| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20260112142009.1006236-7-herve.codina@bootlin.com>
Date: Mon, 12 Jan 2026 15:18:56 +0100
From: Herve Codina <herve.codina@...tlin.com>
To: David Gibson <david@...son.dropbear.id.au>,
Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk@...nel.org>,
Conor Dooley <conor+dt@...nel.org>
Cc: Ayush Singh <ayush@...gleboard.org>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
devicetree-compiler@...r.kernel.org,
devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org,
devicetree-spec@...r.kernel.org,
Hui Pu <hui.pu@...ealthcare.com>,
Ian Ray <ian.ray@...ealthcare.com>,
Luca Ceresoli <luca.ceresoli@...tlin.com>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Herve Codina <herve.codina@...tlin.com>
Subject: [RFC PATCH 06/77] Add support for FDT_REF_LOCAL dtb tag
FDT_REF_LOCAL dtb tag is a meta-data tag attached to a property.
It indicates that the property defined before this tag (FDT_PROP) uses a
phandle value and the node related to this phandle value is local (i.e.
the node is present in the device-tree blob).
It is followed by one value:
- offset (32bit):
Offset in the property data where the phandle is available.
Example:
FDT_PROP 0x00000008 xxxxxxxx 0xca 0xfe 0xde 0xca 0x01 0x02 0x03 0x04
FDT_REF_LOCAL 0x00000004
This means that at the offset 4 of the property data, the value
(0x01020304) is a phandle and the related node is available in the
dtb.
This is what is encoded in the dtb when the related dts has a property
with the value set to <0xcafedeca &foo> with 'foo' a reference to an
existing node where the phandle value is 0x01020304.
If several local phandles are used in the property data, several
FDT_REF_LOCAL are present after the FDT_PROP tag. Each of them points
with its offset value to the position of one phandle.
For instance, if a first property with 8 bytes of data has a phandle
value at offset 4 and a second property with 16 bytes of data has
phandle values at offset 0 and 8, the following tags sequence is
present:
FDT_PROP 0x00000008 xxxxxxxx <data bytes>
FDT_REF_LOCAL 0x00000004
FDT_PROP 0x00000010 xxxxxxxx <data bytes>
FDT_REF_LOCAL 0x00000000
FDT_REF_LOCAL 0x00000008
Add support for this new dtb tag.
Suggested-by: David Gibson <david@...son.dropbear.id.au>
Link: https://lore.kernel.org/all/aL-2fmYsbexEtpNp@zatzit/
Signed-off-by: Herve Codina <herve.codina@...tlin.com>
---
data.c | 1 +
dtc.h | 1 +
fdtdump.c | 14 +++++++++++++-
flattree.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
libfdt/fdt.c | 24 ++++++++++++++++++++++--
libfdt/fdt.h | 1 +
6 files changed, 84 insertions(+), 4 deletions(-)
diff --git a/data.c b/data.c
index 11b2169..9bae704 100644
--- a/data.c
+++ b/data.c
@@ -288,6 +288,7 @@ struct marker *alloc_marker(unsigned int offset, enum markertype type,
m->type = type;
m->ref = ref;
m->next = NULL;
+ m->is_local = 0;
return m;
}
diff --git a/dtc.h b/dtc.h
index 3bbd97e..965321c 100644
--- a/dtc.h
+++ b/dtc.h
@@ -128,6 +128,7 @@ struct marker {
enum markertype type;
unsigned int offset;
char *ref;
+ bool is_local;
struct marker *next;
};
diff --git a/fdtdump.c b/fdtdump.c
index 95a2274..dffa9a6 100644
--- a/fdtdump.c
+++ b/fdtdump.c
@@ -57,8 +57,9 @@ static void dump_blob(void *blob, bool debug)
const char *p_strings = (const char *)blob + off_str;
uint32_t version = fdt32_to_cpu(bph->version);
uint32_t totalsize = fdt32_to_cpu(bph->totalsize);
- uint32_t tag;
+ uint32_t tag, offset;
const char *p, *s, *t;
+ const char *last_prop_name = NULL;
int depth, sz, shift;
int i;
uint64_t addr, size;
@@ -105,6 +106,7 @@ static void dump_blob(void *blob, bool debug)
(uintptr_t)p - blob_off - 4, tag, tagname(tag));
if (tag == FDT_BEGIN_NODE) {
+ last_prop_name = NULL;
s = p;
p = PALIGN(p + strlen(s) + 1, 4);
@@ -118,6 +120,7 @@ static void dump_blob(void *blob, bool debug)
}
if (tag == FDT_END_NODE) {
+ last_prop_name = NULL;
depth--;
printf("%*s};\n", depth * shift, "");
@@ -143,6 +146,15 @@ static void dump_blob(void *blob, bool debug)
printf("%*s%s", depth * shift, "", s);
utilfdt_print_data(t, sz);
printf(";\n");
+ last_prop_name = s;
+ continue;
+ }
+
+ if (tag == FDT_REF_LOCAL) {
+ offset = fdt32_to_cpu(GET_CELL(p));
+
+ printf("%*s// [FDT_REF_LOCAL] %s[%"PRIu32"]\n", depth * shift, "",
+ last_prop_name, offset);
continue;
}
diff --git a/flattree.c b/flattree.c
index c3887da..5c597ad 100644
--- a/flattree.c
+++ b/flattree.c
@@ -13,6 +13,7 @@
#define FTF_STRTABSIZE 0x10
#define FTF_STRUCTSIZE 0x20
#define FTF_NOPS 0x40
+#define FTF_REF_XXX 0x80
static struct version_info {
int version;
@@ -31,7 +32,7 @@ static struct version_info {
{17, 16, FDT_V17_SIZE,
FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_STRUCTSIZE|FTF_NOPS},
{18, 18, FDT_V18_SIZE,
- FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_STRUCTSIZE|FTF_NOPS},
+ FTF_BOOTCPUID|FTF_STRTABSIZE|FTF_STRUCTSIZE|FTF_NOPS|FTF_REF_XXX},
};
struct emitter {
@@ -42,6 +43,7 @@ struct emitter {
void (*beginnode)(void *, struct label *labels);
void (*endnode)(void *, struct label *labels);
void (*property)(void *, struct label *labels);
+ void (*ref_local)(void *);
};
static void bin_emit_cell(void *e, cell_t val)
@@ -91,6 +93,11 @@ static void bin_emit_property(void *e, struct label *labels)
bin_emit_cell(e, FDT_PROP);
}
+static void bin_emit_ref_local(void *e)
+{
+ bin_emit_cell(e, FDT_REF_LOCAL);
+}
+
static struct emitter bin_emitter = {
.cell = bin_emit_cell,
.string = bin_emit_string,
@@ -99,6 +106,7 @@ static struct emitter bin_emitter = {
.beginnode = bin_emit_beginnode,
.endnode = bin_emit_endnode,
.property = bin_emit_property,
+ .ref_local = bin_emit_ref_local,
};
static void emit_label(FILE *f, const char *prefix, const char *label)
@@ -210,6 +218,14 @@ static void asm_emit_property(void *e, struct label *labels)
asm_emit_cell(e, FDT_PROP);
}
+static void asm_emit_ref_local(void *e)
+{
+ FILE *f = e;
+
+ fprintf(f, "\t/* FDT_REF_LOCAL */\n");
+ asm_emit_cell(e, FDT_REF_LOCAL);
+}
+
static struct emitter asm_emitter = {
.cell = asm_emit_cell,
.string = asm_emit_string,
@@ -218,6 +234,7 @@ static struct emitter asm_emitter = {
.beginnode = asm_emit_beginnode,
.endnode = asm_emit_endnode,
.property = asm_emit_property,
+ .ref_local = asm_emit_ref_local,
};
static int stringtable_insert(struct data *d, const char *str)
@@ -242,6 +259,7 @@ static void flatten_tree(struct node *tree, struct emitter *emit,
struct property *prop;
struct node *child;
bool seen_name_prop = false;
+ struct marker *m;
if (tree->deleted)
return;
@@ -272,6 +290,17 @@ static void flatten_tree(struct node *tree, struct emitter *emit,
emit->data(etarget, prop->val);
emit->align(etarget, sizeof(cell_t));
+
+ if (vi->flags & FTF_REF_XXX) {
+ m = prop->val.markers;
+ for_each_marker_of_type(m, REF_PHANDLE) {
+ if (m->is_local) {
+ emit->ref_local(etarget);
+ emit->cell(etarget, m->offset);
+ continue;
+ }
+ }
+ }
}
if ((vi->flags & FTF_NAMEPROPS) && !seen_name_prop) {
@@ -737,6 +766,7 @@ static struct node *unflatten_tree(struct inbuf *dtbuf,
struct node *node;
const char *flatname;
uint32_t val;
+ uint32_t offset;
node = build_node(NULL, NULL, NULL);
@@ -751,6 +781,7 @@ static struct node *unflatten_tree(struct inbuf *dtbuf,
do {
struct property *prop;
struct node *child;
+ struct marker *m;
val = flat_read_word(dtbuf);
switch (val) {
@@ -782,6 +813,17 @@ static struct node *unflatten_tree(struct inbuf *dtbuf,
/* Ignore */
break;
+ case FDT_REF_LOCAL:
+ if (!(flags & FTF_REF_XXX))
+ die("REF_LOCAL tag found in flat tree"
+ " version <18\n");
+
+ offset = flat_read_word(dtbuf);
+ m = alloc_marker(offset, REF_PHANDLE, NULL);
+ m->is_local = true;
+ prop->val = data_append_markers(prop->val, m);
+ break;
+
default:
die("Invalid opcode word %08x in device tree blob\n",
val);
@@ -900,6 +942,9 @@ struct dt_info *dt_from_blob(const char *fname)
flags |= FTF_NOPS;
}
+ if (version >= 18)
+ flags |= FTF_REF_XXX;
+
inbuf_init(&memresvbuf,
blob + off_mem_rsvmap, blob + totalsize);
inbuf_init(&dtbuf, blob + off_dt, blob + totalsize);
diff --git a/libfdt/fdt.c b/libfdt/fdt.c
index ce051a0..7268fb6 100644
--- a/libfdt/fdt.c
+++ b/libfdt/fdt.c
@@ -161,7 +161,7 @@ const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
uint32_t fdt_next_tag_full(const void *fdt, int startoffset, int *nextoffset)
{
- const fdt32_t *tagp, *lenp;
+ const fdt32_t *tagp, *lenp, *tmp32p;
uint32_t tag, len, sum;
int offset = startoffset;
const char *p;
@@ -209,6 +209,14 @@ uint32_t fdt_next_tag_full(const void *fdt, int startoffset, int *nextoffset)
case FDT_NOP:
break;
+ case FDT_REF_LOCAL:
+ /* Skip offset value */
+ tmp32p = fdt_offset_ptr(fdt, offset, sizeof(*tmp32p));
+ if (!can_assume(VALID_DTB) && !tmp32p)
+ return FDT_END; /* premature end */
+ offset += sizeof(fdt32_t);
+ break;
+
default:
return FDT_END;
}
@@ -239,10 +247,22 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
case FDT_PROP:
case FDT_NOP:
case FDT_END:
- /* Next tag is not new tag introduced in v18 -> Ok */
+ /*
+ * Next tag is not a meta-data tag -> Ok this next tag
+ * has to be handle by fd_next_tag().
+ * Filter out any potential meta-data tag returning
+ * nextoffset pointing to this current next tag.
+ */
*nextoffset = tmp_offset;
return tag;
+ case FDT_REF_LOCAL:
+ /*
+ * Next tag is a meta-data tag present in the middle
+ * of the structure -> Skip it and look at next one
+ */
+ break;
+
default:
break;
}
diff --git a/libfdt/fdt.h b/libfdt/fdt.h
index 9372353..f8efdf1 100644
--- a/libfdt/fdt.h
+++ b/libfdt/fdt.h
@@ -55,6 +55,7 @@ struct fdt_property {
#define FDT_PROP 0x3 /* Property: name off,
size, content */
#define FDT_NOP 0x4 /* nop */
+#define FDT_REF_LOCAL 0x5 /* local phandle reference: offset */
#define FDT_END 0x9
#define FDT_V1_SIZE (7*sizeof(fdt32_t))
--
2.52.0
Powered by blists - more mailing lists