diff options
| author | Andy Lutomirski <luto@amacapital.net> | 2014-10-31 00:58:01 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2014-11-03 15:41:53 +0300 |
| commit | e76b027e6408f5570dc940b731ec9ae870c6188a (patch) | |
| tree | d94287f98ee13c7e2fedd4890499f178079ce6ab /arch/x86/include/asm | |
| parent | a92f101bc99d17b75021cf29f18cc57f39a37d1f (diff) | |
| download | linux-e76b027e6408f5570dc940b731ec9ae870c6188a.tar.xz | |
x86,vdso: Use LSL unconditionally for vgetcpu
LSL is faster than RDTSCP and works everywhere; there's no need to
switch between them depending on CPU.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Andi Kleen <andi@firstfloor.org>
Link: http://lkml.kernel.org/r/72f73d5ec4514e02bba345b9759177ef03742efb.1414706021.git.luto@amacapital.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/vgtod.h | 19 | ||||
| -rw-r--r-- | arch/x86/include/asm/vsyscall.h | 29 | ||||
| -rw-r--r-- | arch/x86/include/asm/vvar.h | 1 |
3 files changed, 19 insertions, 30 deletions
diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h index 3c3366c2e37f..e7e9682a33e9 100644 --- a/arch/x86/include/asm/vgtod.h +++ b/arch/x86/include/asm/vgtod.h @@ -70,4 +70,23 @@ static inline void gtod_write_end(struct vsyscall_gtod_data *s) ++s->seq; } +#ifdef CONFIG_X86_64 + +#define VGETCPU_CPU_MASK 0xfff + +static inline unsigned int __getcpu(void) +{ + unsigned int p; + + /* + * Load per CPU data from GDT. LSL is faster than RDTSCP and + * works on all CPUs. + */ + asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG)); + + return p; +} + +#endif /* CONFIG_X86_64 */ + #endif /* _ASM_X86_VGTOD_H */ diff --git a/arch/x86/include/asm/vsyscall.h b/arch/x86/include/asm/vsyscall.h index 2a46ca720afc..34f7d8857542 100644 --- a/arch/x86/include/asm/vsyscall.h +++ b/arch/x86/include/asm/vsyscall.h @@ -4,15 +4,6 @@ #include <linux/seqlock.h> #include <uapi/asm/vsyscall.h> -#define VGETCPU_RDTSCP 1 -#define VGETCPU_LSL 2 - -/* kernel space (writeable) */ -extern int vgetcpu_mode; -extern struct timezone sys_tz; - -#include <asm/vvar.h> - extern void map_vsyscall(void); /* @@ -21,24 +12,4 @@ extern void map_vsyscall(void); */ extern bool emulate_vsyscall(struct pt_regs *regs, unsigned long address); -#ifdef CONFIG_X86_64 - -#define VGETCPU_CPU_MASK 0xfff - -static inline unsigned int __getcpu(void) -{ - unsigned int p; - - if (VVAR(vgetcpu_mode) == VGETCPU_RDTSCP) { - /* Load per CPU data from RDTSCP */ - native_read_tscp(&p); - } else { - /* Load per CPU data from GDT */ - asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG)); - } - - return p; -} -#endif /* CONFIG_X86_64 */ - #endif /* _ASM_X86_VSYSCALL_H */ diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h index 5f6d40734a3b..3f32dfc2ab73 100644 --- a/arch/x86/include/asm/vvar.h +++ b/arch/x86/include/asm/vvar.h @@ -44,7 +44,6 @@ extern char __vvar_page; /* DECLARE_VVAR(offset, type, name) */ -DECLARE_VVAR(16, int, vgetcpu_mode) DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data) #undef DECLARE_VVAR |