[PATCH 3.13 093/105] kernel: add support for gcc 5

Kamal Mostafa
2014-10-27T19:02:54Z

From: Sasha Levin <sasha.levin@oracle.com>

commit 71458cfc782eafe4b27656e078d379a34e472adf upstream.

We're missing include/linux/compiler-gcc5.h which is required now
because gcc branched off to v5 in trunk.

Just copy the relevant bits out of include/linux/compiler-gcc4.h,
no new code is added as of now.

This fixes a build error when using gcc 5.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
include/linux/compiler-gcc5.h | 66 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)
create mode 100644 include/linux/compiler-gcc5.h

diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h
new file mode 100644
index 0000000..cdd1cc2
--- /dev/null
+++ b/include/linux/compiler-gcc5.h
@@ -0,0 +1,66 @@
+#ifndef __LINUX_COMPILER_H
+#error "Please don't include <linux/compiler-gcc5.h> directly, include <linux/compiler.h> instead."
+#endif
+
+#define __used __attribute__((__used__))
+#define __must_check __attribute__((warn_unused_result))
+#define __compiler_offsetof(a, b) __builtin_offsetof(a, b)
+
+/* Mark functions as cold. gcc will assume any path leading to a call
+ to them will be unlikely. This means a lot of manual unlikely()s
+ are unnecessary now for any paths leading to the usual suspects
+ like BUG(), printk(), panic() etc. [but let's keep them for now for
+ older compilers]
+
+ Early snapshots of gcc 4.3 don't support this and we can't detect this
+ in the preprocessor, but we can live with this because they're unreleased.
+ Maketime probing would be overkill here.
+
+ gcc also has a __attribute__((__hot__)) to move hot functions into
+ a special section, but I don't see any sense in this right now in
+ the kernel context */
+#define __cold __attribute__((__cold__))
+
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+
+#ifndef __CHECKER__
+# define __compiletime_warning(message) __attribute__((warning(message)))
+# define __compiletime_error(message) __attribute__((error(message)))
+#endif /* __CHECKER__ */
+
+/*
+ * Mark a position in code as unreachable. This can be used to
+ * suppress control flow warnings after asm blocks that transfer
+ * control elsewhere.
+ *
+ * Early snapshots of gcc 4.5 don't support this and we can't detect
+ * this in the preprocessor, but we can live with this because they're
+ * unreleased. Really, we need to have autoconf for the kernel.
+ */
+#define unreachable() __builtin_unreachable()
+
+/* Mark a function definition as prohibited from being cloned. */
+#define __noclone __attribute__((__noclone__))
+
+/*
+ * Tell the optimizer that something else uses this function or variable.
+ */
+#define __visible __attribute__((externally_visible))
+
+/*
+ * GCC 'asm goto' miscompiles certain code sequences:
+ *
+ * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
+ *
+ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
+ * Fixed in GCC 4.8.2 and later versions.
+ *
+ * (asm goto is automatically volatile - the naming reflects this.)
+ */
+#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
+
+#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+#define __HAVE_BUILTIN_BSWAP32__
+#define __HAVE_BUILTIN_BSWAP64__
+#define __HAVE_BUILTIN_BSWAP16__
+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
--
1.9.1