From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- arch/alpha/boot/Makefile | 120 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 arch/alpha/boot/Makefile (limited to 'arch/alpha/boot/Makefile') diff --git a/arch/alpha/boot/Makefile b/arch/alpha/boot/Makefile new file mode 100644 index 000000000..d8dba85e6 --- /dev/null +++ b/arch/alpha/boot/Makefile @@ -0,0 +1,120 @@ +# +# arch/alpha/boot/Makefile +# +# This file is subject to the terms and conditions of the GNU General Public +# License. See the file "COPYING" in the main directory of this archive +# for more details. +# +# Copyright (C) 1994 by Linus Torvalds +# + +hostprogs := tools/mkbb tools/objstrip +targets := vmlinux.gz vmlinux \ + vmlinux.nh tools/lxboot tools/bootlx tools/bootph \ + tools/bootpzh bootloader bootpheader bootpzheader +OBJSTRIP := $(obj)/tools/objstrip + +KBUILD_HOSTCFLAGS := -Wall -I$(objtree)/usr/include +BOOTCFLAGS += -I$(objtree)/$(obj) -I$(srctree)/$(obj) + +# SRM bootable image. Copy to offset 512 of a partition. +$(obj)/bootimage: $(addprefix $(obj)/tools/,mkbb lxboot bootlx) $(obj)/vmlinux.nh + ( cat $(obj)/tools/lxboot $(obj)/tools/bootlx $(obj)/vmlinux.nh ) > $@ + $(obj)/tools/mkbb $@ $(obj)/tools/lxboot + @echo ' Bootimage $@ is ready' + +# BOOTP bootable image. Define INITRD during make to append initrd image. +$(obj)/bootpfile: $(obj)/tools/bootph $(obj)/vmlinux.nh + cat $(obj)/tools/bootph $(obj)/vmlinux.nh > $@ +ifdef INITRD + cat $(INITRD) >> $@ +endif + +# Compressed kernel BOOTP bootable image. +# Define INITRD during make to append initrd image. +$(obj)/bootpzfile: $(obj)/tools/bootpzh $(obj)/vmlinux.nh.gz + cat $(obj)/tools/bootpzh $(obj)/vmlinux.nh.gz > $@ +ifdef INITRD + cat $(INITRD) >> $@ +endif + +# Compressed kernel image +$(obj)/vmlinux.gz: $(obj)/vmlinux FORCE + $(call if_changed,gzip) + @echo ' Kernel $@ is ready' + +$(obj)/main.o: $(obj)/ksize.h +$(obj)/bootp.o: $(obj)/ksize.h +$(obj)/bootpz.o: $(obj)/kzsize.h + +$(obj)/ksize.h: $(obj)/vmlinux.nh FORCE + echo "#define KERNEL_SIZE `ls -l $(obj)/vmlinux.nh | awk '{print $$5}'`" > $@T +ifdef INITRD + [ -f $(INITRD) ] || exit 1 + echo "#define INITRD_IMAGE_SIZE `ls -l $(INITRD) | awk '{print $$5}'`" >> $@T +endif + cmp -s $@T $@ || mv -f $@T $@ + rm -f $@T + +$(obj)/kzsize.h: $(obj)/vmlinux.nh.gz FORCE + echo "#define KERNEL_SIZE `ls -l $(obj)/vmlinux.nh | awk '{print $$5}'`" > $@T + echo "#define KERNEL_Z_SIZE `ls -l $(obj)/vmlinux.nh.gz | awk '{print $$5}'`" >> $@T +ifdef INITRD + [ -f $(INITRD) ] || exit 1 + echo "#define INITRD_IMAGE_SIZE `ls -l $(INITRD) | awk '{print $$5}'`" >> $@T +endif + cmp -s $@T $@ || mv -f $@T $@ + rm -f $@T + +quiet_cmd_strip = STRIP $@ + cmd_strip = $(STRIP) -o $@ $< + +$(obj)/vmlinux: vmlinux FORCE + $(call if_changed,strip) + +quiet_cmd_objstrip = OBJSTRIP $@ + cmd_objstrip = $(OBJSTRIP) $(OSFLAGS_$(@F)) $< $@ + +OSFLAGS_vmlinux.nh := -v +OSFLAGS_lxboot := -p +OSFLAGS_bootlx := -vb +OSFLAGS_bootph := -vb +OSFLAGS_bootpzh := -vb + +$(obj)/vmlinux.nh: vmlinux $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +$(obj)/vmlinux.nh.gz: $(obj)/vmlinux.nh FORCE + $(call if_changed,gzip) + +$(obj)/tools/lxboot: $(obj)/bootloader $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +$(obj)/tools/bootlx: $(obj)/bootloader $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +$(obj)/tools/bootph: $(obj)/bootpheader $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +$(obj)/tools/bootpzh: $(obj)/bootpzheader $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +LDFLAGS_bootloader := -static -T # -N -relax +LDFLAGS_bootloader := -static -T # -N -relax +LDFLAGS_bootpheader := -static -T # -N -relax +LDFLAGS_bootpzheader := -static -T # -N -relax + +OBJ_bootlx := $(obj)/head.o $(obj)/stdio.o $(obj)/main.o +OBJ_bootph := $(obj)/head.o $(obj)/stdio.o $(obj)/bootp.o +OBJ_bootpzh := $(obj)/head.o $(obj)/stdio.o $(obj)/bootpz.o $(obj)/misc.o + +$(obj)/bootloader: $(obj)/bootloader.lds $(OBJ_bootlx) $(LIBS_Y) FORCE + $(call if_changed,ld) + +$(obj)/bootpheader: $(obj)/bootloader.lds $(OBJ_bootph) $(LIBS_Y) FORCE + $(call if_changed,ld) + +$(obj)/bootpzheader: $(obj)/bootloader.lds $(OBJ_bootpzh) $(LIBS_Y) FORCE + $(call if_changed,ld) + +$(obj)/misc.o: lib/inflate.c -- cgit v1.3.1