[PATCH V14 5/7] rust: Make __udivdi3() and __umoddi3() panic

Mukesh Kumar Chaurasiya (IBM)
2026-04-26T08:58:44Z

From: Link Mauve <linkmauve@linkmauve.fr>

The core crate currently depends on these two functions for i64/u64/
i128/u128/core::time::Duration formatting, but we shouldn’t use that in
the kernel so let’s panic if they are ever called.

This doesn’t yet fix drm_panic_qr.rs, which also uses __udivdi3 when
CONFIG_CC_OPTIMIZE_FOR_SIZE=y, but at least makes the rest of the kernel
build on PPC32.

Signed-off-by: Link Mauve <linkmauve@linkmauve.fr>
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
rust/Makefile | 4 ++++
rust/compiler_builtins.rs | 6 ++++++
2 files changed, 10 insertions(+)

diff --git a/rust/Makefile b/rust/Makefile
index f6369d121c50..9aa18cff2fae 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -615,6 +615,10 @@ ifneq ($(or $(CONFIG_ARM64),$(and $(CONFIG_RISCV),$(CONFIG_64BIT))),)
__ashrti3 \
__ashlti3 __lshrti3
endif
+ifdef CONFIG_PPC32
+ redirect-intrinsics += \
+ __udivdi3 __umoddi3
+endif

ifdef CONFIG_MODVERSIONS
cmd_gendwarfksyms = $(if $(skip_gendwarfksyms),, \
diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs
index dd16c1dc899c..fc6b54636dd5 100644
--- a/rust/compiler_builtins.rs
+++ b/rust/compiler_builtins.rs
@@ -97,5 +97,11 @@ pub extern "C" fn $ident() {
__aeabi_uldivmod,
});

+#[cfg(target_arch = "powerpc")]
+define_panicking_intrinsics!("`u64` division/modulo should not be used", {
+ __udivdi3,
+ __umoddi3,
+});
+
// NOTE: if you are adding a new intrinsic here, you should also add it to
// `redirect-intrinsics` in `rust/Makefile`.
--
2.53.0