From d4990a46485f2f6592ae29f2b822043dbdeae15d Mon Sep 17 00:00:00 2001 From: Sean Anderson Date: Mon, 21 Sep 2020 07:51:36 -0400 Subject: [PATCH] riscv: Match memory barriers between send_ipi_many and handle_ipi Without a matching barrier on the write side, the barrier in handle_ipi does nothing. It was entirely possible for the boot hart to write to addr, arg0, and arg1 *after* sending the IPI, because there was no barrier on the sending side. Fixes: 90ae281437 ("riscv: add option to wait for ack from secondary harts in smp functions") Signed-off-by: Sean Anderson Reviewed-by: Bin Meng Reviewed-by: Rick Chen Reviewed-by: Leo Liang --- arch/riscv/lib/smp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c index ac22136314..ab6d8bd7fa 100644 --- a/arch/riscv/lib/smp.c +++ b/arch/riscv/lib/smp.c @@ -54,6 +54,8 @@ static int send_ipi_many(struct ipi_data *ipi, int wait) gd->arch.ipi[reg].arg0 = ipi->arg0; gd->arch.ipi[reg].arg1 = ipi->arg1; + __smp_mb(); + ret = riscv_send_ipi(reg); if (ret) { pr_err("Cannot send IPI to hart %d\n", reg); -- 2.39.5