summaryrefslogtreecommitdiff
path: root/include/linux/compiler-gcc4.h
diff options
context:
space:
mode:
authorMikael Pettersson <mikpe@it.uu.se>2010-06-30 02:05:25 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-06-30 02:29:31 +0400
commit9c695203a7ddbe49dba5f22f4c941d24f47475df (patch)
tree0dcfa624ecb7c5810f7062fe950bf3f0de2e55b2 /include/linux/compiler-gcc4.h
parent2952095c6b2eefd068dda0dee6317cf95155a304 (diff)
downloadlinux-9c695203a7ddbe49dba5f22f4c941d24f47475df.tar.xz
compiler-gcc.h: gcc-4.5 needs noclone and noinline on __naked functions
A __naked function is defined in C but with a body completely implemented by asm(), including any prologue and epilogue. These asm() bodies expect standard calling conventions for parameter passing. Older GCCs implement that correctly, but 4.[56] currently do not, see GCC PR44290. In the Linux kernel this breaks ARM, causing most arch/arm/mm/copypage-*.c modules to get miscompiled, resulting in kernel crashes during bootup. Part of the kernel fix is to augment the __naked function attribute to also imply noinline and noclone. This patch implements that, and has been verified to fix boot failures with gcc-4.5 compiled 2.6.34 and 2.6.35-rc1 kernels. The patch is a no-op with older GCCs. Signed-off-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: Khem Raj <raj.khem@gmail.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/compiler-gcc4.h')
-rw-r--r--include/linux/compiler-gcc4.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index 94dea3ffbfa1..fcfa5b9a4317 100644
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -48,6 +48,10 @@
* 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__))
+
#endif
#endif