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 (mailing list archive)
State New, archived
Headers show
Series Carry forward IMA measurement log on kexec on ARM64 | expand

Commit Message

Lakshmi Ramasubramanian 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
Lakshmi Ramasubramanian 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 */