The motivation for commit abb2ea7d ("compiler, clang: suppress
warning for unused static inline functions") was to suppress clang's
warnings about unused static inline functions.

For configs without CONFIG_OPTIMIZE_INLINING enabled, such as any non-x86
architecture, `inline' in the kernel implies that
__attribute__((always_inline)) is used.

Some code depends on that behavior, see
  https://lkml.org/lkml/2017/6/13/918:

  net/built-in.o: In function `__xchg_mb':
  arch/arm64/include/asm/cmpxchg.h:99: undefined reference to `__compiletime_assert_99'
  arch/arm64/include/asm/cmpxchg.h:99: undefined reference to `__compiletime_assert_99

The full fix would be to identify these breakages and annotate the
functions with __always_inline instead of `inline'.  But since we are
late in the 4.12-rc cycle, simply carry forward the forced inlining
behavior and work toward moving arm64, and other architectures, toward
CONFIG_OPTIMIZE_INLINING behavior.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1706261552200.1075@chino.kir.corp.google.comSigned-off-by: NDavid Rientjes <rientjes@google.com>
Reported-by: NSodagudi Prasad <psodagud@codeaurora.org>
Tested-by: NSodagudi Prasad <psodagud@codeaurora.org>
Tested-by: NMatthias Kaehlcke <mka@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit abb2ea7d ("compiler, clang: suppress warning for unused
static inline functions") just caused more warnings due to re-defining
the 'inline' macro.

So undef it before re-defining it, and also add the 'notrace' attribute
like the gcc version that this is overriding does.

Maybe this makes clang happier.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

GCC explicitly does not warn for unused static inline functions for
-Wunused-function.  The manual states:

	Warn whenever a static function is declared but not defined or
	a non-inline static function is unused.

Clang does warn for static inline functions that are unused.

It turns out that suppressing the warnings avoids potentially complex
#ifdef directives, which also reduces LOC.

Suppress the warning for clang.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The default __UNIQUE_ID macro in compiler.h fails to work for some drivers:

drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c:615:1: error: redefinition of
      '__UNIQUE_ID_firmware615'
BRCMF_FW_NVRAM_DEF(4354, "brcmfmac4354-sdio.bin", "brcmfmac4354-sdio.txt");

This adds a copy of the version we use for gcc-4.3 and higher, as the same
one works with all versions of clang that I could find in svn (2.6 and higher).
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NMichal Marek <mmarek@suse.com>

Add a compiler-clang.h file to add specific macros needed for compiling the
kernel with clang.

Initially the only override required is the macro for silencing the
compiler for a purposefully uninintialized variable.

Author: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: NMark Charlebois <charlebm@gmail.com>
Signed-off-by: NBehan Webster <behanw@converseincode.com>