Fangrui Song 90ceddcb49 bpf: Support llvm-objcopy for vmlinux BTF ... Simplify gen_btf logic to make it work with llvm-objcopy. The existing 'file format' and 'architecture' parsing logic is brittle and does not work with llvm-objcopy/llvm-objdump. 'file format' output of llvm-objdump>=11 will match GNU objdump, but 'architecture' (bfdarch) may not. .BTF in .tmp_vmlinux.btf is non-SHF_ALLOC. Add the SHF_ALLOC flag because it is part of vmlinux image used for introspection. C code can reference the section via linker script defined __start_BTF and __stop_BTF. This fixes a small problem that previous .BTF had the SHF_WRITE flag (objcopy -I binary -O elf* synthesized .data). Additionally, `objcopy -I binary` synthesized symbols _binary__btf_vmlinux_bin_start and _binary__btf_vmlinux_bin_stop (not used elsewhere) are replaced with more commonplace __start_BTF and __stop_BTF. Add 2>/dev/null because GNU objcopy (but not llvm-objcopy) warns "empty loadable segment detected at vaddr=0xffffffff81000000, is this intentional?" We use a dd command to change the e_type field in the ELF header from ET_EXEC to ET_REL so that lld will accept .btf.vmlinux.bin.o. Accepting ET_EXEC as an input file is an extremely rare GNU ld feature that lld does not intend to support, because this is error-prone. The output section description .BTF in include/asm-generic/vmlinux.lds.h avoids potential subtle orphan section placement issues and suppresses --orphan-handling=warn warnings. Fixes: df786c9b94 ("bpf: Force .BTF section start to zero when dumping from vmlinux") Fixes: cb0cc635c7 ("powerpc: Include .BTF section") Reported-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Fangrui Song <maskray@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Stanislav Fomichev <sdf@google.com> Tested-by: Andrii Nakryiko <andriin@fb.com> Reviewed-by: Stanislav Fomichev <sdf@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Link: https://github.com/ClangBuiltLinux/linux/issues/871 Link: https://lore.kernel.org/bpf/20200318222746.173648-1-maskray@google.com		2020-03-19 12:32:38 +01:00
..
arraymap.c
bpf_lru_list.c
bpf_lru_list.h
bpf_struct_ops.c	bpf: Refactor trampoline update code	2020-03-04 13:41:05 -08:00
bpf_struct_ops_types.h
btf.c	bpf: Support llvm-objcopy for vmlinux BTF	2020-03-19 12:32:38 +01:00
cgroup.c
core.c	bpf: Add bpf_ksym_add/del functions	2020-03-13 12:49:52 -07:00
cpumap.c
devmap.c
disasm.c
disasm.h
dispatcher.c	bpf: Remove bpf_image tree	2020-03-13 12:49:52 -07:00
hashtab.c	bpf: Replace zero-length array with flexible-array member	2020-02-28 01:21:02 +01:00
helpers.c	bpf: Added new helper bpf_get_ns_current_pid_tgid	2020-03-12 17:33:11 -07:00
inode.c	bpf: Introduce pinnable bpf_link abstraction	2020-03-02 22:06:27 -08:00
local_storage.c
lpm_trie.c	bpf: Replace zero-length array with flexible-array member	2020-02-28 01:21:02 +01:00
Makefile
map_in_map.c
map_in_map.h
offload.c
percpu_freelist.c	bpf: Dont iterate over possible CPUs with interrupts disabled	2020-02-24 16:18:20 -08:00
percpu_freelist.h
queue_stack_maps.c
reuseport_array.c	net: Generate reuseport group ID on group creation	2020-02-21 22:29:45 +01:00
stackmap.c	bpf/stackmap: Dont trylock mmap_sem with PREEMPT_RT and interrupts disabled	2020-02-24 16:20:10 -08:00
syscall.c	bpf: Abstract away entire bpf_link clean up procedure	2020-03-13 12:49:51 -07:00
sysfs_btf.c	bpf: Support llvm-objcopy for vmlinux BTF	2020-03-19 12:32:38 +01:00
tnum.c
trampoline.c	bpf: Add missing annotations for __bpf_prog_enter() and __bpf_prog_exit()	2020-03-13 20:55:07 +01:00
verifier.c	bpf: Add bpf_xdp_output() helper	2020-03-12 17:47:38 -07:00
xskmap.c