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[108.51.35.162]) by smtp.gmail.com with ESMTPSA id w3sm11577212qkc.10.2020.09.07.11.17.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Sep 2020 11:17:19 -0700 (PDT) From: Sean Anderson To: u-boot@lists.denx.de Cc: Rick Chen , Heinrich Schuchardt , Bin Meng , Sean Anderson Subject: [PATCH 5/7] riscv: Add fence to available_harts_lock Date: Mon, 7 Sep 2020 14:16:57 -0400 Message-Id: <20200907181659.92449-6-seanga2@gmail.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200907181659.92449-1-seanga2@gmail.com> References: <20200907181659.92449-1-seanga2@gmail.com> MIME-Version: 1.0 X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.34 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" X-Virus-Scanned: clamav-milter 0.102.3 at phobos.denx.de X-Virus-Status: Clean 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 --- 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