diff options
Diffstat (limited to 'meta-agl-bsp/meta-raspberrypi/recipes-kernel/dtc/files/0001-fdtoverlay-Prevent-overlays-from-modifying-phandle-p.patch')
| -rw-r--r-- | meta-agl-bsp/meta-raspberrypi/recipes-kernel/dtc/files/0001-fdtoverlay-Prevent-overlays-from-modifying-phandle-p.patch | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/meta-agl-bsp/meta-raspberrypi/recipes-kernel/dtc/files/0001-fdtoverlay-Prevent-overlays-from-modifying-phandle-p.patch b/meta-agl-bsp/meta-raspberrypi/recipes-kernel/dtc/files/0001-fdtoverlay-Prevent-overlays-from-modifying-phandle-p.patch new file mode 100644 index 000000000..0f275f1ac --- /dev/null +++ b/meta-agl-bsp/meta-raspberrypi/recipes-kernel/dtc/files/0001-fdtoverlay-Prevent-overlays-from-modifying-phandle-p.patch @@ -0,0 +1,154 @@ +From caba0117dc30f2357eac6d04f3510095dcbaa7f4 Mon Sep 17 00:00:00 2001 +From: Paul Barker <pbarker@konsulko.com> +Date: Fri, 18 Dec 2020 23:00:07 +0000 +Subject: [PATCH] fdtoverlay: Prevent overlays from modifying phandle + properties +To: David Gibson <david@gibson.dropbear.id.au>, + Jon Loeliger <jdl@jdl.com>, + devicetree-compiler@vger.kernel.org +Cc: Rob Herring <robh@kernel.org>, + Pantelis Antoniou <pantelis.antoniou@konsulko.com>, + Scott Murray <scott.murray@konsulko.com>, + Jan Simon Moeller <jsmoeller@linuxfoundation.org> + +When applying an overlay fragment, we should take care not to overwrite +an existing phandle property of the target node as this could break +references to the target node elsewhere in the base dtb. + +In addition to potentially breaking references within the resulting fdt, +if the overlay is built with symbols enabled (`-@` option to dtc) then +fdtoverlay will be unable to merge the overlay with a base dtb file. + +A new test case is added to check how fdtoverlay handles this case. +Attempting to apply this test overlay without the fix in this patch +results in the following output: + + input = tests/overlay_base_ref.test.dtb + output = tests/overlay_overlay_ref.fdtoverlay.dtb + overlay[0] = tests/overlay_overlay_ref.test.dtb + + Failed to apply 'tests/overlay_overlay_ref.test.dtb': FDT_ERR_NOTFOUND + +In this test case the __overlay__ node in question does not explicitly +contain a phandle property in the dts file, the phandle is added during +compilation as it is referenced by another node within the overlay dts. + +This failure occurs due to a sequence of events in the functions called +by fdt_overlay_apply(): + +1) In overlay_fixup_phandles(), the target of the overlay fragment is + looked up and the target property is set to the phandle of the target + node. + +2) In overlay_merge(), the target node is looked up by phandle via + overlay_get_target(). As the __overlay__ node in this test case + itself has a phandle property, the phandle of the target node is + modified. + +3) In overlay_symbol_update(), the target node is again looked up by + phandle via overlay_get_target(). But this time the target node + cannot be found as its phandle property was modified. + +The fix for this issue is to skip modification of the phandle property +of the target node in step (2) of the above sequence. If the target node +doesn't already contain a phandle property, we can add one without risk. + +Upstream-Status: Submitted + https://www.spinics.net/lists/devicetree-compiler/msg03537.html +Signed-off-by: Paul Barker <pbarker@konsulko.com> +--- + libfdt/fdt_overlay.c | 2 ++ + tests/overlay_base_ref.dts | 19 +++++++++++++++++++ + tests/overlay_overlay_ref.dts | 24 ++++++++++++++++++++++++ + tests/run_tests.sh | 5 +++++ + 4 files changed, 50 insertions(+) + create mode 100644 tests/overlay_base_ref.dts + create mode 100644 tests/overlay_overlay_ref.dts + +diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c +index d217e79..b3c217a 100644 +--- a/libfdt/fdt_overlay.c ++++ b/libfdt/fdt_overlay.c +@@ -573,6 +573,8 @@ static int overlay_apply_node(void *fdt, int target, + if (prop_len < 0) + return prop_len; + ++ if (!strcmp(name, "phandle") && fdt_getprop(fdt, target, name, NULL)) ++ continue; + ret = fdt_setprop(fdt, target, name, prop, prop_len); + if (ret) + return ret; +diff --git a/tests/overlay_base_ref.dts b/tests/overlay_base_ref.dts +new file mode 100644 +index 0000000..1fc02a2 +--- /dev/null ++++ b/tests/overlay_base_ref.dts +@@ -0,0 +1,19 @@ ++/* ++ * Copyright (c) 2016 NextThing Co ++ * Copyright (c) 2016 Free Electrons ++ * Copyright (c) 2016 Konsulko Inc. ++ * ++ * SPDX-License-Identifier: GPL-2.0+ ++ */ ++ ++/dts-v1/; ++ ++/ { ++ test: test-node { ++ test-int-property = <42>; ++ }; ++ ++ test-refs { ++ refs = <&test>; ++ }; ++}; +diff --git a/tests/overlay_overlay_ref.dts b/tests/overlay_overlay_ref.dts +new file mode 100644 +index 0000000..a45c95d +--- /dev/null ++++ b/tests/overlay_overlay_ref.dts +@@ -0,0 +1,24 @@ ++/* ++ * Copyright (c) 2016 NextThing Co ++ * Copyright (c) 2016 Free Electrons ++ * Copyright (c) 2016 Konsulko Inc. ++ * ++ * SPDX-License-Identifier: GPL-2.0+ ++ */ ++ ++/dts-v1/; ++/plugin/; ++ ++/ { ++ fragment@0 { ++ target = <&test>; ++ ++ frag0: __overlay__ { ++ test-int-property = <43>; ++ }; ++ }; ++ ++ test-ref { ++ ref = <&frag0>; ++ }; ++}; +diff --git a/tests/run_tests.sh b/tests/run_tests.sh +index 294585b..a65b166 100755 +--- a/tests/run_tests.sh ++++ b/tests/run_tests.sh +@@ -329,6 +329,11 @@ dtc_overlay_tests () { + run_test check_path overlay_base_with_aliases.dtb not-exists "/__symbols__" + run_test check_path overlay_base_with_aliases.dtb not-exists "/__fixups__" + run_test check_path overlay_base_with_aliases.dtb not-exists "/__local_fixups__" ++ ++ # Test taking a reference to an overlay fragment ++ run_dtc_test -@ -I dts -O dtb -o overlay_base_ref.test.dtb "$SRCDIR/overlay_base_ref.dts" ++ run_dtc_test -@ -I dts -O dtb -o overlay_overlay_ref.test.dtb "$SRCDIR/overlay_overlay_ref.dts" ++ run_wrap_test $FDTOVERLAY -i overlay_base_ref.test.dtb overlay_overlay_ref.test.dtb -o overlay_overlay_ref.fdtoverlay.dtb + } + + tree1_tests () { +-- +2.26.2 + |