$ cpu-mqpro.sh /bbin/kexec -d ./vmlinux
...
1970/01/02 00:03:48 Kernel: /tmp/kexec-image2840883519
1970/01/02 00:03:48 Command line:
2022/08/25 23:30:57 Wait: wait: remote command exited without exit status or exit signal
[ 222.632355] kexec_image: The entry point of kernel at 0x40200000
[ 222.641547] kexec_image: Loaded device tree at 0x5fff6000
[ 223.841061] kexec_core: Starting new kernel
[ 223.845396] Will call new kernel at 5fffda30 from hart id 0
[ 223.850996] FDT image at 5fff6000
[ 223.854328] Bye...
$ cpu-mqpro.sh /bbin/kexec -d ./kernel
........
1970/01/02 00:02:18 Kernel: /tmp/kexec-image2185782358
1970/01/02 00:02:18 Command line:
1970/01/02 00:02:18 SYS_kexec_file_load(11, 0, , 4) = exec format error
1970/01/02 00:02:18 CPUD(as remote):exit status 1
2022/08/25 23:29:12 Wait: Process exited with status 1
[ 132.666024] kexec_elf: Requires an ELF interpreter.
kernel/kexec_elf.c
346 for (i = 0; i < ehdr->e_phnum; i++) {
347 /*
348 * Kexec does not support loading interpreters.
349 * In addition this check keeps us from attempting
350 * to kexec ordinay executables.
351 */
352 if (elf_info->proghdrs[i].p_type == PT_INTERP) {
353 pr_err("Requires an ELF interpreter.\n");
354 goto error;
355 }
356 }
kernel: ELF 64-bit LSB executable, UCB RISC-V, RVC, soft-float ABI, version 1 (SYSV), dynamically linked, interpreter /red/herring, BuildID[sha1]=ecc741985e0e7ea342cc734587e27ef2c9df34af, not stripped
freebsd
src/sys/conf/kern.post.mk
SYSTEM_LD_BASECMD= \
${LD} -m ${LD_EMULATION} -Bdynamic -T ${LDSCRIPT} ${_LDFLAGS} \
--no-warn-mismatch --warn-common --export-dynamic \
--dynamic-linker /red/herring -X
src/sys/conf/kern.pre.mk
# This is a hack. BFD "optimizes" away dynamic mode if there are no
# dynamic references. We could probably do a '-Bforcedynamic' mode like
# in the a.out ld. For now, this works.
force-dynamic-hack.c:
:> ${.TARGET}
force-dynamic-hack.pico: force-dynamic-hack.c Makefile
${CC} ${CCLDFLAGS} -shared ${CFLAGS} -nostdlib \
force-dynamic-hack.c -o ${.TARGET}
41c8eb30396a1 (Warner Losh 2001-11-02 21:34:20 +0000 230) # This is a hack. BFD "optimizes" away dynamic mode if there are no
41c8eb30396a1 (Warner Losh 2001-11-02 21:34:20 +0000 231) # dynamic references. We could probably do a '-Bforcedynamic' mode like
41c8eb30396a1 (Warner Losh 2001-11-02 21:34:20 +0000 232) # in the a.out ld. For now, this works.
aea2a658ef8b7 (David E. O'Brien 2022-02-13 18:24:36 -0800 233) force-dynamic-hack.c:
aea2a658ef8b7 (David E. O'Brien 2022-02-13 18:24:36 -0800 234) :> ${.TARGET}
aea2a658ef8b7 (David E. O'Brien 2022-02-13 18:24:36 -0800 235)
aea2a658ef8b7 (David E. O'Brien 2022-02-13 18:24:36 -0800 236) force-dynamic-hack.pico: force-dynamic-hack.c Makefile
aea2a658ef8b7 (David E. O'Brien 2022-02-13 18:24:36 -0800 237) ${CC} ${CCLDFLAGS} -shared ${CFLAGS} -nostdlib \
aea2a658ef8b7 (David E. O'Brien 2022-02-13 18:24:36 -0800 238) force-dynamic-hack.c -o ${.TARGET}
41c8eb30396a1 (Warner Losh 2001-11-02 21:34:20 +0000 239)
TODO: work out freebsd/src/sys/kern/link_elf.c?
Hacked up for now:
kstatic: ELF 64-bit LSB executable, UCB RISC-V, RVC, soft-float ABI, version 1 (SYSV), statically linked, BuildID[sha1]=c996484a2e6122e1ed3bd741826b7dbbf0117786, not stripped
$ cpu-mqpro.sh /bbin/kexec -d ./kstatic
........
1970/01/02 00:13:37 Kernel: /tmp/kexec-image3762681189
1970/01/02 00:13:37 Command line:
1970/01/02 00:13:37 SYS_kexec_file_load(11, 0, , 4) = cannot assign requested address
1970/01/02 00:13:38 CPUD(as remote):exit status 1
2022/08/26 22:11:11 Wait: Process exited with status 1
vendor/golang.org/x/sys/unix/zerrors_linux_riscv64.go
739: {99, "EADDRNOTAVAIL", "cannot assign requested address"},
https://man7.org/linux/man-pages/man2/kexec_load.2.html
EADDRNOTAVAIL
The value in a mem or memsz field in one of the segments
entries is not a multiple of the system page size.
arch/riscv/kernel/elf_kexec.c
*elf_kexec_load -> elf_find_pbase -> arch_kexec_locate_mem_hole
kernel/kexec_file.c
arch_kexec_locate_mem_hole - Find free memory to place the segments.
->
kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
calls into kernel/resource.c:
kexec_walk_resources -> walk_system_ram_res
kernel/resource.c:
walk_system_ram_res -> __walk_iomem_res_desc -> find_next_iomem_res
kexec Freebsd
[ 131.327365] kexec_file: kexec_image_load_default: fops->load
[ 131.346115] kexec_image: elf_kexec_load: elf_find_pbase
[ 131.351855] kexec_image: elf_find_pbase: locate_mem_hole
[ 131.357556] kexec_file: kexec_locate_mem_hole: 0 42172416
[ 131.363557] resource: __walk_iomem_res_desc: from 0 to 18446744073709551615
[ 131.371254] resource: find_next_iomem_res: searching...
[ 131.377115] resource: __walk_iomem_res_desc: ret 0, next 1610612736
[ 131.384072] resource: find_next_iomem_res: searching...
[ 131.389785] kexec_file: kexec_locate_mem_hole: trouble ahead! 0
With Linux:
[ 143.041564] resource: __walk_iomem_res_desc: from 0 to 18446744073709551615
[ 143.061282] resource: find_next_iomem_res: searching...
[ 143.066909] resource: __walk_iomem_res_desc: ret 0, next 1610612736
[ 143.073581] resource: find_next_iomem_res: searching...
[ 143.079214] kexec_file: kexec_locate_mem_hole: trouble ahead! 0
[ 4455.190117] resource: __walk_iomem_res_desc: from 0 to 18446744073709551615
[ 4455.197694] resource: find_next_iomem_res: searching...
[ 4455.203426] resource: __walk_iomem_res_desc: ret 1, next 1610612736
[ 4455.210322] kexec_image: The entry point of kernel at 0x40200000
[ 4455.216951] resource: __walk_iomem_res_desc: from 0 to 18446744073709551615
[ 4455.224562] resource: find_next_iomem_res: searching...
[ 4455.230262] resource: __walk_iomem_res_desc: ret 1, next 1610612736
[ 4455.240036] resource: __walk_iomem_res_desc: from 0 to 18446744073709551615
[ 4455.247611] resource: find_next_iomem_res: searching...
[ 4455.253508] resource: __walk_iomem_res_desc: ret 1, next 1610612736
[ 4455.260435] kexec_image: Loaded device tree at 0x5fff6000
[ 4456.467686] kexec_core: Starting new kernel
[ 4456.472028] Will call new kernel at 5fffda30 from hart id 0
[ 4456.477627] FDT image at 5fff6000
[ 4456.480966] Bye...