selftests/bpf: test cases for compute_live_registers()

Cover instructions from each kind:
- assignment
- arithmetic
- store/load
- endian conversion
- atomics
- branches, conditional branches, may_goto, calls
- LD_ABS/LD_IND
- address_space_cast

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>

Author: eddyz87

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

@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "compute_live_registers.skel.h"
+#include "test_progs.h"
+
+void test_compute_live_registers(void)
+{
+	RUN_TESTS(compute_live_registers);
+}

tools/testing/selftests/bpf/progs/bpf_misc.h

@@ -208,4 +208,16 @@
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 #endif
 
+#if (defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86) ||	\
+     (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64) ||		\
+     defined(__TARGET_ARCH_arm) || defined(__TARGET_ARCH_s390) ||	\
+     defined(__TARGET_ARCH_loongarch)) &&				\
+	__clang_major__ >= 18
+#define CAN_USE_GOTOL
+#endif
+
+#if _clang_major__ >= 18
+#define CAN_USE_BPF_ST
+#endif
+
 #endif

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

@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "../../../include/linux/filter.h"
+#include "bpf_arena_common.h"
+#include "bpf_misc.h"
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, __u64);
+} test_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARENA);
+	__uint(map_flags, BPF_F_MMAPABLE);
+	__uint(max_entries, 1);
+} arena SEC(".maps");
+
+SEC("socket")
+__log_level(2)
+__msg(" 0: .......... (b7) r0 = 42")
+__msg(" 1: 0......... (bf) r1 = r0")
+__msg(" 2: .1........ (bf) r2 = r1")
+__msg(" 3: ..2....... (bf) r3 = r2")
+__msg(" 4: ...3...... (bf) r4 = r3")
+__msg(" 5: ....4..... (bf) r5 = r4")
+__msg(" 6: .....5.... (bf) r6 = r5")
+__msg(" 7: ......6... (bf) r7 = r6")
+__msg(" 8: .......7.. (bf) r8 = r7")
+__msg(" 9: ........8. (bf) r9 = r8")
+__msg("10: .........9 (bf) r0 = r9")
+__msg("11: 0......... (95) exit")
+__naked void assign_chain(void)
+{
+	asm volatile (
+		"r0 = 42;"
+		"r1 = r0;"
+		"r2 = r1;"
+		"r3 = r2;"
+		"r4 = r3;"
+		"r5 = r4;"
+		"r6 = r5;"
+		"r7 = r6;"
+		"r8 = r7;"
+		"r9 = r8;"
+		"r0 = r9;"
+		"exit;"
+		::: __clobber_all);
+}
+
+SEC("socket")
+__log_level(2)
+__msg("0: .......... (b7) r1 = 7")
+__msg("1: .1........ (07) r1 += 7")
+__msg("2: .......... (b7) r2 = 7")
+__msg("3: ..2....... (b7) r3 = 42")
+__msg("4: ..23...... (0f) r2 += r3")
+__msg("5: .......... (b7) r0 = 0")
+__msg("6: 0......... (95) exit")
+__naked void arithmetics(void)
+{
+	asm volatile (
+		"r1 = 7;"
+		"r1 += 7;"
+		"r2 = 7;"
+		"r3 = 42;"
+		"r2 += r3;"
+		"r0 = 0;"
+		"exit;"
+		::: __clobber_all);
+}
+
+#ifdef CAN_USE_BPF_ST
+SEC("socket")
+__log_level(2)
+__msg("  1: .1........ (07) r1 += -8")
+__msg("  2: .1........ (7a) *(u64 *)(r1 +0) = 7")
+__msg("  3: .1........ (b7) r2 = 42")
+__msg("  4: .12....... (7b) *(u64 *)(r1 +0) = r2")
+__msg("  5: .12....... (7b) *(u64 *)(r1 +0) = r2")
+__msg("  6: .......... (b7) r0 = 0")
+__naked void store(void)
+{
+	asm volatile (
+		"r1 = r10;"
+		"r1 += -8;"
+		"*(u64 *)(r1 +0) = 7;"
+		"r2 = 42;"
+		"*(u64 *)(r1 +0) = r2;"
+		"*(u64 *)(r1 +0) = r2;"
+		"r0 = 0;"
+		"exit;"
+		::: __clobber_all);
+}
+#endif
+
+SEC("socket")
+__log_level(2)
+__msg("1: ....4..... (07) r4 += -8")
+__msg("2: ....4..... (79) r5 = *(u64 *)(r4 +0)")
+__msg("3: ....45.... (07) r4 += -8")
+__naked void load(void)
+{
+	asm volatile (
+		"r4 = r10;"
+		"r4 += -8;"
+		"r5 = *(u64 *)(r4 +0);"
+		"r4 += -8;"
+		"r0 = r5;"
+		"exit;"
+		::: __clobber_all);
+}
+
+SEC("socket")
+__log_level(2)
+__msg("0: .1........ (61) r2 = *(u32 *)(r1 +0)")
+__msg("1: ..2....... (d4) r2 = le64 r2")
+__msg("2: ..2....... (bf) r0 = r2")
+__naked void endian(void)
+{
+	asm volatile (
+		"r2 = *(u32 *)(r1 +0);"
+		"r2 = le64 r2;"
+		"r0 = r2;"
+		"exit;"
+		::: __clobber_all);
+}
+
+SEC("socket")
+__log_level(2)
+__msg(" 8: 0......... (b7) r1 = 1")
+__msg(" 9: 01........ (db) r1 = atomic64_fetch_add((u64 *)(r0 +0), r1)")
+__msg("10: 01........ (c3) lock *(u32 *)(r0 +0) += r1")
+__msg("11: 01........ (db) r1 = atomic64_xchg((u64 *)(r0 +0), r1)")
+__msg("12: 01........ (bf) r2 = r0")
+__msg("13: .12....... (bf) r0 = r1")
+__msg("14: .12....... (db) r0 = atomic64_cmpxchg((u64 *)(r2 +0), r0, r1)")
+__naked void atomic(void)
+{
+	asm volatile (
+		"r2 = r10;"
+		"r2 += -8;"
+		"r1 = 0;"
+		"*(u64 *)(r2 +0) = r1;"
+		"r1 = %[test_map] ll;"
+		"call %[bpf_map_lookup_elem];"
+		"if r0 == 0 goto 1f;"
+		"r1 = 1;"
+		"r1 = atomic_fetch_add((u64 *)(r0 +0), r1);"
+		"lock *(u32 *)(r0 +0) += r1;"
+		"r1 = xchg_64(r0 + 0, r1);"
+		"r2 = r0;"
+		"r0 = r1;"
+		"r0 = cmpxchg_64(r2 + 0, r0, r1);"
+		"1: exit;"
+		:
+		: __imm(bpf_map_lookup_elem),
+		  __imm_addr(test_map)
+		: __clobber_all);
+}
+
+SEC("socket")
+__log_level(2)
+__msg("4: .12345.7.. (85) call bpf_trace_printk#6")
+__msg("5: 0......7.. (0f) r0 += r7")
+__naked void regular_call(void)
+{
+	asm volatile (
+		"r7 = 1;"
+		"r1 = r10;"
+		"r1 += -8;"
+		"r2 = 1;"
+		"call %[bpf_trace_printk];"
+		"r0 += r7;"
+		"exit;"
+		:
+		: __imm(bpf_trace_printk)
+		: __clobber_all);
+}
+
+SEC("socket")
+__log_level(2)
+__msg("2: 012....... (25) if r1 > 0x7 goto pc+1")
+__msg("3: ..2....... (bf) r0 = r2")
+__naked void if1(void)
+{
+	asm volatile (
+		"r0 = 1;"
+		"r2 = 2;"
+		"if r1 > 0x7 goto +1;"
+		"r0 = r2;"
+		"exit;"
+		::: __clobber_all);
+}
+
+SEC("socket")
+__log_level(2)
+__msg("3: 0123...... (2d) if r1 > r3 goto pc+1")
+__msg("4: ..2....... (bf) r0 = r2")
+__naked void if2(void)
+{
+	asm volatile (
+		"r0 = 1;"
+		"r2 = 2;"
+		"r3 = 7;"
+		"if r1 > r3 goto +1;"
+		"r0 = r2;"
+		"exit;"
+		::: __clobber_all);
+}
+
+SEC("socket")
+__log_level(2)
+__msg("0: .......... (b7) r1 = 0")
+__msg("1: .1........ (b7) r2 = 7")
+__msg("2: .12....... (25) if r1 > 0x7 goto pc+4")
+__msg("3: .12....... (07) r1 += 1")
+__msg("4: .12....... (27) r2 *= 2")
+__msg("5: .12....... (05) goto pc+0")
+__msg("6: .12....... (05) goto pc-5")
+__msg("7: .......... (b7) r0 = 0")
+__msg("8: 0......... (95) exit")
+__naked void loop(void)
+{
+	asm volatile (
+		"r1 = 0;"
+		"r2 = 7;"
+		"if r1 > 0x7 goto +4;"
+		"r1 += 1;"
+		"r2 *= 2;"
+		"goto +0;"
+		"goto -5;"
+		"r0 = 0;"
+		"exit;"
+		:
+		: __imm(bpf_trace_printk)
+		: __clobber_all);
+}
+
+#ifdef CAN_USE_GOTOL
+SEC("socket")
+__log_level(2)
+__msg("2: .123...... (25) if r1 > 0x7 goto pc+2")
+__msg("3: ..2....... (bf) r0 = r2")
+__msg("4: 0......... (06) gotol pc+1")
+__msg("5: ...3...... (bf) r0 = r3")
+__msg("6: 0......... (95) exit")
+__naked void gotol(void)
+{
+	asm volatile (
+		"r2 = 42;"
+		"r3 = 24;"
+		"if r1 > 0x7 goto +2;"
+		"r0 = r2;"
+		"gotol +1;"
+		"r0 = r3;"
+		"exit;"
+		:
+		: __imm(bpf_trace_printk)
+		: __clobber_all);
+}
+#endif
+
+SEC("socket")
+__log_level(2)
+__msg("0: 0......... (b7) r1 = 1")
+__msg("1: 01........ (e5) may_goto pc+1")
+__msg("2: 0......... (05) goto pc-3")
+__msg("3: .1........ (bf) r0 = r1")
+__msg("4: 0......... (95) exit")
+__naked void may_goto(void)
+{
+	asm volatile (
+	"1: r1 = 1;"
+	".8byte %[may_goto];"
+	"goto 1b;"
+	"r0 = r1;"
+	"exit;"
+	:
+	: __imm(bpf_get_smp_processor_id),
+	  __imm_insn(may_goto, BPF_RAW_INSN(BPF_JMP | BPF_JCOND, 0, 0, +1 /* offset */, 0))
+	: __clobber_all);
+}
+
+SEC("socket")
+__log_level(2)
+__msg("1: 0......... (18) r2 = 0x7")
+__msg("3: 0.2....... (0f) r0 += r2")
+__naked void ldimm64(void)
+{
+	asm volatile (
+		"r0 = 0;"
+		"r2 = 0x7 ll;"
+		"r0 += r2;"
+		"exit;"
+		:
+		:: __clobber_all);
+}
+
+/* No rules specific for LD_ABS/LD_IND, default behaviour kicks in */
+SEC("socket")
+__log_level(2)
+__msg("2: 0123456789 (30) r0 = *(u8 *)skb[42]")
+__msg("3: 012.456789 (0f) r7 += r0")
+__msg("4: 012.456789 (b7) r3 = 42")
+__msg("5: 0123456789 (50) r0 = *(u8 *)skb[r3 + 0]")
+__msg("6: 0......7.. (0f) r7 += r0")
+__naked void ldabs(void)
+{
+	asm volatile (
+		"r6 = r1;"
+		"r7 = 0;"
+		"r0 = *(u8 *)skb[42];"
+		"r7 += r0;"
+		"r3 = 42;"
+		"r0 = *(u8 *)skb[r3];"
+		"r7 += r0;"
+		"r0 = r7;"
+		"exit;"
+		:
+		:: __clobber_all);
+}
+
+
+#ifdef __BPF_FEATURE_ADDR_SPACE_CAST
+SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
+__log_level(2)
+__msg(" 6: .12345.... (85) call bpf_arena_alloc_pages")
+__msg(" 7: 0......... (bf) r1 = addr_space_cast(r0, 0, 1)")
+__msg(" 8: .1........ (b7) r2 = 42")
+__naked void addr_space_cast(void)
+{
+	asm volatile (
+		"r1 = %[arena] ll;"
+		"r2 = 0;"
+		"r3 = 1;"
+		"r4 = 0;"
+		"r5 = 0;"
+		"call %[bpf_arena_alloc_pages];"
+		"r1 = addr_space_cast(r0, 0, 1);"
+		"r2 = 42;"
+		"*(u64 *)(r1 +0) = r2;"
+		"r0 = 0;"
+		"exit;"
+		:
+		: __imm(bpf_arena_alloc_pages),
+		  __imm_addr(arena)
+		: __clobber_all);
+}
+#endif
+
+/* to retain debug info for BTF generation */
+void kfunc_root(void)
+{
+	bpf_arena_alloc_pages(0, 0, 0, 0, 0);
+}
+
+char _license[] SEC("license") = "GPL";