From 309995b315b9ffef999810af212cccb7a50004bc Mon Sep 17 00:00:00 2001 From: Sean Anderson Date: Mon, 21 Sep 2020 07:51:39 -0400 Subject: [PATCH] riscv: Consolidate fences into AMOs for available_harts_lock We can reduce the number of instructions needed to use available_harts_lock by using the aq and rl suffixes for AMOs. Signed-off-by: Sean Anderson Reviewed-by: Bin Meng Reviewed-by: Rick Chen --- arch/riscv/cpu/start.S | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index e3222b1ea7..66ca1c7020 100644 --- a/arch/riscv/cpu/start.S +++ b/arch/riscv/cpu/start.S @@ -125,14 +125,12 @@ 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) - fence r, rw +1: amoswap.w.aq t1, t1, 0(t0) bnez t1, 1b /* register available harts in the available_harts mask */ @@ -142,8 +140,7 @@ wait_for_gd_init: or t2, t2, t1 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 -- 2.39.5