x86-32: Make sure the stack is set up before we use it

Since checkin ebba638ae723d8a8fc2f7abce5ec18b688b791d7 we call
verify_cpu even in 32-bit mode.  Unfortunately, calling a function
means using the stack, and the stack pointer was not initialized in
the 32-bit setup code!  This code initializes the stack pointer, and
simplifies the interface slightly since it is easier to rely on just a
pointer value rather than a descriptor; we need to have different
values for the segment register anyway.

This retains start_stack as a virtual address, even though a physical
address would be more convenient for 32 bits; the 64-bit code wants
the other way around...

Reported-by: Matthieu Castet <castet.matthieu@free.fr>
LKML-Reference: <4D41E86D.8060205@free.fr>
Tested-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 69fd72aa5594..4d9ebbab2230 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -100,7 +100,7 @@ int acpi_save_state_mem(void)
 #else /* CONFIG_64BIT */
         header->trampoline_segment = setup_trampoline() >> 4;
 #ifdef CONFIG_SMP
-        stack_start.sp = temp_stack + sizeof(temp_stack);
+        stack_start = (unsigned long)temp_stack + sizeof(temp_stack);
         early_gdt_descr.address =
                         (unsigned long)get_cpu_gdt_table(smp_processor_id());
         initial_gs = per_cpu_offset(smp_processor_id());