[dpdk-stable] patch 'bpf: fix x86 JIT for immediate loads' has been queued to stable release 18.08.1

[Kevin Traynor]

Hi,

FYI, your patch has been queued to stable release 18.08.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/29/18. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the patch applied
to the branch. If the code is different (ie: not only metadata diffs), due for example to
a change in context or macro names, please double check it.

Thanks.

Kevin Traynor

---
>From 7e5b6aa6cc75c0129cc23cd1778c8d743fafbf81 Mon Sep 17 00:00:00 2001
From: Konstantin Ananyev <konstantin.ananyev at intel.com>
Date: Thu, 8 Nov 2018 12:36:43 +0000
Subject: [PATCH] bpf: fix x86 JIT for immediate loads

[ upstream commit 95df7307a77de5d28b4c81151a8dcc100be8172c ]

x86 jit can generate invalid code for (BPF_LD | BPF_IMM | EBPF_DW)
instructions, when immediate value is bigger then INT32_MAX.

Fixes: cc752e43e079 ("bpf: add JIT compilation for x86_64 ISA")

Signed-off-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
---
 lib/librte_bpf/bpf_jit_x86.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/lib/librte_bpf/bpf_jit_x86.c b/lib/librte_bpf/bpf_jit_x86.c
index 68ea389f2..f70cd6be5 100644
--- a/lib/librte_bpf/bpf_jit_x86.c
+++ b/lib/librte_bpf/bpf_jit_x86.c
@@ -209,4 +209,17 @@ emit_sib(struct bpf_jit_state *st, uint32_t scale, uint32_t idx, uint32_t base)
 }
 
+/*
+ * emit OPCODE+REGIDX byte
+ */
+static void
+emit_opcode(struct bpf_jit_state *st, uint8_t ops, uint32_t reg)
+{
+	uint8_t v;
+
+	v = ops | (reg & 7);
+	emit_bytes(st, &v, sizeof(v));
+}
+
+
 /*
  * emit xchg %<sreg>, %<dreg>
@@ -473,17 +486,16 @@ emit_ld_imm64(struct bpf_jit_state *st, uint32_t dreg, uint32_t imm0,
 	uint32_t imm1)
 {
+	uint32_t op;
+
 	const uint8_t ops = 0xB8;
 
-	if (imm1 == 0) {
-		emit_mov_imm(st, EBPF_ALU64 | EBPF_MOV | BPF_K, dreg, imm0);
-		return;
-	}
+	op = (imm1 == 0) ? BPF_ALU : EBPF_ALU64;
 
-	emit_rex(st, EBPF_ALU64, 0, dreg);
-	emit_bytes(st, &ops, sizeof(ops));
-	emit_modregrm(st, MOD_DIRECT, 0, dreg);
+	emit_rex(st, op, 0, dreg);
+	emit_opcode(st, ops, dreg);
 
 	emit_imm(st, imm0, sizeof(imm0));
-	emit_imm(st, imm1, sizeof(imm1));
+	if (imm1 != 0)
+		emit_imm(st, imm1, sizeof(imm1));
 }
 
-- 
2.19.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2018-11-23 10:22:55.825256066 +0000
+++ 0061-bpf-fix-x86-JIT-for-immediate-loads.patch	2018-11-23 10:22:54.000000000 +0000
@@ -1,13 +1,14 @@
-From 95df7307a77de5d28b4c81151a8dcc100be8172c Mon Sep 17 00:00:00 2001
+From 7e5b6aa6cc75c0129cc23cd1778c8d743fafbf81 Mon Sep 17 00:00:00 2001
 From: Konstantin Ananyev <konstantin.ananyev at intel.com>
 Date: Thu, 8 Nov 2018 12:36:43 +0000
 Subject: [PATCH] bpf: fix x86 JIT for immediate loads
 
+[ upstream commit 95df7307a77de5d28b4c81151a8dcc100be8172c ]
+
 x86 jit can generate invalid code for (BPF_LD | BPF_IMM | EBPF_DW)
 instructions, when immediate value is bigger then INT32_MAX.
 
 Fixes: cc752e43e079 ("bpf: add JIT compilation for x86_64 ISA")
-Cc: stable at dpdk.org
 
 Signed-off-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
 ---