cpu/x86/smm: Add smm_size to relocatable smmstub

To mitigate against sinkhole in software which is required on
pre-sandybridge hardware, the smm entry point needs to check if the
LAPIC base is between smbase and smbase + smmsize. The size needs to
be available early so add them to the relocatable module parameters.

When the smmstub is used to relocate SMM the default SMM size 0x10000
is provided. On the permanent handler the size provided by
get_smm_info() is used.

Change-Id: I0df6e51bcba284350f1c849ef3d012860757544b
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37288
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/include/cpu/x86/smm.h

@@ -63,6 +63,7 @@ extern unsigned char _binary_smm_end[];
 
 struct smm_runtime {
 	u32 smbase;
+	u32 smm_size;
 	u32 save_state_size;
 	u32 num_cpus;
 	/* STM's 32bit entry into SMI handler */