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authorNick Desaulniers <ndesaulniers@google.com>2019-03-14 23:14:57 +0100
committerThomas Gleixner <tglx@linutronix.de>2019-03-21 12:24:38 +0100
commita9c640ac96e19b3966357ec9bb586edd2e1e74de (patch)
tree2c9c70d9d87f1963455624459681d33533d1be90
parentx86/mm: Don't leak kernel addresses (diff)
downloadlinux-a9c640ac96e19b3966357ec9bb586edd2e1e74de.tar.xz
linux-a9c640ac96e19b3966357ec9bb586edd2e1e74de.zip
x86/boot: Restrict header scope to make Clang happy
The inclusion of <linux/kernel.h> was causing issue as the definition of __arch_hweight64 from arch/x86/include/asm/arch_hweight.h eventually gets included. The definition is problematic when compiled with -m16 (all code in arch/x86/boot/ is) as the "D" inline assembly constraint is rejected by both compilers when passed an argument of type long long (regardless of signedness, anything smaller is fine). Because GCC performs inlining before semantic analysis, and __arch_hweight64 is dead in this translation unit, GCC does not report any issues at compile time. Clang does the semantic analysis in the front end, before inlining (run in the middle) can determine the code is dead. I consider this another case of PR33587, which I think we can do more work to solve. It turns out that arch/x86/boot/string.c doesn't actually need linux/kernel.h, simply linux/limits.h and linux/compiler.h. Suggested-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: bp@alien8.de Cc: niravd@google.com Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Chao Fan <fanc.fnst@cn.fujitsu.com> Cc: Uros Bizjak <ubizjak@gmail.com> Link: https://bugs.llvm.org/show_bug.cgi?id=33587 Link: https://github.com/ClangBuiltLinux/linux/issues/347 Link: https://lkml.kernel.org/r/20190314221458.83047-1-ndesaulniers@google.com
-rw-r--r--arch/x86/boot/string.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index 315a67b8896b..90154df8f125 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -13,8 +13,9 @@
*/
#include <linux/types.h>
-#include <linux/kernel.h>
+#include <linux/compiler.h>
#include <linux/errno.h>
+#include <linux/limits.h>
#include <asm/asm.h>
#include "ctype.h"
#include "string.h"