[PATCH 5/7] riscv: Add fence to available_harts_lock

[Sean Anderson]

Without these fences, it is perfectly valid for an out-of-order core to
re-order memory accesses to outside of the available_harts_lock critical
section.

Signed-off-by: Sean Anderson <seanga2 at gmail.com>
---

 arch/riscv/cpu/start.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
index e3222b1ea7..ad18e746b6 100644
--- a/arch/riscv/cpu/start.S
+++ b/arch/riscv/cpu/start.S
@@ -126,12 +126,12 @@ call_board_init_f_0:
 #ifndef CONFIG_XIP
 	la	t0, available_harts_lock
 	fence	rw, w
-	amoswap.w zero, zero, 0(t0)
+	amoswap.w.rl zero, zero, 0(t0)
 
 wait_for_gd_init:
 	la	t0, available_harts_lock
 	li	t1, 1
-1:	amoswap.w t1, t1, 0(t0)
+1:	amoswap.w.aq t1, t1, 0(t0)
 	fence	r, rw
 	bnez	t1, 1b
 
@@ -143,7 +143,7 @@ wait_for_gd_init:
 	SREG	t2, GD_AVAILABLE_HARTS(gp)
 
 	fence	rw, w
-	amoswap.w zero, zero, 0(t0)
+	amoswap.w.rl zero, zero, 0(t0)
 
 	/*
 	 * Continue on hart lottery winner, others branch to
-- 
2.28.0