On Wed, May 13, 2020 at 11:35 AM Andre Przywara <andre.przywara@xxxxxxx> wrote:
>
> The interrupt-map in an interrupt nexus is quite a tricky property: Each
> entry contains five fields, the size of four of those depending on some
> *-cells entries from two different nodes. This is even hard to validate
> in a .dts file, especially when the associated interrupt controller is
> described in a separate (included) file.
>
> Add checks to validate those entries, by:
> - Checking some basic properties of the interrupt nexus node.
> - Checking that a map entry contains at least enough cells to point to
> the associated interrupt controller.
> - Checking that the phandle points to an actual interrupt controller.
> - Checking that there are enough entries to describe an interrupt in
> that interrupt controller's domain.
>
> If each iteration passes and we exhaust exactly all the cells in the
> interrupt-map property, the check passes.
> Report errors on the way, and abort the check if that happens.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> ---
> checks.c | 86 +++++++++++++++++++++++++++++++++++++++++++++
> tests/bad-interrupt-map.dts | 21 +++++++++++
> tests/run_tests.sh | 2 ++
> 3 files changed, 109 insertions(+)
> create mode 100644 tests/bad-interrupt-map.dts
>
> diff --git a/checks.c b/checks.c
> index 4b3c486..12518db 100644
> --- a/checks.c
> +++ b/checks.c
> @@ -924,6 +924,90 @@ static void check_pci_device_reg(struct check *c, struct dt_info *dti, struct no
> }
> WARNING(pci_device_reg, check_pci_device_reg, NULL, ®_format, &pci_bridge);
>
> +static void check_interrupt_map(struct check *c, struct dt_info *dti,
> + struct node *node)
> +{
> + struct property *map = get_property(node, "interrupt-map");
> + struct property *prop;
> + int i, cells, irq_cells;
> +
> + /* We are only interested in interrupt nexus nodes. */
> + if (!map)
> + return;
> +
> + if (map->val.len % sizeof(cell_t)) {
> + FAIL_PROP(c, dti, node, map, "invalid length of interrupt-map");
It's good to say what size you found and what was expected.
> + return;
> + }
> + cells = map->val.len / sizeof(cell_t);
> +
> + prop = get_property(node, "#interrupt-cells");
> + if (!prop) {
> + FAIL(c, dti, node, "missing #interrupt-cells in nexus\n");
> + return;
> + }
> + irq_cells = propval_cell(prop);
> +
> + for (i = 0; i < cells;) {
> + int phandle_idx = i + node_addr_cells(node) + irq_cells;
IIRC, node_addr_cells() will give you a default if not found which is
not really what you want.
> + cell_t intc_phandle, intc_irq_cells, intc_addr_cells;
> + struct node *intc = NULL;
> +
> + if (phandle_idx + 1 >= cells) {
> + FAIL_PROP(c, dti, node, map,
> + "insufficient cells for interrupt-map entry");
> + return;
> + }
> + intc_phandle = propval_cell_n(map, phandle_idx);
> + /* Avoid the assert in get_node_by_phandle(). */
> + if (intc_phandle != 0)
> + intc = get_node_by_phandle(dti->dt, intc_phandle);
> + if (!intc) {
> + FAIL_PROP(c, dti, node, map,
> + "invalid phandle for interrupt-map entry");
> + return;
> + }
> +
> + prop = get_property(intc, "interrupt-controller");
> + if (!prop) {
> + FAIL_PROP(c,dti, node, map,
> + "interrupt-map phandle does not point to interrupt controller");
interrupt-map can point to another interrupt-map.
> + return;
> + }
> +
> + prop = get_property(intc, "#address-cells");
> + if (!prop) {
> + FAIL_PROP(c,dti, node, map,
> + "interrupt-controller misses #address-cells property");
> + /*
> + * Linux treats non-existing #address-cells in the
> + * interrupt parent as 0, and not 2, as the spec
> + * suggests. Deal with that, but print the warning,
> + * since we should have an explicit #a-c = 0 in the
> + * controller node in this case.
IMO, we should not print a warning. Or make it separately enabled.
> + */
> + intc_addr_cells = 0;
> + } else
> + intc_addr_cells = propval_cell(prop);
> +
> + prop = get_property(intc, "#interrupt-cells");
> + if (!prop) {
> + FAIL_PROP(c,dti, node, map,
> + "interrupt-controller misses #interrupt-cells property");
> + return;
> + }
> + intc_irq_cells = propval_cell(prop);
> +
> + if (phandle_idx + intc_addr_cells + intc_irq_cells >= cells) {
> + FAIL_PROP(c, dti, node, map,
> + "insufficient cells for interrupt-map entry");
> + return;
> + }
> + i = phandle_idx + 1 + intc_addr_cells + intc_irq_cells;
> + }
> +}
> +WARNING(interrupt_map, check_interrupt_map, NULL);
> +
> static const struct bus_type simple_bus = {
> .name = "simple-bus",
> };
> @@ -1792,6 +1876,8 @@ static struct check *check_table[] = {
> &pci_device_reg,
> &pci_device_bus_num,
>
> + &interrupt_map,
> +
> &simple_bus_bridge,
> &simple_bus_reg,
>
> diff --git a/tests/bad-interrupt-map.dts b/tests/bad-interrupt-map.dts
> new file mode 100644
> index 0000000..cf9618f
> --- /dev/null
> +++ b/tests/bad-interrupt-map.dts
> @@ -0,0 +1,21 @@
> +/dts-v1/;
> +
> +/ {
> + intc: interrupt-controller {
> + interrupt-controller;
> + #address-cells = <2>;
> + #interrupt-cells = <3>;
> + };
> +
> + nexus-node {
> + #address-cells = <1>;
> + #interrupt-cells = <1>;
> +/*
> + * The cells after the phandle are the address in the interrupt controller's
> + * domain. This here encodes 0 cells , but the actual number is 2 above.
> + */
> + interrupt-map = <0 0 &intc 1 42 4>,
> + <0 1 &intc 1 43 4>,
> + <0 2 &intc 1 44 4>;
> + };
> +};
> diff --git a/tests/run_tests.sh b/tests/run_tests.sh
> index eccb85d..aec92fb 100755
> --- a/tests/run_tests.sh
> +++ b/tests/run_tests.sh
> @@ -732,6 +732,8 @@ dtc_tests () {
> check_tests "$SRCDIR/pci-bridge-bad1.dts" pci_bridge
> check_tests "$SRCDIR/pci-bridge-bad2.dts" pci_bridge
>
> + check_tests "$SRCDIR/bad-interrupt-map.dts" interrupt_map
> +
> check_tests "$SRCDIR/unit-addr-simple-bus-reg-mismatch.dts" simple_bus_reg
> check_tests "$SRCDIR/unit-addr-simple-bus-compatible.dts" simple_bus_reg
>
> --
> 2.14.1
>
