selftests/bpf: Add tracing prog private stack tests

Some private stack tests are added including:
  - prog with stack size greater than BPF_PSTACK_MIN_SUBTREE_SIZE.
  - prog with stack size less than BPF_PSTACK_MIN_SUBTREE_SIZE.
  - prog with one subprog having MAX_BPF_STACK stack size and another
    subprog having non-zero stack size.
  - prog with callback function.
  - prog with exception in main prog or subprog.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>

Author: Yonghong Song

tools/testing/selftests/bpf/prog_tests/verifier.c

@@ -59,6 +59,7 @@
 #include "verifier_or_jmp32_k.skel.h"
 #include "verifier_precision.skel.h"
 #include "verifier_prevent_map_lookup.skel.h"
+#include "verifier_private_stack.skel.h"
 #include "verifier_raw_stack.skel.h"
 #include "verifier_raw_tp_writable.skel.h"
 #include "verifier_reg_equal.skel.h"
@@ -185,6 +186,7 @@ void test_verifier_bpf_fastcall(void)         { RUN(verifier_bpf_fastcall); }
 void test_verifier_or_jmp32_k(void)           { RUN(verifier_or_jmp32_k); }
 void test_verifier_precision(void)            { RUN(verifier_precision); }
 void test_verifier_prevent_map_lookup(void)   { RUN(verifier_prevent_map_lookup); }
+void test_verifier_private_stack(void)        { RUN(verifier_private_stack); }
 void test_verifier_raw_stack(void)            { RUN(verifier_raw_stack); }
 void test_verifier_raw_tp_writable(void)      { RUN(verifier_raw_tp_writable); }
 void test_verifier_reg_equal(void)            { RUN(verifier_reg_equal); }

tools/testing/selftests/bpf/progs/verifier_private_stack.c

@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+#include "bpf_experimental.h"
+
+/* From include/linux/filter.h */
+#define MAX_BPF_STACK    512
+
+#if defined(__TARGET_ARCH_x86)
+
+SEC("kprobe")
+__description("Private stack, single prog")
+__success
+__arch_x86_64
+__jited("	movabsq	$0x{{.*}}, %r9")
+__jited("	addq	%gs:0x{{.*}}, %r9")
+__jited("	movl	$0x2a, %edi")
+__jited("	movq	%rdi, -0x100(%r9)")
+__naked void private_stack_single_prog(void)
+{
+	asm volatile (
+	"r1 = 42;"
+	"*(u64 *)(r10 - 256) = r1;"
+	"r0 = 0;"
+	"exit;"
+	:
+	:
+	: __clobber_all);
+}
+
+__used
+__naked static void cumulative_stack_depth_subprog(void)
+{
+        asm volatile (
+	"r1 = 41;"
+        "*(u64 *)(r10 - 32) = r1;"
+        "call %[bpf_get_smp_processor_id];"
+        "exit;"
+        :: __imm(bpf_get_smp_processor_id)
+	: __clobber_all);
+}
+
+SEC("kprobe")
+__description("Private stack, subtree > MAX_BPF_STACK")
+__success
+__arch_x86_64
+/* private stack fp for the main prog */
+__jited("	movabsq	$0x{{.*}}, %r9")
+__jited("	addq	%gs:0x{{.*}}, %r9")
+__jited("	movl	$0x2a, %edi")
+__jited("	movq	%rdi, -0x200(%r9)")
+__jited("	pushq	%r9")
+__jited("	callq	0x{{.*}}")
+__jited("	popq	%r9")
+__jited("	xorl	%eax, %eax")
+__naked void private_stack_nested_1(void)
+{
+	asm volatile (
+	"r1 = 42;"
+	"*(u64 *)(r10 - %[max_bpf_stack]) = r1;"
+	"call cumulative_stack_depth_subprog;"
+	"r0 = 0;"
+	"exit;"
+	:
+	: __imm_const(max_bpf_stack, MAX_BPF_STACK)
+	: __clobber_all);
+}
+
+SEC("kprobe")
+__description("Private stack, subtree > MAX_BPF_STACK")
+__success
+__arch_x86_64
+/* private stack fp for the subprog */
+__jited("	addq	$0x20, %r9")
+__naked void private_stack_nested_2(void)
+{
+	asm volatile (
+	"r1 = 42;"
+	"*(u64 *)(r10 - %[max_bpf_stack]) = r1;"
+	"call cumulative_stack_depth_subprog;"
+	"r0 = 0;"
+	"exit;"
+	:
+	: __imm_const(max_bpf_stack, MAX_BPF_STACK)
+	: __clobber_all);
+}
+
+SEC("raw_tp")
+__description("No private stack, nested")
+__success
+__arch_x86_64
+__jited("	subq	$0x8, %rsp")
+__naked void no_private_stack_nested(void)
+{
+	asm volatile (
+	"r1 = 42;"
+	"*(u64 *)(r10 - 8) = r1;"
+	"call cumulative_stack_depth_subprog;"
+	"r0 = 0;"
+	"exit;"
+	:
+	:
+	: __clobber_all);
+}
+
+__naked __noinline __used
+static unsigned long loop_callback(void)
+{
+	asm volatile (
+	"call %[bpf_get_prandom_u32];"
+	"r1 = 42;"
+	"*(u64 *)(r10 - 512) = r1;"
+	"call cumulative_stack_depth_subprog;"
+	"r0 = 0;"
+	"exit;"
+	:
+	: __imm(bpf_get_prandom_u32)
+	: __clobber_common);
+}
+
+SEC("raw_tp")
+__description("Private stack, callback")
+__success
+__arch_x86_64
+/* for func loop_callback */
+__jited("func #1")
+__jited("	endbr64")
+__jited("	nopl	(%rax,%rax)")
+__jited("	nopl	(%rax)")
+__jited("	pushq	%rbp")
+__jited("	movq	%rsp, %rbp")
+__jited("	endbr64")
+__jited("	movabsq	$0x{{.*}}, %r9")
+__jited("	addq	%gs:0x{{.*}}, %r9")
+__jited("	pushq	%r9")
+__jited("	callq")
+__jited("	popq	%r9")
+__jited("	movl	$0x2a, %edi")
+__jited("	movq	%rdi, -0x200(%r9)")
+__jited("	pushq	%r9")
+__jited("	callq")
+__jited("	popq	%r9")
+__naked void private_stack_callback(void)
+{
+	asm volatile (
+	"r1 = 1;"
+	"r2 = %[loop_callback];"
+	"r3 = 0;"
+	"r4 = 0;"
+	"call %[bpf_loop];"
+	"r0 = 0;"
+	"exit;"
+	:
+	: __imm_ptr(loop_callback),
+	  __imm(bpf_loop)
+	: __clobber_common);
+}
+
+SEC("fentry/bpf_fentry_test9")
+__description("Private stack, exception in main prog")
+__success __retval(0)
+__arch_x86_64
+__jited("	pushq	%r9")
+__jited("	callq")
+__jited("	popq	%r9")
+int private_stack_exception_main_prog(void)
+{
+	asm volatile (
+	"r1 = 42;"
+	"*(u64 *)(r10 - 512) = r1;"
+	::: __clobber_common);
+
+	bpf_throw(0);
+	return 0;
+}
+
+__used static int subprog_exception(void)
+{
+	bpf_throw(0);
+	return 0;
+}
+
+SEC("fentry/bpf_fentry_test9")
+__description("Private stack, exception in subprog")
+__success __retval(0)
+__arch_x86_64
+__jited("	movq	%rdi, -0x200(%r9)")
+__jited("	pushq	%r9")
+__jited("	callq")
+__jited("	popq	%r9")
+int private_stack_exception_sub_prog(void)
+{
+	asm volatile (
+	"r1 = 42;"
+	"*(u64 *)(r10 - 512) = r1;"
+	"call subprog_exception;"
+	::: __clobber_common);
+
+	return 0;
+}
+
+#else
+
+SEC("kprobe")
+__description("private stack is not supported, use a dummy test")
+__success
+int dummy_test(void)
+{
+        return 0;
+}
+
+#endif
+
+char _license[] SEC("license") = "GPL";