diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2015-02-27 14:50:19 -0500 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-10-28 16:20:25 -0400 |
| commit | 4534a1c432551e5588955a5eb8f6cb26c69b047f (patch) | |
| tree | 41245e4858505820f753063491341a62f51a83a1 | |
| parent | 4f1a98a2e0cabac1ddcd9aa83cec37526a545bac (diff) | |
x86: Init per-cpu shadow copy of CR4 on 32-bit CPUs too
[ Upstream commit 5b2bdbc84556774afbe11bcfd24c2f6411cfa92b ]
Commit:
1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4")
added a shadow CR4 such that reads and writes that do not
modify the CR4 execute much faster than always reading the
register itself.
The change modified cpu_init() in common.c, so that the
shadow CR4 gets initialized before anything uses it.
Unfortunately, there's two cpu_init()s in common.c. There's
one for 64-bit and one for 32-bit. The commit only added
the shadow init to the 64-bit path, but the 32-bit path
needs the init too.
Link: http://lkml.kernel.org/r/20150227125208.71c36402@gandalf.local.home Fixes: 1e02ce4cccdc "x86: Store a per-cpu shadow copy of CR4"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150227145019.2bdd4354@gandalf.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index e757fcbe90db..88635b301694 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1405,6 +1405,12 @@ void cpu_init(void) wait_for_master_cpu(cpu); + /* + * Initialize the CR4 shadow before doing anything that could + * try to read it. + */ + cr4_init_shadow(); + show_ucode_info_early(); printk(KERN_INFO "Initializing CPU#%d\n", cpu); |