[coreboot-gerrit] New patch to review for coreboot: 0e14942 arm64: add indirection to C entry point

[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/9015

-gerrit

commit 0e14942db1dc6d3defb97bed658aa03cce786e30
Author: Aaron Durbin <adurbin at chromium.org>
Date:   Wed Aug 27 15:52:01 2014 -0500

    arm64: add indirection to C entry point
    
    To allow setting the entry point for the secondary CPUs
    provide a pointer, c_entry, which contains the location
    to branch to after setting up the stack.
    
    BUG=chrome-os-partner:31545
    BRANCH=None
    TEST=Built and booted to the kernel on ryu.
    
    Change-Id: I03e54b081aa5ff70b90fbd7f1b243fdb4f42c5a6
    Signed-off-by: Patrick Georgi <pgeorgi at chromium.org>
    Original-Commit-Id: f692c5814ea5c7ff4895576e1db8361ff3b7d9fb
    Original-Change-Id: Ic2f6c79cde708b24c379345aed1e2cc0760ccad8
    Original-Signed-off-by: Aaron Durbin <adurbin at chromium.org>
    Original-Reviewed-on: https://chromium-review.googlesource.com/214771
    Original-Reviewed-by: Furquan Shaikh <furquan at chromium.org>
---
 src/arch/arm64/c_entry.c     | 8 ++++++++
 src/arch/arm64/stage_entry.S | 8 +++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/arch/arm64/c_entry.c b/src/arch/arm64/c_entry.c
index f08a585..3e9d44e 100644
--- a/src/arch/arm64/c_entry.c
+++ b/src/arch/arm64/c_entry.c
@@ -20,6 +20,14 @@
 #include <arch/stages.h>
 #include <arch/cpu.h>
 
+
+/*
+ * This variable holds entry point for CPUs starting up. Before the other
+ * CPUs are brought up this value will change to provide the secondary
+ * code path.
+ */
+void (*c_entry)(void) = &arm64_init;
+
 void __attribute__((weak)) arm64_soc_init(void)
 {
 	/* Default weak implementation does nothing. */
diff --git a/src/arch/arm64/stage_entry.S b/src/arch/arm64/stage_entry.S
index 8613655..e323de5 100644
--- a/src/arch/arm64/stage_entry.S
+++ b/src/arch/arm64/stage_entry.S
@@ -99,7 +99,13 @@ ENTRY(arm64_c_environment)
 	bl	cpu_get_stack
 	mov	sp, x0
 
-	b	arm64_init
+	/* Get entry point by dereferencing c_entry. */
+	ldr	x0, 1f
+	ldr	x0, [x0]
+	br	x0
+.align 3
+	1:
+	.quad	c_entry
 ENDPROC(arm64_c_environment)
 
 CPU_RESET_ENTRY(arm64_cpu_startup)