From: Ian Rogers <irogers@google.com>
To: Quentin Monnet <quentin@isovalent.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Ian Rogers <irogers@google.com>
Subject: [PATCH v4 2/2] bpftool: Align bpf_load_and_run_opts insns and data
Date: Wed, 4 Oct 2023 15:23:23 -0700 [thread overview]
Message-ID: <20231004222323.3503030-2-irogers@google.com> (raw)
In-Reply-To: <20231004222323.3503030-1-irogers@google.com>
A C string lacks alignment so use aligned arrays to avoid potential
alignment problems. Switch to using sizeof (less 1 for the \0
terminator) rather than a hardcode size constant.
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/bpf/bpftool/gen.c | 47 ++++++++++++++++++++++-------------------
1 file changed, 25 insertions(+), 22 deletions(-)
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index b8ebcee9bc56..7a545dcabe38 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -408,8 +408,8 @@ static void codegen(const char *template, ...)
/* skip baseline indentation tabs */
for (n = skip_tabs; n > 0; n--, src++) {
if (*src != '\t') {
- p_err("not enough tabs at pos %td in template '%s'",
- src - template - 1, template);
+ p_err("not enough tabs at pos %td in template '%s'\n'%s'",
+ src - template - 1, template, src);
free(s);
exit(-1);
}
@@ -708,17 +708,22 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
codegen("\
\n\
- skel->%1$s = skel_prep_map_data((void *)\"\\ \n\
- ", ident);
+ { \n\
+ static const char data[] __attribute__((__aligned__(8))) = \"\\\n\
+ ");
mmap_data = bpf_map__initial_value(map, &mmap_size);
print_hex(mmap_data, mmap_size);
codegen("\
\n\
- \", %1$zd, %2$zd); \n\
- if (!skel->%3$s) \n\
- goto cleanup; \n\
- skel->maps.%3$s.initial_value = (__u64) (long) skel->%3$s;\n\
- ", bpf_map_mmap_sz(map), mmap_size, ident);
+ \"; \n\
+ \n\
+ skel->%1$s = skel_prep_map_data((void *)data, %2$zd,\n\
+ sizeof(data) - 1);\n\
+ if (!skel->%1$s) \n\
+ goto cleanup; \n\
+ skel->maps.%1$s.initial_value = (__u64) (long) skel->%1$s;\n\
+ } \n\
+ ", ident, bpf_map_mmap_sz(map));
}
codegen("\
\n\
@@ -733,32 +738,30 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
{ \n\
struct bpf_load_and_run_opts opts = {}; \n\
int err; \n\
- \n\
- opts.ctx = (struct bpf_loader_ctx *)skel; \n\
- opts.data_sz = %2$d; \n\
- opts.data = (void *)\"\\ \n\
+ static const char opts_data[] __attribute__((__aligned__(8))) = \"\\\n\
",
- obj_name, opts.data_sz);
+ obj_name);
print_hex(opts.data, opts.data_sz);
codegen("\
\n\
\"; \n\
+ static const char opts_insn[] __attribute__((__aligned__(8))) = \"\\\n\
");
-
- codegen("\
- \n\
- opts.insns_sz = %d; \n\
- opts.insns = (void *)\"\\ \n\
- ",
- opts.insns_sz);
print_hex(opts.insns, opts.insns_sz);
codegen("\
\n\
\"; \n\
+ \n\
+ opts.ctx = (struct bpf_loader_ctx *)skel; \n\
+ opts.data_sz = sizeof(opts_data) - 1; \n\
+ opts.data = (void *)opts_data; \n\
+ opts.insns_sz = sizeof(opts_insn) - 1; \n\
+ opts.insns = (void *)opts_insn; \n\
+ \n\
err = bpf_load_and_run(&opts); \n\
if (err < 0) \n\
return err; \n\
- ", obj_name);
+ ");
bpf_object__for_each_map(map, obj) {
const char *mmap_flags;
--
2.42.0.609.gbb76f46606-goog
next prev parent reply other threads:[~2023-10-04 22:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-04 22:23 [PATCH v4 1/2] bpftool: Align output skeleton ELF code Ian Rogers
2023-10-04 22:23 ` Ian Rogers [this message]
2023-10-05 15:54 ` [PATCH v4 2/2] bpftool: Align bpf_load_and_run_opts insns and data Quentin Monnet
2023-10-05 22:03 ` Ian Rogers
2023-10-05 15:51 ` [PATCH v4 1/2] bpftool: Align output skeleton ELF code Quentin Monnet
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