diff mbox series

[3/3] ARM: aspeed: Add secure boot controller support

Message ID 20211117035106.321454-4-joel@jms.id.au (mailing list archive)
State New, archived
Headers show
Series ARM: aspeed: Secure Boot Controller support | expand

Commit Message

Joel Stanley Nov. 17, 2021, 3:51 a.m. UTC
This reads out the status of the secure boot controller and exposes it
in sysfs.

An example on a AST2600A3 QEMU model:

 # grep . /sys/bus/soc/devices/soc0/*
 /sys/bus/soc/devices/soc0/abr_image:0
 /sys/bus/soc/devices/soc0/family:AST2600
 /sys/bus/soc/devices/soc0/low_security_key:0
 /sys/bus/soc/devices/soc0/machine:Rainier 2U
 /sys/bus/soc/devices/soc0/otp_protected:0
 /sys/bus/soc/devices/soc0/revision:A3
 /sys/bus/soc/devices/soc0/secure_boot:1
 /sys/bus/soc/devices/soc0/serial_number:888844441234abcd
 /sys/bus/soc/devices/soc0/soc_id:05030303
 /sys/bus/soc/devices/soc0/uart_boot:1

On boot the state of the system according to the secure boot controller
will be printed:

 [    0.037634] AST2600 secure boot enabled

or

 [    0.037935] AST2600 secure boot disabled

Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Ryan Chen <ryan_chen@aspeedtech.com>
---
 drivers/soc/aspeed/aspeed-socinfo.c | 73 +++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

Comments

kernel test robot Nov. 25, 2021, 8:38 a.m. UTC | #1
Hi Joel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on robh/for-next]
[also build test WARNING on soc/for-next rockchip/for-next shawnguo/for-next v5.16-rc2 next-20211125]
[cannot apply to arm/for-next arm64/for-next/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Joel-Stanley/ARM-aspeed-Secure-Boot-Controller-support/20211117-115258
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
config: sparc64-randconfig-s032-20211118 (https://download.01.org/0day-ci/archive/20211125/202111251600.hBmyvSD0-lkp@intel.com/config)
compiler: sparc64-linux-gcc (GCC) 11.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://github.com/0day-ci/linux/commit/5057997868102d26f0af9c8d769a4809a3bd60be
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Joel-Stanley/ARM-aspeed-Secure-Boot-Controller-support/20211117-115258
        git checkout 5057997868102d26f0af9c8d769a4809a3bd60be
        # save the config file to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=sparc64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
>> drivers/soc/aspeed/aspeed-socinfo.c:166:38: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected void *base @@     got void [noderef] __iomem * @@
   drivers/soc/aspeed/aspeed-socinfo.c:166:38: sparse:     expected void *base
   drivers/soc/aspeed/aspeed-socinfo.c:166:38: sparse:     got void [noderef] __iomem *
>> drivers/soc/aspeed/aspeed-socinfo.c:171:46: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected void const volatile [noderef] __iomem *addr @@     got void * @@
   drivers/soc/aspeed/aspeed-socinfo.c:171:46: sparse:     expected void const volatile [noderef] __iomem *addr
   drivers/soc/aspeed/aspeed-socinfo.c:171:46: sparse:     got void *
>> drivers/soc/aspeed/aspeed-socinfo.c:173:25: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected void volatile [noderef] __iomem *addr @@     got void *base @@
   drivers/soc/aspeed/aspeed-socinfo.c:173:25: sparse:     expected void volatile [noderef] __iomem *addr
   drivers/soc/aspeed/aspeed-socinfo.c:173:25: sparse:     got void *base

vim +166 drivers/soc/aspeed/aspeed-socinfo.c

   126	
   127	static int __init aspeed_socinfo_init(void)
   128	{
   129		struct soc_device_attribute *attrs;
   130		struct soc_device *soc_dev;
   131		struct device_node *np;
   132		void __iomem *reg;
   133		bool has_chipid = false;
   134		bool has_sbe = false;
   135		u32 siliconid;
   136		u32 chipid[2];
   137		const char *machine = NULL;
   138	
   139		np = of_find_compatible_node(NULL, NULL, "aspeed,silicon-id");
   140		if (!of_device_is_available(np)) {
   141			of_node_put(np);
   142			return -ENODEV;
   143		}
   144	
   145		reg = of_iomap(np, 0);
   146		if (!reg) {
   147			of_node_put(np);
   148			return -ENODEV;
   149		}
   150		siliconid = readl(reg);
   151		iounmap(reg);
   152	
   153		/* This is optional, the ast2400 does not have it */
   154		reg = of_iomap(np, 1);
   155		if (reg) {
   156			has_chipid = true;
   157			chipid[0] = readl(reg);
   158			chipid[1] = readl(reg + 4);
   159			iounmap(reg);
   160		}
   161		of_node_put(np);
   162	
   163		/* AST2600 only */
   164		np = of_find_compatible_node(NULL, NULL, "aspeed,ast2600-sbc");
   165		if (of_device_is_available(np)) {
 > 166			void *base = of_iomap(np, 0);
   167			if (!base) {
   168				of_node_put(np);
   169				return -ENODEV;
   170			}
 > 171			security_status = readl(base + SEC_STATUS);
   172			has_sbe = true;
 > 173			iounmap(base);

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Joel Stanley Jan. 10, 2022, 11:29 p.m. UTC | #2
Hi Arnd,

On Wed, 17 Nov 2021 at 03:51, Joel Stanley <joel@jms.id.au> wrote:
>
> This reads out the status of the secure boot controller and exposes it
> in sysfs.
>
> An example on a AST2600A3 QEMU model:
>
>  # grep . /sys/bus/soc/devices/soc0/*
>  /sys/bus/soc/devices/soc0/abr_image:0
>  /sys/bus/soc/devices/soc0/family:AST2600
>  /sys/bus/soc/devices/soc0/low_security_key:0
>  /sys/bus/soc/devices/soc0/machine:Rainier 2U
>  /sys/bus/soc/devices/soc0/otp_protected:0
>  /sys/bus/soc/devices/soc0/revision:A3
>  /sys/bus/soc/devices/soc0/secure_boot:1
>  /sys/bus/soc/devices/soc0/serial_number:888844441234abcd
>  /sys/bus/soc/devices/soc0/soc_id:05030303
>  /sys/bus/soc/devices/soc0/uart_boot:1

Quoting from your response to my pull request:

> - I actually want to avoid custom attributes on soc device instances as much
>   as possible. I have not looked in detail at what you add here, but the
>   number of custom attributes means we should discuss this properly.

Can you explain the reasoning here?

I am a bit surprised given we have this nice feature in struct
soc_device_attribute:

struct soc_device_attribute {
...
        const struct attribute_group *custom_attr_group;
};

Cheers,

Joel


>
> On boot the state of the system according to the secure boot controller
> will be printed:
>
>  [    0.037634] AST2600 secure boot enabled
>
> or
>
>  [    0.037935] AST2600 secure boot disabled
>
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> Reviewed-by: Ryan Chen <ryan_chen@aspeedtech.com>
> ---
>  drivers/soc/aspeed/aspeed-socinfo.c | 73 +++++++++++++++++++++++++++++
>  1 file changed, 73 insertions(+)
>
> diff --git a/drivers/soc/aspeed/aspeed-socinfo.c b/drivers/soc/aspeed/aspeed-socinfo.c
> index 1ca140356a08..6faf2c199c90 100644
> --- a/drivers/soc/aspeed/aspeed-socinfo.c
> +++ b/drivers/soc/aspeed/aspeed-socinfo.c
> @@ -9,6 +9,8 @@
>  #include <linux/slab.h>
>  #include <linux/sys_soc.h>
>
> +static u32 security_status;
> +
>  static struct {
>         const char *name;
>         const u32 id;
> @@ -74,6 +76,54 @@ static const char *siliconid_to_rev(u32 siliconid)
>         return "??";
>  }
>
> +#define SEC_STATUS             0x14
> +#define ABR_IMAGE_SOURCE       BIT(13)
> +#define OTP_PROTECTED          BIT(8)
> +#define LOW_SEC_KEY            BIT(7)
> +#define SECURE_BOOT            BIT(6)
> +#define UART_BOOT              BIT(5)
> +
> +static ssize_t abr_image_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +       return sprintf(buf, "%d\n", !!(security_status & ABR_IMAGE_SOURCE));
> +}
> +static DEVICE_ATTR_RO(abr_image);
> +
> +static ssize_t low_security_key_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +       return sprintf(buf, "%d\n", !!(security_status & LOW_SEC_KEY));
> +}
> +static DEVICE_ATTR_RO(low_security_key);
> +
> +static ssize_t otp_protected_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +       return sprintf(buf, "%d\n", !!(security_status & OTP_PROTECTED));
> +}
> +static DEVICE_ATTR_RO(otp_protected);
> +
> +static ssize_t secure_boot_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +       return sprintf(buf, "%d\n", !!(security_status & SECURE_BOOT));
> +}
> +static DEVICE_ATTR_RO(secure_boot);
> +
> +static ssize_t uart_boot_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +       /* Invert the bit, as 1 is boot from SPI/eMMC */
> +       return sprintf(buf, "%d\n", !(security_status & UART_BOOT));
> +}
> +static DEVICE_ATTR_RO(uart_boot);
> +
> +static struct attribute *aspeed_attrs[] = {
> +       &dev_attr_abr_image.attr,
> +       &dev_attr_low_security_key.attr,
> +       &dev_attr_otp_protected.attr,
> +       &dev_attr_secure_boot.attr,
> +       &dev_attr_uart_boot.attr,
> +       NULL,
> +};
> +ATTRIBUTE_GROUPS(aspeed);
> +
>  static int __init aspeed_socinfo_init(void)
>  {
>         struct soc_device_attribute *attrs;
> @@ -81,6 +131,7 @@ static int __init aspeed_socinfo_init(void)
>         struct device_node *np;
>         void __iomem *reg;
>         bool has_chipid = false;
> +       bool has_sbe = false;
>         u32 siliconid;
>         u32 chipid[2];
>         const char *machine = NULL;
> @@ -109,6 +160,20 @@ static int __init aspeed_socinfo_init(void)
>         }
>         of_node_put(np);
>
> +       /* AST2600 only */
> +       np = of_find_compatible_node(NULL, NULL, "aspeed,ast2600-sbc");
> +       if (of_device_is_available(np)) {
> +               void *base = of_iomap(np, 0);
> +               if (!base) {
> +                       of_node_put(np);
> +                       return -ENODEV;
> +               }
> +               security_status = readl(base + SEC_STATUS);
> +               has_sbe = true;
> +               iounmap(base);
> +               of_node_put(np);
> +       }
> +
>         attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
>         if (!attrs)
>                 return -ENODEV;
> @@ -135,6 +200,9 @@ static int __init aspeed_socinfo_init(void)
>                 attrs->serial_number = kasprintf(GFP_KERNEL, "%08x%08x",
>                                                  chipid[1], chipid[0]);
>
> +       if (has_sbe)
> +               attrs->custom_attr_group = aspeed_groups[0];
> +
>         soc_dev = soc_device_register(attrs);
>         if (IS_ERR(soc_dev)) {
>                 kfree(attrs->soc_id);
> @@ -148,6 +216,11 @@ static int __init aspeed_socinfo_init(void)
>                         attrs->revision,
>                         attrs->soc_id);
>
> +       if (has_sbe) {
> +               pr_info("AST2600 secure boot %s\n",
> +                       (security_status & SECURE_BOOT) ? "enabled" : "disabled");
> +       }
> +
>         return 0;
>  }
>  early_initcall(aspeed_socinfo_init);
> --
> 2.33.0
>
Arnd Bergmann Jan. 17, 2022, 2:51 p.m. UTC | #3
On Tue, Jan 11, 2022 at 12:29 AM Joel Stanley <joel@jms.id.au> wrote:
> On Wed, 17 Nov 2021 at 03:51, Joel Stanley <joel@jms.id.au> wrote:
> >
> > This reads out the status of the secure boot controller and exposes it
> > in sysfs.
> >
> > An example on a AST2600A3 QEMU model:
> >
> >  # grep . /sys/bus/soc/devices/soc0/*
> >  /sys/bus/soc/devices/soc0/abr_image:0
> >  /sys/bus/soc/devices/soc0/family:AST2600
> >  /sys/bus/soc/devices/soc0/low_security_key:0
> >  /sys/bus/soc/devices/soc0/machine:Rainier 2U
> >  /sys/bus/soc/devices/soc0/otp_protected:0
> >  /sys/bus/soc/devices/soc0/revision:A3
> >  /sys/bus/soc/devices/soc0/secure_boot:1
> >  /sys/bus/soc/devices/soc0/serial_number:888844441234abcd
> >  /sys/bus/soc/devices/soc0/soc_id:05030303
> >  /sys/bus/soc/devices/soc0/uart_boot:1
>
> Quoting from your response to my pull request:
>
> > - I actually want to avoid custom attributes on soc device instances as much
> >   as possible. I have not looked in detail at what you add here, but the
> >   number of custom attributes means we should discuss this properly.
>
> Can you explain the reasoning here?
>
> I am a bit surprised given we have this nice feature in struct
> soc_device_attribute:
>
> struct soc_device_attribute {
> ...
>         const struct attribute_group *custom_attr_group;
> };

I have two main concerns:

- any attribute that makes sense across multiple SoC families should probably be
  part of the standard set of attributes. Ideally this could fit
within the existing
  attributes, but if you can make a reasonable case for adding further
ones, that
  is fine as well. The standard attributes can then also be accessed from within
  the kernel with soc_device_match(), rather than just being available
to user space.

- The attributes should all be used to identify the SoC, not a
particular part of
  the SoC that is better represented as a separate device.

If you are adding five attributes at once, it's likely that these
don't all fit the
constraints, though I had not yet looked at the implementation.

From what I see in

+static ssize_t abr_image_show(struct device *dev, struct
device_attribute *attr, char *buf)
+{
+       return sprintf(buf, "%d\n", !!(security_status & ABR_IMAGE_SOURCE));
+}
+
+static ssize_t low_security_key_show(struct device *dev, struct
device_attribute *attr, char *buf)
+{
+       return sprintf(buf, "%d\n", !!(security_status & LOW_SEC_KEY));
+}
+
+static ssize_t otp_protected_show(struct device *dev, struct
device_attribute *attr, char *buf)
+{
+       return sprintf(buf, "%d\n", !!(security_status & OTP_PROTECTED));
+}
+
+static ssize_t secure_boot_show(struct device *dev, struct
device_attribute *attr, char *buf)
+{
+       return sprintf(buf, "%d\n", !!(security_status & SECURE_BOOT));
+}
+
+static ssize_t uart_boot_show(struct device *dev, struct
device_attribute *attr, char *buf)
+{
+       return sprintf(buf, "%d\n", !(security_status & UART_BOOT));
+}

it appears that these are related to how the system was started, which doesn't
fit either of the requirements: the same information may be useful for
non-aspeed
systems, so it would be good to have it in a standardized interface rather than
vendor extensions, and it doesn't really identify the SoC but instead provides
information from a device that is inside of the SoC.

Maybe this could be turned into a generalized interface similar to soc_device
that exposes the boot status in sysfs? We have a couple of files that
determine e.g. whether the kernel was booted securely, and those could
all hook up here. It doesn't have to be anything complex, just a node under
/sys/firmware or /sys/power that has a couple of documented attributes
that can be filled by drivers.

          Arnd
diff mbox series

Patch

diff --git a/drivers/soc/aspeed/aspeed-socinfo.c b/drivers/soc/aspeed/aspeed-socinfo.c
index 1ca140356a08..6faf2c199c90 100644
--- a/drivers/soc/aspeed/aspeed-socinfo.c
+++ b/drivers/soc/aspeed/aspeed-socinfo.c
@@ -9,6 +9,8 @@ 
 #include <linux/slab.h>
 #include <linux/sys_soc.h>
 
+static u32 security_status;
+
 static struct {
 	const char *name;
 	const u32 id;
@@ -74,6 +76,54 @@  static const char *siliconid_to_rev(u32 siliconid)
 	return "??";
 }
 
+#define SEC_STATUS		0x14
+#define ABR_IMAGE_SOURCE	BIT(13)
+#define OTP_PROTECTED		BIT(8)
+#define LOW_SEC_KEY		BIT(7)
+#define SECURE_BOOT		BIT(6)
+#define UART_BOOT		BIT(5)
+
+static ssize_t abr_image_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", !!(security_status & ABR_IMAGE_SOURCE));
+}
+static DEVICE_ATTR_RO(abr_image);
+
+static ssize_t low_security_key_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", !!(security_status & LOW_SEC_KEY));
+}
+static DEVICE_ATTR_RO(low_security_key);
+
+static ssize_t otp_protected_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", !!(security_status & OTP_PROTECTED));
+}
+static DEVICE_ATTR_RO(otp_protected);
+
+static ssize_t secure_boot_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", !!(security_status & SECURE_BOOT));
+}
+static DEVICE_ATTR_RO(secure_boot);
+
+static ssize_t uart_boot_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	/* Invert the bit, as 1 is boot from SPI/eMMC */
+	return sprintf(buf, "%d\n", !(security_status & UART_BOOT));
+}
+static DEVICE_ATTR_RO(uart_boot);
+
+static struct attribute *aspeed_attrs[] = {
+	&dev_attr_abr_image.attr,
+	&dev_attr_low_security_key.attr,
+	&dev_attr_otp_protected.attr,
+	&dev_attr_secure_boot.attr,
+	&dev_attr_uart_boot.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(aspeed);
+
 static int __init aspeed_socinfo_init(void)
 {
 	struct soc_device_attribute *attrs;
@@ -81,6 +131,7 @@  static int __init aspeed_socinfo_init(void)
 	struct device_node *np;
 	void __iomem *reg;
 	bool has_chipid = false;
+	bool has_sbe = false;
 	u32 siliconid;
 	u32 chipid[2];
 	const char *machine = NULL;
@@ -109,6 +160,20 @@  static int __init aspeed_socinfo_init(void)
 	}
 	of_node_put(np);
 
+	/* AST2600 only */
+	np = of_find_compatible_node(NULL, NULL, "aspeed,ast2600-sbc");
+	if (of_device_is_available(np)) {
+		void *base = of_iomap(np, 0);
+		if (!base) {
+			of_node_put(np);
+			return -ENODEV;
+		}
+		security_status = readl(base + SEC_STATUS);
+		has_sbe = true;
+		iounmap(base);
+		of_node_put(np);
+	}
+
 	attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
 	if (!attrs)
 		return -ENODEV;
@@ -135,6 +200,9 @@  static int __init aspeed_socinfo_init(void)
 		attrs->serial_number = kasprintf(GFP_KERNEL, "%08x%08x",
 						 chipid[1], chipid[0]);
 
+	if (has_sbe)
+		attrs->custom_attr_group = aspeed_groups[0];
+
 	soc_dev = soc_device_register(attrs);
 	if (IS_ERR(soc_dev)) {
 		kfree(attrs->soc_id);
@@ -148,6 +216,11 @@  static int __init aspeed_socinfo_init(void)
 			attrs->revision,
 			attrs->soc_id);
 
+	if (has_sbe) {
+		pr_info("AST2600 secure boot %s\n",
+			(security_status & SECURE_BOOT) ? "enabled" : "disabled");
+	}
+
 	return 0;
 }
 early_initcall(aspeed_socinfo_init);