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

Thiago Jung Bauermann
2020-12-05T19:53:33Z

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:

> 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",

s/ima_kexec.c/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>

Looks good. Thanks!

Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.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;

--
Thiago Jung Bauermann
IBM Linux Technology Center