tree 084ea355a1f7d84e3d1a33759e3105ff116e2d28
parent a2e7f0e3a4f0f23fe4cd8cc22da547872f0170bb
author Andi Kleen <ak@linux.intel.com> 1382458077 -0700
committer H. Peter Anvin <hpa@linux.intel.com> 1391062637 -0800

x86: Use inline assembler instead of global register variable to get sp

LTO in gcc 4.6/47. has trouble with global register variables. They were used
to read the stack pointer. Use a simple inline assembler statement with
a mov instead.

This also helps LLVM/clang, which does not support global register
variables.

[ hpa: Ideally this should become a builtin in both gcc and clang. ]

v2: More general asm constraint. Fix description (Jan Beulich)

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1382458079-24450-6-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>