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

[Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx>]

On 12/5/20 11:51 AM, Thiago Jung Bauermann wrote:
> Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx> 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/
Thanks for catching this. I'll fix it.

> > 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@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Prakhar Srivastava <prsriva@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx>
>
> Looks good. Thanks!
>
> Reviewed-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx>

Thanks Thiago.

 -lakshmi

> > ---
> >   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;