s390/Kconfig: sort config S390 select list once again

[linux-2.6-microblaze.git] / include / linux / compiler.h

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 6810d80..b8fe0c2 100644 (file)
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -24,7 +24,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
                        long ______r;                                   \
                        static struct ftrace_likely_data                \
                                __aligned(4)                            \
-                               __section(_ftrace_annotated_branch)     \
+                               __section("_ftrace_annotated_branch")   \
                                ______f = {                             \
                                .data.func = __func__,                  \
                                .data.file = __FILE__,                  \
@@ -60,7 +60,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #define __trace_if_value(cond) ({                      \
        static struct ftrace_branch_data                \
                __aligned(4)                            \
-               __section(_ftrace_branch)               \
+               __section("_ftrace_branch")             \
                __if_trace = {                          \
                        .func = __func__,               \
                        .file = __FILE__,               \
@@ -80,11 +80,25 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 
 /* Optimization barrier */
 #ifndef barrier
-# define barrier() __memory_barrier()
+/* The "volatile" is due to gcc bugs */
+# define barrier() __asm__ __volatile__("": : :"memory")
 #endif
 
 #ifndef barrier_data
-# define barrier_data(ptr) barrier()
+/*
+ * This version is i.e. to prevent dead stores elimination on @ptr
+ * where gcc and llvm may behave differently when otherwise using
+ * normal barrier(): while gcc behavior gets along with a normal
+ * barrier(), llvm needs an explicit input variable to be assumed
+ * clobbered. The issue is as follows: while the inline asm might
+ * access any memory it wants, the compiler could have fit all of
+ * @ptr into memory registers instead, and since @ptr never escaped
+ * from that, it proved that the inline asm wasn't touching any of
+ * it. This version works well with both compilers, i.e. we're telling
+ * the compiler that the inline asm absolutely may see the contents
+ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
+ */
+# define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
 #endif
 
 /* workaround for GCC PR82365 if needed */
@@ -118,7 +132,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
        ".popsection\n\t"
 
 /* Annotate a C jump table to allow objtool to follow the code flow */
-#define __annotate_jump_table __section(.rodata..c_jump_table)
+#define __annotate_jump_table __section(".rodata..c_jump_table")
 
 #else
 #define annotate_reachable()
@@ -155,7 +169,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
        extern typeof(sym) sym;                                 \
        static const unsigned long __kentry_##sym               \
        __used                                                  \
-       __section("___kentry" "+" #sym )                        \
+       __attribute__((__section__("___kentry+" #sym)))         \
        = (unsigned long)&sym;
 #endif
 
@@ -206,8 +220,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
  * visible to the compiler.
  */
 #define __ADDRESSABLE(sym) \
-       static void * __section(.discard.addressable) __used \
-               __PASTE(__addressable_##sym, __LINE__) = (void *)&sym;
+       static void * __section(".discard.addressable") __used \
+               __UNIQUE_ID(__PASTE(__addressable_,sym)) = (void *)&sym;
 
 /**
  * offset_to_ptr - convert a relative memory offset to an absolute pointer