[PATCH] i386: Fix broken CONFIG_COMPAT_VDSO on i386

After updating several machines to 2.6.20, I can't boot  anymore the single
one of them that supports the NX bit and is configured as a 32-bit system.

My understanding is that the VDSO changes in 2.6.20-rc7 were not fully
cooked, in that with that config option enabled VDSO_SYM(x) now equals
x, meaning that an address in the fixmap area is now being passed to
apps via AT_SYSINFO. However, the page is mapped with PAGE_READONLY
rather than PAGE_READONLY_EXEC.

I'm not certain whether having app code go through the fixmap area is
intended, but in case it is here is the simple patch that makes things work
again.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>

diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c
index bc882a2..13ca54a 100644 (file)
--- a/arch/i386/kernel/sysenter.c
+++ b/arch/i386/kernel/sysenter.c
@@ -78,7 +78,7 @@ int __init sysenter_setup(void)
        syscall_pages[0] = virt_to_page(syscall_page);
 
 #ifdef CONFIG_COMPAT_VDSO
-       __set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_READONLY);
+       __set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_READONLY_EXEC);
        printk("Compat vDSO mapped to %08lx.\n", __fix_to_virt(FIX_VDSO));
 #endif