Hi,
On Sun, 14 May 2017 21:03:23 -0600 Simon Glass wrote:
> Hi Lothar,
>
> On 11 May 2017 at 08:59, Lothar Waßmann <l...@karo-electronics.de> wrote:
> > Hi,
> >
> > On Wed, 10 May 2017 08:20:44 -0600 Simon Glass wrote:
> >> This function converts the flat device tree into a hierarchical one with
> >> C structures and pointers. This is easier to access.
> >>
> >> Signed-off-by: Simon Glass <s...@chromium.org>
> >> ---
> >>
> >> Changes in v2: None
> >>
> >> include/of_live.h | 24 ++++
> >> lib/Makefile | 1 +
> >> lib/of_live.c | 333
> >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >> 3 files changed, 358 insertions(+)
> >> create mode 100644 include/of_live.h
> >> create mode 100644 lib/of_live.c
> >>
> >> diff --git a/include/of_live.h b/include/of_live.h
> >> new file mode 100644
> >> index 0000000000..f5303bb018
> >> --- /dev/null
> >> +++ b/include/of_live.h
> >> @@ -0,0 +1,24 @@
> >> +/*
> >> + * Copyright (c) 2017 Google, Inc
> >> + * Written by Simon Glass <s...@chromium.org>
> >> + *
> >> + * SPDX-License-Identifier: GPL-2.0+
> >> + *
> >> + * Support for a 'live' (as opposed to flat) device tree
> >> + */
> >> +
> >> +#ifndef _OF_LIVE_H
> >> +#define _OF_LIVE_H
> >> +
> >> +struct device_node;
> >> +
> >> +/**
> >> + * of_live_build() - build a live (hierarchical) tree from a flat DT
> >> + *
> >> + * @fdt_blob: Input tree to convert
> >> + * @rootp: Returns live tree that was created
> >> + * @return 0 if OK, -ve on error
> >> + */
> >> +int of_live_build(const void *fdt_blob, struct device_node **rootp);
> >> +
> >> +#endif
> >> diff --git a/lib/Makefile b/lib/Makefile
> >> index 23e9f1ef11..bc2fb0a361 100644
> >> --- a/lib/Makefile
> >> +++ b/lib/Makefile
> >> @@ -15,6 +15,7 @@ obj-$(CONFIG_ZLIB) += zlib/
> >> obj-$(CONFIG_BZIP2) += bzip2/
> >> obj-$(CONFIG_TIZEN) += tizen/
> >> obj-$(CONFIG_FIT) += libfdt/
> >> +obj-$(CONFIG_OF_LIVE) += of_live.o
> >> obj-$(CONFIG_CMD_DHRYSTONE) += dhry/
> >>
> >> obj-$(CONFIG_AES) += aes.o
> >> diff --git a/lib/of_live.c b/lib/of_live.c
> >> new file mode 100644
> >> index 0000000000..51927f9e91
> >> --- /dev/null
> >> +++ b/lib/of_live.c
> >> @@ -0,0 +1,333 @@
> >> +/*
> >> + * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
> >> + * b...@kernel.crashing.org
> >> + *
> >> + * Based on parts of drivers/of/fdt.c from Linux v4.9
> >> + * Modifications for U-Boot
> >> + * Copyright (c) 2017 Google, Inc
> >> + *
> >> + * SPDX-License-Identifier: GPL-2.0+
> >> + */
> >> +
> >> +#include <common.h>
> >> +#include <libfdt.h>
> >> +#include <of_live.h>
> >> +#include <malloc.h>
> >> +#include <dm/of_access.h>
> >> +#include <linux/err.h>
> >> +
> >> +DECLARE_GLOBAL_DATA_PTR;
> >> +
> >> +static void *unflatten_dt_alloc(void **mem, unsigned long size,
> >> + unsigned long align)
> >> +{
> >> + void *res;
> >> +
> >> + *mem = PTR_ALIGN(*mem, align);
> >> + res = *mem;
> >> + *mem += size;
> >> +
> >> + return res;
> >> +}
> >> +
> >> +/**
> >> + * unflatten_dt_node() - Alloc and populate a device_node from the flat
> >> tree
> >> + * @blob: The parent device tree blob
> >> + * @mem: Memory chunk to use for allocating device nodes and properties
> >> + * @poffset: pointer to node in flat tree
> >> + * @dad: Parent struct device_node
> >> + * @nodepp: The device_node tree created by the call
> >> + * @fpsize: Size of the node path up at t05he current depth.
> >> + * @dryrun: If true, do not allocate device nodes but still calculate
> >> needed
> >> + * memory size
> >> + */
> >> +static void *unflatten_dt_node(const void *blob, void *mem, int *poffset,
> >> + struct device_node *dad,
> >> + struct device_node **nodepp,
> >> + unsigned long fpsize, bool dryrun)
> >> +{
> >> + const __be32 *p;
> >> + struct device_node *np;
> >> + struct property *pp, **prev_pp = NULL;
> >> + const char *pathp;
> >> + int l;
> >> + unsigned int allocl;
> >> + static int depth;
> >> + int old_depth;
> >> + int offset;
> >> + int has_name = 0;
> >> + int new_format = 0;
> >> +
> >> + pathp = fdt_get_name(blob, *poffset, &l);
> >> + if (!pathp)
> >> + return mem;
> >> +
> >> + allocl = ++l;
> >> +
> >> + /*
> >> + * version 0x10 has a more compact unit name here instead of the full
> >> + * path. we accumulate the full path size using "fpsize", we'll
> >> rebuild
> >> + * it later. We detect this because the first character of the name
> >> is
> >> + * not '/'.
> >> + */
> >> + if ((*pathp) != '/') {
> >> + new_format = 1;
> >> + if (fpsize == 0) {
> >> + /*
> >> + * root node: special case. fpsize accounts for path
> >> + * plus terminating zero. root node only has '/', so
> >> + * fpsize should be 2, but we want to avoid the first
> >> + * level nodes to have two '/' so we use fpsize 1
> >> here
> >> + */
> >> + fpsize = 1;
> >> + allocl = 2;
> >> + l = 1;
> >> + pathp = "";
> >> + } else {
> >> + /*
> >> + * account for '/' and path size minus terminal 0
> >> + * already in 'l'
> >> + */
> >> + fpsize += l;
> >> + allocl = fpsize;
> >> + }
> >> + }
> >> +
> >> + np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
> >> + __alignof__(struct device_node));
> >> + if (!dryrun) {
> >> + char *fn;
> >> +
> >> + fn = (char *)np + sizeof(*np);
> >> + np->full_name = fn;
> >> + if (new_format) {
> >> + /* rebuild full path for new format */
> >> + if (dad && dad->parent) {
> >> + strcpy(fn, dad->full_name);
> >>
> > strcpy() is EVIL! How do you ascertain, that the string
> > at dad->full_name cannot overflow the buffer at fn?
>
> The size has been calculated the code above. This is a two-pass
> approach - one pass figures out the total size of the required buffer,
> and the next pass actually copies in the data.
>
> If the length were wrong that would indicate a bug in the code above.
> See the part where it sets new_format to 1.
>
dad->full_name is touched nowhere else in the code, so it is not
apparent from the code that its strlen() is accounted for in any way.
Lothar Waßmann
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
https://lists.denx.de/listinfo/u-boot
