[PATCH] common/efi: deviate Rule 2.1 violation in read_file()

[Dmytro Prokopchuk1 <dmytro_prokopchuk1@xxxxxxxx>]

MISRA C Rule 2.1 states: "A project shall not contain unreachable code."

The return statements in the 'read_file()' function is unreachable due
to function 'PrintErrMesg()' which is noreturn:
    PrintErrMesg(name, ret);
    /* not reached */
    return false;

This is deviated using a SAF-xx-safe comment (specified in the file
'docs/misra/safe.json').
No functional change.

Signed-off-by: Dmytro Prokopchuk <dmytro_prokopchuk1@xxxxxxxx>
---
Previous thread:
https://patchew.org/Xen/5944d87aae330246b7dab6eebd04d5d71a7d7e8f.1755608417.git.dmytro._5Fprokopchuk1@xxxxxxxx/

Test CI pipeline:
https://gitlab.com/xen-project/people/dimaprkp4k/xen/-/pipelines/1994619131
---
 docs/misra/safe.json  | 8 ++++++++
 xen/common/efi/boot.c | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/docs/misra/safe.json b/docs/misra/safe.json
index 3584cb90c6..2b3178de2d 100644
--- a/docs/misra/safe.json
+++ b/docs/misra/safe.json
@@ -124,6 +124,14 @@
         },
         {
             "id": "SAF-15-safe",
+            "analyser": {
+                "eclair": "MC3A2.R2.1"
+            },
+            "name": "Rule 2.1: unreachable code",
+            "text": "This is a deliberate use of unreachable code. The return 
statement is retained to improve code clarity and readability by explicitly 
specifying the intended behavior for a case if PrintErrMesg() was to return."
+        },
+        {
+            "id": "SAF-16-safe",
             "analyser": {},
             "name": "Sentinel",
             "text": "Next ID to be used"
diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
index 50ff1d1bd2..860c41c8e7 100644
--- a/xen/common/efi/boot.c
+++ b/xen/common/efi/boot.c
@@ -852,7 +852,7 @@ static bool __init read_file(EFI_FILE_HANDLE dir_handle, 
CHAR16 *name,
     PrintErr(L" failed for ");
     PrintErrMesg(name, ret);
 
-    /* not reached */
+    /* SAF-15-safe deliberately unreachable code */
     return false;
 }
 
-- 
2.43.0