis/ECLAIR/deviations.ecl 
b/automation/eclair_analysis/ECLAIR/deviations.ecl
index 0af1cb93d1..1c39a9a16d 100644
--- a/automation/eclair_analysis/ECLAIR/deviations.ecl
+++ b/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))"}
diff --git a/docs/misra/safe.json b/docs/misra/safe.json
index b865caac73..282013aa4e 100644
--- a/docs/misra/safe.json
+++ b/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"
diff --git a/xen/arch/arm/efi/runtime.h b/xen/arch/arm/efi/runtime.h
index 25afcebed1..4d2d40bf3c 100644
--- a/xen/arch/arm/efi/runtime.h
+++ b/xen/arch/arm/efi/runtime.h
@@ -1 +1,2 @@
 /* Placeholder for ARM-specific runtime include/declarations */
+/* SAF-9-safe empty header */
diff --git a/xen/include/Makefile b/xen/include/Makefile
index 2e61b50139..058b0a566b 100644
--- a/xen/include/Makefile
+++ b/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 $@ $<
-- 
2.34.1