x86/gen-cpuid: Avoid violations of Misra rule 1.3

Add the script to the X86 section in ./MAINTAINERS.

Structures or unions without any named members aren't liked by Misra
(nor the C standard). Avoid emitting such for leaves without any known
bits.

The placeholders are affected similarly, but are only visible to MISRA in the
middle of a patch series adding a new leaf.  The absence of a name was
intentional as these defines need to not duplicate names.

As that's not deemed acceptable any more, move placeholder processing into the
main loop and append the the word number to generate unique names.

  $ diff cpuid-autogen-{before,after}.h
  @@ -1034,7 +1034,7 @@
       bool intel_psfd:1, ipred_ctrl:1, rrsba_ctrl:1, ddp_ctrl:1,     ...

   #define CPUID_BITFIELD_14 \
  -    bool :1, :1, :1, :1, :1, :1, :1, :1, :1, :1, :1, :1, :1, :1,   ...
  +    uint32_t _placeholder_14

   #define CPUID_BITFIELD_15 \
       bool :1, :1, :1, :1, avx_vnni_int8:1, avx_ne_convert:1, :1,    ...
  @@ -1043,19 +1043,19 @@
       bool rdcl_no:1, eibrs:1, rsba:1, skip_l1dfl:1, intel_ssb_no:1, ...

   #define CPUID_BITFIELD_17 \
  -    bool :1, :1, :1, :1, :1, :1, :1, :1, :1, :1, :1, :1, :1, :1,   ...
  +    uint32_t _placeholder_17

   #define CPUID_BITFIELD_18 \
  -    uint32_t :32 /* placeholder */
  +    uint32_t _placeholder_18

   #define CPUID_BITFIELD_19 \
  -    uint32_t :32 /* placeholder */
  +    uint32_t _placeholder_19

   #define CPUID_BITFIELD_20 \
  -    uint32_t :32 /* placeholder */
  +    uint32_t _placeholder_20

   #define CPUID_BITFIELD_21 \
  -    uint32_t :32 /* placeholder */
  +    uint32_t _placeholder_21

   #endif /* __XEN_X86__FEATURESET_DATA__ */

No functional change.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

MAINTAINERS

@@ -601,6 +601,7 @@ F:	xen/arch/x86/
 F:	xen/include/public/arch-x86/
 F:	xen/include/xen/lib/x86
 F:	xen/lib/x86
+F:	xen/tools/gen-cpuid.py
 F:	tools/firmware/hvmloader/
 F:	tools/firmware/rombios/
 F:	tools/firmware/vgabios/

xen/tools/gen-cpuid.py

@@ -363,8 +363,8 @@ def crunch_numbers(state):
     state.deep_features = deps.keys()
     state.nr_deep_deps = len(state.deep_deps.keys())
 
-    # Calculate the bitfield name declarations
-    for word in range(state.nr_entries):
+    # Calculate the bitfield name declarations.  Leave 4 placeholders on the end
+    for word in range(state.nr_entries + 4):
 
         names = []
         for bit in range(32):
@@ -382,7 +382,10 @@ def crunch_numbers(state):
 
             names.append(name.lower())
 
-        state.bitfields.append("bool " + ":1, ".join(names) + ":1")
+        if any(names):
+            state.bitfields.append("bool " + ":1, ".join(names) + ":1")
+        else:
+            state.bitfields.append("uint32_t _placeholder_%u" % (word, ))
 
 
 def write_results(state):
@@ -464,8 +467,6 @@ def write_results(state):
 
 """)
 
-    state.bitfields += ["uint32_t :32 /* placeholder */"] * 4
-
     for idx, text in enumerate(state.bitfields):
         state.output.write(
             "#define CPUID_BITFIELD_%d \\\n    %s\n\n"