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authorJohannes Berg <[email protected]>2024-10-09 08:59:14 +0200
committerJohannes Berg <[email protected]>2024-10-09 08:59:22 +0200
commita0efa2f362a69e47b9d8b48f770ef3a0249a7911 (patch)
tree384d2c79a9b613213ef7591583d820d18c7be9c3 /rust/helpers/build_assert.c
parentdb03488897a70367aeafe82d07a78943d2a6068e (diff)
parent36efaca9cb28a893cad98f0448c39a8b698859e2 (diff)
Merge net-next/main to resolve conflicts
The wireless-next tree was based on something older, and there are now conflicts between -rc2 and work here. Merge net-next, which has enough of -rc2 for the conflicts to happen, resolving them in the process. Signed-off-by: Johannes Berg <[email protected]>
Diffstat (limited to 'rust/helpers/build_assert.c')
-rw-r--r--rust/helpers/build_assert.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/rust/helpers/build_assert.c b/rust/helpers/build_assert.c
new file mode 100644
index 000000000000..6a54b2680b14
--- /dev/null
+++ b/rust/helpers/build_assert.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/build_bug.h>
+
+/*
+ * `bindgen` binds the C `size_t` type as the Rust `usize` type, so we can
+ * use it in contexts where Rust expects a `usize` like slice (array) indices.
+ * `usize` is defined to be the same as C's `uintptr_t` type (can hold any
+ * pointer) but not necessarily the same as `size_t` (can hold the size of any
+ * single object). Most modern platforms use the same concrete integer type for
+ * both of them, but in case we find ourselves on a platform where
+ * that's not true, fail early instead of risking ABI or
+ * integer-overflow issues.
+ *
+ * If your platform fails this assertion, it means that you are in
+ * danger of integer-overflow bugs (even if you attempt to add
+ * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
+ * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
+ * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
+ */
+static_assert(
+ sizeof(size_t) == sizeof(uintptr_t) &&
+ __alignof__(size_t) == __alignof__(uintptr_t),
+ "Rust code expects C `size_t` to match Rust `usize`"
+);