[PATCH v10 4/8] powerpc: Use ima kexec node functions

Lakshmi Ramasubramanian
2020-12-04T19:53:12Z

do_get_kexec_buffer() and get_addr_size_cells() are called by
ima_get_kexec_buffer(), ima_free_kexec_buffer, and remove_ima_buffer()
to retrieve the address and size of the buffer used for carrying
forward the IMA measurement log across kexec system call. These
functions correctly handle a device tree property that is a child node
of the root node, but not anything other than the immediate root
child nodes.

Use the architecture independent functions get_ima_kexec_buffer()
and get_root_addr_size_cells() defined in "drivers/of/ima_kexec.c",
to get the address and size of the IMA measurement log buffer from
the device tree. Remove do_get_kexec_buffer() and get_addr_size_cells()
since they are not used anymore.

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>
---
arch/powerpc/kexec/ima.c | 58 +++++-----------------------------------
1 file changed, 7 insertions(+), 51 deletions(-)

diff --git a/arch/powerpc/kexec/ima.c b/arch/powerpc/kexec/ima.c
index a36c39db4b1a..906e8212435d 100644
--- a/arch/powerpc/kexec/ima.c
+++ b/arch/powerpc/kexec/ima.c
@@ -13,40 +13,6 @@
#include <linux/libfdt.h>
#include <asm/ima.h>

-static int get_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;
-}
-
-static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
- size_t *size)
-{
- int ret, addr_cells, size_cells;
-
- ret = get_addr_size_cells(&addr_cells, &size_cells);
- if (ret)
- return ret;
-
- if (len < 4 * (addr_cells + size_cells))
- return -ENOENT;
-
- *addr = of_read_number(prop, addr_cells);
- *size = of_read_number(prop + 4 * addr_cells, size_cells);
-
- return 0;
-}
-
/**
* ima_get_kexec_buffer - get IMA buffer from the previous kernel
* @addr: On successful return, set to point to the buffer contents.
@@ -56,16 +22,11 @@ static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
*/
int ima_get_kexec_buffer(void **addr, size_t *size)
{
- int ret, len;
+ int ret;
unsigned long tmp_addr;
size_t tmp_size;
- const void *prop;

- prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
- if (!prop)
- return -ENOENT;
-
- ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
+ ret = get_ima_kexec_buffer(NULL, 0, &tmp_addr, &tmp_size);
if (ret)
return ret;

@@ -89,7 +50,7 @@ int ima_free_kexec_buffer(void)
if (!prop)
return -ENOENT;

- ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
+ ret = get_ima_kexec_buffer(NULL, 0, &addr, &size);
if (ret)
return ret;

@@ -98,7 +59,6 @@ int ima_free_kexec_buffer(void)
return ret;

return memblock_free(addr, size);
-
}

/**
@@ -112,19 +72,15 @@ int ima_free_kexec_buffer(void)
*/
void remove_ima_buffer(void *fdt, int chosen_node)
{
- int ret, len;
+ int ret;
unsigned long addr;
size_t size;
- const void *prop;

- prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
- if (!prop)
+ ret = get_ima_kexec_buffer(fdt, chosen_node, &addr, &size);
+ if (ret)
return;

- ret = do_get_kexec_buffer(prop, len, &addr, &size);
fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
- if (ret)
- return;

ret = delete_fdt_mem_rsv(fdt, addr, size);
if (!ret)
@@ -191,7 +147,7 @@ int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)
if (!image->arch.ima_buffer_size)
return 0;

- ret = get_addr_size_cells(&addr_cells, &size_cells);
+ ret = get_root_addr_size_cells(&addr_cells, &size_cells);
if (ret)
return ret;

--
2.29.2