diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0096-x86-bpf_jit-small-optimization-in-emit_bpf_tail_call.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0096-x86-bpf_jit-small-optimization-in-emit_bpf_tail_call.patch | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0096-x86-bpf_jit-small-optimization-in-emit_bpf_tail_call.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0096-x86-bpf_jit-small-optimization-in-emit_bpf_tail_call.patch new file mode 100644 index 00000000..28963f0c --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0096-x86-bpf_jit-small-optimization-in-emit_bpf_tail_call.patch @@ -0,0 +1,71 @@ +From 7beac55cc4c612a3e74debd1d82a01f375b5a187 Mon Sep 17 00:00:00 2001 +From: Eric Dumazet <edumazet@google.com> +Date: Mon, 29 Jan 2018 02:48:54 +0100 +Subject: [PATCH 096/103] x86: bpf_jit: small optimization in + emit_bpf_tail_call() + +[ upstream commit 84ccac6e7854ebbfb56d2fc6d5bef9be49bb304c ] + +Saves 4 bytes replacing following instructions : + +lea rax, [rsi + rdx * 8 + offsetof(...)] +mov rax, qword ptr [rax] +cmp rax, 0 + +by : + +mov rax, [rsi + rdx * 8 + offsetof(...)] +test rax, rax + +Signed-off-by: Eric Dumazet <edumazet@google.com> +Cc: Alexei Starovoitov <ast@kernel.org> +Cc: Daniel Borkmann <daniel@iogearbox.net> +Acked-by: Daniel Borkmann <daniel@iogearbox.net> +Acked-by: Alexei Starovoitov <ast@kernel.org> +Signed-off-by: David S. Miller <davem@davemloft.net> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/net/bpf_jit_comp.c | 9 ++++----- + 1 file changed, 4 insertions(+), 5 deletions(-) + +diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c +index 15f7436..ece29e2 100644 +--- a/arch/x86/net/bpf_jit_comp.c ++++ b/arch/x86/net/bpf_jit_comp.c +@@ -281,7 +281,7 @@ static void emit_bpf_tail_call(u8 **pprog) + EMIT4(0x48, 0x8B, 0x46, /* mov rax, qword ptr [rsi + 16] */ + offsetof(struct bpf_array, map.max_entries)); + EMIT3(0x48, 0x39, 0xD0); /* cmp rax, rdx */ +-#define OFFSET1 47 /* number of bytes to jump */ ++#define OFFSET1 43 /* number of bytes to jump */ + EMIT2(X86_JBE, OFFSET1); /* jbe out */ + label1 = cnt; + +@@ -290,21 +290,20 @@ static void emit_bpf_tail_call(u8 **pprog) + */ + EMIT2_off32(0x8B, 0x85, -STACKSIZE + 36); /* mov eax, dword ptr [rbp - 516] */ + EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */ +-#define OFFSET2 36 ++#define OFFSET2 32 + EMIT2(X86_JA, OFFSET2); /* ja out */ + label2 = cnt; + EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */ + EMIT2_off32(0x89, 0x85, -STACKSIZE + 36); /* mov dword ptr [rbp - 516], eax */ + + /* prog = array->ptrs[index]; */ +- EMIT4_off32(0x48, 0x8D, 0x84, 0xD6, /* lea rax, [rsi + rdx * 8 + offsetof(...)] */ ++ EMIT4_off32(0x48, 0x8B, 0x84, 0xD6, /* mov rax, [rsi + rdx * 8 + offsetof(...)] */ + offsetof(struct bpf_array, ptrs)); +- EMIT3(0x48, 0x8B, 0x00); /* mov rax, qword ptr [rax] */ + + /* if (prog == NULL) + * goto out; + */ +- EMIT4(0x48, 0x83, 0xF8, 0x00); /* cmp rax, 0 */ ++ EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */ + #define OFFSET3 10 + EMIT2(X86_JE, OFFSET3); /* je out */ + label3 = cnt; +-- +2.7.4 + |