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From: Puranjay Mohan <puranjay12@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Shubham Bansal <illusionist.neo@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>,
	"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Luke Nelson <luke.r.nels@gmail.com>, Xi Wang <xi.wang@gmail.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Wang YanQing <udknight@gmail.com>,
	bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
	netdev@vger.kernel.org
Cc: puranjay12@gmail.com
Subject: [PATCH bpf-next 5/6] bpf, arm32: Always zero extend for LDX with B/H/W
Date: Tue, 12 Sep 2023 22:46:53 +0000	[thread overview]
Message-ID: <20230912224654.6556-6-puranjay12@gmail.com> (raw)
In-Reply-To: <20230912224654.6556-1-puranjay12@gmail.com>

The JITs should not depend on the verifier for zero extending the upper
32 bits of the destination register when loading a byte, half-word, or
word.

A following patch will make the verifier stop patching zext instructions
after LDX.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
---
 arch/arm/net/bpf_jit_32.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 6a1c9fca5260..757a99febba5 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -1081,20 +1081,17 @@ static inline void emit_ldx_r(const s8 dst[], const s8 src,
 	case BPF_B:
 		/* Load a Byte */
 		emit(ARM_LDRB_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_H:
 		/* Load a HalfWord */
 		emit(ARM_LDRH_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_W:
 		/* Load a Word */
 		emit(ARM_LDR_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_DW:
 		/* Load a Double Word */
-- 
2.39.2


WARNING: multiple messages have this Message-ID (diff)
From: Puranjay Mohan <puranjay12@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Shubham Bansal <illusionist.neo@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>,
	"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Luke Nelson <luke.r.nels@gmail.com>, Xi Wang <xi.wang@gmail.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Wang YanQing <udknight@gmail.com>,
	bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
	netdev@vger.kernel.org
Cc: puranjay12@gmail.com
Subject: [PATCH bpf-next 5/6] bpf, arm32: Always zero extend for LDX with B/H/W
Date: Tue, 12 Sep 2023 22:46:53 +0000	[thread overview]
Message-ID: <20230912224654.6556-6-puranjay12@gmail.com> (raw)
In-Reply-To: <20230912224654.6556-1-puranjay12@gmail.com>

The JITs should not depend on the verifier for zero extending the upper
32 bits of the destination register when loading a byte, half-word, or
word.

A following patch will make the verifier stop patching zext instructions
after LDX.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
---
 arch/arm/net/bpf_jit_32.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 6a1c9fca5260..757a99febba5 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -1081,20 +1081,17 @@ static inline void emit_ldx_r(const s8 dst[], const s8 src,
 	case BPF_B:
 		/* Load a Byte */
 		emit(ARM_LDRB_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_H:
 		/* Load a HalfWord */
 		emit(ARM_LDRH_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_W:
 		/* Load a Word */
 		emit(ARM_LDR_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_DW:
 		/* Load a Double Word */
-- 
2.39.2


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Puranjay Mohan <puranjay12@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Shubham Bansal <illusionist.neo@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>,
	"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Luke Nelson <luke.r.nels@gmail.com>, Xi Wang <xi.wang@gmail.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Wang YanQing <udknight@gmail.com>,
	bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
	netdev@vger.kernel.org
Cc: puranjay12@gmail.com
Subject: [PATCH bpf-next 5/6] bpf, arm32: Always zero extend for LDX with B/H/W
Date: Tue, 12 Sep 2023 22:46:53 +0000	[thread overview]
Message-ID: <20230912224654.6556-6-puranjay12@gmail.com> (raw)
In-Reply-To: <20230912224654.6556-1-puranjay12@gmail.com>

The JITs should not depend on the verifier for zero extending the upper
32 bits of the destination register when loading a byte, half-word, or
word.

A following patch will make the verifier stop patching zext instructions
after LDX.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
---
 arch/arm/net/bpf_jit_32.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 6a1c9fca5260..757a99febba5 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -1081,20 +1081,17 @@ static inline void emit_ldx_r(const s8 dst[], const s8 src,
 	case BPF_B:
 		/* Load a Byte */
 		emit(ARM_LDRB_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_H:
 		/* Load a HalfWord */
 		emit(ARM_LDRH_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_W:
 		/* Load a Word */
 		emit(ARM_LDR_I(rd[1], rm, off), ctx);
-		if (!ctx->prog->aux->verifier_zext)
-			emit_a32_mov_i(rd[0], 0, ctx);
+		emit_a32_mov_i(rd[0], 0, ctx);
 		break;
 	case BPF_DW:
 		/* Load a Double Word */
-- 
2.39.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2023-09-12 22:47 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-12 22:46 [PATCH bpf-next 0/6] bpf: verifier: stop emitting zext for LDX Puranjay Mohan
2023-09-12 22:46 ` Puranjay Mohan
2023-09-12 22:46 ` Puranjay Mohan
2023-09-12 22:46 ` [PATCH bpf-next 1/6] bpf, riscv32: Always zero extend for LDX with B/W/H Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46 ` [PATCH bpf-next 2/6] bpf, x86-32: " Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46 ` [PATCH bpf-next 3/6] bpf, parisc32: " Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46 ` [PATCH bpf-next 4/6] bpf, powerpc32: Always zero extend for LDX Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46 ` Puranjay Mohan [this message]
2023-09-12 22:46   ` [PATCH bpf-next 5/6] bpf, arm32: Always zero extend for LDX with B/H/W Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 23:03   ` Russell King (Oracle)
2023-09-12 23:03     ` Russell King (Oracle)
2023-09-12 23:03     ` Russell King (Oracle)
2023-09-12 23:03     ` Russell King (Oracle)
2023-09-12 23:16     ` Puranjay Mohan
2023-09-12 23:16       ` Puranjay Mohan
2023-09-12 23:16       ` Puranjay Mohan
2023-09-12 23:16       ` Puranjay Mohan
2023-09-13  0:10       ` Alexei Starovoitov
2023-09-13  0:10         ` Alexei Starovoitov
2023-09-13  0:10         ` Alexei Starovoitov
2023-09-13  0:10         ` Alexei Starovoitov
2023-09-12 22:46 ` [PATCH bpf-next 6/6] bpf, verifier: always mark destination of LDX as 64-bit Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan
2023-09-12 22:46   ` Puranjay Mohan

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