From 8c49d9a74bac5ea3f18480307057241b808fcc0c Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 23 May 2011 09:31:24 -0400 Subject: 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 Cc: Andi Kleen Cc: Linus Torvalds Cc: "David S. Miller" Cc: Eric Dumazet Cc: Peter Zijlstra Cc: Borislav Petkov Link: http://lkml.kernel.org/r/%3C7357882fbb51fa30491636a7b6528747301b7ee9.1306156808.git.luto%40mit.edu%3E Signed-off-by: Thomas Gleixner --- arch/x86/vdso/vma.c | 27 --------------------------- 1 file changed, 27 deletions(-) (limited to 'arch/x86/vdso/vma.c') diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c index 4b5d26f108bb..7abd2be0f9b9 100644 --- a/arch/x86/vdso/vma.c +++ b/arch/x86/vdso/vma.c @@ -15,9 +15,6 @@ #include #include -#include "vextern.h" /* Just for VMAGIC. */ -#undef VEXTERN - unsigned int __read_mostly vdso_enabled = 1; extern char vdso_start[], vdso_end[]; @@ -26,20 +23,10 @@ extern unsigned short vdso_sync_cpuid; static struct page **vdso_pages; static unsigned vdso_size; -static inline void *var_ref(void *p, char *name) -{ - if (*(void **)p != (void *)VMAGIC) { - printk("VDSO: variable %s broken\n", name); - vdso_enabled = 0; - } - return p; -} - static int __init init_vdso_vars(void) { int npages = (vdso_end - vdso_start + PAGE_SIZE - 1) / PAGE_SIZE; int i; - char *vbase; vdso_size = npages << PAGE_SHIFT; vdso_pages = kmalloc(sizeof(struct page *) * npages, GFP_KERNEL); @@ -54,20 +41,6 @@ static int __init init_vdso_vars(void) copy_page(page_address(p), vdso_start + i*PAGE_SIZE); } - vbase = vmap(vdso_pages, npages, 0, PAGE_KERNEL); - if (!vbase) - goto oom; - - if (memcmp(vbase, "\177ELF", 4)) { - printk("VDSO: I'm broken; not ELF\n"); - vdso_enabled = 0; - } - -#define VEXTERN(x) \ - *(typeof(__ ## x) **) var_ref(VDSO64_SYMBOL(vbase, x), #x) = &__ ## x; -#include "vextern.h" -#undef VEXTERN - vunmap(vbase); return 0; oom: -- cgit v1.2.3