This is a note to let you know that I've just added the patch titled
iio: imu: fxos8700: fix IMU data bits returned to user space
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From a53f945879c0cb9de3a4c05a665f5157884b5208 Mon Sep 17 00:00:00 2001
From: Carlos Song <carlos.song(a)nxp.com>
Date: Thu, 8 Dec 2022 15:19:08 +0800
Subject: iio: imu: fxos8700: fix IMU data bits returned to user space
ACCEL output data registers contain the X-axis, Y-axis, and Z-axis
14-bit left-justified sample data and MAGN output data registers
contain the X-axis, Y-axis, and Z-axis 16-bit sample data. The ACCEL
raw register output data should be divided by 4 before sent to
userspace.
Apply a 2 bits signed right shift to the raw data from ACCEL output
data register but keep that from MAGN sensor as the origin.
Fixes: 84e5ddd5c46e ("iio: imu: Add support for the FXOS8700 IMU")
Signed-off-by: Carlos Song <carlos.song(a)nxp.com>
Link: https://lore.kernel.org/r/20221208071911.2405922-5-carlos.song@nxp.com
Cc: <Stable(a)vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com>
---
drivers/iio/imu/fxos8700_core.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/imu/fxos8700_core.c b/drivers/iio/imu/fxos8700_core.c
index b62bc92bbacc..06948a8cc315 100644
--- a/drivers/iio/imu/fxos8700_core.c
+++ b/drivers/iio/imu/fxos8700_core.c
@@ -394,6 +394,7 @@ static int fxos8700_get_data(struct fxos8700_data *data, int chan_type,
int axis, int *val)
{
u8 base, reg;
+ s16 tmp;
int ret;
/*
@@ -421,8 +422,33 @@ static int fxos8700_get_data(struct fxos8700_data *data, int chan_type,
/* Convert axis to buffer index */
reg = axis - IIO_MOD_X;
+ /*
+ * Convert to native endianness. The accel data and magn data
+ * are signed, so a forced type conversion is needed.
+ */
+ tmp = be16_to_cpu(data->buf[reg]);
+
+ /*
+ * ACCEL output data registers contain the X-axis, Y-axis, and Z-axis
+ * 14-bit left-justified sample data and MAGN output data registers
+ * contain the X-axis, Y-axis, and Z-axis 16-bit sample data. Apply
+ * a signed 2 bits right shift to the readback raw data from ACCEL
+ * output data register and keep that from MAGN sensor as the origin.
+ * Value should be extended to 32 bit.
+ */
+ switch (chan_type) {
+ case IIO_ACCEL:
+ tmp = tmp >> 2;
+ break;
+ case IIO_MAGN:
+ /* Nothing to do */
+ break;
+ default:
+ return -EINVAL;
+ }
+
/* Convert to native endianness */
- *val = sign_extend32(be16_to_cpu(data->buf[reg]), 15);
+ *val = sign_extend32(tmp, 15);
return 0;
}
--
2.39.1
This is a note to let you know that I've just added the patch titled
iio: imu: fxos8700: fix incomplete ACCEL and MAGN channels readback
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From 37a94d86d7050665d6d01378b2c916c28e454f10 Mon Sep 17 00:00:00 2001
From: Carlos Song <carlos.song(a)nxp.com>
Date: Thu, 8 Dec 2022 15:19:07 +0800
Subject: iio: imu: fxos8700: fix incomplete ACCEL and MAGN channels readback
The length of ACCEL and MAGN 3-axis channels output data is 6 byte
individually. However block only read 3 bytes data into buffer from
ACCEL or MAGN output data registers every time. It causes an incomplete
ACCEL and MAGN channels readback.
Set correct value count for regmap_bulk_read to get 6 bytes ACCEL and
MAGN channels readback.
Fixes: 84e5ddd5c46e ("iio: imu: Add support for the FXOS8700 IMU")
Signed-off-by: Carlos Song <carlos.song(a)nxp.com>
Link: https://lore.kernel.org/r/20221208071911.2405922-4-carlos.song@nxp.com
Cc: <Stable(a)vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com>
---
drivers/iio/imu/fxos8700_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iio/imu/fxos8700_core.c b/drivers/iio/imu/fxos8700_core.c
index 977eb7dc7dbd..b62bc92bbacc 100644
--- a/drivers/iio/imu/fxos8700_core.c
+++ b/drivers/iio/imu/fxos8700_core.c
@@ -414,7 +414,7 @@ static int fxos8700_get_data(struct fxos8700_data *data, int chan_type,
/* Block read 6 bytes of device output registers to avoid data loss */
ret = regmap_bulk_read(data->regmap, base, data->buf,
- FXOS8700_DATA_BUF_SIZE);
+ sizeof(data->buf));
if (ret)
return ret;
--
2.39.1
This is a note to let you know that I've just added the patch titled
iio: imu: fxos8700: fix swapped ACCEL and MAGN channels readback
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From c68b44bc7d9b1469774a1c985ee71d2cbc5ebef5 Mon Sep 17 00:00:00 2001
From: Carlos Song <carlos.song(a)nxp.com>
Date: Thu, 8 Dec 2022 15:19:06 +0800
Subject: iio: imu: fxos8700: fix swapped ACCEL and MAGN channels readback
Because ACCEL and MAGN channels data register base address is
swapped the accelerometer and magnetometer channels readback is
swapped.
Fixes: 84e5ddd5c46e ("iio: imu: Add support for the FXOS8700 IMU")
Signed-off-by: Carlos Song <carlos.song(a)nxp.com>
Link: https://lore.kernel.org/r/20221208071911.2405922-3-carlos.song@nxp.com
Cc: <Stable(a)vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com>
---
drivers/iio/imu/fxos8700_core.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/imu/fxos8700_core.c b/drivers/iio/imu/fxos8700_core.c
index 235b02b2f4e5..977eb7dc7dbd 100644
--- a/drivers/iio/imu/fxos8700_core.c
+++ b/drivers/iio/imu/fxos8700_core.c
@@ -395,9 +395,22 @@ static int fxos8700_get_data(struct fxos8700_data *data, int chan_type,
{
u8 base, reg;
int ret;
- enum fxos8700_sensor type = fxos8700_to_sensor(chan_type);
- base = type ? FXOS8700_OUT_X_MSB : FXOS8700_M_OUT_X_MSB;
+ /*
+ * Different register base addresses varies with channel types.
+ * This bug hasn't been noticed before because using an enum is
+ * really hard to read. Use an a switch statement to take over that.
+ */
+ switch (chan_type) {
+ case IIO_ACCEL:
+ base = FXOS8700_OUT_X_MSB;
+ break;
+ case IIO_MAGN:
+ base = FXOS8700_M_OUT_X_MSB;
+ break;
+ default:
+ return -EINVAL;
+ }
/* Block read 6 bytes of device output registers to avoid data loss */
ret = regmap_bulk_read(data->regmap, base, data->buf,
--
2.39.1
This is a note to let you know that I've just added the patch titled
iio: imu: fxos8700: fix map label of channel type to MAGN sensor
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From 429e1e8ec696e0e7a0742904e3dc2f83b7b23dfb Mon Sep 17 00:00:00 2001
From: Carlos Song <carlos.song(a)nxp.com>
Date: Thu, 8 Dec 2022 15:19:05 +0800
Subject: iio: imu: fxos8700: fix map label of channel type to MAGN sensor
FXOS8700 is an IMU sensor with ACCEL sensor and MAGN sensor.
Sensor type is indexed by corresponding channel type in a switch.
IIO_ANGL_VEL channel type mapped to MAGN sensor has caused confusion.
Fix the mapping label of "IIO_MAGN" channel type instead of
"IIO_ANGL_VEL" channel type to MAGN sensor.
Fixes: 84e5ddd5c46e ("iio: imu: Add support for the FXOS8700 IMU")
Signed-off-by: Carlos Song <carlos.song(a)nxp.com>
Link: https://lore.kernel.org/r/20221208071911.2405922-2-carlos.song@nxp.com
Cc: <Stable(a)vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com>
---
drivers/iio/imu/fxos8700_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iio/imu/fxos8700_core.c b/drivers/iio/imu/fxos8700_core.c
index 423cfe526f2a..235b02b2f4e5 100644
--- a/drivers/iio/imu/fxos8700_core.c
+++ b/drivers/iio/imu/fxos8700_core.c
@@ -320,7 +320,7 @@ static enum fxos8700_sensor fxos8700_to_sensor(enum iio_chan_type iio_type)
switch (iio_type) {
case IIO_ACCEL:
return FXOS8700_ACCEL;
- case IIO_ANGL_VEL:
+ case IIO_MAGN:
return FXOS8700_MAGN;
default:
return -EINVAL;
--
2.39.1
This is a note to let you know that I've just added the patch titled
iio:adc:twl6030: Enable measurements of VUSB, VBAT and others
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From f804bd0dc28683a93a60f271aaefb2fc5b0853dd Mon Sep 17 00:00:00 2001
From: Andreas Kemnade <andreas(a)kemnade.info>
Date: Thu, 1 Dec 2022 19:16:35 +0100
Subject: iio:adc:twl6030: Enable measurements of VUSB, VBAT and others
Some inputs need to be wired up to produce proper measurements,
without this change only near zero values are reported.
Signed-off-by: Andreas Kemnade <andreas(a)kemnade.info>
Fixes: 1696f36482e70 ("iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver")
Link: https://lore.kernel.org/r/20221201181635.3522962-1-andreas@kemnade.info
Cc: <Stable(a)vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com>
---
drivers/iio/adc/twl6030-gpadc.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/drivers/iio/adc/twl6030-gpadc.c b/drivers/iio/adc/twl6030-gpadc.c
index f53e8558b560..40438e5b4970 100644
--- a/drivers/iio/adc/twl6030-gpadc.c
+++ b/drivers/iio/adc/twl6030-gpadc.c
@@ -57,6 +57,18 @@
#define TWL6030_GPADCS BIT(1)
#define TWL6030_GPADCR BIT(0)
+#define USB_VBUS_CTRL_SET 0x04
+#define USB_ID_CTRL_SET 0x06
+
+#define TWL6030_MISC1 0xE4
+#define VBUS_MEAS 0x01
+#define ID_MEAS 0x01
+
+#define VAC_MEAS 0x04
+#define VBAT_MEAS 0x02
+#define BB_MEAS 0x01
+
+
/**
* struct twl6030_chnl_calib - channel calibration
* @gain: slope coefficient for ideal curve
@@ -927,6 +939,26 @@ static int twl6030_gpadc_probe(struct platform_device *pdev)
return ret;
}
+ ret = twl_i2c_write_u8(TWL_MODULE_USB, VBUS_MEAS, USB_VBUS_CTRL_SET);
+ if (ret < 0) {
+ dev_err(dev, "failed to wire up inputs\n");
+ return ret;
+ }
+
+ ret = twl_i2c_write_u8(TWL_MODULE_USB, ID_MEAS, USB_ID_CTRL_SET);
+ if (ret < 0) {
+ dev_err(dev, "failed to wire up inputs\n");
+ return ret;
+ }
+
+ ret = twl_i2c_write_u8(TWL6030_MODULE_ID0,
+ VBAT_MEAS | BB_MEAS | BB_MEAS,
+ TWL6030_MISC1);
+ if (ret < 0) {
+ dev_err(dev, "failed to wire up inputs\n");
+ return ret;
+ }
+
indio_dev->name = DRIVER_NAME;
indio_dev->info = &twl6030_gpadc_iio_info;
indio_dev->modes = INDIO_DIRECT_MODE;
--
2.39.1
This is a note to let you know that I've just added the patch titled
iio: imx8qxp-adc: fix irq flood when call imx8qxp_adc_read_raw()
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From 0fc3562a993c3dc41d1177b3983d9300d0db1d4d Mon Sep 17 00:00:00 2001
From: Frank Li <Frank.Li(a)nxp.com>
Date: Thu, 1 Dec 2022 09:01:10 -0500
Subject: iio: imx8qxp-adc: fix irq flood when call imx8qxp_adc_read_raw()
irq flood happen when run
cat /sys/bus/iio/devices/iio:device0/in_voltage1_raw
imx8qxp_adc_read_raw()
{
...
enable irq
/* adc start */
writel(1, adc->regs + IMX8QXP_ADR_ADC_SWTRIG);
^^^^ trigger irq flood.
wait_for_completion_interruptible_timeout();
readl(adc->regs + IMX8QXP_ADR_ADC_RESFIFO);
^^^^ clear irq here.
...
}
There is only FIFO watermark interrupt at this ADC controller.
IRQ line will be assert until software read data from FIFO.
So IRQ flood happen during wait_for_completion_interruptible_timeout().
Move FIFO read into irq handle to avoid irq flood.
Fixes: 1e23dcaa1a9f ("iio: imx8qxp-adc: Add driver support for NXP IMX8QXP ADC")
Cc: stable(a)vger.kernel.org
Signed-off-by: Frank Li <Frank.Li(a)nxp.com>
Reviewed-by: Cai Huoqing <cai.huoqing(a)linux.dev>
Reviewed-by: Haibo Chen <haibo.chen(a)nxp.com>
Link: https://lore.kernel.org/r/20221201140110.2653501-1-Frank.Li@nxp.com
Cc: <Stable(a)vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com>
---
drivers/iio/adc/imx8qxp-adc.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/adc/imx8qxp-adc.c b/drivers/iio/adc/imx8qxp-adc.c
index 36777b827165..f5a0fc9e64c5 100644
--- a/drivers/iio/adc/imx8qxp-adc.c
+++ b/drivers/iio/adc/imx8qxp-adc.c
@@ -86,6 +86,8 @@
#define IMX8QXP_ADC_TIMEOUT msecs_to_jiffies(100)
+#define IMX8QXP_ADC_MAX_FIFO_SIZE 16
+
struct imx8qxp_adc {
struct device *dev;
void __iomem *regs;
@@ -95,6 +97,7 @@ struct imx8qxp_adc {
/* Serialise ADC channel reads */
struct mutex lock;
struct completion completion;
+ u32 fifo[IMX8QXP_ADC_MAX_FIFO_SIZE];
};
#define IMX8QXP_ADC_CHAN(_idx) { \
@@ -238,8 +241,7 @@ static int imx8qxp_adc_read_raw(struct iio_dev *indio_dev,
return ret;
}
- *val = FIELD_GET(IMX8QXP_ADC_RESFIFO_VAL_MASK,
- readl(adc->regs + IMX8QXP_ADR_ADC_RESFIFO));
+ *val = adc->fifo[0];
mutex_unlock(&adc->lock);
return IIO_VAL_INT;
@@ -265,10 +267,15 @@ static irqreturn_t imx8qxp_adc_isr(int irq, void *dev_id)
{
struct imx8qxp_adc *adc = dev_id;
u32 fifo_count;
+ int i;
fifo_count = FIELD_GET(IMX8QXP_ADC_FCTRL_FCOUNT_MASK,
readl(adc->regs + IMX8QXP_ADR_ADC_FCTRL));
+ for (i = 0; i < fifo_count; i++)
+ adc->fifo[i] = FIELD_GET(IMX8QXP_ADC_RESFIFO_VAL_MASK,
+ readl_relaxed(adc->regs + IMX8QXP_ADR_ADC_RESFIFO));
+
if (fifo_count)
complete(&adc->completion);
--
2.39.1
This is a note to let you know that I've just added the patch titled
iio: adc: xilinx-ams: fix devm_krealloc() return value check
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From 6794ed0cfcc6ce737240eccc48b3e8190df36703 Mon Sep 17 00:00:00 2001
From: Marco Pagani <marpagan(a)redhat.com>
Date: Fri, 25 Nov 2022 12:31:12 +0100
Subject: iio: adc: xilinx-ams: fix devm_krealloc() return value check
The clang-analyzer reported a warning: "Value stored to 'ret'
is never read".
Fix the return value check if devm_krealloc() fails to resize
ams_channels.
Fixes: d5c70627a794 ("iio: adc: Add Xilinx AMS driver")
Signed-off-by: Marco Pagani <marpagan(a)redhat.com>
Acked-by: Michal Simek <michal.simek(a)amd.com>
Link: https://lore.kernel.org/r/20221125113112.219290-1-marpagan@redhat.com
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com>
---
drivers/iio/adc/xilinx-ams.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iio/adc/xilinx-ams.c b/drivers/iio/adc/xilinx-ams.c
index 5b4bdf3a26bb..a507d2e17079 100644
--- a/drivers/iio/adc/xilinx-ams.c
+++ b/drivers/iio/adc/xilinx-ams.c
@@ -1329,7 +1329,7 @@ static int ams_parse_firmware(struct iio_dev *indio_dev)
dev_channels = devm_krealloc(dev, ams_channels, dev_size, GFP_KERNEL);
if (!dev_channels)
- ret = -ENOMEM;
+ return -ENOMEM;
indio_dev->channels = dev_channels;
indio_dev->num_channels = num_channels;
--
2.39.1
This is a note to let you know that I've just added the patch titled
iio: adc: berlin2-adc: Add missing of_node_put() in error path
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From cbd3a0153cd18a2cbef6bf3cf31bb406c3fc9f55 Mon Sep 17 00:00:00 2001
From: Xiongfeng Wang <wangxiongfeng2(a)huawei.com>
Date: Tue, 29 Nov 2022 10:03:16 +0800
Subject: iio: adc: berlin2-adc: Add missing of_node_put() in error path
of_get_parent() will return a device_node pointer with refcount
incremented. We need to use of_node_put() on it when done. Add the
missing of_node_put() in the error path of berlin2_adc_probe();
Fixes: 70f1937911ca ("iio: adc: add support for Berlin")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2(a)huawei.com>
Link: https://lore.kernel.org/r/20221129020316.191731-1-wangxiongfeng2@huawei.com
Cc: <Stable(a)vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron(a)huawei.com>
---
drivers/iio/adc/berlin2-adc.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/adc/berlin2-adc.c b/drivers/iio/adc/berlin2-adc.c
index 3d2e8b4db61a..a4e7c7eff5ac 100644
--- a/drivers/iio/adc/berlin2-adc.c
+++ b/drivers/iio/adc/berlin2-adc.c
@@ -298,8 +298,10 @@ static int berlin2_adc_probe(struct platform_device *pdev)
int ret;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
- if (!indio_dev)
+ if (!indio_dev) {
+ of_node_put(parent_np);
return -ENOMEM;
+ }
priv = iio_priv(indio_dev);
--
2.39.1
From: Joerg Roedel <jroedel(a)suse.de>
In kernels compiled with CONFIG_PARAVIRT=n the compiler re-orders the
DR7 read in exc_nmi() to happen before the call to sev_es_ist_enter().
This is problematic when running as an SEV-ES guest because in this
environment the DR7 read might cause a #VC exception, and taking #VC
exceptions is not safe in exc_nmi() before sev_es_ist_enter() has run.
The result is stack recursion if the NMI was caused on the #VC IST
stack, because a subsequent #VC exception in the NMI handler will
overwrite the stack frame of the interrupted #VC handler.
As there are no compiler barriers affecting the ordering of DR7
reads/writes, make the accesses to this register volatile, forbidding
the compiler to re-order them.
[ bp: Massage text. ]
Cc: stable(a)vger.kernel.org
Fixes: 315562c9af3d ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler")
Signed-off-by: Joerg Roedel <jroedel(a)suse.de>
---
arch/x86/include/asm/debugreg.h | 27 ++++++++++++++++++++++++---
1 file changed, 24 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h
index b049d950612f..d54d5dbfb4b9 100644
--- a/arch/x86/include/asm/debugreg.h
+++ b/arch/x86/include/asm/debugreg.h
@@ -39,7 +39,20 @@ static __always_inline unsigned long native_get_debugreg(int regno)
asm("mov %%db6, %0" :"=r" (val));
break;
case 7:
- asm("mov %%db7, %0" :"=r" (val));
+ /*
+ * Apply __FORCE_ORDER to DR7 reads to forbid re-ordering them
+ * with other code.
+ *
+ * This is needed because a DR7 access can cause a #VC exception
+ * when running under SEV-ES. Taking a #VC exception is not a
+ * safe thing to do just anywhere in the entry code and
+ * re-ordering might place the access into an unsafe location.
+ *
+ * This happened in the NMI handler, where the DR7 read was
+ * re-ordered to happen before the call to sev_es_ist_enter(),
+ * causing stack recursion.
+ */
+ asm("mov %%db7, %0" : "=r" (val) : __FORCE_ORDER);
break;
default:
BUG();
@@ -66,8 +79,16 @@ static __always_inline void native_set_debugreg(int regno, unsigned long value)
asm("mov %0, %%db6" ::"r" (value));
break;
case 7:
- asm("mov %0, %%db7" ::"r" (value));
- break;
+ /*
+ * Apply __FORCE_ORDER to DR7 writes to forbid re-ordering them
+ * with other code.
+ *
+ * While is didn't happen with a DR7 write (see the DR7 read
+ * comment above which explains where it happened), add the
+ * __FORCE_ORDER here too to avoid similar problems in the
+ * future.
+ */
+ asm("mov %0, %%db7" ::"r" (value), __FORCE_ORDER); break;
default:
BUG();
}
--
2.39.0