[Xen-changelog] [xen master] x86: avoid overriding initialisers in arrays

[patchbot@xxxxxxx]

commit dab76ffdfa29ac3e50d908649638decb32c14483
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Thu Feb 11 16:44:01 2016 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Feb 11 16:44:01 2016 +0100

    x86: avoid overriding initialisers in arrays
    
    Clang objects to having multiple initialisers when creating an array.
    
    As this warning is useful for spotting obscure bugs, disabling it is
    unhelpful.  Instead, fix our two deliberate usecases.
    
    In the p2m-ept case, pull the array out into a helper function, so the 
helper
    can guarentee to cover the NULL pointer case.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: George Dunlap <george.dunlap@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/cpu/mtrr/generic.c |  3 +--
 xen/arch/x86/mm/p2m-ept.c       | 27 ++++++++++++++++-----------
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/xen/arch/x86/cpu/mtrr/generic.c b/xen/arch/x86/cpu/mtrr/generic.c
index ea0efe2..8839f8d 100644
--- a/xen/arch/x86/cpu/mtrr/generic.c
+++ b/xen/arch/x86/cpu/mtrr/generic.c
@@ -91,7 +91,6 @@ static const char *__init mtrr_attrib_to_str(mtrr_type x)
 {
        static const char __initconst strings[MTRR_NUM_TYPES][16] =
        {
-               [0 ... MTRR_NUM_TYPES - 1] = "?",
                [MTRR_TYPE_UNCACHABLE]     = "uncachable",
                [MTRR_TYPE_WRCOMB]         = "write-combining",
                [MTRR_TYPE_WRTHROUGH]      = "write-through",
@@ -99,7 +98,7 @@ static const char *__init mtrr_attrib_to_str(mtrr_type x)
                [MTRR_TYPE_WRBACK]         = "write-back",
        };
 
-       return x < MTRR_NUM_TYPES ? strings[x] : "?";
+       return x < MTRR_NUM_TYPES ? (strings[x] ?: "?") : "?";
 }
 
 static unsigned int __initdata last_fixed_start;
diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index c094320..c5fe906 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -1201,6 +1201,20 @@ void ept_p2m_uninit(struct p2m_domain *p2m)
     free_cpumask_var(ept->invalidate);
 }
 
+static const char *memory_type_to_str(unsigned int x)
+{
+    static const char memory_types[8][2] = {
+        [MTRR_TYPE_UNCACHABLE]     = "UC",
+        [MTRR_TYPE_WRCOMB]         = "WC",
+        [MTRR_TYPE_WRTHROUGH]      = "WT",
+        [MTRR_TYPE_WRPROT]         = "WP",
+        [MTRR_TYPE_WRBACK]         = "WB",
+        [MTRR_NUM_TYPES]           = "??"
+    };
+
+    return x < ARRAY_SIZE(memory_types) ? (memory_types[x] ?: "?") : "?";
+}
+
 static void ept_dump_p2m_table(unsigned char key)
 {
     struct domain *d;
@@ -1212,15 +1226,6 @@ static void ept_dump_p2m_table(unsigned char key)
     unsigned long record_counter = 0;
     struct p2m_domain *p2m;
     struct ept_data *ept;
-    static const char memory_types[8][2] = {
-        [0 ... 7] = "?",
-        [MTRR_TYPE_UNCACHABLE]     = "UC",
-        [MTRR_TYPE_WRCOMB]         = "WC",
-        [MTRR_TYPE_WRTHROUGH]      = "WT",
-        [MTRR_TYPE_WRPROT]         = "WP",
-        [MTRR_TYPE_WRBACK]         = "WB",
-        [MTRR_NUM_TYPES]           = "??"
-    };
 
     for_each_domain(d)
     {
@@ -1260,8 +1265,8 @@ static void ept_dump_p2m_table(unsigned char key)
                            ept_entry->r ? 'r' : ' ',
                            ept_entry->w ? 'w' : ' ',
                            ept_entry->x ? 'x' : ' ',
-                           memory_types[ept_entry->emt][0],
-                           memory_types[ept_entry->emt][1]
+                           memory_type_to_str(ept_entry->emt)[0],
+                           memory_type_to_str(ept_entry->emt)[1]
                            ?: ept_entry->emt + '0',
                            c ?: ept_entry->ipat ? '!' : ' ');
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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