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authorNick Desaulniers <ndesaulniers@google.com>2018-08-22 16:37:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 17:31:34 -0700
commit815f0ddb346c196018d4d8f8f55c12b83da1de3f (patch)
tree4805bf7e3cb7ec4e727aba8e62f9211e9001a760 /drivers
parent899fbc33fd775b9dfa363db28f322272920a2196 (diff)
include/linux/compiler*.h: make compiler-*.h mutually exclusive
Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6") recently exposed a brittle part of the build for supporting non-gcc compilers. Both Clang and ICC define __GNUC__, __GNUC_MINOR__, and __GNUC_PATCHLEVEL__ for quick compatibility with code bases that haven't added compiler specific checks for __clang__ or __INTEL_COMPILER. This is brittle, as they happened to get compatibility by posing as a certain version of GCC. This broke when upgrading the minimal version of GCC required to build the kernel, to a version above what ICC and Clang claim to be. Rather than always including compiler-gcc.h then undefining or redefining macros in compiler-intel.h or compiler-clang.h, let's separate out the compiler specific macro definitions into mutually exclusive headers, do more proper compiler detection, and keep shared definitions in compiler_types.h. Fixes: cafa0010cd51 ("Raise the minimum required gcc version to 4.6") Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com> Suggested-by: Eli Friedman <efriedma@codeaurora.org> Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpu/drm/i915/i915_utils.h2
-rw-r--r--drivers/watchdog/kempld_wdt.c5
2 files changed, 1 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index 00165ad55fb3..395dd2511568 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -43,7 +43,7 @@
#define MISSING_CASE(x) WARN(1, "Missing case (%s == %ld)\n", \
__stringify(x), (long)(x))
-#if GCC_VERSION >= 70000
+#if defined(GCC_VERSION) && GCC_VERSION >= 70000
#define add_overflows(A, B) \
__builtin_add_overflow_p((A), (B), (typeof((A) + (B)))0)
#else
diff --git a/drivers/watchdog/kempld_wdt.c b/drivers/watchdog/kempld_wdt.c
index 2f3b049ea301..e268add43010 100644
--- a/drivers/watchdog/kempld_wdt.c
+++ b/drivers/watchdog/kempld_wdt.c
@@ -146,12 +146,7 @@ static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data,
u32 remainder;
u8 stage_cfg;
-#if GCC_VERSION < 40400
- /* work around a bug compiling do_div() */
- prescaler = READ_ONCE(kempld_prescaler[PRESCALER_21]);
-#else
prescaler = kempld_prescaler[PRESCALER_21];
-#endif
if (!stage)
return -EINVAL;