linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Brendan Jackman <jackmanb@google.com>
To: bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>, Yonghong Song <yhs@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	KP Singh <kpsingh@chromium.org>,
	Florent Revest <revest@chromium.org>,
	linux-kernel@vger.kernel.org, Jann Horn <jannh@google.com>,
	Brendan Jackman <jackmanb@google.com>
Subject: [PATCH v2 bpf-next 03/13] bpf: x86: Factor out function to emit NEG
Date: Fri, 27 Nov 2020 17:57:28 +0000	[thread overview]
Message-ID: <20201127175738.1085417-4-jackmanb@google.com> (raw)
In-Reply-To: <20201127175738.1085417-1-jackmanb@google.com>

There's currently only one usage of this but implementation of
atomic_sub add another.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
 arch/x86/net/bpf_jit_comp.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index a839c1a54276..49dea0c1a130 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -783,6 +783,22 @@ static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
 	*pprog = prog;
 }
 
+
+static void emit_neg(u8 **pprog, u32 reg, bool is64)
+{
+	u8 *prog = *pprog;
+	int cnt = 0;
+
+	/* Emit REX byte if necessary */
+	if (is64)
+		EMIT1(add_1mod(0x48, reg));
+	else if (is_ereg(reg))
+		EMIT1(add_1mod(0x40, reg));
+
+	EMIT2(0xF7, add_1reg(0xD8, reg)); /* x86 NEG */
+	*pprog = prog;
+}
+
 static bool ex_handler_bpf(const struct exception_table_entry *x,
 			   struct pt_regs *regs, int trapnr,
 			   unsigned long error_code, unsigned long fault_addr)
@@ -884,11 +900,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 			/* neg dst */
 		case BPF_ALU | BPF_NEG:
 		case BPF_ALU64 | BPF_NEG:
-			if (BPF_CLASS(insn->code) == BPF_ALU64)
-				EMIT1(add_1mod(0x48, dst_reg));
-			else if (is_ereg(dst_reg))
-				EMIT1(add_1mod(0x40, dst_reg));
-			EMIT2(0xF7, add_1reg(0xD8, dst_reg));
+			emit_neg(&prog, dst_reg,
+				 BPF_CLASS(insn->code) == BPF_ALU64);
 			break;
 
 		case BPF_ALU | BPF_ADD | BPF_K:
-- 
2.29.2.454.gaff20da3a2-goog


  parent reply	other threads:[~2020-11-27 17:58 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-27 17:57 [PATCH v2 bpf-next 00/13] Atomics for eBPF Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 01/13] bpf: x86: Factor out emission of ModR/M for *(reg + off) Brendan Jackman
2020-11-29  1:15   ` Alexei Starovoitov
2020-12-01 12:14     ` Brendan Jackman
2020-12-02  5:50       ` Alexei Starovoitov
2020-12-02 10:52         ` Brendan Jackman
2020-12-02 17:35           ` Alexei Starovoitov
2020-11-27 17:57 ` [PATCH v2 bpf-next 02/13] bpf: x86: Factor out emission of REX byte Brendan Jackman
2020-11-29  1:14   ` Alexei Starovoitov
2020-12-01 12:12     ` Brendan Jackman
2020-12-02  5:48       ` Alexei Starovoitov
2020-12-02 10:54         ` Brendan Jackman
2020-11-27 17:57 ` Brendan Jackman [this message]
2020-11-27 17:57 ` [PATCH v2 bpf-next 04/13] bpf: x86: Factor out a lookup table for some ALU opcodes Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 05/13] bpf: Rename BPF_XADD and prepare to encode other atomics in .imm Brendan Jackman
2020-11-28  3:43   ` Yonghong Song
2020-12-01 12:17     ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 06/13] bpf: Move BPF_STX reserved field check into BPF_STX verifier code Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 07/13] bpf: Add BPF_FETCH field / create atomic_fetch_add instruction Brendan Jackman
2020-11-28  4:15   ` Yonghong Song
2020-12-01 12:22     ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 08/13] bpf: Add instructions for atomic_[cmp]xchg Brendan Jackman
2020-11-28  5:25   ` Yonghong Song
2020-12-01 12:27     ` Brendan Jackman
2020-11-29  1:27   ` Alexei Starovoitov
2020-12-01 12:32     ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 09/13] bpf: Pull out a macro for interpreting atomic ALU operations Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 10/13] bpf: Add instructions for atomic[64]_[fetch_]sub Brendan Jackman
2020-11-27 21:39   ` kernel test robot
2020-11-27 21:39   ` [RFC PATCH] bpf: bpf_atomic_alu_string[] can be static kernel test robot
2020-11-28  5:35   ` [PATCH v2 bpf-next 10/13] bpf: Add instructions for atomic[64]_[fetch_]sub Yonghong Song
2020-11-29  1:34     ` Alexei Starovoitov
2020-11-30 17:18       ` Yonghong Song
2020-12-01 12:38         ` Brendan Jackman
2020-12-02  5:55           ` Alexei Starovoitov
2020-12-02 11:19             ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 11/13] bpf: Add bitwise atomic instructions Brendan Jackman
2020-11-28  5:39   ` Yonghong Song
2020-11-29  1:36     ` Alexei Starovoitov
2020-11-30 17:20       ` Yonghong Song
2020-11-27 17:57 ` [PATCH v2 bpf-next 12/13] bpf: Add tests for new BPF atomic operations Brendan Jackman
2020-12-01  3:55   ` Yonghong Song
2020-12-01 12:56     ` Brendan Jackman
2020-12-01 17:24       ` Yonghong Song
2020-12-02  2:22   ` Andrii Nakryiko
2020-12-02 12:26     ` Brendan Jackman
2020-11-27 17:57 ` [PATCH v2 bpf-next 13/13] bpf: Document new atomic instructions Brendan Jackman
2020-11-28  5:53 ` [PATCH v2 bpf-next 00/13] Atomics for eBPF Yonghong Song
2020-11-29  1:40   ` Alexei Starovoitov
2020-11-30 17:22     ` Yonghong Song
2020-12-01  3:48       ` Yonghong Song
2020-12-02  2:00         ` Andrii Nakryiko
2020-12-02  5:05           ` Yonghong Song
2020-12-02  5:53             ` John Fastabend
2020-12-02  5:59               ` Andrii Nakryiko
2020-12-02  6:27                 ` John Fastabend
2020-12-02  8:03             ` Yonghong Song

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201127175738.1085417-4-jackmanb@google.com \
    --to=jackmanb@google.com \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=jannh@google.com \
    --cc=kpsingh@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=revest@chromium.org \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).