[PATCH bpf-next v3 2/2] selftests/bpf: Add ldsx selftests for ldsx and subreg compare

[Yonghong Song <yonghong.song@linux.dev>]

Add a few selftests to test 32/16/8-bit ldsx followed by subreg comparison.
Without the previous patch, all added tests will fail.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 .../selftests/bpf/progs/verifier_ldsx.c       | 106 ++++++++++++++++++
 1 file changed, 106 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/verifier_ldsx.c b/tools/testing/selftests/bpf/progs/verifier_ldsx.c
index d4427d8e1217..3b96a9436a0c 100644
--- a/tools/testing/selftests/bpf/progs/verifier_ldsx.c
+++ b/tools/testing/selftests/bpf/progs/verifier_ldsx.c
@@ -144,6 +144,112 @@ __naked void ldsx_s32_range(void)
 	: __clobber_all);
 }
 
+#define MAX_ENTRIES 12
+
+struct test_val {
+        int foo[MAX_ENTRIES];
+};
+
+struct {
+        __uint(type, BPF_MAP_TYPE_HASH);
+        __uint(max_entries, 1);
+        __type(key, long long);
+        __type(value, struct test_val);
+} map_hash_48b SEC(".maps");
+
+SEC("socket")
+__description("LDSX, S8, subreg compare")
+__success __success_unpriv
+__naked void ldsx_s8_subreg_compare(void)
+{
+	asm volatile (
+	"call %[bpf_get_prandom_u32];"
+	"*(u64 *)(r10 - 8) = r0;"
+	"w6 = w0;"
+	"if w6 > 0x1f goto l0_%=;"
+	"r7 = *(s8 *)(r10 - 8);"
+	"if w7 > w6 goto l0_%=;"
+	"r1 = 0;"
+	"*(u64 *)(r10 - 8) = r1;"
+	"r2 = r10;"
+	"r2 += -8;"
+	"r1 = %[map_hash_48b] ll;"
+	"call %[bpf_map_lookup_elem];"
+	"if r0 == 0 goto l0_%=;"
+	"r0 += r7;"
+	"*(u64 *)(r0 + 0) = 1;"
+"l0_%=:"
+	"r0 = 0;"
+	"exit;"
+	:
+	: __imm(bpf_get_prandom_u32),
+	  __imm_addr(map_hash_48b),
+	  __imm(bpf_map_lookup_elem)
+	: __clobber_all);
+}
+
+SEC("socket")
+__description("LDSX, S16, subreg compare")
+__success __success_unpriv
+__naked void ldsx_s16_subreg_compare(void)
+{
+	asm volatile (
+	"call %[bpf_get_prandom_u32];"
+	"*(u64 *)(r10 - 8) = r0;"
+	"w6 = w0;"
+	"if w6 > 0x1f goto l0_%=;"
+	"r7 = *(s16 *)(r10 - 8);"
+	"if w7 > w6 goto l0_%=;"
+	"r1 = 0;"
+	"*(u64 *)(r10 - 8) = r1;"
+	"r2 = r10;"
+	"r2 += -8;"
+	"r1 = %[map_hash_48b] ll;"
+	"call %[bpf_map_lookup_elem];"
+	"if r0 == 0 goto l0_%=;"
+	"r0 += r7;"
+	"*(u64 *)(r0 + 0) = 1;"
+"l0_%=:"
+	"r0 = 0;"
+	"exit;"
+	:
+	: __imm(bpf_get_prandom_u32),
+	  __imm_addr(map_hash_48b),
+	  __imm(bpf_map_lookup_elem)
+	: __clobber_all);
+}
+
+SEC("socket")
+__description("LDSX, S32, subreg compare")
+__success __success_unpriv
+__naked void ldsx_s32_subreg_compare(void)
+{
+	asm volatile (
+	"call %[bpf_get_prandom_u32];"
+	"*(u64 *)(r10 - 8) = r0;"
+	"w6 = w0;"
+	"if w6 > 0x1f goto l0_%=;"
+	"r7 = *(s32 *)(r10 - 8);"
+	"if w7 > w6 goto l0_%=;"
+	"r1 = 0;"
+	"*(u64 *)(r10 - 8) = r1;"
+	"r2 = r10;"
+	"r2 += -8;"
+	"r1 = %[map_hash_48b] ll;"
+	"call %[bpf_map_lookup_elem];"
+	"if r0 == 0 goto l0_%=;"
+	"r0 += r7;"
+	"*(u64 *)(r0 + 0) = 1;"
+"l0_%=:"
+	"r0 = 0;"
+	"exit;"
+	:
+	: __imm(bpf_get_prandom_u32),
+	  __imm_addr(map_hash_48b),
+	  __imm(bpf_map_lookup_elem)
+	: __clobber_all);
+}
+
 #else
 
 SEC("socket")
-- 
2.43.0