[kvm-unit-tests RFC PATCH 09/19] arm/arm64: Zero secondary CPUs' stack

[Alexandru Elisei <alexandru.elisei@arm.com>]

For the boot CPU, the entire stack is zeroed in the entry code. For the
secondaries, only struct thread_info, which lives at the bottom of the
stack, is zeroed in thread_info_init().

Be consistent and zero the entire stack for the secondaries. This should
also improve reproducibility of the testsuite, as all the stacks now start
with the same contents, which is zero. And now that all the stacks are
zeroed in the entry code, there is no need to explicitely zero struct
thread_info in thread_info_init().

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---
 arm/cstart.S          | 6 ++++++
 arm/cstart64.S        | 3 +++
 lib/arm/processor.c   | 1 -
 lib/arm64/processor.c | 1 -
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arm/cstart.S b/arm/cstart.S
index 39260e0fa470..39e70f40986a 100644
--- a/arm/cstart.S
+++ b/arm/cstart.S
@@ -151,7 +151,13 @@ secondary_entry:
 	 */
 	ldr	r1, =secondary_data
 	ldr	r0, [r1]
+	mov	r2, r0
+	lsr	r2, #THREAD_SHIFT
+	lsl	r2, #THREAD_SHIFT
+	add	r3, r2, #THREAD_SIZE
+	zero_range r2, r3, r4, r5
 	mov	sp, r0
+
 	bl	exceptions_init
 	bl	enable_vfp
 
diff --git a/arm/cstart64.S b/arm/cstart64.S
index d62360cf3859..54773676d1d5 100644
--- a/arm/cstart64.S
+++ b/arm/cstart64.S
@@ -156,6 +156,9 @@ secondary_entry:
 	/* set the stack */
 	adrp	x0, secondary_data
 	ldr	x0, [x0, :lo12:secondary_data]
+	and	x1, x0, #THREAD_MASK
+	add	x2, x1, #THREAD_SIZE
+	zero_range x1, x2
 	mov	sp, x0
 
 	/* finish init in C code */
diff --git a/lib/arm/processor.c b/lib/arm/processor.c
index 9d5759686b73..ceff1c0a1bd2 100644
--- a/lib/arm/processor.c
+++ b/lib/arm/processor.c
@@ -117,7 +117,6 @@ void do_handle_exception(enum vector v, struct pt_regs *regs)
 
 void thread_info_init(struct thread_info *ti, unsigned int flags)
 {
-	memset(ti, 0, sizeof(struct thread_info));
 	ti->cpu = mpidr_to_cpu(get_mpidr());
 	ti->flags = flags;
 }
diff --git a/lib/arm64/processor.c b/lib/arm64/processor.c
index 831207c16587..268b2858f0be 100644
--- a/lib/arm64/processor.c
+++ b/lib/arm64/processor.c
@@ -232,7 +232,6 @@ void install_vector_handler(enum vector v, vector_fn fn)
 
 static void __thread_info_init(struct thread_info *ti, unsigned int flags)
 {
-	memset(ti, 0, sizeof(struct thread_info));
 	ti->cpu = mpidr_to_cpu(get_mpidr());
 	ti->flags = flags;
 }
-- 
2.37.1