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authorJohn Fastabend <john.fastabend@gmail.com>2020-08-11 15:05:33 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2020-08-13 22:40:43 +0200
commit8e0c1517565f06027b68caf2875620ddf6914eee (patch)
tree051e08414da75fce447096328062eb773690fd14
parent86ed4be68fdee23df4843a59f91c1ac7fc05e860 (diff)
bpf, selftests: Add tests for sock_ops load with r9, r8.r7 registers
Loads in sock_ops case when using high registers requires extra logic to ensure the correct temporary value is used. We need to ensure the temp register does not use either the src_reg or dst_reg. Lets add an asm test to force the logic is triggered. The xlated code is here, 30: (7b) *(u64 *)(r9 +32) = r7 31: (61) r7 = *(u32 *)(r9 +28) 32: (15) if r7 == 0x0 goto pc+2 33: (79) r7 = *(u64 *)(r9 +0) 34: (63) *(u32 *)(r7 +916) = r8 35: (79) r7 = *(u64 *)(r9 +32) Notice r9 and r8 are not used for temp registers and r7 is chosen. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/159718353345.4728.8805043614257933227.stgit@john-Precision-5820-Tower
-rw-r--r--tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c b/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
index f8b136827fcc..6420b61fbbc8 100644
--- a/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
+++ b/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
@@ -75,6 +75,13 @@ int bpf_testcb(struct bpf_sock_ops *skops)
: [skops] "r"(skops)
:);
+ asm volatile (
+ "r9 = %[skops];\n"
+ "r8 = *(u32 *)(r9 +164);\n"
+ "*(u32 *)(r9 +164) = r8;\n"
+ :: [skops] "r"(skops)
+ : "r9", "r8");
+
op = (int) skops->op;
update_event_map(op);