From: Borislav Petkov <bp(a)suse.de>
commit 337e4cc84021212a87b04b77b65cccc49304909e upstream
Add .altinstr_aux for additional instructions which will be used
before and/or during patching. All stuff which needs more
sophisticated patching should go there. See next patch.
Signed-off-by: Borislav Petkov <bp(a)suse.de>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Brian Gerst <brgerst(a)gmail.com>
Cc: Denys Vlasenko <dvlasenk(a)redhat.com>
Cc: H. Peter Anvin <hpa(a)zytor.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Link: http://lkml.kernel.org/r/1453842730-28463-8-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com>
Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com>
Reviewed-by: Bo Gan <ganb(a)vmware.com>
---
arch/x86/kernel/vmlinux.lds.S | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index e065065..a703842 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -202,6 +202,17 @@ SECTIONS
:init
#endif
+ /*
+ * Section for code used exclusively before alternatives are run. All
+ * references to such code must be patched out by alternatives, normally
+ * by using X86_FEATURE_ALWAYS CPU feature bit.
+ *
+ * See static_cpu_has() for an example.
+ */
+ .altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) {
+ *(.altinstr_aux)
+ }
+
INIT_DATA_SECTION(16)
.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
From: Andi Kleen <ak(a)linux.intel.com>
commit 153a4334c439cfb62e1d31cee0c790ba4157813d upstream
asm/atomic.h doesn't really need asm/processor.h anymore. Everything
it uses has moved to other header files. So remove that include.
processor.h is a nasty header that includes lots of
other headers and makes it prone to include loops. Removing the
include here makes asm/atomic.h a "leaf" header that can
be safely included in most other headers.
The only fallout is in the lib/atomic tester which relied on
this implicit include. Give it an explicit include.
(the include is in ifdef because the user is also in ifdef)
Signed-off-by: Andi Kleen <ak(a)linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com>
Cc: Jiri Olsa <jolsa(a)redhat.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Mike Galbraith <efault(a)gmx.de>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Stephane Eranian <eranian(a)google.com>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Vince Weaver <vincent.weaver(a)maine.edu>
Cc: rostedt(a)goodmis.org
Link: http://lkml.kernel.org/r/1449018060-1742-1-git-send-email-andi@firstfloor.o…
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com>
Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com>
Reviewed-by: Bo Gan <ganb(a)vmware.com>
---
arch/x86/include/asm/atomic.h | 1 -
arch/x86/include/asm/atomic64_32.h | 1 -
lib/atomic64_test.c | 4 ++++
3 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index ae5fb83..3e86742 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -3,7 +3,6 @@
#include <linux/compiler.h>
#include <linux/types.h>
-#include <asm/processor.h>
#include <asm/alternative.h>
#include <asm/cmpxchg.h>
#include <asm/rmwcc.h>
diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index a11c30b..a984111 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -3,7 +3,6 @@
#include <linux/compiler.h>
#include <linux/types.h>
-#include <asm/processor.h>
//#include <asm/cmpxchg.h>
/* An 64bit atomic type */
diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index 83c33a5b..d51e25a 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -16,6 +16,10 @@
#include <linux/kernel.h>
#include <linux/atomic.h>
+#ifdef CONFIG_X86
+#include <asm/processor.h> /* for boot_cpu_has below */
+#endif
+
#define TEST(bit, op, c_op, val) \
do { \
atomic##bit##_set(&v, v0); \
From: Borislav Petkov <bp(a)suse.de>
commit 6e1315fe82308cd29e7550eab967262e8bbc71a3 upstream
This brings .text savings of about ~1.6K when building a tinyconfig. It
is off by default so nothing changes for the default.
Kconfig help text from Josh.
Signed-off-by: Borislav Petkov <bp(a)suse.de>
Reviewed-by: Josh Triplett <josh(a)joshtriplett.org>
Link: http://lkml.kernel.org/r/1449481182-27541-5-git-send-email-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Signed-off-by: Srivatsa S. Bhat <srivatsa(a)csail.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley(a)gmail.com>
Reviewed-by: Alexey Makhalov <amakhalov(a)vmware.com>
Reviewed-by: Bo Gan <ganb(a)vmware.com>
---
arch/x86/Kconfig | 11 +++++++++++
arch/x86/include/asm/cpufeature.h | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index eab1ef2..d9afe6d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -346,6 +346,17 @@ config X86_FEATURE_NAMES
If in doubt, say Y.
+config X86_FAST_FEATURE_TESTS
+ bool "Fast CPU feature tests" if EMBEDDED
+ default y
+ ---help---
+ Some fast-paths in the kernel depend on the capabilities of the CPU.
+ Say Y here for the kernel to patch in the appropriate code at runtime
+ based on the capabilities of the CPU. The infrastructure for patching
+ code at runtime takes up some additional space; space-constrained
+ embedded systems may wish to say N here to produce smaller, slightly
+ slower code.
+
config X86_X2APIC
bool "Support x2apic"
depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 54c7a0b..67f917b 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -422,7 +422,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
* fast paths and boot_cpu_has() otherwise!
*/
-#if __GNUC__ >= 4
+#if __GNUC__ >= 4 && defined(CONFIG_X86_FAST_FEATURE_TESTS)
extern void warn_pre_alternatives(void);
extern bool __static_cpu_has_safe(u16 bit);