Messages in this thread | | | Subject | Re: [PATCH v11 2/8] powerpc: Move ima buffer functions to drivers/of/kexec.c | From | Lakshmi Ramasubramanian <> | Date | Wed, 16 Dec 2020 08:58:00 -0800 |
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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
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