diff options
Diffstat (limited to 'arch/x86/include/asm/vvar.h')
| -rw-r--r-- | arch/x86/include/asm/vvar.h | 33 |
1 files changed, 17 insertions, 16 deletions
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h index 341b3559452..5d2b9ad2c6d 100644 --- a/arch/x86/include/asm/vvar.h +++ b/arch/x86/include/asm/vvar.h @@ -10,15 +10,14 @@ * In normal kernel code, they are used like any other variable. * In user code, they are accessed through the VVAR macro. * - * Each of these variables lives in the vsyscall page, and each - * one needs a unique offset within the little piece of the page - * reserved for vvars. Specify that offset in DECLARE_VVAR. - * (There are 896 bytes available. If you mess up, the linker will - * catch it.) + * These variables live in a page of kernel data that has an extra RO + * mapping for userspace. Each variable needs a unique offset within + * that page; specify that offset with the DECLARE_VVAR macro. (If + * you mess up, the linker will catch it.) */ -/* Offset of vars within vsyscall page */ -#define VSYSCALL_VARS_OFFSET (3072 + 128) +#ifndef _ASM_X86_VVAR_H +#define _ASM_X86_VVAR_H #if defined(__VVAR_KERNEL_LDS) @@ -26,27 +25,29 @@ * right place. */ #define DECLARE_VVAR(offset, type, name) \ - EMIT_VVAR(name, VSYSCALL_VARS_OFFSET + offset) + EMIT_VVAR(name, offset) #else +extern char __vvar_page; + #define DECLARE_VVAR(offset, type, name) \ - static type const * const vvaraddr_ ## name = \ - (void *)(VSYSCALL_START + VSYSCALL_VARS_OFFSET + (offset)); + extern type vvar_ ## name __attribute__((visibility("hidden"))); -#define DEFINE_VVAR(type, name) \ - type __vvar_ ## name \ - __attribute__((section(".vsyscall_var_" #name), aligned(16))) +#define VVAR(name) (vvar_ ## name) -#define VVAR(name) (*vvaraddr_ ## name) +#define DEFINE_VVAR(type, name) \ + type name \ + __attribute__((section(".vvar_" #name), aligned(16))) __visible #endif /* DECLARE_VVAR(offset, type, name) */ DECLARE_VVAR(0, volatile unsigned long, jiffies) -DECLARE_VVAR(8, int, vgetcpu_mode) +DECLARE_VVAR(16, int, vgetcpu_mode) DECLARE_VVAR(128, struct vsyscall_gtod_data, vsyscall_gtod_data) #undef DECLARE_VVAR -#undef VSYSCALL_VARS_OFFSET + +#endif |