[PATCH] x86-64: 64bit PIC SMP trampoline

This modifies the SMP trampoline and all of the associated code so
it can jump to a 64bit kernel loaded at an arbitrary address.

The dependencies on having an idenetity mapped page in the kernel
page tables for SMP bootup have all been removed.

In addition the trampoline has been modified to verify
that long mode is supported.  Asking if long mode is implemented is
down right silly but we have traditionally had some of these checks,
and they can't hurt anything.  So when the totally ludicrous happens
we just might handle it correctly.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 1 insertions, 8 deletions

diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index 3d98b696881d..4b114ee31ebc 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -329,15 +329,8 @@ void __init setup_arch(char **cmdline_p)
 #endif
 
 #ifdef CONFIG_SMP
-        /*
-         * But first pinch a few for the stack/trampoline stuff
-         * FIXME: Don't need the extra page at 4K, but need to fix
-         * trampoline before removing it. (see the GDT stuff)
-         */
-        reserve_bootmem_generic(PAGE_SIZE, PAGE_SIZE);
-
         /* Reserve SMP trampoline */
-        reserve_bootmem_generic(SMP_TRAMPOLINE_BASE, PAGE_SIZE);
+        reserve_bootmem_generic(SMP_TRAMPOLINE_BASE, 2*PAGE_SIZE);
 #endif
 
 #ifdef CONFIG_ACPI_SLEEP