retpoline: add indirect thunk support

for gcc version > 7.3, enable CONFIG_RETPOLINE

Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>

hypervisor/bsp/ld/link_ram.ld.in

@@ -30,6 +30,7 @@ SECTIONS
         *(.text .text*) ;
         *(.gnu.linkonce.t*)
         *(.note.gnu.build-id)
+        *(.retpoline_thunk)
     } > ram
 
     .rodata :

hypervisor/bsp/sbl/include/bsp/bsp_cfg.h

@@ -45,5 +45,4 @@
 #define	CONFIG_LOW_RAM_SIZE	0x000CF000
 #define	CONFIG_RAM_START	0x6E000000
 #define	CONFIG_RAM_SIZE		0x02000000	/* 32M */
-#define	CONFIG_RETPOLINE
 #endif /* BSP_CFG_H */

hypervisor/bsp/uefi/include/bsp/bsp_cfg.h

@@ -48,5 +48,4 @@
 #define	CONFIG_DMAR_PARSE_ENABLED	1
 #define	CONFIG_GPU_SBDF		0x00000010	/* 0000:00:02.0 */
 #define CONFIG_EFI_STUB       1
-#define	CONFIG_RETPOLINE
 #endif /* BSP_CFG_H */