Commit-ID: 03bbd596ac04fef47ce93a730b8f086d797c3021 Gitweb: http://git.kernel.org/tip/03bbd596ac04fef47ce93a730b8f086d797c3021 Author: H. Peter Anvin <h...@linux.intel.com> AuthorDate: Thu, 13 Feb 2014 07:34:30 -0800 Committer: H. Peter Anvin <h...@linux.intel.com> CommitDate: Thu, 13 Feb 2014 07:50:25 -0800
x86, smap: Don't enable SMAP if CONFIG_X86_SMAP is disabled If SMAP support is not compiled into the kernel, don't enable SMAP in CR4 -- in fact, we should clear it, because the kernel doesn't contain the proper STAC/CLAC instructions for SMAP support. Found by Fengguang Wu's test system. Reported-by: Fengguang Wu <fengguang...@intel.com> Link: http://lkml.kernel.org/r/20140213124550.GA30497@localhost Signed-off-by: H. Peter Anvin <h...@linux.intel.com> Cc: <sta...@vger.kernel.org> # v3.7+ --- arch/x86/kernel/cpu/common.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 24b6fd1..8e28bf2 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -284,8 +284,13 @@ static __always_inline void setup_smap(struct cpuinfo_x86 *c) raw_local_save_flags(eflags); BUG_ON(eflags & X86_EFLAGS_AC); - if (cpu_has(c, X86_FEATURE_SMAP)) + if (cpu_has(c, X86_FEATURE_SMAP)) { +#ifdef CONFIG_X86_SMAP set_in_cr4(X86_CR4_SMAP); +#else + clear_in_cr4(X86_CR4_SMAP); +#endif + } } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
