[Xen-devel] [PATCH 13/34] xen/arm: gic: Introduce GIC_SGI_MAX

[Julien Grall <julien.grall@xxxxxxxxxx>]

All the functions that send an SGI takes an enum. Therefore checking everytime
if the value is in the range is not correct.

Introduce GIC_SGI_MAX to check the enum will never reach more than 16 values.

This is fix the compilation with Clang 3.5:

gic.c:515:15: error: comparison of constant 16 with expression of type 'enum 
gic_sgi' is always true [-Werror,-Wtautological-constant-out-of-range-compare]
   ASSERT(sgi < 16); /* There are only 16 SGIs */
          ~~~ ^ ~~
xen/xen/include/xen/lib.h:43:26: note: expanded from macro 'ASSERT'
    do { if ( unlikely(!(p)) ) assert_failed(#p); } while (0)
                         ^
xen/xen/include/xen/compiler.h:11:41: note: expanded from macro 'unlikely'
 #define unlikely(x)   __builtin_expect((x),0)

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
---
 xen/arch/arm/gic.c        |    7 ++++---
 xen/include/asm-arm/gic.h |    2 ++
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 0095b97..41142a5 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -481,7 +481,8 @@ void send_SGI_mask(const cpumask_t *cpumask, enum gic_sgi 
sgi)
     unsigned int mask = 0;
     cpumask_t online_mask;
 
-    ASSERT(sgi < 16); /* There are only 16 SGIs */
+    BUILD_BUG_ON(GIC_SGI_MAX >= 16);
+    ASSERT(sgi != GIC_SGI_MAX);
 
     cpumask_and(&online_mask, cpumask, &cpu_online_map);
     mask = gic_cpu_mask(&online_mask);
@@ -501,7 +502,7 @@ void send_SGI_one(unsigned int cpu, enum gic_sgi sgi)
 
 void send_SGI_self(enum gic_sgi sgi)
 {
-    ASSERT(sgi < 16); /* There are only 16 SGIs */
+    ASSERT(sgi != GIC_SGI_MAX);
 
     dsb(sy);
 
@@ -511,7 +512,7 @@ void send_SGI_self(enum gic_sgi sgi)
 
 void send_SGI_allbutself(enum gic_sgi sgi)
 {
-   ASSERT(sgi < 16); /* There are only 16 SGIs */
+   ASSERT(sgi != GIC_SGI_MAX);
 
    dsb(sy);
 
diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
index 071280b..968125d 100644
--- a/xen/include/asm-arm/gic.h
+++ b/xen/include/asm-arm/gic.h
@@ -205,6 +205,8 @@ enum gic_sgi {
     GIC_SGI_EVENT_CHECK = 0,
     GIC_SGI_DUMP_STATE  = 1,
     GIC_SGI_CALL_FUNCTION = 2,
+    /* GIC_SGI_MAX must be the last type of the enum */
+    GIC_SGI_MAX,
 };
 extern void send_SGI_mask(const cpumask_t *cpumask, enum gic_sgi sgi);
 extern void send_SGI_one(unsigned int cpu, enum gic_sgi sgi);
-- 
1.7.10.4


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