Commit-ID: d223246ef7e6d73c8e3d9b58f27f2eb3fe95e25d
Gitweb: http://git.kernel.org/tip/d223246ef7e6d73c8e3d9b58f27f2eb3fe95e25d
Author: Anders Kaseorg <andersk@xxxxxxxxxxx>
AuthorDate: Wed, 16 Sep 2009 16:44:26 -0400
Committer: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Fri, 18 Sep 2009 10:21:45 -0700
x86: fix fragile computation of vsyscall address
Previously, the address of the vsyscall page (VSYSCALL_PHYS_ADDR,
VSYSCALL_VIRT_ADDR) was computed by arithmetic on the address of the
last section. This leads to bugs when new sections are inserted, such
as the one fixed by commit d312ceda567ab91acd756cde95ac5fbc6b40ed40.
Let's compute it from the current address instead.
Signed-off-by: Anders Kaseorg <andersk@xxxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
---
arch/x86/kernel/vmlinux.lds.S | 19 +++++++------------
1 files changed, 7 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 0ccb57d..b96ca47 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -135,24 +135,21 @@ SECTIONS
#ifdef CONFIG_X86_64
#define VSYSCALL_ADDR (-10*1024*1024)
-#define VSYSCALL_PHYS_ADDR ((LOADADDR(.data) + SIZEOF(.data) + \
- PAGE_SIZE - 1) & ~(PAGE_SIZE - 1))
-#define VSYSCALL_VIRT_ADDR ((ADDR(.data) + SIZEOF(.data) + \
- PAGE_SIZE - 1) & ~(PAGE_SIZE - 1))
-#define VLOAD_OFFSET (VSYSCALL_ADDR - VSYSCALL_PHYS_ADDR)
+#define VLOAD_OFFSET (VSYSCALL_ADDR - __vsyscall_0 + LOAD_OFFSET)
#define VLOAD(x) (ADDR(x) - VLOAD_OFFSET)
-#define VVIRT_OFFSET (VSYSCALL_ADDR - VSYSCALL_VIRT_ADDR)
+#define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0)
#define VVIRT(x) (ADDR(x) - VVIRT_OFFSET)
+ . = ALIGN(4096);
+ __vsyscall_0 = .;
+
. = VSYSCALL_ADDR;
- .vsyscall_0 : AT(VSYSCALL_PHYS_ADDR) {
+ .vsyscall_0 : AT(VLOAD(.vsyscall_0)) {
*(.vsyscall_0)
} :user
- __vsyscall_0 = VSYSCALL_VIRT_ADDR;
-
. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
.vsyscall_fn : AT(VLOAD(.vsyscall_fn)) {
*(.vsyscall_fn)
@@ -192,11 +189,9 @@ SECTIONS
*(.vsyscall_3)
}
- . = VSYSCALL_VIRT_ADDR + PAGE_SIZE;
+ . = __vsyscall_0 + PAGE_SIZE;
#undef VSYSCALL_ADDR
-#undef VSYSCALL_PHYS_ADDR
-#undef VSYSCALL_VIRT_ADDR
#undef VLOAD_OFFSET
#undef VLOAD
#undef VVIRT_OFFSET
--
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