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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: bpf@vger.kernel.org
Cc: daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org,
	dxu@dxuuu.xyz, memxor@gmail.com, john.fastabend@gmail.com,
	jolsa@kernel.org, kernel-team@fb.com
Subject: [PATCH v3 bpf-next 3/6] selftests/bpf: Convert exceptions_assert.c to bpf_cmp
Date: Tue, 26 Dec 2023 11:11:45 -0800	[thread overview]
Message-ID: <20231226191148.48536-4-alexei.starovoitov@gmail.com> (raw)
In-Reply-To: <20231226191148.48536-1-alexei.starovoitov@gmail.com>

From: Alexei Starovoitov <ast@kernel.org>

Convert exceptions_assert.c to bpf_cmp_unlikely() macro.

Since

bpf_assert(bpf_cmp_unlikely(var, ==, 100));
other code;

will generate assembly code:

  if r1 == 100 goto L2;
  r0 = 0
  call bpf_throw
L1:
  other code;
  ...

L2: goto L1;

LLVM generates redundant basic block with extra goto. LLVM will be fixed eventually.
Right now it's less efficient than __bpf_assert(var, ==, 100) macro that produces:
  if r1 == 100 goto L1;
  r0 = 0
  call bpf_throw
L1:
  other code;

But extra goto doesn't hurt the verification process.

Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 .../selftests/bpf/progs/exceptions_assert.c   | 80 +++++++++----------
 1 file changed, 40 insertions(+), 40 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/exceptions_assert.c b/tools/testing/selftests/bpf/progs/exceptions_assert.c
index 0ef81040da59..5e0a1ca96d4e 100644
--- a/tools/testing/selftests/bpf/progs/exceptions_assert.c
+++ b/tools/testing/selftests/bpf/progs/exceptions_assert.c
@@ -11,51 +11,51 @@
 #define check_assert(type, op, name, value)				\
 	SEC("?tc")							\
 	__log_level(2) __failure					\
-	int check_assert_##op##_##name(void *ctx)			\
+	int check_assert_##name(void *ctx)				\
 	{								\
 		type num = bpf_ktime_get_ns();				\
-		bpf_assert_##op(num, value);				\
+		bpf_assert(bpf_cmp_unlikely(num, op, value));		\
 		return *(u64 *)num;					\
 	}
 
-__msg(": R0_w=0xffffffff80000000 R10=fp0")
-check_assert(s64, eq, int_min, INT_MIN);
-__msg(": R0_w=0x7fffffff R10=fp0")
-check_assert(s64, eq, int_max, INT_MAX);
-__msg(": R0_w=0 R10=fp0")
-check_assert(s64, eq, zero, 0);
-__msg(": R0_w=0x8000000000000000 R1_w=0x8000000000000000 R10=fp0")
-check_assert(s64, eq, llong_min, LLONG_MIN);
-__msg(": R0_w=0x7fffffffffffffff R1_w=0x7fffffffffffffff R10=fp0")
-check_assert(s64, eq, llong_max, LLONG_MAX);
-
-__msg(": R0_w=scalar(smax=0x7ffffffe) R10=fp0")
-check_assert(s64, lt, pos, INT_MAX);
-__msg(": R0_w=scalar(smax=-1,umin=0x8000000000000000,var_off=(0x8000000000000000; 0x7fffffffffffffff))")
-check_assert(s64, lt, zero, 0);
-__msg(": R0_w=scalar(smax=0xffffffff7fffffff,umin=0x8000000000000000,umax=0xffffffff7fffffff,var_off=(0x8000000000000000; 0x7fffffffffffffff))")
-check_assert(s64, lt, neg, INT_MIN);
-
-__msg(": R0_w=scalar(smax=0x7fffffff) R10=fp0")
-check_assert(s64, le, pos, INT_MAX);
-__msg(": R0_w=scalar(smax=0) R10=fp0")
-check_assert(s64, le, zero, 0);
-__msg(": R0_w=scalar(smax=0xffffffff80000000,umin=0x8000000000000000,umax=0xffffffff80000000,var_off=(0x8000000000000000; 0x7fffffffffffffff))")
-check_assert(s64, le, neg, INT_MIN);
-
-__msg(": R0_w=scalar(smin=umin=0x80000000,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))")
-check_assert(s64, gt, pos, INT_MAX);
-__msg(": R0_w=scalar(smin=umin=1,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))")
-check_assert(s64, gt, zero, 0);
-__msg(": R0_w=scalar(smin=0xffffffff80000001) R10=fp0")
-check_assert(s64, gt, neg, INT_MIN);
-
-__msg(": R0_w=scalar(smin=umin=0x7fffffff,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))")
-check_assert(s64, ge, pos, INT_MAX);
-__msg(": R0_w=scalar(smin=0,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff)) R10=fp0")
-check_assert(s64, ge, zero, 0);
-__msg(": R0_w=scalar(smin=0xffffffff80000000) R10=fp0")
-check_assert(s64, ge, neg, INT_MIN);
+__msg(": R0_w=0xffffffff80000000")
+check_assert(s64, ==, eq_int_min, INT_MIN);
+__msg(": R0_w=0x7fffffff")
+check_assert(s64, ==, eq_int_max, INT_MAX);
+__msg(": R0_w=0")
+check_assert(s64, ==, eq_zero, 0);
+__msg(": R0_w=0x8000000000000000 R1_w=0x8000000000000000")
+check_assert(s64, ==, eq_llong_min, LLONG_MIN);
+__msg(": R0_w=0x7fffffffffffffff R1_w=0x7fffffffffffffff")
+check_assert(s64, ==, eq_llong_max, LLONG_MAX);
+
+__msg(": R0_w=scalar(id=1,smax=0x7ffffffe)")
+check_assert(s64, <, lt_pos, INT_MAX);
+__msg(": R0_w=scalar(id=1,smax=-1,umin=0x8000000000000000,var_off=(0x8000000000000000; 0x7fffffffffffffff))")
+check_assert(s64, <, lt_zero, 0);
+__msg(": R0_w=scalar(id=1,smax=0xffffffff7fffffff")
+check_assert(s64, <, lt_neg, INT_MIN);
+
+__msg(": R0_w=scalar(id=1,smax=0x7fffffff)")
+check_assert(s64, <=, le_pos, INT_MAX);
+__msg(": R0_w=scalar(id=1,smax=0)")
+check_assert(s64, <=, le_zero, 0);
+__msg(": R0_w=scalar(id=1,smax=0xffffffff80000000")
+check_assert(s64, <=, le_neg, INT_MIN);
+
+__msg(": R0_w=scalar(id=1,smin=umin=0x80000000,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))")
+check_assert(s64, >, gt_pos, INT_MAX);
+__msg(": R0_w=scalar(id=1,smin=umin=1,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))")
+check_assert(s64, >, gt_zero, 0);
+__msg(": R0_w=scalar(id=1,smin=0xffffffff80000001")
+check_assert(s64, >, gt_neg, INT_MIN);
+
+__msg(": R0_w=scalar(id=1,smin=umin=0x7fffffff,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))")
+check_assert(s64, >=, ge_pos, INT_MAX);
+__msg(": R0_w=scalar(id=1,smin=0,umax=0x7fffffffffffffff,var_off=(0x0; 0x7fffffffffffffff))")
+check_assert(s64, >=, ge_zero, 0);
+__msg(": R0_w=scalar(id=1,smin=0xffffffff80000000")
+check_assert(s64, >=, ge_neg, INT_MIN);
 
 SEC("?tc")
 __log_level(2) __failure
-- 
2.34.1


  parent reply	other threads:[~2023-12-26 19:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-26 19:11 [PATCH v3 bpf-next 0/6] bpf: volatile compare Alexei Starovoitov
2023-12-26 19:11 ` [PATCH v3 bpf-next 1/6] selftests/bpf: Attempt to build BPF programs with -Wsign-compare Alexei Starovoitov
2023-12-26 19:11 ` [PATCH v3 bpf-next 2/6] bpf: Introduce "volatile compare" macros Alexei Starovoitov
2024-01-03 19:20   ` Andrii Nakryiko
2024-01-04  6:03     ` Alexei Starovoitov
2024-01-04 19:04       ` Andrii Nakryiko
2023-12-26 19:11 ` Alexei Starovoitov [this message]
2023-12-26 19:11 ` [PATCH v3 bpf-next 4/6] selftests/bpf: Remove bpf_assert_eq-like macros Alexei Starovoitov
2023-12-26 19:11 ` [PATCH v3 bpf-next 5/6] bpf: Add bpf_nop_mov() asm macro Alexei Starovoitov
2023-12-26 19:11 ` [PATCH v3 bpf-next 6/6] selftests/bpf: Convert profiler.c to bpf_cmp Alexei Starovoitov
2024-01-03 19:30 ` [PATCH v3 bpf-next 0/6] bpf: volatile compare patchwork-bot+netdevbpf

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