[coreboot-gerrit] New patch to review for coreboot: arm64: Define stage_entry as weak symbol

[Patrick Georgi (pgeorgi@google.com)]

Patrick Georgi (pgeorgi at google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/10897

-gerrit

commit 7c9eba16a7da49de650905e43a81c4f761086b7a
Author: Furquan Shaikh <furquan at google.com>
Date:   Fri Jul 10 15:25:26 2015 -0700

    arm64: Define stage_entry as weak symbol
    
    This allows SoCs/CPUs to have custom stage_entry in order to apply any
    fixups that need to run before standard cpu reset procedure.
    
    BUG=chrome-os-partner:41877
    BRANCH=None
    TEST=Compiles successfully
    
    Change-Id: Iaae7636349140664b19e81b0082017b63b13f45b
    Signed-off-by: Patrick Georgi <pgeorgi at chromium.org>
    Original-Commit-Id: 498d04b0e9a3394943f03cad603c30ae8b3805d4
    Original-Change-Id: I9a005502d4cfcb76017dcae3a655efc0c8814a93
    Original-Signed-off-by: Furquan Shaikh <furquan at google.com>
    Original-Reviewed-on: https://chromium-review.googlesource.com/284867
    Original-Trybot-Ready: Furquan Shaikh <furquan at chromium.org>
    Original-Tested-by: Furquan Shaikh <furquan at chromium.org>
    Original-Reviewed-by: Aaron Durbin <adurbin at chromium.org>
    Original-Commit-Queue: Furquan Shaikh <furquan at chromium.org>
---
 src/arch/arm64/include/arch/asm.h | 4 ++++
 src/arch/arm64/stage_entry.S      | 8 +++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/arch/arm64/include/arch/asm.h b/src/arch/arm64/include/arch/asm.h
index 0dc2974..851f3f9 100644
--- a/src/arch/arm64/include/arch/asm.h
+++ b/src/arch/arm64/include/arch/asm.h
@@ -41,4 +41,8 @@
  */
 #define CPU_RESET_ENTRY(name) ENTRY_WITH_ALIGN(name, 6)
 
+#define ENTRY_WEAK(name)	\
+	ENTRY(name)		\
+	.weak name		\
+
 #endif	/* __ARM_ARM64_ASM_H */
diff --git a/src/arch/arm64/stage_entry.S b/src/arch/arm64/stage_entry.S
index 5ff2c4e..4e15dbb 100644
--- a/src/arch/arm64/stage_entry.S
+++ b/src/arch/arm64/stage_entry.S
@@ -228,6 +228,12 @@ CPU_RESET_ENTRY(arm64_cpu_startup_resume)
 	b	arm64_c_environment
 ENDPROC(arm64_cpu_startup_resume)
 
-ENTRY(stage_entry)
+/*
+ * stage_entry is defined as a weak symbol to allow SoCs/CPUs to define a custom
+ * entry point to perform any fixups that need to be done immediately after
+ * power on reset. In case SoC/CPU does not need any custom-defined entrypoint,
+ * this weak symbol can be used to jump directly to arm64_cpu_startup.
+ */
+ENTRY_WEAK(stage_entry)
 	b	arm64_cpu_startup
 ENDPROC(stage_entry)