diff options
| author | Andy Lutomirski <luto@MIT.EDU> | 2011-05-23 09:31:24 -0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-05-24 14:51:28 +0200 |
| commit | 8c49d9a74bac5ea3f18480307057241b808fcc0c (patch) | |
| tree | a9d2d8160ca37e9292e605cf3cdd85b29646c4b7 /arch/x86/kernel/vmlinux.lds.S | |
| parent | d762f4383100c2a87b1a3f2d678cd3b5425655b4 (diff) | |
x86-64: Clean up vdso/kernel shared variables
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>
Diffstat (limited to 'arch/x86/kernel/vmlinux.lds.S')
| -rw-r--r-- | arch/x86/kernel/vmlinux.lds.S | 34 |
1 files changed, 11 insertions, 23 deletions
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 49927a863cc1..74b5ad450c7e 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -161,6 +161,12 @@ SECTIONS #define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0) #define VVIRT(x) (ADDR(x) - VVIRT_OFFSET) +#define EMIT_VVAR(x, offset) .vsyscall_var_ ## x \ + ADDR(.vsyscall_0) + offset \ + : AT(VLOAD(.vsyscall_var_ ## x)) { \ + *(.vsyscall_var_ ## x) \ + } \ + x = VVIRT(.vsyscall_var_ ## x); . = ALIGN(4096); __vsyscall_0 = .; @@ -175,18 +181,6 @@ SECTIONS *(.vsyscall_fn) } - . = ALIGN(L1_CACHE_BYTES); - .vsyscall_gtod_data : AT(VLOAD(.vsyscall_gtod_data)) { - *(.vsyscall_gtod_data) - } - - vsyscall_gtod_data = VVIRT(.vsyscall_gtod_data); - .vsyscall_clock : AT(VLOAD(.vsyscall_clock)) { - *(.vsyscall_clock) - } - vsyscall_clock = VVIRT(.vsyscall_clock); - - .vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) { *(.vsyscall_1) } @@ -194,21 +188,14 @@ SECTIONS *(.vsyscall_2) } - .vgetcpu_mode : AT(VLOAD(.vgetcpu_mode)) { - *(.vgetcpu_mode) - } - vgetcpu_mode = VVIRT(.vgetcpu_mode); - - . = ALIGN(L1_CACHE_BYTES); - .jiffies : AT(VLOAD(.jiffies)) { - *(.jiffies) - } - jiffies = VVIRT(.jiffies); - .vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) { *(.vsyscall_3) } +#define __VVAR_KERNEL_LDS +#include <asm/vvar.h> +#undef __VVAR_KERNEL_LDS + . = __vsyscall_0 + PAGE_SIZE; #undef VSYSCALL_ADDR @@ -216,6 +203,7 @@ SECTIONS #undef VLOAD #undef VVIRT_OFFSET #undef VVIRT +#undef EMIT_VVAR #endif /* CONFIG_X86_64 */ |