Re: [PATCH v2 3/4] Add hwcap2 for x86

2016-10-12 Thread Thomas Gleixner 
On Wed, 12 Oct 2016, Grzegorz Andrejczuk wrote:
> +/* HWCAP2 supplies kernel enabled CPU feature, so that the application
> +   can know that it can safely use them. The bits are defined in
> +   uapi/asm/hwcap.h. */

Please read: http://lkml.iu.edu/hypermail/linux/kernel/1607.1/00627.html

Re: [PATCH v2 3/4] Add hwcap2 for x86

2016-10-12 Thread Thomas Gleixner 
On Wed, 12 Oct 2016, Grzegorz Andrejczuk wrote:
> +/* HWCAP2 supplies kernel enabled CPU feature, so that the application
> +   can know that it can safely use them. The bits are defined in
> +   uapi/asm/hwcap.h. */

Please read: http://lkml.iu.edu/hypermail/linux/kernel/1607.1/00627.html

Re: [PATCH v2 3/4] Add hwcap2 for x86

2016-10-12 Thread Thomas Gleixner 
On Wed, 12 Oct 2016, Grzegorz Andrejczuk wrote:
> +extern unsigned int elf_hwcap2;
> +unsigned elf_hwcap2 __read_mostly;

Oh well. Getting two lines straight is hard, right?

Thanks,

tglx

Re: [PATCH v2 3/4] Add hwcap2 for x86

2016-10-12 Thread Thomas Gleixner 
On Wed, 12 Oct 2016, Grzegorz Andrejczuk wrote:
> +extern unsigned int elf_hwcap2;
> +unsigned elf_hwcap2 __read_mostly;

Oh well. Getting two lines straight is hard, right?

Thanks,

tglx

[PATCH v2 3/4] Add hwcap2 for x86

2016-10-12 Thread Grzegorz Andrejczuk 
Add hwcap2 attribute for x86.
Reserve 1st bit of HWCAP2 for exposing Xeon Phi ring 3 monitor/mwait.
With this userspace apps can detect Ring 3 MONITOR/MWAIT instructions.

Change-Id: I37d0354d1e2b9594d7feebc2bacda30b68163efe
Signed-off-by: Grzegorz Andrejczuk 
---
 arch/x86/include/asm/elf.h| 7 +++
 arch/x86/include/uapi/asm/hwcap.h | 7 +++
 arch/x86/kernel/cpu/common.c  | 3 +++
 3 files changed, 17 insertions(+)
 create mode 100644 arch/x86/include/uapi/asm/hwcap.h

diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index e7f155c..a3f7856 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -258,6 +258,13 @@ extern int force_personality32;
 
 #define ELF_HWCAP  (boot_cpu_data.x86_capability[CPUID_1_EDX])
 
+extern unsigned int elf_hwcap2;
+
+/* HWCAP2 supplies kernel enabled CPU feature, so that the application
+   can know that it can safely use them. The bits are defined in
+   uapi/asm/hwcap.h. */
+#define ELF_HWCAP2 elf_hwcap2
+
 /* This yields a string that ld.so will use to load implementation
specific libraries for optimization.  This is more specific in
intent than poking at uname or /proc/cpuinfo.
diff --git a/arch/x86/include/uapi/asm/hwcap.h 
b/arch/x86/include/uapi/asm/hwcap.h
new file mode 100644
index 000..d1f4f98
--- /dev/null
+++ b/arch/x86/include/uapi/asm/hwcap.h
@@ -0,0 +1,7 @@
+#ifndef _ASM_HWCAP_H
+#define _ASM_HWCAP_H 1
+
+/* Kernel enabled Ring 3 MWAIT for Xeon Phi*/
+#define HWCAP2_PHIR3MWAIT  (1 << 0)
+/* upto bit 31 free */
+#endif
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index bcc9ccc..93ffaa5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -35,6 +35,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -51,6 +52,8 @@
 
 #include "cpu.h"
 
+unsigned elf_hwcap2 __read_mostly;
+
 /* all of these masks are initialized in setup_cpu_local_masks() */
 cpumask_var_t cpu_initialized_mask;
 cpumask_var_t cpu_callout_mask;
-- 
2.5.1

[PATCH v2 3/4] Add hwcap2 for x86

2016-10-12 Thread Grzegorz Andrejczuk 
Add hwcap2 attribute for x86.
Reserve 1st bit of HWCAP2 for exposing Xeon Phi ring 3 monitor/mwait.
With this userspace apps can detect Ring 3 MONITOR/MWAIT instructions.

Change-Id: I37d0354d1e2b9594d7feebc2bacda30b68163efe
Signed-off-by: Grzegorz Andrejczuk 
---
 arch/x86/include/asm/elf.h| 7 +++
 arch/x86/include/uapi/asm/hwcap.h | 7 +++
 arch/x86/kernel/cpu/common.c  | 3 +++
 3 files changed, 17 insertions(+)
 create mode 100644 arch/x86/include/uapi/asm/hwcap.h

diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index e7f155c..a3f7856 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -258,6 +258,13 @@ extern int force_personality32;
 
 #define ELF_HWCAP  (boot_cpu_data.x86_capability[CPUID_1_EDX])
 
+extern unsigned int elf_hwcap2;
+
+/* HWCAP2 supplies kernel enabled CPU feature, so that the application
+   can know that it can safely use them. The bits are defined in
+   uapi/asm/hwcap.h. */
+#define ELF_HWCAP2 elf_hwcap2
+
 /* This yields a string that ld.so will use to load implementation
specific libraries for optimization.  This is more specific in
intent than poking at uname or /proc/cpuinfo.
diff --git a/arch/x86/include/uapi/asm/hwcap.h 
b/arch/x86/include/uapi/asm/hwcap.h
new file mode 100644
index 000..d1f4f98
--- /dev/null
+++ b/arch/x86/include/uapi/asm/hwcap.h
@@ -0,0 +1,7 @@
+#ifndef _ASM_HWCAP_H
+#define _ASM_HWCAP_H 1
+
+/* Kernel enabled Ring 3 MWAIT for Xeon Phi*/
+#define HWCAP2_PHIR3MWAIT  (1 << 0)
+/* upto bit 31 free */
+#endif
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index bcc9ccc..93ffaa5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -35,6 +35,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -51,6 +52,8 @@
 
 #include "cpu.h"
 
+unsigned elf_hwcap2 __read_mostly;
+
 /* all of these masks are initialized in setup_cpu_local_masks() */
 cpumask_var_t cpu_initialized_mask;
 cpumask_var_t cpu_callout_mask;
-- 
2.5.1