[PATCH v11 6/8] selftests/bpf: Add tailcall verifier selftest for powerpc64

[Saket Kumar Bhaskar <skb99@linux.ibm.com>]

From: Abhishek Dubey <adubey@linux.ibm.com>

Verifier testcase result for tailcalls:

Summary: 2/3 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Abhishek Dubey <adubey@linux.ibm.com>
Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
Tested-by: Yeswanth Krishna Tellakula <yeswanth@linux.ibm.com>
---
 .../bpf/progs/verifier_tailcall_jit.c         | 75 +++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/verifier_tailcall_jit.c b/tools/testing/selftests/bpf/progs/verifier_tailcall_jit.c
index 48fa34d2959f..182302ff1db0 100644
--- a/tools/testing/selftests/bpf/progs/verifier_tailcall_jit.c
+++ b/tools/testing/selftests/bpf/progs/verifier_tailcall_jit.c
@@ -91,6 +91,81 @@ __jited("	popq	%rax")
 __jited("	jmp	{{.*}}")		/* jump to tail call tgt   */
 __jited("L0:	leave")
 __jited("	{{(retq|jmp	0x)}}")		/* return or jump to rethunk */
+__arch_powerpc64
+/* program entry for main(), regular function prologue */
+__jited("	nop")
+__jited("...")                          /* ld 2, 16(13) absent with CONFIG_PPC_KERNEL_PCREL */
+__jited("	li 9, 0")
+__jited("	std 9, -8(1)")
+__jited("	mflr 0")
+__jited("	std 0, 16(1)")
+__jited("	stdu 1, {{.*}}(1)")
+/* load address and call sub() via count register
+ *
+ * Address materialization differs between PCREL and non-PCREL kernels.
+ * Skip the address generation sequence and verify only that the call
+ * target is loaded into CTR before branching.
+ */
+__jited("...")
+__jited("...")
+__jited("...")
+__jited("...")
+__jited("...")
+__jited("	mtctr 12")
+__jited("	bctrl")
+__jited("	mr	8, 3")
+__jited("	li 8, 0")
+__jited("	addi 1, 1, {{.*}}")
+__jited("	ld 0, 16(1)")
+__jited("	mtlr 0")
+__jited("	mr	3, 8")
+__jited("	blr")
+__jited("...")
+__jited("func #1")
+/* subprogram entry for sub() */
+__jited("	nop")
+__jited("...")                          /* ld 2, 16(13) absent with CONFIG_PPC_KERNEL_PCREL */
+/* tail call prologue for subprogram */
+__jited("	ld 10, 0(1)")
+__jited("	ld 9, -8(10)")
+__jited("	cmpldi	9, 33")
+__jited("	bt	{{.*}}, {{.*}}")
+__jited("	addi 9, 10, -8")
+__jited("	std 9, -8(1)")
+__jited("	lis {{.*}}, {{.*}}")
+__jited("	sldi {{.*}}, {{.*}}, 32")
+__jited("	oris {{.*}}, {{.*}}, {{.*}}")
+__jited("	ori {{.*}}, {{.*}}, {{.*}}")
+__jited("	li {{.*}}, 0")
+__jited("	lwz 9, {{.*}}({{.*}})")
+__jited("	slwi {{.*}}, {{.*}}, 0")
+__jited("	cmplw	{{.*}}, 9")
+__jited("	bf	0, {{.*}}")
+/* bpf_tail_call implementation */
+__jited("	ld 9, -8(1)")
+__jited("	cmpldi	9, 33")
+__jited("	bf	{{.*}}, {{.*}}")
+__jited("	ld 9, 0(9)")
+__jited("	cmpldi	9, 33")
+__jited("	bt	{{.*}}, {{.*}}")
+__jited("	addi 9, 9, 1")
+__jited("	mulli 10, {{.*}}, 8")
+__jited("	add 10, 10, {{.*}}")
+__jited("	ld 10, {{.*}}(10)")
+__jited("	cmpldi	10, 0")
+__jited("	bt	{{.*}}, {{.*}}")
+__jited("	ld 10, {{.*}}(10)")
+__jited("	addi 10, 10, {{.*}}")    /* offset depends on CONFIG_PPC_KERNEL_PCREL */
+__jited("	mtctr 10")
+__jited("	ld 10, -8(1)")
+__jited("	cmpldi	10, 33")
+__jited("	bt	{{.*}}, {{.*}}")
+__jited("	addi 10, 1, -8")
+__jited("	std 9, 0(10)")
+__jited("	bctr")
+__jited("	mr	3, 8")
+__jited("	blr")
+
 SEC("tc")
 __naked int main(void)
 {
-- 
2.54.0