New patch to review for coreboot: arch/x86: always use _start as entry symbol for all stages

[Aaron Durbin]

Aaron Durbin ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13882

-gerrit

commit b4f2e69b8f391e9c6e5e01b8909415027dd0c5c9
Author: Aaron Durbin 
Date:   Wed Mar 2 15:26:10 2016 -0600

arch/x86: always use _start as entry symbol for all stages

Instead of keeping track of all the combinations of entry points
    depending on the stage and other options just use _start. That way,
    there's no need to update the arch/header.ld for complicated cases
    as _start is always the entry point for a stage.

Change-Id: I7795a5ee1caba92ab533bdb8c3ad80294901a48b
    Signed-off-by: Aaron Durbin 
---
 src/arch/x86/include/arch/header.ld | 23 -----------------------
 src/cpu/x86/32bit/entry32.inc       | 12 ++++++++++--
 2 files changed, 10 insertions(+), 25 deletions(-)

diff --git a/src/arch/x86/include/arch/header.ld b/src/arch/x86/include/arch/header.ld
index d7fbf07..77eb187 100644
--- a/src/arch/x86/include/arch/header.ld
+++ b/src/arch/x86/include/arch/header.ld
@@ -20,27 +20,4 @@ PHDRS
    to_load PT_LOAD;
 }

-/*
- * For CONFIG_SEPARATE_VERSTAGE romstage doesn't have the cache-as-ram setup.
- * It only contains the teardown code. The verstage has the cache-as-ram setup
- * code. Therefore, it needs the protected_start symbol as its entry point.
- * The romstage entry will be named _start for consistency, but it's likely
- * to be implemented in the chipset code in order to control the logic flow.
- */
-#if IS_ENABLED(CONFIG_SEPARATE_VERSTAGE)
-	#if ENV_RAMSTAGE || ENV_RMODULE || ENV_ROMSTAGE
-	ENTRY(_start)
-	#elif ENV_VERSTAGE
-	ENTRY(protected_start)
-	#endif
-#else
-	#if ENV_RAMSTAGE || ENV_RMODULE
-	ENTRY(_start)
-	#elif ENV_ROMSTAGE
-	ENTRY(protected_start)
-	#endif
-#endif
-
-#if IS_ENABLED(CONFIG_C_ENVIRONMENT_BOOTBLOCK) && ENV_BOOTBLOCK
 ENTRY(_start)
-#endif
diff --git a/src/cpu/x86/32bit/entry32.inc b/src/cpu/x86/32bit/entry32.inc
index 9ef3bc1..8c39008 100644
--- a/src/cpu/x86/32bit/entry32.inc
+++ b/src/cpu/x86/32bit/entry32.inc
@@ -2,6 +2,7 @@

#include <arch/rom_segs.h>
 #include <cpu/x86/post_code.h>
+#include <rules.h>

.code32

@@ -44,10 +45,17 @@ gdt_end:
  *
  *	NOTE aligned to 4 so that we are sure that the prefetch
  *	cache will be reloaded.
+ *
+ *	In the bootblock there is already a ljmp to __protected_start and
+ *	the reset vector jumps to symbol _start16bit in entry16.inc from
+ *	the reset vectors's symbol which is _start. Therefore, don't
+ *	expose the _start symbol for bootblock.
  */
    .align	4
-.globl protected_start
-protected_start:
+#if !ENV_BOOTBLOCK
+.globl _start
+_start:
+#endif

lgdt	%cs:gdtptr
    ljmp	$ROM_CODE_SEG, $__protected_start