[xen staging] xen/x86: resolve the last 3 MISRA R16.6 violations

[patchbot@xxxxxxx]

commit 37d6d8daba4698b2254629022ed0884fca49b4e1
Author:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
AuthorDate: Thu Feb 20 13:32:46 2025 -0800
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
CommitDate: Thu Feb 20 13:32:46 2025 -0800

    xen/x86: resolve the last 3 MISRA R16.6 violations
    
    MISRA R16.6 states that "Every switch statement shall have at least two
    switch-clauses". There are only 3 violations left on x86 (zero on ARM).
    
    One of them is only a violation depending on the kconfig configuration.
    So deviate it instead with a SAF comment.
    
    Two of them are deliberate to enable future additions. Deviate them as
    such.
    
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
    Reviewed-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 docs/misra/safe.json   | 16 ++++++++++++++++
 xen/arch/x86/hvm/hvm.c |  2 ++
 xen/arch/x86/traps.c   |  1 +
 3 files changed, 19 insertions(+)

diff --git a/docs/misra/safe.json b/docs/misra/safe.json
index b8a4f878ea..3d68b59169 100644
--- a/docs/misra/safe.json
+++ b/docs/misra/safe.json
@@ -92,6 +92,22 @@
         },
         {
             "id": "SAF-11-safe",
+            "analyser": {
+                "eclair": "MC3A2.R16.6"
+            },
+            "name": "Rule 16.6: single clause due to kconfig",
+            "text": "A switch statement with a single switch clause because 
other switch clauses are disabled in a given kconfig is safe."
+        },
+        {
+            "id": "SAF-12-safe",
+            "analyser": {
+                "eclair": "MC3A2.R16.6"
+            },
+            "name": "Rule 16.6: single clause due to future expansion",
+            "text": "A switch statement with a single switch clause to 
purposely enable future additions of new cases is safe."
+        },
+        {
+            "id": "SAF-13-safe",
             "analyser": {},
             "name": "Sentinel",
             "text": "Next ID to be used"
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 39e39ce4ce..0f0630769b 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3797,6 +3797,7 @@ uint64_t hvm_get_reg(struct vcpu *v, unsigned int reg)
 {
     ASSERT(v == current || !vcpu_runnable(v));
 
+    /* SAF-12-safe */
     switch ( reg )
     {
     default:
@@ -3808,6 +3809,7 @@ void hvm_set_reg(struct vcpu *v, unsigned int reg, 
uint64_t val)
 {
     ASSERT(v == current || !vcpu_runnable(v));
 
+    /* SAF-12-safe */
     switch ( reg )
     {
     default:
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 87b30ce4df..dca11a613d 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -436,6 +436,7 @@ unsigned long get_stack_trace_bottom(unsigned long sp)
 
 static unsigned long get_shstk_bottom(unsigned long sp)
 {
+    /* SAF-11-safe */
     switch ( get_stack_page(sp) )
     {
 #ifdef CONFIG_XEN_SHSTK
--
generated by git-patchbot for /home/xen/git/xen.git#staging