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From: Xu Kuohai <xukuohai@huaweicloud.com>
To: bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org
Cc: "Ivan Babrou" <ivan@cloudflare.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Björn Töpel" <bjorn@kernel.org>, "Pu Lehui" <pulehui@huawei.com>
Subject: [PATCH bpf-next 1/2] bpf, arm64: Fix incorrect runtime stats
Date: Tue, 16 Apr 2024 14:42:07 +0800	[thread overview]
Message-ID: <20240416064208.2919073-2-xukuohai@huaweicloud.com> (raw)
In-Reply-To: <20240416064208.2919073-1-xukuohai@huaweicloud.com>

From: Xu Kuohai <xukuohai@huawei.com>

When __bpf_prog_enter() returns zero, the arm64 register x20 that stores
prog start time is not assigned to zero, causing incorrect runtime stats.

To fix it, assign the return value of bpf_prog_enter() to x20 register
immediately upon its return.

Fixes: efc9909fdce0 ("bpf, arm64: Add bpf trampoline for arm64")
Reported-by: Ivan Babrou <ivan@cloudflare.com>
Tested-by: Ivan Babrou <ivan@cloudflare.com>
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 arch/arm64/net/bpf_jit_comp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 76b91f36c729..cf9a9ebb4cda 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1905,15 +1905,15 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
 
 	emit_call(enter_prog, ctx);
 
+	/* save return value to callee saved register x20 */
+	emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
+
 	/* if (__bpf_prog_enter(prog) == 0)
 	 *         goto skip_exec_of_prog;
 	 */
 	branch = ctx->image + ctx->idx;
 	emit(A64_NOP, ctx);
 
-	/* save return value to callee saved register x20 */
-	emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
-
 	emit(A64_ADD_I(1, A64_R(0), A64_SP, args_off), ctx);
 	if (!p->jited)
 		emit_addr_mov_i64(A64_R(1), (const u64)p->insnsi, ctx);
-- 
2.40.1


WARNING: multiple messages have this Message-ID (diff)
From: Xu Kuohai <xukuohai@huaweicloud.com>
To: bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org
Cc: "Ivan Babrou" <ivan@cloudflare.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Björn Töpel" <bjorn@kernel.org>, "Pu Lehui" <pulehui@huawei.com>
Subject: [PATCH bpf-next 1/2] bpf, arm64: Fix incorrect runtime stats
Date: Tue, 16 Apr 2024 14:42:07 +0800	[thread overview]
Message-ID: <20240416064208.2919073-2-xukuohai@huaweicloud.com> (raw)
In-Reply-To: <20240416064208.2919073-1-xukuohai@huaweicloud.com>

From: Xu Kuohai <xukuohai@huawei.com>

When __bpf_prog_enter() returns zero, the arm64 register x20 that stores
prog start time is not assigned to zero, causing incorrect runtime stats.

To fix it, assign the return value of bpf_prog_enter() to x20 register
immediately upon its return.

Fixes: efc9909fdce0 ("bpf, arm64: Add bpf trampoline for arm64")
Reported-by: Ivan Babrou <ivan@cloudflare.com>
Tested-by: Ivan Babrou <ivan@cloudflare.com>
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 arch/arm64/net/bpf_jit_comp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 76b91f36c729..cf9a9ebb4cda 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1905,15 +1905,15 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
 
 	emit_call(enter_prog, ctx);
 
+	/* save return value to callee saved register x20 */
+	emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
+
 	/* if (__bpf_prog_enter(prog) == 0)
 	 *         goto skip_exec_of_prog;
 	 */
 	branch = ctx->image + ctx->idx;
 	emit(A64_NOP, ctx);
 
-	/* save return value to callee saved register x20 */
-	emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
-
 	emit(A64_ADD_I(1, A64_R(0), A64_SP, args_off), ctx);
 	if (!p->jited)
 		emit_addr_mov_i64(A64_R(1), (const u64)p->insnsi, ctx);
-- 
2.40.1


_______________________________________________
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: Xu Kuohai <xukuohai@huaweicloud.com>
To: bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org
Cc: "Ivan Babrou" <ivan@cloudflare.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Björn Töpel" <bjorn@kernel.org>, "Pu Lehui" <pulehui@huawei.com>
Subject: [PATCH bpf-next 1/2] bpf, arm64: Fix incorrect runtime stats
Date: Tue, 16 Apr 2024 14:42:07 +0800	[thread overview]
Message-ID: <20240416064208.2919073-2-xukuohai@huaweicloud.com> (raw)
In-Reply-To: <20240416064208.2919073-1-xukuohai@huaweicloud.com>

From: Xu Kuohai <xukuohai@huawei.com>

When __bpf_prog_enter() returns zero, the arm64 register x20 that stores
prog start time is not assigned to zero, causing incorrect runtime stats.

To fix it, assign the return value of bpf_prog_enter() to x20 register
immediately upon its return.

Fixes: efc9909fdce0 ("bpf, arm64: Add bpf trampoline for arm64")
Reported-by: Ivan Babrou <ivan@cloudflare.com>
Tested-by: Ivan Babrou <ivan@cloudflare.com>
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 arch/arm64/net/bpf_jit_comp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 76b91f36c729..cf9a9ebb4cda 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1905,15 +1905,15 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l,
 
 	emit_call(enter_prog, ctx);
 
+	/* save return value to callee saved register x20 */
+	emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
+
 	/* if (__bpf_prog_enter(prog) == 0)
 	 *         goto skip_exec_of_prog;
 	 */
 	branch = ctx->image + ctx->idx;
 	emit(A64_NOP, ctx);
 
-	/* save return value to callee saved register x20 */
-	emit(A64_MOV(1, A64_R(20), A64_R(0)), ctx);
-
 	emit(A64_ADD_I(1, A64_R(0), A64_SP, args_off), ctx);
 	if (!p->jited)
 		emit_addr_mov_i64(A64_R(1), (const u64)p->insnsi, ctx);
-- 
2.40.1


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

  reply	other threads:[~2024-04-16  6:39 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-16  6:42 [PATCH bpf-next 0/2] Fix incorrect bpf runtime stats for arm64 and riscv64 Xu Kuohai
2024-04-16  6:42 ` Xu Kuohai
2024-04-16  6:42 ` Xu Kuohai
2024-04-16  6:42 ` Xu Kuohai [this message]
2024-04-16  6:42   ` [PATCH bpf-next 1/2] bpf, arm64: Fix incorrect runtime stats Xu Kuohai
2024-04-16  6:42   ` Xu Kuohai
2024-04-16  6:42 ` [PATCH bpf-next 2/2] riscv, bpf: " Xu Kuohai
2024-04-16  6:42   ` Xu Kuohai
2024-04-16  6:42   ` Xu Kuohai
2024-04-16  9:35   ` Pu Lehui
2024-04-16  9:35     ` Pu Lehui
2024-04-16  9:35     ` Pu Lehui
2024-04-16 14:09     ` Björn Töpel
2024-04-16 14:09       ` Björn Töpel
2024-04-16 14:09       ` Björn Töpel
2024-04-16 15:30 ` [PATCH bpf-next 0/2] Fix incorrect bpf runtime stats for arm64 and riscv64 patchwork-bot+netdevbpf
2024-04-16 15:30   ` patchwork-bot+netdevbpf
2024-04-16 15:30   ` patchwork-bot+netdevbpf

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