From: Xu Kuohai <xukuohai@huawei.com>
To: <bpf@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Will Deacon <will@kernel.org>, KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Zi Shen Lim <zlim.lnx@gmail.com>, Martin KaFai Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
David Ahern <dsahern@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>,
"H . Peter Anvin" <hpa@zytor.com>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Russell King <rmk+kernel@armlinux.org.uk>,
James Morse <james.morse@arm.com>, Hou Tao <houtao1@huawei.com>,
Jason Wang <wangborong@cdjrlc.com>
Subject: [PATCH bpf-next v8 1/4] bpf: Remove is_valid_bpf_tramp_flags()
Date: Mon, 11 Jul 2022 10:47:19 -0400 [thread overview]
Message-ID: <20220711144722.2100039-2-xukuohai@huawei.com> (raw)
In-Reply-To: <20220711144722.2100039-1-xukuohai@huawei.com>
Before generating bpf trampoline, x86 calls is_valid_bpf_tramp_flags()
to check the input flags. This check is architecture independent.
So, to be consistent with x86, arm64 should also do this check
before generating bpf trampoline.
However, the BPF_TRAMP_F_XXX flags are not used by user code and the
flags argument is almost constant at compile time, so this run time
check is a bit redundant.
Remove is_valid_bpf_tramp_flags() and add some comments to the usage of
BPF_TRAMP_F_XXX flags, as suggested by Alexei.
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Acked-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
arch/x86/net/bpf_jit_comp.c | 20 --------------------
kernel/bpf/bpf_struct_ops.c | 3 +++
kernel/bpf/trampoline.c | 3 +++
3 files changed, 6 insertions(+), 20 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index b88f43c9f050..d2614f1bf838 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1936,23 +1936,6 @@ static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog,
return 0;
}
-static bool is_valid_bpf_tramp_flags(unsigned int flags)
-{
- if ((flags & BPF_TRAMP_F_RESTORE_REGS) &&
- (flags & BPF_TRAMP_F_SKIP_FRAME))
- return false;
-
- /*
- * BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops,
- * and it must be used alone.
- */
- if ((flags & BPF_TRAMP_F_RET_FENTRY_RET) &&
- (flags & ~BPF_TRAMP_F_RET_FENTRY_RET))
- return false;
-
- return true;
-}
-
/* Example:
* __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
* its 'struct btf_func_model' will be nr_args=2
@@ -2031,9 +2014,6 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
if (nr_args > 6)
return -ENOTSUPP;
- if (!is_valid_bpf_tramp_flags(flags))
- return -EINVAL;
-
/* Generated trampoline stack layout:
*
* RBP + 8 [ return address ]
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 7e0068c3399c..84b2d9dba79a 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -341,6 +341,9 @@ int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks,
tlinks[BPF_TRAMP_FENTRY].links[0] = link;
tlinks[BPF_TRAMP_FENTRY].nr_links = 1;
+ /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops,
+ * and it must be used alone.
+ */
flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0;
return arch_prepare_bpf_trampoline(NULL, image, image_end,
model, flags, tlinks, NULL);
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 6cd226584c33..fd69812412ca 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -360,6 +360,9 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr)
if (tlinks[BPF_TRAMP_FEXIT].nr_links ||
tlinks[BPF_TRAMP_MODIFY_RETURN].nr_links)
+ /* NOTE: BPF_TRAMP_F_RESTORE_REGS and BPF_TRAMP_F_SKIP_FRAME
+ * should not be set together.
+ */
flags = BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME;
if (ip_arg)
--
2.30.2
next prev parent reply other threads:[~2022-07-11 14:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-11 14:47 [PATCH bpf-next v8 0/4] bpf trampoline for arm64 Xu Kuohai
2022-07-11 14:47 ` Xu Kuohai [this message]
2022-07-11 14:47 ` [PATCH bpf-next v8 2/4] arm64: Add LDR (literal) instruction Xu Kuohai
2022-07-11 14:47 ` [PATCH bpf-next v8 3/4] bpf, arm64: Implement bpf_arch_text_poke() for arm64 Xu Kuohai
2022-07-11 14:47 ` [PATCH bpf-next v8 4/4] bpf, arm64: bpf trampoline " Xu Kuohai
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=20220711144722.2100039-2-xukuohai@huawei.com \
--to=xukuohai@huawei.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bp@alien8.de \
--cc=bpf@vger.kernel.org \
--cc=catalin.marinas@arm.com \
--cc=daniel@iogearbox.net \
--cc=dave.hansen@linux.intel.com \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=hawk@kernel.org \
--cc=houtao1@huawei.com \
--cc=hpa@zytor.com \
--cc=james.morse@arm.com \
--cc=jean-philippe@linaro.org \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kpsingh@kernel.org \
--cc=kuba@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=rmk+kernel@armlinux.org.uk \
--cc=songliubraving@fb.com \
--cc=tglx@linutronix.de \
--cc=wangborong@cdjrlc.com \
--cc=will@kernel.org \
--cc=x86@kernel.org \
--cc=yhs@fb.com \
--cc=yoshfuji@linux-ipv6.org \
--cc=zlim.lnx@gmail.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).