[PATH bpf-next 04/13] x86_64: bpf: implement jitting of JMP32

[Jiong Wang]

This patch implements code-gen for new JMP32 instructions on x86_64.

Cc: Alexei Starovoitov <a...@kernel.org>
Cc: Daniel Borkmann <dan...@iogearbox.net>
Signed-off-by: Jiong Wang <jiong.w...@netronome.com>
---
 arch/x86/net/bpf_jit_comp.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 5542303..499f1c1 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -882,8 +882,12 @@ xadd:                      if (is_imm8(insn->off))
                case BPF_JMP | BPF_JSGE | BPF_X:
                case BPF_JMP | BPF_JSLE | BPF_X:
                        /* cmp dst_reg, src_reg */
-                       EMIT3(add_2mod(0x48, dst_reg, src_reg), 0x39,
-                             add_2reg(0xC0, dst_reg, src_reg));
+                       if (!imm32) /* JMP32 */
+                               EMIT1(add_2mod(0x48, dst_reg, src_reg));
+                       else if (is_ereg(dst_reg) || is_ereg(src_reg))
+                               EMIT1(add_2mod(0x40, dst_reg, src_reg));
+
+                       EMIT2(0x39, add_2reg(0xC0, dst_reg, src_reg));
                        goto emit_cond_jmp;
 
                case BPF_JMP | BPF_JSET | BPF_X:
@@ -909,7 +913,10 @@ xadd:                      if (is_imm8(insn->off))
                case BPF_JMP | BPF_JSGE | BPF_K:
                case BPF_JMP | BPF_JSLE | BPF_K:
                        /* cmp dst_reg, imm8/32 */
-                       EMIT1(add_1mod(0x48, dst_reg));
+                       if (!src_reg) /* JMP32 */
+                               EMIT1(add_1mod(0x48, dst_reg));
+                       else if (is_ereg(dst_reg))
+                               EMIT1(add_1mod(0x40, dst_reg));
 
                        if (is_imm8(imm32))
                                EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32);
-- 
2.7.4