[PATCH 0/3] firmware: google: Fix minor bugs

From: Patrick Rudolph

This patch series fixes 3 independent bugs in the google firmware
drivers.

Patch 1-2 do proper cleanup at kernel module unloading.

Patch 3 adds a check if the optional GSMI SMM handler is actually
present in the firmware and responses to the driver.

Arthur Heymans (2):
  firmware: google: Unregister driver_info on failure and exit in gsmi
  firmware: google: Probe for a GSMI handler in firmware

Patrick Rudolph (1):
  firmware: google: Release devices before unregistering the bus

drivers/firmware/google/coreboot_table.c |  6 ++++++
 drivers/firmware/google/gsmi.c           | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

[PATCH 1/3] firmware: google: Release devices before unregistering the bus

From: Patrick Rudolph

Fix a bug where the kernel module can't be loaded after it has been
unloaded as the devices are still present and conflicting with the
to be created coreboot devices.

Signed-off-by: Patrick Rudolph 
---
 drivers/firmware/google/coreboot_table.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c
index 8d132e4f008a..88c6545bebf4 100644
--- a/drivers/firmware/google/coreboot_table.c
+++ b/drivers/firmware/google/coreboot_table.c
@@ -163,8 +163,14 @@ static int coreboot_table_probe(struct platform_device *pdev)
    return ret;
 }

+static int __cb_dev_unregister(struct device *dev, void *dummy)
+{
+	device_unregister(dev);
+}
+
 static int coreboot_table_remove(struct platform_device *pdev)
 {
+	bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister);
    bus_unregister(&coreboot_bus_type);
    return 0;
 }

[PATCH 1/3] firmware: google: Release devices before unregistering the bus

[kbuild test robot]

Hi,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.4-rc7 next-20191115]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/patrick-rudolph-9elements-com/firmw...
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 96b95eff4a591dbac582c2590d067e356a18aacb
config: mips-allmodconfig (attached as .config)
compiler: mips-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=mips

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot

All warnings (new ones prefixed by >>):

drivers/firmware/google/coreboot_table.c: In function '__cb_dev_unregister':
> > drivers/firmware/google/coreboot_table.c:169:1: warning: no return statement in function returning non-void [-Wreturn-type]

}
    ^

vim +169 drivers/firmware/google/coreboot_table.c

165	
   166	static int __cb_dev_unregister(struct device *dev, void *dummy)
   167	{
   168		device_unregister(dev);
> 169	}

170

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/[e-mail] Intel Corporation

[PATCH 1/3] firmware: google: Release devices before unregistering the bus

[Greg Kroah-Hartman]

On Fri, Nov 15, 2019 at 02:48:37PM +0100, [e-mail] wrote:
> From: Patrick Rudolph
>
> Fix a bug where the kernel module can't be loaded after it has been
> unloaded as the devices are still present and conflicting with the
> to be created coreboot devices.
> Signed-off-by: Patrick Rudolph
>
> drivers/firmware/google/coreboot_table.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c
> index 8d132e4f008a..88c6545bebf4 100644
> --- a/drivers/firmware/google/coreboot_table.c
> +++ b/drivers/firmware/google/coreboot_table.c
> @@ -163,8 +163,14 @@ static int coreboot_table_probe(struct platform_device *pdev)
>    return ret;
>  }
>
> +static int __cb_dev_unregister(struct device *dev, void *dummy)
> +{
> device_unregister(dev);

Did you build this patch???

Did it work when you tested it?  How?

Please fix up,

greg k-h

[PATCH 2/3] firmware: google: Unregister driver_info on failure and exit in gsmi

From: Arthur Heymans

Fix a bug where the kernel module couldn't be loaded after unloading,
as the platform driver wasn't released on exit.

Signed-off-by: Arthur Heymans 
---
 drivers/firmware/google/gsmi.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c
index edaa4e5d84ad..974c769b75cf 100644
--- a/drivers/firmware/google/gsmi.c
+++ b/drivers/firmware/google/gsmi.c
@@ -1016,6 +1016,9 @@ static __init int gsmi_init(void)
    dma_pool_destroy(gsmi_dev.dma_pool);
    platform_device_unregister(gsmi_dev.pdev);
    pr_info("gsmi: failed to load: %d\n", ret);
+#ifdef CONFIG_PM
+	platform_driver_unregister(&gsmi_driver_info);
+#endif
    return ret;
 }

@@ -1037,6 +1040,9 @@ static void __exit gsmi_exit(void)
    gsmi_buf_free(gsmi_dev.name_buf);
    dma_pool_destroy(gsmi_dev.dma_pool);
    platform_device_unregister(gsmi_dev.pdev);
+#ifdef CONFIG_PM
+	platform_driver_unregister(&gsmi_driver_info);
+#endif
 }

module_init(gsmi_init);

[PATCH 2/3] firmware: google: Unregister driver_info on failure and exit in gsmi

[Greg Kroah-Hartman]

On Fri, Nov 15, 2019 at 02:48:38PM +0100, [e-mail] wrote:
> From: Arthur Heymans
>
> Fix a bug where the kernel module couldn't be loaded after unloading,
> as the platform driver wasn't released on exit.
> Signed-off-by: Arthur Heymans

When sending a patch from someone else, you too have to add your s-o-b
so that we can accept it as that shows the progression of the patch (and
you are accepting responsibility for it being correct.)

Please fix up when you resend.

thanks,

greg k-h

[PATCH 2/3] firmware: google: Unregister driver_info on failure and exit in gsmi

[Greg Kroah-Hartman]

On Fri, Nov 15, 2019 at 02:48:38PM +0100, [e-mail] wrote:
> From: Arthur Heymans
>
> Fix a bug where the kernel module couldn't be loaded after unloading,
> as the platform driver wasn't released on exit.
> Signed-off-by: Arthur Heymans
>
> drivers/firmware/google/gsmi.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c
> index edaa4e5d84ad..974c769b75cf 100644
> --- a/drivers/firmware/google/gsmi.c
> +++ b/drivers/firmware/google/gsmi.c
> @@ -1016,6 +1016,9 @@ static __init int gsmi_init(void)
>    dma_pool_destroy(gsmi_dev.dma_pool);
>    platform_device_unregister(gsmi_dev.pdev);
>    pr_info("gsmi: failed to load: %d\n", ret);
> +#ifdef CONFIG_PM
> platform_driver_unregister(&gsmi_driver_info);
>
> +#endif
>    return ret;
>  }
>
> @@ -1037,6 +1040,9 @@ static void __exit gsmi_exit(void)
>    gsmi_buf_free(gsmi_dev.name_buf);
>    dma_pool_destroy(gsmi_dev.dma_pool);
>    platform_device_unregister(gsmi_dev.pdev);
> +#ifdef CONFIG_PM
> platform_driver_unregister(&gsmi_driver_info);

Why the #ifdef here?  Why does PM change things?

#ifdefs in .c code is really frowned on.

thanks,

greg k-h

[PATCH 3/3] firmware: google: Probe for a GSMI handler in firmware

From: Arthur Heymans

Currently this driver is loaded if the DMI string matches coreboot
and has a proper smi_command in the ACPI FADT table, but a GSMI handler in
SMM is an optional feature in coreboot.

So probe for a SMM GSMI handler before initializing the driver.
If the smihandler leaves the calling argument in %eax in the SMM save state
untouched that generally means the is no handler for GSMI.

Signed-off-by: Arthur Heymans 
---
 drivers/firmware/google/gsmi.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c
index 974c769b75cf..a3eaa9f41125 100644
--- a/drivers/firmware/google/gsmi.c
+++ b/drivers/firmware/google/gsmi.c
@@ -746,6 +746,7 @@ MODULE_DEVICE_TABLE(dmi, gsmi_dmi_table);
 static __init int gsmi_system_valid(void)
 {
    u32 hash;
+	u16 cmd, result;

if (!dmi_check_system(gsmi_dmi_table))
    	return -ENODEV;
@@ -780,6 +781,23 @@ static __init int gsmi_system_valid(void)
    	return -ENODEV;
    }

+	/* Test the smihandler with a bogus command. If it leaves the
+	 * calling argument in %ax untouched, there is no handler for
+	 * GSMI commands.
+	 */
+	cmd = GSMI_CALLBACK | 0xff << 8;
+	asm volatile (
+		"outb %%al, %%dx\n\t"
+		: "=a" (result)
+		: "0" (cmd),
+		  "d" (acpi_gbl_FADT.smi_command)
+		: "memory", "cc"
+		);
+	if (cmd == result) {
+		pr_info("gsmi: no gsmi handler in firmware\n");
+		return -ENODEV;
+	}
+
    /* Found */
    return 0;
 }