Subject: [PATCH V13 5/7] rust: Make __udivdi3() and __umoddi3() panic

From: "Mukesh Kumar Chaurasiya (IBM)" <[email-masked]>
Date: Fri, 24 Apr 2026 11:17:40 +0530

From: Link Mauve <[email-masked]>

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 <[email-masked]>
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <[email-masked]>
---
 rust/Makefile             | 4 ++++
 rust/compiler_builtins.rs | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/rust/Makefile b/rust/Makefile
index 2a5428a5503d..ee11fba7a03d 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -616,6 +616,10 @@ 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