mirror of
https://github.com/torvalds/linux.git
synced 2024-11-14 16:12:02 +00:00
8c49d9a74b
Variables that are shared between the vdso and the kernel are currently a bit of a mess. They are each defined with their own magic, they are accessed differently in the kernel, the vsyscall page, and the vdso, and one of them (vsyscall_clock) doesn't even really exist. This changes them all to use a common mechanism. All of them are delcared in vvar.h with a fixed address (validated by the linker script). In the kernel (as before), they look like ordinary read-write variables. In the vsyscall page and the vdso, they are accessed through a new macro VVAR, which gives read-only access. The vdso is now loaded verbatim into memory without any fixups. As a side bonus, access from the vdso is faster because a level of indirection is removed. While we're at it, pack jiffies and vgetcpu_mode into the same cacheline. Signed-off-by: Andy Lutomirski <luto@mit.edu> Cc: Andi Kleen <andi@firstfloor.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Borislav Petkov <bp@amd64.org> Link: http://lkml.kernel.org/r/%3C7357882fbb51fa30491636a7b6528747301b7ee9.1306156808.git.luto%40mit.edu%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
37 lines
779 B
C
37 lines
779 B
C
#ifndef _ASM_X86_VSYSCALL_H
|
|
#define _ASM_X86_VSYSCALL_H
|
|
|
|
enum vsyscall_num {
|
|
__NR_vgettimeofday,
|
|
__NR_vtime,
|
|
__NR_vgetcpu,
|
|
};
|
|
|
|
#define VSYSCALL_START (-10UL << 20)
|
|
#define VSYSCALL_SIZE 1024
|
|
#define VSYSCALL_END (-2UL << 20)
|
|
#define VSYSCALL_MAPPED_PAGES 1
|
|
#define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
|
|
|
|
#ifdef __KERNEL__
|
|
#include <linux/seqlock.h>
|
|
|
|
/* Definitions for CONFIG_GENERIC_TIME definitions */
|
|
#define __vsyscall_fn \
|
|
__attribute__ ((unused, __section__(".vsyscall_fn"))) notrace
|
|
|
|
#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);
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
#endif /* _ASM_X86_VSYSCALL_H */
|