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From: Eduard Zingerman <eddyz87@gmail.com>
To: Yonghong Song <yhs@fb.com>, bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	 Daniel Borkmann <daniel@iogearbox.net>,
	Fangrui Song <maskray@google.com>,
	kernel-team@fb.com
Subject: Re: [PATCH bpf-next v2 09/15] selftests/bpf: Add unit tests for new sign-extension load insns
Date: Wed, 19 Jul 2023 02:06:25 +0300	[thread overview]
Message-ID: <3b14f5d209973469ebcbffcfb84654715c19f4f4.camel@gmail.com> (raw)
In-Reply-To: <20230713060805.393133-1-yhs@fb.com>

On Wed, 2023-07-12 at 23:08 -0700, Yonghong Song wrote:
> Add unit tests for new ldsx insns. The test includes sign-extension
> with a single value or with a value range.
> 
> Signed-off-by: Yonghong Song <yhs@fb.com>
> ---
>  .../selftests/bpf/prog_tests/verifier.c       |   2 +
>  .../selftests/bpf/progs/verifier_ldsx.c       | 115 ++++++++++++++++++
>  2 files changed, 117 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/progs/verifier_ldsx.c
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c
> index c375e59ff28d..6eec6a9463c8 100644
> --- a/tools/testing/selftests/bpf/prog_tests/verifier.c
> +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c
> @@ -31,6 +31,7 @@
>  #include "verifier_int_ptr.skel.h"
>  #include "verifier_jeq_infer_not_null.skel.h"
>  #include "verifier_ld_ind.skel.h"
> +#include "verifier_ldsx.skel.h"
>  #include "verifier_leak_ptr.skel.h"
>  #include "verifier_loops1.skel.h"
>  #include "verifier_lwt.skel.h"
> @@ -133,6 +134,7 @@ void test_verifier_helper_value_access(void)  { RUN(verifier_helper_value_access
>  void test_verifier_int_ptr(void)              { RUN(verifier_int_ptr); }
>  void test_verifier_jeq_infer_not_null(void)   { RUN(verifier_jeq_infer_not_null); }
>  void test_verifier_ld_ind(void)               { RUN(verifier_ld_ind); }
> +void test_verifier_ldsx(void)                  { RUN(verifier_ldsx); }
>  void test_verifier_leak_ptr(void)             { RUN(verifier_leak_ptr); }
>  void test_verifier_loops1(void)               { RUN(verifier_loops1); }
>  void test_verifier_lwt(void)                  { RUN(verifier_lwt); }
> diff --git a/tools/testing/selftests/bpf/progs/verifier_ldsx.c b/tools/testing/selftests/bpf/progs/verifier_ldsx.c
> new file mode 100644
> index 000000000000..cd90913583b9
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/verifier_ldsx.c
> @@ -0,0 +1,115 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +#include "bpf_misc.h"
> +
> +SEC("socket")
> +__description("LDSX, S8")
> +__success __success_unpriv __retval(-2)
> +__naked void ldsx_s8(void)
> +{
> +	asm volatile ("					\
> +	r1 = 0x3fe;					\
> +	*(u64 *)(r10 - 8) = r1;				\
> +	r0 = *(s8 *)(r10 - 8);				\
> +	exit;						\
> +"	::: __clobber_all);
> +}
> +
> +SEC("socket")
> +__description("LDSX, S16")
> +__success __success_unpriv __retval(-2)
> +__naked void ldsx_s16(void)
> +{
> +	asm volatile ("					\
> +	r1 = 0x3fffe;					\
> +	*(u64 *)(r10 - 8) = r1;				\
> +	r0 = *(s16 *)(r10 - 8);				\
> +	exit;						\
> +"	::: __clobber_all);
> +}
> +
> +SEC("socket")
> +__description("LDSX, S32")
> +__success __success_unpriv __retval(-2)
> +__naked void ldsx_s32(void)
> +{
> +	asm volatile ("					\
> +	r1 = 0xfffffffe;				\
> +	*(u64 *)(r10 - 8) = r1;				\
> +	r0 = *(s32 *)(r10 - 8);				\
> +	exit;						\
> +"	::: __clobber_all);
> +}

Note that __retval is a 32-bit value, so if I change
  r0 = *(s32 *)(r10 - 8); to
  r0 = *(u32 *)(r10 - 8);
         ^
__retval would be the same, probably better to add
some shift right as a last instruction or something
like that.
(Also applies to a similar test in the movsx tests).

> +
> +SEC("socket")
> +__description("LDSX, S8 range checking")
> +__success __success_unpriv __retval(1)
> +__naked void ldsx_s8_range(void)

Maybe add __log_level(2) and a few
__msg("... R1_w=scalar(smin=-128,smax=127)") ?
So that verifier range logic is checked as well.

> +{
> +	asm volatile ("					\
> +	call %[bpf_get_prandom_u32];			\
> +	*(u64 *)(r10 - 8) = r0;				\
> +	r1 = *(s8 *)(r10 - 8);				\
> +	/* r1 with s8 range */				\
> +	if r1 s> 0x7f goto l0_%=;			\
> +	if r1 s< -0x80 goto l0_%=;			\
> +	r0 = 1;						\
> +l1_%=:							\
> +	exit;						\
> +l0_%=:							\
> +	r0 = 2;						\
> +	goto l1_%=;					\
> +"	:
> +	: __imm(bpf_get_prandom_u32)
> +	: __clobber_all);
> +}
> +
> +SEC("socket")
> +__description("LDSX, S16 range checking")
> +__success __success_unpriv __retval(1)
> +__naked void ldsx_s16_range(void)
> +{
> +	asm volatile ("					\
> +	call %[bpf_get_prandom_u32];			\
> +	*(u64 *)(r10 - 8) = r0;				\
> +	r1 = *(s16 *)(r10 - 8);				\
> +	/* r1 with s16 range */				\
> +	if r1 s> 0x7fff goto l0_%=;			\
> +	if r1 s< -0x8000 goto l0_%=;			\
> +	r0 = 1;						\
> +l1_%=:							\
> +	exit;						\
> +l0_%=:							\
> +	r0 = 2;						\
> +	goto l1_%=;					\
> +"	:
> +	: __imm(bpf_get_prandom_u32)
> +	: __clobber_all);
> +}
> +
> +SEC("socket")
> +__description("LDSX, S32 range checking")
> +__success __success_unpriv __retval(1)
> +__naked void ldsx_s32_range(void)
> +{
> +	asm volatile ("					\
> +	call %[bpf_get_prandom_u32];			\
> +	*(u64 *)(r10 - 8) = r0;				\
> +	r1 = *(s32 *)(r10 - 8);				\
> +	/* r1 with s16 range */				\
> +	if r1 s> 0x7fffFFFF goto l0_%=;			\
> +	if r1 s< -0x80000000 goto l0_%=;		\
> +	r0 = 1;						\
> +l1_%=:							\
> +	exit;						\
> +l0_%=:							\
> +	r0 = 2;						\
> +	goto l1_%=;					\
> +"	:
> +	: __imm(bpf_get_prandom_u32)
> +	: __clobber_all);
> +}
> +
> +char _license[] SEC("license") = "GPL";


  reply	other threads:[~2023-07-18 23:06 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-13  6:07 [PATCH bpf-next v2 00/15] bpf: Support new insns from cpu v4 Yonghong Song
2023-07-13  6:07 ` [PATCH bpf-next v2 01/15] bpf: Support new sign-extension load insns Yonghong Song
2023-07-14 18:13   ` Alexei Starovoitov
2023-07-14 23:22     ` Yonghong Song
2023-07-17  1:39   ` Eduard Zingerman
2023-07-19  0:15   ` Eduard Zingerman
2023-07-19  2:28     ` Yonghong Song
2023-07-13  6:07 ` [PATCH bpf-next v2 02/15] bpf: Fix sign-extension ctx member accesses Yonghong Song
2023-07-17  1:40   ` Eduard Zingerman
2023-07-19  0:40     ` Yonghong Song
2023-07-13  6:07 ` [PATCH bpf-next v2 03/15] bpf: Support new sign-extension mov insns Yonghong Song
2023-07-17  1:41   ` Eduard Zingerman
2023-07-19  1:17     ` Yonghong Song
2023-07-19 12:53       ` Eduard Zingerman
2023-07-19 15:59         ` Fangrui Song
2023-07-19 16:57           ` Eduard Zingerman
2023-07-13  6:07 ` [PATCH bpf-next v2 04/15] bpf: Support new unconditional bswap instruction Yonghong Song
2023-07-17  1:42   ` Eduard Zingerman
2023-07-19  1:22     ` Yonghong Song
2023-07-13  6:07 ` [PATCH bpf-next v2 05/15] bpf: Support new signed div/mod instructions Yonghong Song
2023-07-18 23:00   ` Eduard Zingerman
2023-07-19  2:30     ` Yonghong Song
2023-07-19  2:44       ` Alexei Starovoitov
2023-07-19  6:57         ` Yonghong Song
2023-07-13  6:07 ` [PATCH bpf-next v2 06/15] bpf: Fix jit blinding with new sdiv/smov insns Yonghong Song
2023-07-13  6:07 ` [PATCH bpf-next v2 07/15] bpf: Support new 32bit offset jmp instruction Yonghong Song
2023-07-13  6:08 ` [PATCH bpf-next v2 08/15] selftests/bpf: Add a cpuv4 test runner for cpu=v4 testing Yonghong Song
2023-07-13  6:18   ` Fangrui Song
2023-07-13  6:25     ` Yonghong Song
2023-07-13  6:08 ` [PATCH bpf-next v2 09/15] selftests/bpf: Add unit tests for new sign-extension load insns Yonghong Song
2023-07-18 23:06   ` Eduard Zingerman [this message]
2023-07-13  6:08 ` [PATCH bpf-next v2 10/15] selftests/bpf: Add unit tests for new sign-extension mov insns Yonghong Song
2023-07-13  6:08 ` [PATCH bpf-next v2 11/15] selftests/bpf: Add unit tests for new bswap insns Yonghong Song
2023-07-13  6:08 ` [PATCH bpf-next v2 12/15] selftests/bpf: Add unit tests for new sdiv/smod insns Yonghong Song
2023-07-18 23:10   ` Eduard Zingerman
2023-07-13  6:08 ` [PATCH bpf-next v2 13/15] selftests/bpf: Add unit tests for new gotol insn Yonghong Song
2023-07-13  6:08 ` [PATCH bpf-next v2 14/15] selftests/bpf: Test ldsx with more complex cases Yonghong Song
2023-07-13  6:08 ` [PATCH bpf-next v2 15/15] docs/bpf: Add documentation for new instructions Yonghong Song
2023-07-14 18:28   ` Alexei Starovoitov
2023-07-14 23:26     ` Yonghong Song
2023-07-14 23:33   ` Dave Thaler
2023-07-14 23:33     ` [Bpf] " Dave Thaler
2023-07-15  0:23     ` Alexei Starovoitov
2023-07-15  0:23       ` [Bpf] " Alexei Starovoitov
2023-07-14 23:34   ` Dave Thaler
2023-07-14 23:34     ` [Bpf] " Dave Thaler
2023-07-17  1:39 ` [PATCH bpf-next v2 00/15] bpf: Support new insns from cpu v4 Eduard Zingerman
2023-07-17 16:56   ` Alexei Starovoitov
2023-07-17 17:04     ` Eduard Zingerman
2023-07-17 21:52   ` Yonghong Song
2023-07-21 14:56     ` Jose E. Marchesi
2023-07-24  0:17       ` Jose E. Marchesi
2023-07-24  1:04         ` Jose E. Marchesi
2023-07-24  2:35           ` Yonghong Song

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