From d223246ef7e6d73c8e3d9b58f27f2eb3fe95e25d Mon Sep 17 00:00:00 2001 From: Anders Kaseorg Date: Wed, 16 Sep 2009 16:44:26 -0400 Subject: [PATCH] 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 Signed-off-by: H. Peter Anvin --- arch/x86/kernel/vmlinux.lds.S | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 0ccb57d5ee35..b96ca472fa26 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 -- 2.39.2