diff mbox series

[v11,2/8] powerpc: Move ima buffer functions to drivers/of/kexec.c

Message ID 20201214191854.9050-3-nramas@linux.microsoft.com
State New
Headers show
Series None | expand

Commit Message

nramas Dec. 14, 2020, 7:18 p.m. UTC 
The functions do_get_kexec_buffer() and get_addr_size_cells(),
defined in arch/powerpc/kexec/ima.c, retrieve the address and size
of the given property from the device tree blob. These functions do
not have architecture specific code, but are currently limited to
powerpc. do_get_kexec_buffer() correctly handles a device tree property
that is a child node of the root node, but not anything other than
the immediate root child nodes.

Move architecture independent functions get_ima_kexec_buffer() and
get_root_addr_size_cells() to "drivers/of/kexec.c". These functions
retrieve the chosen node "linux,ima-kexec-buffer" from the device tree,
and return the address and size of the buffer used for carrying forward
the IMA measurement log across kexec system call.

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 drivers/of/kexec.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |  3 ++
 2 files changed, 71 insertions(+)

Comments

Rob Herring Dec. 15, 2020, 6:16 p.m. UTC | #1 
On Mon, Dec 14, 2020 at 11:18:48AM -0800, Lakshmi Ramasubramanian wrote:
> The functions do_get_kexec_buffer() and get_addr_size_cells(),

> defined in arch/powerpc/kexec/ima.c, retrieve the address and size

> of the given property from the device tree blob. These functions do

> not have architecture specific code, but are currently limited to

> powerpc. do_get_kexec_buffer() correctly handles a device tree property

> that is a child node of the root node, but not anything other than

> the immediate root child nodes.

> 

> Move architecture independent functions get_ima_kexec_buffer() and

> get_root_addr_size_cells() to "drivers/of/kexec.c". These functions

> retrieve the chosen node "linux,ima-kexec-buffer" from the device tree,

> and return the address and size of the buffer used for carrying forward

> the IMA measurement log across kexec system call.

> 

> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>

> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>

> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>

> ---

>  drivers/of/kexec.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++

>  include/linux/of.h |  3 ++

>  2 files changed, 71 insertions(+)

> 

> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c

> index 66787be081fe..9af5371340b1 100644

> --- a/drivers/of/kexec.c

> +++ b/drivers/of/kexec.c

> @@ -30,6 +30,10 @@

>  /**

>   * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size

>   *

> + * @fdt: Flattened Device Tree to update

> + * @start: Starting address of the reservation to delete

> + * @size: Size of the reservation to delete

> + *


This belongs in the patch adding fdt_find_and_del_mem_rsv.

>   * Return: 0 on success, or negative errno on error.

>   */

>  static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)

> @@ -226,3 +230,67 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,

>  

>  	return 0;

>  }

> +

> +/**

> + * get_root_addr_size_cells - Get address and size of root node

> + *

> + * @addr_cells: Return address of the root node

> + * @size_cells: Return size of the root node

> + *

> + * Return: 0 on success, or negative errno on error.

> + */

> +int get_root_addr_size_cells(int *addr_cells, int *size_cells)

> +{

> +	struct device_node *root;

> +

> +	root = of_find_node_by_path("/");

> +	if (!root)

> +		return -EINVAL;

> +

> +	*addr_cells = of_n_addr_cells(root);

> +	*size_cells = of_n_size_cells(root);

> +

> +	of_node_put(root);

> +

> +	return 0;

> +}

> +

> +/**

> + * get_ima_kexec_buffer - Get address and size of IMA kexec buffer

> + *

> + * @fdt: Flattened Device Tree

> + * @chosen_node: Offset of chosen node in the FDT

> + * @addr: Return address of the node

> + * @size: Return size of the node

> + *

> + * Return: 0 on success, or negative errno on error.

> + */

> +int get_ima_kexec_buffer(void *fdt, int chosen_node,

> +			 unsigned long *addr, size_t *size)

> +{

> +	const void *prop;

> +	int addr_cells, size_cells, prop_len;

> +	int rc;

> +

> +	rc = get_root_addr_size_cells(&addr_cells, &size_cells);

> +	if (rc)

> +		return rc;

> +

> +	if (fdt)

> +		prop = fdt_getprop(fdt, chosen_node,

> +				   "linux,ima-kexec-buffer", &prop_len);

> +	else

> +		prop = of_get_property(of_chosen,

> +				       "linux,ima-kexec-buffer", &prop_len);


This is an odd structure. The DT APIs are generally of_foo() for 
unflattened tree and of_flat_foo() for FDT.

> +

> +	if (!prop)

> +		return -ENOENT;

> +

> +	if (prop_len < 4 * (addr_cells + size_cells))

> +		return -EINVAL;

> +

> +	*addr = of_read_number(prop, addr_cells);

> +	*size = of_read_number(prop + 4 * addr_cells, size_cells);

> +

> +	return 0;

> +}

> diff --git a/include/linux/of.h b/include/linux/of.h

> index 3375f5295875..fb2ef274135d 100644

> --- a/include/linux/of.h

> +++ b/include/linux/of.h

> @@ -562,6 +562,9 @@ struct kimage;

>  int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,

>  			   unsigned long initrd_load_addr, unsigned long initrd_len,

>  			   const char *cmdline);

> +int get_root_addr_size_cells(int *addr_cells, int *size_cells);

> +int get_ima_kexec_buffer(void *fdt, int chosen_node,

> +			 unsigned long *addr, size_t *size);


The whole point of moving code out of arch code was to avoid all these 
cross tree calls.

I was expecting the next step to be moving setup_ima_buffer() call into 
of_kexec_setup_new_fdt with all the code in powerpc/kexec/ima.c moved 
here. Then the end result to enable on arm64 is just selecting 
HAVE_IMA_KEXEC and adding fields to kimage_arch.

Rob
nramas Dec. 16, 2020, 4:58 p.m. UTC | #2 
On 12/15/20 10:16 AM, Rob Herring wrote:
> On Mon, Dec 14, 2020 at 11:18:48AM -0800, Lakshmi Ramasubramanian wrote:

>> The functions do_get_kexec_buffer() and get_addr_size_cells(),

>> defined in arch/powerpc/kexec/ima.c, retrieve the address and size

>> of the given property from the device tree blob. These functions do

>> not have architecture specific code, but are currently limited to

>> powerpc. do_get_kexec_buffer() correctly handles a device tree property

>> that is a child node of the root node, but not anything other than

>> the immediate root child nodes.

>>

>> Move architecture independent functions get_ima_kexec_buffer() and

>> get_root_addr_size_cells() to "drivers/of/kexec.c". These functions

>> retrieve the chosen node "linux,ima-kexec-buffer" from the device tree,

>> and return the address and size of the buffer used for carrying forward

>> the IMA measurement log across kexec system call.

>>

>> Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>

>> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>

>> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>

>> ---

>>   drivers/of/kexec.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++

>>   include/linux/of.h |  3 ++

>>   2 files changed, 71 insertions(+)

>>

>> diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c

>> index 66787be081fe..9af5371340b1 100644

>> --- a/drivers/of/kexec.c

>> +++ b/drivers/of/kexec.c

>> @@ -30,6 +30,10 @@

>>   /**

>>    * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size

>>    *

>> + * @fdt: Flattened Device Tree to update

>> + * @start: Starting address of the reservation to delete

>> + * @size: Size of the reservation to delete

>> + *

> 

> This belongs in the patch adding fdt_find_and_del_mem_rsv.


Yes.

> 

>>    * Return: 0 on success, or negative errno on error.

>>    */

>>   static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)

>> @@ -226,3 +230,67 @@ int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,

>>   

>>   	return 0;

>>   }

>> +

>> +/**

>> + * get_root_addr_size_cells - Get address and size of root node

>> + *

>> + * @addr_cells: Return address of the root node

>> + * @size_cells: Return size of the root node

>> + *

>> + * Return: 0 on success, or negative errno on error.

>> + */

>> +int get_root_addr_size_cells(int *addr_cells, int *size_cells)

>> +{

>> +	struct device_node *root;

>> +

>> +	root = of_find_node_by_path("/");

>> +	if (!root)

>> +		return -EINVAL;

>> +

>> +	*addr_cells = of_n_addr_cells(root);

>> +	*size_cells = of_n_size_cells(root);

>> +

>> +	of_node_put(root);

>> +

>> +	return 0;

>> +}

>> +

>> +/**

>> + * get_ima_kexec_buffer - Get address and size of IMA kexec buffer

>> + *

>> + * @fdt: Flattened Device Tree

>> + * @chosen_node: Offset of chosen node in the FDT

>> + * @addr: Return address of the node

>> + * @size: Return size of the node

>> + *

>> + * Return: 0 on success, or negative errno on error.

>> + */

>> +int get_ima_kexec_buffer(void *fdt, int chosen_node,

>> +			 unsigned long *addr, size_t *size)

>> +{

>> +	const void *prop;

>> +	int addr_cells, size_cells, prop_len;

>> +	int rc;

>> +

>> +	rc = get_root_addr_size_cells(&addr_cells, &size_cells);

>> +	if (rc)

>> +		return rc;

>> +

>> +	if (fdt)

>> +		prop = fdt_getprop(fdt, chosen_node,

>> +				   "linux,ima-kexec-buffer", &prop_len);

>> +	else

>> +		prop = of_get_property(of_chosen,

>> +				       "linux,ima-kexec-buffer", &prop_len);

> 

> This is an odd structure. The DT APIs are generally of_foo() for

> unflattened tree and of_flat_foo() for FDT.

> 

Ok - will update.

>> +

>> +	if (!prop)

>> +		return -ENOENT;

>> +

>> +	if (prop_len < 4 * (addr_cells + size_cells))

>> +		return -EINVAL;

>> +

>> +	*addr = of_read_number(prop, addr_cells);

>> +	*size = of_read_number(prop + 4 * addr_cells, size_cells);

>> +

>> +	return 0;

>> +}

>> diff --git a/include/linux/of.h b/include/linux/of.h

>> index 3375f5295875..fb2ef274135d 100644

>> --- a/include/linux/of.h

>> +++ b/include/linux/of.h

>> @@ -562,6 +562,9 @@ struct kimage;

>>   int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,

>>   			   unsigned long initrd_load_addr, unsigned long initrd_len,

>>   			   const char *cmdline);

>> +int get_root_addr_size_cells(int *addr_cells, int *size_cells);

>> +int get_ima_kexec_buffer(void *fdt, int chosen_node,

>> +			 unsigned long *addr, size_t *size);

> 

> The whole point of moving code out of arch code was to avoid all these

> cross tree calls.

> 

> I was expecting the next step to be moving setup_ima_buffer() call into

> of_kexec_setup_new_fdt with all the code in powerpc/kexec/ima.c moved

> here. Then the end result to enable on arm64 is just selecting

> HAVE_IMA_KEXEC and adding fields to kimage_arch.

> 


setup_ima_buffer() implemented for powerpc can be simplified by using
fdt_appendprop_addrrange() to add the IMA buffer's address and size to 
"linux,ima-kexec-buffer" node. With that change, setup_ima_buffer() can 
be moved into of_kexec_setup_new_fdt along with all the code in 
powerpc/kexec/ima.c to drivers'of/kexec.c

I'll make the above change and post the next version shortly.

thanks,
  -lakshmi
diff mbox series

Patch

diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index 66787be081fe..9af5371340b1 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -30,6 +30,10 @@ 
 /**
  * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
  *
+ * @fdt: Flattened Device Tree to update
+ * @start: Starting address of the reservation to delete
+ * @size: Size of the reservation to delete
+ *
  * Return: 0 on success, or negative errno on error.
  */
 static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
@@ -226,3 +230,67 @@  int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 
 	return 0;
 }
+
+/**
+ * get_root_addr_size_cells - Get address and size of root node
+ *
+ * @addr_cells: Return address of the root node
+ * @size_cells: Return size of the root node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int get_root_addr_size_cells(int *addr_cells, int *size_cells)
+{
+	struct device_node *root;
+
+	root = of_find_node_by_path("/");
+	if (!root)
+		return -EINVAL;
+
+	*addr_cells = of_n_addr_cells(root);
+	*size_cells = of_n_size_cells(root);
+
+	of_node_put(root);
+
+	return 0;
+}
+
+/**
+ * get_ima_kexec_buffer - Get address and size of IMA kexec buffer
+ *
+ * @fdt: Flattened Device Tree
+ * @chosen_node: Offset of chosen node in the FDT
+ * @addr: Return address of the node
+ * @size: Return size of the node
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int get_ima_kexec_buffer(void *fdt, int chosen_node,
+			 unsigned long *addr, size_t *size)
+{
+	const void *prop;
+	int addr_cells, size_cells, prop_len;
+	int rc;
+
+	rc = get_root_addr_size_cells(&addr_cells, &size_cells);
+	if (rc)
+		return rc;
+
+	if (fdt)
+		prop = fdt_getprop(fdt, chosen_node,
+				   "linux,ima-kexec-buffer", &prop_len);
+	else
+		prop = of_get_property(of_chosen,
+				       "linux,ima-kexec-buffer", &prop_len);
+
+	if (!prop)
+		return -ENOENT;
+
+	if (prop_len < 4 * (addr_cells + size_cells))
+		return -EINVAL;
+
+	*addr = of_read_number(prop, addr_cells);
+	*size = of_read_number(prop + 4 * addr_cells, size_cells);
+
+	return 0;
+}
diff --git a/include/linux/of.h b/include/linux/of.h
index 3375f5295875..fb2ef274135d 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -562,6 +562,9 @@  struct kimage;
 int of_kexec_setup_new_fdt(const struct kimage *image, void *fdt,
 			   unsigned long initrd_load_addr, unsigned long initrd_len,
 			   const char *cmdline);
+int get_root_addr_size_cells(int *addr_cells, int *size_cells);
+int get_ima_kexec_buffer(void *fdt, int chosen_node,
+			 unsigned long *addr, size_t *size);
 
 #else /* CONFIG_OF */