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From: Rick Chen <rickchen36@gmail.com>
To: u-boot@lists.denx.de
Subject: [PATCH 1/7] Revert "riscv: Clear pending interrupts before enabling IPIs"
Date: Thu, 10 Sep 2020 14:39:07 +0800	[thread overview]
Message-ID: <CAN5B=e+y7SFFx8JkAxopVc5t0jcoWw84XF2z4oPER1AM1JyBbA@mail.gmail.com> (raw)
In-Reply-To: <6b3713b5-8e79-5717-1e24-2e65f1cafb37@gmail.com>

Hi Sean

> On 9/9/20 3:50 AM, Rick Chen wrote:
> > Hi Sean
> >
> >> Clearing MIP doesn't do anything. Whoops. The following commits should
> >> tackle this problem in a more robust manner.
> >
> > I still not catch your points about that  this commit 947263033 really
> > help to fix  pending IPIs not clean problem on k210 platform at that
> > time, but you just said it do nothing and remove it here currently.
>
> After refactoring the original smp patch to remove the null check, I
> neglected to re-test with a debug uart enabled. Without doing that test,
> it is impossible to catch the pending IPI bug. The secondary hart will
> crash before the serial driver is initialized. I didn't do that test at
> the time, because I was mostly worried about the secondary hart
> corrupting the device tree and causing the boot to fail. That failure
> mode was fixed by 40686c394. So I saw that and thought that the pending
> IPI issue was solved as well.

Can you describe more clearly why with a debug uart enabled will
trigger the pending IPI bug ?

And why the pending IPI be raised and not clear before jump to U-Boot ?

Why the
csrc MODE_PREFIX(ip), t0
don't help to fix this bug ?

Thanks,
Rick


>
> --Sean
>
> >>
> >> This reverts commit 9472630337e7c4ac442066b5a752aaa8c3b4d4a6.
> >>
> >> Signed-off-by: Sean Anderson <seanga2@gmail.com>
> >> ---
> >>
> >>  arch/riscv/cpu/start.S | 2 --
> >>  1 file changed, 2 deletions(-)
> >>
> >> diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
> >> index bf9fdf369b..e3222b1ea7 100644
> >> --- a/arch/riscv/cpu/start.S
> >> +++ b/arch/riscv/cpu/start.S
> >> @@ -65,8 +65,6 @@ _start:
> >>  #else
> >>         li      t0, SIE_SSIE
> >>  #endif
> >> -       /* Clear any pending IPIs */
> >> -       csrc    MODE_PREFIX(ip), t0
> >>         csrs    MODE_PREFIX(ie), t0
> >>  #endif
> >>
> >> --
> >> 2.28.0
> >>
>

  reply	other threads:[~2020-09-10  6:39 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 [this message]
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 ` [PATCH 2/7] riscv: Match memory barriers between send_ipi_many and handle_ipi Sean Anderson
2020-09-11  7:45   ` 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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