| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <6b59725a-f42b-b6f7-c93d-da218d050529@nokia.com>
Date: Mon, 16 Sep 2019 08:52:14 +0000
From: "Sverdlin, Alexander (Nokia - DE/Ulm)" <alexander.sverdlin@...ia.com>
To: Jean Delvare <jdelvare@...e.de>,
"Xu, Lingyan (NSB - CN/Hangzhou)" <lingyan.xu@...ia-sbell.com>
CC: "Adamski, Krzysztof (Nokia - PL/Wroclaw)"
<krzysztof.adamski@...ia.com>,
"Wiebe, Wladislav (Nokia - DE/Ulm)" <wladislav.wiebe@...ia.com>,
"linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] i801_smbus: clear SMBALERT status bit and disable
SMBALERT interrupt
Hello Jean,
On 05/09/2019 14:57, Jean Delvare wrote:
> If this is of any value to you, I tried implementing it in i2c-i801 a
> few days ago. I can't really test it though as I don't have any device
> which triggers an alert on my system, but I am sharing it with you if
> you want to give it a try. You would still need to write the code in
> the slave driver.
I'm going to test your patch (I actually made very similar one couple of days
ago), but I have a couple of comments to the below version:
> ---
> drivers/i2c/busses/i2c-i801.c | 77 +++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 69 insertions(+), 8 deletions(-)
>
> --- linux-5.2.orig/drivers/i2c/busses/i2c-i801.c 2019-08-28 15:58:52.725828215 +0200
> +++ linux-5.2/drivers/i2c/busses/i2c-i801.c 2019-08-28 16:50:09.212696037 +0200
> @@ -196,6 +196,7 @@
>
> /* Host Notify Command register bits */
> #define SMBSLVCMD_HST_NTFY_INTREN BIT(0)
> +#define SMBSLVCMD_SMBALERT_DIS BIT(2)
>
> #define STATUS_ERROR_FLAGS (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
> SMBHSTSTS_DEV_ERR)
> @@ -281,6 +282,10 @@ struct i801_priv {
> */
> bool acpi_reserved;
> struct mutex acpi_lock;
> +
> + /* SMBus alert */
> + struct i2c_smbus_alert_setup alert_data;
> + struct i2c_client *ara;
> };
>
> #define FEATURE_SMBUS_PEC BIT(0)
> @@ -289,6 +294,7 @@ struct i801_priv {
> #define FEATURE_I2C_BLOCK_READ BIT(3)
> #define FEATURE_IRQ BIT(4)
> #define FEATURE_HOST_NOTIFY BIT(5)
> +#define FEATURE_SMBUS_ALERT BIT(6)
> /* Not really a feature, but it's convenient to handle it as such */
> #define FEATURE_IDF BIT(15)
> #define FEATURE_TCO_SPT BIT(16)
> @@ -301,6 +307,7 @@ static const char *i801_feature_names[]
> "I2C block read",
> "Interrupt",
> "SMBus Host Notify",
> + "SMBus Alert",
> };
>
> static unsigned int disable_features;
> @@ -310,7 +317,8 @@ MODULE_PARM_DESC(disable_features, "Disa
> "\t\t 0x02 disable the block buffer\n"
> "\t\t 0x08 disable the I2C block read functionality\n"
> "\t\t 0x10 don't use interrupts\n"
> - "\t\t 0x20 disable SMBus Host Notify ");
> + "\t\t 0x20 disable SMBus Host Notify\n"
> + "\t\t 0x40 disable SMBus Alert ");
>
> /* Make sure the SMBus host is ready to start transmitting.
> Return 0 if it is, -EBUSY if it is not. */
> @@ -620,8 +628,24 @@ static irqreturn_t i801_host_notify_isr(
> return IRQ_HANDLED;
> }
>
> +static irqreturn_t i801_smbus_alert_isr(struct i801_priv *priv)
> +{
> + struct i2c_client *ara = priv->ara;
> +
> + if (ara) {
> + dev_dbg(&ara->dev, "SMBus alert received\n");
> + i2c_handle_smbus_alert(ara);
> + } else
> + dev_dbg(&priv->adapter.dev,
> + "SMBus alert received but no ARA client!\n");
> +
> + /* clear SMBus Alert bit and return */
> + outb_p(SMBHSTSTS_SMBALERT_STS, SMBHSTSTS(priv));
> + return IRQ_HANDLED;
> +}
> +
> /*
> - * There are three kinds of interrupts:
> + * There are four kinds of interrupts:
> *
> * 1) i801 signals transaction completion with one of these interrupts:
> * INTR - Success
> @@ -635,6 +659,8 @@ static irqreturn_t i801_host_notify_isr(
> * occurs for each byte of a byte-by-byte to prepare the next byte.
> *
> * 3) Host Notify interrupts
> + *
> + * 4) SMBus Alert interrupts
> */
> static irqreturn_t i801_isr(int irq, void *dev_id)
> {
> @@ -653,6 +679,12 @@ static irqreturn_t i801_isr(int irq, voi
> return i801_host_notify_isr(priv);
> }
>
> + if (priv->features & FEATURE_SMBUS_ALERT) {
> + status = inb_p(SMBHSTSTS(priv));
> + if (status & SMBHSTSTS_SMBALERT_STS)
> + return i801_smbus_alert_isr(priv);
> + }
> +
> status = inb_p(SMBHSTSTS(priv));
> if (status & SMBHSTSTS_BYTE_DONE)
> i801_isr_byte_done(priv);
> @@ -1006,9 +1038,35 @@ static void i801_enable_host_notify(stru
> outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
> }
>
> -static void i801_disable_host_notify(struct i801_priv *priv)
> +static void i801_enable_smbus_alert(struct i2c_adapter *adapter)
> {
> - if (!(priv->features & FEATURE_HOST_NOTIFY))
> + struct i801_priv *priv = i2c_get_adapdata(adapter);
> +
> + if (!(priv->features & FEATURE_SMBUS_ALERT))
> + return;
> +
> + priv->ara = i2c_setup_smbus_alert(adapter, &priv->alert_data);
> + if (!priv->ara) {
> + dev_warn(&adapter->dev, "Failed to register ARA client\n");
> +
> + /* Disable SMBus Alert interrupts */
> + if (!(SMBSLVCMD_SMBALERT_DIS & priv->original_slvcmd))
> + outb_p(SMBSLVCMD_SMBALERT_DIS | priv->original_slvcmd,
> + SMBSLVCMD(priv));
> + return;
> + }
> +
> + if (SMBSLVCMD_SMBALERT_DIS & priv->original_slvcmd)
> + outb_p(~SMBSLVCMD_SMBALERT_DIS & priv->original_slvcmd,
> + SMBSLVCMD(priv));
> +
> + /* Clear SMBus Alert bit to allow a new notification */
> + outb_p(SMBHSTSTS_SMBALERT_STS, SMBHSTSTS(priv));
I'd rather handle the pending ALERT# not to lose the ALERTS from the boot
time for instance. This clearing of the pending bit here doesn't help
anyway, please refer below:
> +}
> +
> +static void i801_restore_slvcmd(struct i801_priv *priv)
> +{
> + if (!(priv->features & (FEATURE_HOST_NOTIFY | FEATURE_SMBUS_ALERT)))
> return;
>
> outb_p(priv->original_slvcmd, SMBSLVCMD(priv));
> @@ -1823,8 +1881,8 @@ static int i801_probe(struct pci_dev *de
> outb_p(inb_p(SMBAUXCTL(priv)) &
> ~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv));
>
> - /* Remember original Host Notify setting */
> - if (priv->features & FEATURE_HOST_NOTIFY)
I'd propose to disable the ALERT# for the time of setting up ARA here...
> + /* Remember original Host Notify and SMBus Alert setting */
> + if (priv->features & (FEATURE_HOST_NOTIFY | FEATURE_SMBUS_ALERT))
> priv->original_slvcmd = inb_p(SMBSLVCMD(priv));
>
> /* Default timeout in interrupt mode: 200 ms */
Because between these two hunks we enable the interrupts and we will
jump into IRQ handler without ARA being set up.
> @@ -1875,6 +1933,7 @@ static int i801_probe(struct pci_dev *de
> }
>
> i801_enable_host_notify(&priv->adapter);
> + i801_enable_smbus_alert(&priv->adapter);
... and re-enable ALERT# here again...
> i801_probe_optional_slaves(priv);
> /* We ignore errors - multiplexing is optional */
> @@ -1897,8 +1956,10 @@ static void i801_remove(struct pci_dev *
> pm_runtime_forbid(&dev->dev);
> pm_runtime_get_noresume(&dev->dev);
>
> - i801_disable_host_notify(priv);
> + i801_restore_slvcmd(priv);
> i801_del_mux(priv);
> + if (priv->ara)
> + i2c_unregister_device(priv->ara);
> i2c_del_adapter(&priv->adapter);
> i801_acpi_remove(priv);
> pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
> @@ -1916,7 +1977,7 @@ static void i801_shutdown(struct pci_dev
> struct i801_priv *priv = pci_get_drvdata(dev);
>
> /* Restore config registers to avoid hard hang on some systems */
> - i801_disable_host_notify(priv);
> + i801_restore_slvcmd(priv);
> pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
> }
I can do some tests to prove my assumption regarding pending ALERT#.
Or do you agree with the above and I should test only modified version
with disable-registerARA-re-enable setup? What are your thoughts?
--
Best regards,
Alexander Sverdlin.
Powered by blists - more mailing lists