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 <grzegorz.andrejc...@intel.com> --- 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..62d060a 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 0000000..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 <asm/desc.h> #include <asm/fpu/internal.h> #include <asm/mtrr.h> +#include <asm/hwcap.h> #include <linux/numa.h> #include <asm/asm.h> #include <asm/bugs.h> @@ -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