On 10/25/22 3:27 PM, Eduard Zingerman wrote:
Use pahole --header_guards_db flag to enable encoding of header guard
information in kernel BTF. The actual correspondence between header
file and guard string is computed by the scripts/infer_header_guards.pl.
The encoded header guard information could be used to restore the
original guards in the vmlinux.h, e.g.:
include/uapi/linux/tcp.h:
#ifndef _UAPI_LINUX_TCP_H
#define _UAPI_LINUX_TCP_H
...
union tcp_word_hdr {
struct tcphdr hdr;
__be32 words[5];
};
...
#endif /* _UAPI_LINUX_TCP_H */
vmlinux.h:
...
#ifndef _UAPI_LINUX_TCP_H
union tcp_word_hdr {
struct tcphdr hdr;
__be32 words[5];
};
#endif /* _UAPI_LINUX_TCP_H */
...
Signed-off-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
---
scripts/link-vmlinux.sh | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 918470d768e9..f57f621eda1f 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -110,6 +110,7 @@ vmlinux_link()
gen_btf()
{
local pahole_ver
+ local extra_flags
if ! [ -x "$(command -v ${PAHOLE})" ]; then
echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
@@ -122,10 +123,20 @@ gen_btf()
return 1
fi
+ if [ "${pahole_ver}" -ge "124" ]; then
+ scripts/infer_header_guards.pl \
We should have full path like
${srctree}/scripts/infer_header_guards.pl
so it can work if build directory is different from source directory.
+ include/uapi \
+ include/generated/uapi \
+ arch/${SRCARCH}/include/uapi \
+ arch/${SRCARCH}/include/generated/uapi \
+ > .btf.uapi_header_guards || return 1;
+ extra_flags="--header_guards_db .btf.uapi_header_guards"
+ fi
+
vmlinux_link ${1}
info "BTF" ${2}
- LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
+ LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${extra_flags} ${1}
# Create ${2} which contains just .BTF section but no symbols. Add
# SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
