Build fails with lack of auto-generated headers about riscv-linux

[palmer-dabbelt]

riscv-unknown-linux-gnu- isn't usually what we call the compilers, it's usually something more like riscv64-unknown-linux-gnu-.

[jleidel]

Palmer, sorry... that was a typo on my part. My cross compilation prefix is currently set to: riscv64-unknown-linux-gnu-

[palmer-dabbelt]

I don't know, then. asm-offsets.h is a particularly special file (it's generated), so it's possible something is a bit wrong in our build system. Does a make mrproper fix this? I've seen some oddness when bouncing between build directories or ARCH values before.

[jleidel]

I just pulled a fresh tree from master and tried rebuilding (with make mrproper to force a clean), no luck.

$> echo $CCPREFIX
riscv64-unknown-linux-gnu-

$> make ARCH=riscv CROSS_COMPILE=$CCPREFIX
scripts/kconfig/conf --silentoldconfig Kconfig
CHK include/config/kernel.release
UPD include/config/kernel.release
WRAP arch/riscv/include/generated/uapi/asm/setup.h
WRAP arch/riscv/include/generated/uapi/asm/unistd.h
WRAP arch/riscv/include/generated/uapi/asm/bpf_perf_event.h
WRAP arch/riscv/include/generated/uapi/asm/errno.h
WRAP arch/riscv/include/generated/uapi/asm/fcntl.h
WRAP arch/riscv/include/generated/uapi/asm/ioctl.h
WRAP arch/riscv/include/generated/uapi/asm/ioctls.h
WRAP arch/riscv/include/generated/uapi/asm/ipcbuf.h
WRAP arch/riscv/include/generated/uapi/asm/mman.h
WRAP arch/riscv/include/generated/uapi/asm/msgbuf.h
WRAP arch/riscv/include/generated/uapi/asm/param.h
WRAP arch/riscv/include/generated/uapi/asm/poll.h
WRAP arch/riscv/include/generated/uapi/asm/posix_types.h
WRAP arch/riscv/include/generated/uapi/asm/resource.h
WRAP arch/riscv/include/generated/uapi/asm/sembuf.h
WRAP arch/riscv/include/generated/uapi/asm/shmbuf.h
WRAP arch/riscv/include/generated/uapi/asm/signal.h
WRAP arch/riscv/include/generated/uapi/asm/socket.h
WRAP arch/riscv/include/generated/uapi/asm/sockios.h
WRAP arch/riscv/include/generated/uapi/asm/stat.h
WRAP arch/riscv/include/generated/uapi/asm/statfs.h
WRAP arch/riscv/include/generated/uapi/asm/swab.h
WRAP arch/riscv/include/generated/uapi/asm/termbits.h
WRAP arch/riscv/include/generated/uapi/asm/termios.h
WRAP arch/riscv/include/generated/uapi/asm/types.h
WRAP arch/riscv/include/generated/asm/bugs.h
WRAP arch/riscv/include/generated/asm/cacheflush.h
WRAP arch/riscv/include/generated/asm/checksum.h
WRAP arch/riscv/include/generated/asm/clkdev.h
WRAP arch/riscv/include/generated/asm/cputime.h
WRAP arch/riscv/include/generated/asm/device.h
WRAP arch/riscv/include/generated/asm/div64.h
WRAP arch/riscv/include/generated/asm/dma.h
WRAP arch/riscv/include/generated/asm/dma-contiguous.h
WRAP arch/riscv/include/generated/asm/emergency-restart.h
WRAP arch/riscv/include/generated/asm/errno.h
WRAP arch/riscv/include/generated/asm/exec.h
WRAP arch/riscv/include/generated/asm/fb.h
WRAP arch/riscv/include/generated/asm/fcntl.h
WRAP arch/riscv/include/generated/asm/ftrace.h
WRAP arch/riscv/include/generated/asm/futex.h
WRAP arch/riscv/include/generated/asm/hardirq.h
WRAP arch/riscv/include/generated/asm/hash.h
WRAP arch/riscv/include/generated/asm/hw_irq.h
WRAP arch/riscv/include/generated/asm/ioctl.h
WRAP arch/riscv/include/generated/asm/ioctls.h
WRAP arch/riscv/include/generated/asm/ipcbuf.h
WRAP arch/riscv/include/generated/asm/irq_regs.h
WRAP arch/riscv/include/generated/asm/irq_work.h
WRAP arch/riscv/include/generated/asm/kdebug.h
WRAP arch/riscv/include/generated/asm/kmap_types.h
WRAP arch/riscv/include/generated/asm/kvm_para.h
WRAP arch/riscv/include/generated/asm/local.h
WRAP arch/riscv/include/generated/asm/mm-arch-hooks.h
WRAP arch/riscv/include/generated/asm/mman.h
WRAP arch/riscv/include/generated/asm/module.h
WRAP arch/riscv/include/generated/asm/msgbuf.h
WRAP arch/riscv/include/generated/asm/mutex.h
WRAP arch/riscv/include/generated/asm/param.h
WRAP arch/riscv/include/generated/asm/percpu.h
WRAP arch/riscv/include/generated/asm/poll.h
WRAP arch/riscv/include/generated/asm/posix_types.h
WRAP arch/riscv/include/generated/asm/preempt.h
WRAP arch/riscv/include/generated/asm/resource.h
WRAP arch/riscv/include/generated/asm/scatterlist.h
WRAP arch/riscv/include/generated/asm/sections.h
WRAP arch/riscv/include/generated/asm/sembuf.h
WRAP arch/riscv/include/generated/asm/serial.h
WRAP arch/riscv/include/generated/asm/setup.h
WRAP arch/riscv/include/generated/asm/shmbuf.h
WRAP arch/riscv/include/generated/asm/shmparam.h
WRAP arch/riscv/include/generated/asm/signal.h
WRAP arch/riscv/include/generated/asm/socket.h
WRAP arch/riscv/include/generated/asm/sockios.h
WRAP arch/riscv/include/generated/asm/stat.h
WRAP arch/riscv/include/generated/asm/statfs.h
WRAP arch/riscv/include/generated/asm/swab.h
WRAP arch/riscv/include/generated/asm/termbits.h
WRAP arch/riscv/include/generated/asm/termios.h
WRAP arch/riscv/include/generated/asm/topology.h
WRAP arch/riscv/include/generated/asm/trace_clock.h
WRAP arch/riscv/include/generated/asm/types.h
WRAP arch/riscv/include/generated/asm/unaligned.h
WRAP arch/riscv/include/generated/asm/user.h
WRAP arch/riscv/include/generated/asm/vga.h
WRAP arch/riscv/include/generated/asm/vmlinux.lds.h
WRAP arch/riscv/include/generated/asm/xor.h
CHK include/generated/uapi/linux/version.h
UPD include/generated/uapi/linux/version.h
CHK include/generated/utsrelease.h
UPD include/generated/utsrelease.h
HOSTCC scripts/basic/bin2c
CHK include/generated/timeconst.h
UPD include/generated/timeconst.h
CC kernel/bounds.s
CHK include/generated/bounds.h
UPD include/generated/bounds.h
GEN scripts/gdb/linux/constants.py
In file included from ./arch/riscv/include/asm/smp.h:19:0,
from ./include/linux/smp.h:64,
from ./include/linux/percpu.h:7,
from ./include/linux/percpu-rwsem.h:7,
from ./include/linux/fs.h:33,
from /hdd/home/jleidel/dev/working/riscv-linux/scripts/gdb/linux/constants.py.in:15:
./arch/riscv/include/asm/asm-offsets.h:1:10: fatal error: generated/asm-offsets.h: No such file or directory
#include <generated/asm-offsets.h>
^~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
scripts/gdb/linux/Makefile:19: recipe for target 'scripts/gdb/linux/constants.py' failed
make[2]: *** [scripts/gdb/linux/constants.py] Error 1
Kbuild:81: recipe for target 'build_constants_py' failed
make[1]: *** [build_constants_py] Error 2
Makefile:1057: recipe for target 'prepare0' failed
make: *** [prepare0] Error 2

[jleidel]

I found the correct recipe of commands. Posting here for archival purposes:
$> export RISCV=/path/to/riscv/install
$> export PATH=$PATH:$RISCV/bin
$> export CCPREFIX=riscv64-unknown-linux-gnu-
$> make mrproper
$> make ARCH=riscv CROSS_COMPILE=$CCPREFIX defconfig
$> make ARCH=riscv CROSS_COMPILE=$CCPREFIX menuconfig
// Enable SMP build and set max cores to 32
$> make ARCH=riscv CROSS_COMPILE=$CCPREFIX

Since the build fails because GDB scripts cannot be built (because the kernel build system attempts to create them too soon, it seems), CONFIG_GDB_SCRIPTS=n fixes it for me.