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From: Sean Anderson <seanga2@gmail.com>
To: u-boot@lists.denx.de
Subject: [PATCH 2/7] riscv: Match memory barriers between send_ipi_many and handle_ipi
Date: Mon,  7 Sep 2020 14:16:54 -0400	[thread overview]
Message-ID: <20200907181659.92449-3-seanga2@gmail.com> (raw)
In-Reply-To: <20200907181659.92449-1-seanga2@gmail.com>

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: 90ae28143700bae4edd23930a7772899ad259058
Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

 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);
-- 
2.28.0

  parent reply	other threads:[~2020-09-07 18:16 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-07 18:16 [PATCH 0/7] riscv: Correctly handle IPIs already pending upon boot Sean Anderson
2020-09-07 18:16 ` [PATCH 1/7] Revert "riscv: Clear pending interrupts before enabling IPIs" Sean Anderson
2020-09-09  7:50   ` Rick Chen
2020-09-09 10:23     ` Sean Anderson
2020-09-10  6:39       ` Rick Chen
2020-09-10 10:18         ` Sean Anderson
2020-09-11  7:38   ` Bin Meng
2020-09-11 10:22     ` Sean Anderson
2020-09-11 14:45       ` Bin Meng
2020-09-11 18:30         ` Sean Anderson
2020-09-14  3:10           ` Rick Chen
2020-09-14 12:45             ` Sean Anderson
2020-09-07 18:16 ` Sean Anderson [this message]
2020-09-11  7:45   ` [PATCH 2/7] riscv: Match memory barriers between send_ipi_many and handle_ipi Bin Meng
2020-09-07 18:16 ` [PATCH 3/7] riscv: Use NULL as a sentinel value for smp_call_function Sean Anderson
2020-09-09  8:33   ` Rick Chen
2020-09-09  9:01     ` Rick Chen
2020-09-09 10:16       ` Sean Anderson
2020-09-09 10:26         ` Heinrich Schuchardt
2020-09-09 10:36           ` Sean Anderson
2020-09-10  8:09         ` Rick Chen
2020-09-14  3:21         ` Rick Chen
2020-09-11  8:04   ` Bin Meng
2020-09-14  1:58     ` Leo Liang
2020-09-14  2:07       ` Bin Meng
2020-09-14  6:10         ` Leo Liang
2020-09-14  6:15           ` Bin Meng
2020-09-14 14:05     ` Sean Anderson
2020-09-07 18:16 ` [PATCH 4/7] riscv: Clear pending IPIs on initialization Sean Anderson
2020-09-14  2:08   ` Bin Meng
2020-09-07 18:16 ` [PATCH 5/7] riscv: Add fence to available_harts_lock Sean Anderson
2020-09-10  3:26   ` Rick Chen
2020-09-11 10:39     ` Sean Anderson
2020-09-11 14:47   ` Bin Meng
2020-09-07 18:16 ` [PATCH 6/7] riscv: Ensure gp is NULL or points to valid data Sean Anderson
2020-09-14  5:25   ` Bin Meng
2020-09-14 13:03     ` Sean Anderson
2020-09-14 13:27       ` Sean Anderson
2020-09-07 18:16 ` [PATCH 7/7] riscv: Add some comments to start.S Sean Anderson
2020-09-14  5:26   ` Bin Meng
2020-09-09  2:02 ` [PATCH 0/7] riscv: Correctly handle IPIs already pending upon boot Rick Chen
2020-09-09  2:38   ` Sean Anderson
2020-09-09  2:44     ` Sean Anderson
2020-09-10  7:08     ` Rick Chen
2020-09-10 10:49       ` Sean Anderson

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