ARM: stub out read_cpuid and read_cpuid_ext for CPU_CP15=n

Traditionally for !CPU_CP15 read_cpuid and read_cpuid_ext returned the
processor id independent of the parameter passed in. This is wrong of
course but theoretically this doesn't harm because it's only called on
machines having a cp15.

Instead return 0 unconditionally which might make unused code paths be
better optimizable and so smaller and warn about unexpected usage.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Message-Id: 1359646587-1788-2-git-send-email-u.kleine-koenig@pengutronix.de

diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
index a59dcb5ab5fce4ab92f8c372248c3a482d1507dc..574269ed2232d0315f84a4fcebaa8c68f2a59a6b 100644 (file)
--- a/arch/arm/include/asm/cputype.h
+++ b/arch/arm/include/asm/cputype.h
@@ -50,6 +50,7 @@ extern unsigned int processor_id;
                    : "cc");                                            \
                __val;                                                  \
        })
+
 #define read_cpuid_ext(ext_reg)                                                \
        ({                                                              \
                unsigned int __val;                                     \
@@ -59,11 +60,24 @@ extern unsigned int processor_id;
                    : "cc");                                            \
                __val;                                                  \
        })
-#else
-#define read_cpuid(reg) (processor_id)
-#define read_cpuid_ext(reg) 0
-#endif
+
+#else /* ifdef CONFIG_CPU_CP15 */
 
+/*
+ * read_cpuid and read_cpuid_ext should only ever be called on machines that
+ * have cp15 so warn on other usages.
+ */
+#define read_cpuid(reg)                                                        \
+       ({                                                              \
+               WARN_ON_ONCE(1);                                        \
+               0;                                                      \
+       })
+
+#define read_cpuid_ext(reg) read_cpuid(reg)
+
+#endif /* ifdef CONFIG_CPU_CP15 / else */
+
+#ifdef CONFIG_CPU_CP15
 /*
  * The CPU ID never changes at run time, so we might as well tell the
  * compiler that it's constant.  Use this function to read the CPU ID
@@ -74,6 +88,15 @@ static inline unsigned int __attribute_const__ read_cpuid_id(void)
        return read_cpuid(CPUID_ID);
 }
 
+#else /* ifdef CONFIG_CPU_CP15 */
+
+static inline unsigned int __attribute_const__ read_cpuid_id(void)
+{
+       return processor_id;
+}
+
+#endif /* ifdef CONFIG_CPU_CP15 / else */
+
 static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
 {
        return read_cpuid(CPUID_CACHETYPE);