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From: Peter Maydell <peter.maydell@linaro.org>
To: qemu-arm@nongnu.org, qemu-devel@nongnu.org
Cc: Richard Henderson <richard.henderson@linaro.org>
Subject: [PATCH for-5.1] hw/timer/imx_epit: Avoid assertion when CR.SWR is written
Date: Mon, 12 Oct 2020 16:33:42 +0100	[thread overview]
Message-ID: <20201012153408.9747-20-peter.maydell@linaro.org> (raw)
In-Reply-To: <20201012153408.9747-1-peter.maydell@linaro.org>

The imx_epit device has a software-controllable reset triggered by
setting the SWR bit in the CR register. An error in commit cc2722ec83ad9
means that we will end up assert()ing if the guest does this, because
the code in imx_epit_write() starts ptimer transactions, and then
imx_epit_reset() also starts ptimre transactions, triggering
"ptimer_transaction_begin: Assertion `!s->in_transaction' failed".

The cleanest way to avoid this double-transaction is to move the
start-transaction for the CR write handling down below the check of
the SWR bit.

Fixes: https://bugs.launchpad.net/qemu/+bug/1880424
Fixes: cc2722ec83ad944505fe
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
I don't have a test image for KZM so this is the minimal
obviously-safe change. I'm pretty sure that actually we could
add a "break" after the imx_epit_reset() call because all of
the work done by the following code is duplicating the ptimer
setup done by the reset function. But I'm not really happy making
that change without a test image...
---
 hw/timer/imx_epit.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/timer/imx_epit.c b/hw/timer/imx_epit.c
index baf6338e1a6..4f51e6e12da 100644
--- a/hw/timer/imx_epit.c
+++ b/hw/timer/imx_epit.c
@@ -199,15 +199,18 @@ static void imx_epit_write(void *opaque, hwaddr offset, uint64_t value,
 
     switch (offset >> 2) {
     case 0: /* CR */
-        ptimer_transaction_begin(s->timer_cmp);
-        ptimer_transaction_begin(s->timer_reload);
 
         oldcr = s->cr;
         s->cr = value & 0x03ffffff;
         if (s->cr & CR_SWR) {
             /* handle the reset */
             imx_epit_reset(DEVICE(s));
-        } else {
+        }
+
+        ptimer_transaction_begin(s->timer_cmp);
+        ptimer_transaction_begin(s->timer_reload);
+
+        if (!(s->cr & CR_SWR)) {
             imx_epit_set_freq(s);
         }
 
-- 
2.20.1



  parent reply	other threads:[~2020-10-12 15:56 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-12 15:33 [PATCH 00/10] target/arm: Various v8.1M minor features Peter Maydell
2020-10-12 15:33 ` [PATCH] Deprecate TileGX port Peter Maydell
2020-10-12 15:42   ` BALATON Zoltan via
2020-10-12 15:44     ` Peter Maydell
2020-10-12 15:33 ` [PATCH] Deprecate Unicore32 port Peter Maydell
2020-10-12 15:33 ` [PATCH] Deprecate lm32 port Peter Maydell
2020-10-12 15:33 ` [PATCH for-5.1] Makefile: Remove config-devices.mak on "make clean" Peter Maydell
2020-10-12 15:33 ` [PATCH RISU] arm.risu: Add patterns for fp16 insns Peter Maydell
2020-10-12 15:33 ` [PATCH RISU] arm.risu, thumb.risu: Add v8.2 DP and FHM insns Peter Maydell
2020-10-12 15:33 ` [PATCH] configure: Test that gio libs from pkg-config work Peter Maydell
2020-10-12 15:33 ` [PATCH 01/10] decodetree: Fix codegen for non-overlapping group inside overlapping group Peter Maydell
2020-10-12 15:33 ` [PATCH for-5.1] docs/system/arm/virt: Document mte machine option Peter Maydell
2020-10-12 15:45   ` no-reply
2020-10-12 15:33 ` [PATCH for-5.1] hw/arm/armsse: Assert info->num_cpus is in-bounds in armsse_realize() Peter Maydell
2020-10-12 15:33 ` [PATCH] hw/arm/mps2: New board model mps2-386 Peter Maydell
2020-10-12 15:33 ` [PATCH for-5.1] hw/arm/netduino2, netduinoplus2: Set system_clock_scale Peter Maydell
2020-10-14  0:29   ` Alistair Francis
2020-10-14  0:31     ` Alistair Francis
2020-10-14 12:39       ` Peter Maydell
2020-10-14 14:32         ` Alistair Francis
2020-10-12 15:33 ` [PATCH for-5.1] hw/arm/nrf51_soc: " Peter Maydell
2020-10-12 15:33 ` [PATCH] hw/display/bcm2835_fb.c: Initialize all fields of struct Peter Maydell
2020-10-12 15:33 ` [PATCH] hw/input/virtio-input-hid.c: Don't undef CONFIG_CURSES Peter Maydell
2020-10-12 15:33 ` [PATCH] hw/intc/arm_gicv3_cpuif: Don't copy CPU's maintenance interrupt Peter Maydell
2020-10-12 15:33 ` [PATCH] hw/intc/arm_gicv3_cpuif: Make GIC maintenance interrupts work Peter Maydell
2020-10-12 15:33 ` [PATCH] hw/timer/armv7m_systick: assert that board code set system_clock_scale Peter Maydell
2020-10-12 15:33 ` Peter Maydell [this message]
2020-10-12 15:33 ` [PATCH] hw/virtio/virtio-iommu-pci.c: Fix typo in error message Peter Maydell
2020-10-12 15:33 ` [RFC PATCH v2] linux-user: Use FD_32BIT_MODE fd flag for 32-bit guests Peter Maydell
2020-10-12 15:33 ` [PATCH] linux-user/arm/signal.c: Drop TARGET_CONFIG_CPU_32 Peter Maydell
2020-10-12 15:33 ` [PATCH] meson.build: Don't look for libudev for static builds Peter Maydell
2020-10-12 15:33 ` [PATCH] msf2-soc, stellaris: Don't wire up SYSRESETREQ Peter Maydell
2020-10-12 15:33 ` [PATCH] net/tap-solaris.c: Include qemu-common.h for TFR macro Peter Maydell
2020-10-12 15:33 ` [PATCH] osdep.h: Add doc comment for qemu_get_thread_id() Peter Maydell
2020-10-12 15:33 ` [PATCH for-5.1] qapi/machine.json: Fix missing newline in doc comment Peter Maydell
2020-10-12 15:33 ` [PATCH v2] target/arm: Allow user-mode code to write CPSR.E via MSR Peter Maydell
2020-10-12 15:33 ` [PATCH] target/arm: Delete unused ARM_FEATURE_CRC Peter Maydell
2020-10-12 15:33 ` [PATCH] target/arm: Delete unused VFP_DREG macros Peter Maydell
  -- strict thread matches above, loose matches on Subject: below --
2020-07-27 15:45 [PATCH for-5.1] hw/timer/imx_epit: Avoid assertion when CR.SWR is written Peter Maydell
2020-08-03 15:12 ` Philippe Mathieu-Daudé

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