diff mbox series

[v2,2/2] bpftool: Align bpf_load_and_run_opts insns and data

Message ID 20231003191412.3171385-2-irogers@google.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series [v2,1/2] bpftool: Align output skeleton ELF code | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch
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bpf/vmtest-bpf-PR fail PR summary
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bpf/vmtest-bpf-VM_Test-21 success Logs for test_progs_parallel on aarch64 with gcc
bpf/vmtest-bpf-VM_Test-8 success Logs for test_maps on x86_64 with gcc
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bpf/vmtest-bpf-VM_Test-23 success Logs for test_progs_parallel on x86_64 with llvm-16
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bpf/vmtest-bpf-VM_Test-20 success Logs for test_progs_no_alu32_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-13 fail Logs for test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-27 success Logs for test_verifier on x86_64 with llvm-16
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bpf/vmtest-bpf-VM_Test-1 success Logs for ShellCheck
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Commit Message

Ian Rogers Oct. 3, 2023, 7:14 p.m. UTC 
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>
---
I was unable to find a test case for this part of the codegen using
Linux perf and libbpf tools code bases.
---
 tools/bpf/bpftool/gen.c | 43 ++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 20 deletions(-)
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index b8ebcee9bc56..e9a59b254c66 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -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;