On Mon, Oct 12, 2020 at 05:19:42PM +0100, Andre Przywara wrote:
> In several places we check for a returned phandle value to be valid,
> for that it must not be 0 or "-1".
>
> Wrap this check in a macro in dtc.h, and use ~0U instead of -1 on the
> way, to keep everything in the unsigned realm.
We can probably make this a bit safer still, if we made it a typed
inline, instead of a macro.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> ---
> checks.c | 10 +++++-----
> dtc.h | 2 ++
> livetree.c | 4 ++--
> 3 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/checks.c b/checks.c
> index 17cb689..7cb9011 100644
> --- a/checks.c
> +++ b/checks.c
> @@ -497,7 +497,7 @@ static cell_t check_phandle_prop(struct check *c, struct dt_info *dti,
>
> phandle = propval_cell(prop);
>
> - if ((phandle == 0) || (phandle == -1)) {
> + if (!FDT_VALID_PHANDLE(phandle)) {
> FAIL_PROP(c, dti, node, prop, "bad value (0x%x) in %s property",
> phandle, prop->name);
> return 0;
> @@ -1379,14 +1379,14 @@ static void check_property_phandle_args(struct check *c,
> for (cell = 0; cell < prop->val.len / sizeof(cell_t); cell += cellsize + 1) {
> struct node *provider_node;
> struct property *cellprop;
> - int phandle;
> + cell_t phandle;
>
> phandle = propval_cell_n(prop, cell);
> /*
> * Some bindings use a cell value 0 or -1 to skip over optional
> * entries when each index position has a specific definition.
> */
> - if (phandle == 0 || phandle == -1) {
> + if (!FDT_VALID_PHANDLE(phandle)) {
> /* Give up if this is an overlay with external references */
> if (dti->dtsflags & DTSF_PLUGIN)
> break;
> @@ -1603,7 +1603,7 @@ static void check_interrupts_property(struct check *c,
> prop = get_property(parent, "interrupt-parent");
> if (prop) {
> phandle = propval_cell(prop);
> - if ((phandle == 0) || (phandle == -1)) {
> + if (!FDT_VALID_PHANDLE(phandle)) {
> /* Give up if this is an overlay with
> * external references */
> if (dti->dtsflags & DTSF_PLUGIN)
> @@ -1760,7 +1760,7 @@ static struct node *get_remote_endpoint(struct check *c, struct dt_info *dti,
>
> phandle = propval_cell(prop);
> /* Give up if this is an overlay with external references */
> - if (phandle == 0 || phandle == -1)
> + if (!FDT_VALID_PHANDLE(phandle))
> return NULL;
>
> node = get_node_by_phandle(dti->dt, phandle);
> diff --git a/dtc.h b/dtc.h
> index a08f415..f2f96ec 100644
> --- a/dtc.h
> +++ b/dtc.h
> @@ -49,6 +49,8 @@ extern int annotate; /* annotate .dts with input source location */
> #define PHANDLE_EPAPR 0x2
> #define PHANDLE_BOTH 0x3
>
> +#define FDT_VALID_PHANDLE(x) ((x) != 0 && (x) != ~0U)
> +
> typedef uint32_t cell_t;
>
> static inline uint16_t dtb_ld16(const void *p)
> diff --git a/livetree.c b/livetree.c
> index 032df58..aea6095 100644
> --- a/livetree.c
> +++ b/livetree.c
> @@ -559,7 +559,7 @@ struct node *get_node_by_phandle(struct node *tree, cell_t phandle)
> {
> struct node *child, *node;
>
> - if ((phandle == 0) || (phandle == -1)) {
> + if (!FDT_VALID_PHANDLE(phandle)) {
> assert(generate_fixups);
> return NULL;
> }
> @@ -594,7 +594,7 @@ cell_t get_node_phandle(struct node *root, struct node *node)
> static cell_t phandle = 1; /* FIXME: ick, static local */
> struct data d = empty_data;
>
> - if ((node->phandle != 0) && (node->phandle != -1))
> + if (FDT_VALID_PHANDLE(node->phandle))
> return node->phandle;
>
> while (get_node_by_phandle(root, phandle))
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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