From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Yonghong Song <yonghong.song@linux.dev>,
David Vernet <void@manifault.com>,
Puranjay Mohan <puranjay12@gmail.com>
Subject: [PATCH bpf-next v3 01/17] bpf: Use bpf_is_subprog to check for subprogs
Date: Wed, 13 Sep 2023 01:31:58 +0200 [thread overview]
Message-ID: <20230912233214.1518551-2-memxor@gmail.com> (raw)
In-Reply-To: <20230912233214.1518551-1-memxor@gmail.com>
We would like to know whether a bpf_prog corresponds to the main prog or
one of the subprogs. The current JIT implementations simply check this
using the func_idx in bpf_prog->aux->func_idx. When the index is 0, it
belongs to the main program, otherwise it corresponds to some
subprogram.
This will also be necessary to halt exception propagation while walking
the stack when an exception is thrown, so we add a simple helper
function to check this, named bpf_is_subprog, and convert existing JIT
implementations to also make use of it.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
arch/arm64/net/bpf_jit_comp.c | 2 +-
arch/s390/net/bpf_jit_comp.c | 2 +-
arch/x86/net/bpf_jit_comp.c | 2 +-
include/linux/bpf.h | 5 +++++
4 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 150d1c6543f7..7d4af64e3982 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -288,7 +288,7 @@ static bool is_lsi_offset(int offset, int scale)
static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf)
{
const struct bpf_prog *prog = ctx->prog;
- const bool is_main_prog = prog->aux->func_idx == 0;
+ const bool is_main_prog = !bpf_is_subprog(prog);
const u8 r6 = bpf2a64[BPF_REG_6];
const u8 r7 = bpf2a64[BPF_REG_7];
const u8 r8 = bpf2a64[BPF_REG_8];
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index de2fb12120d2..eeb42e5cd7d6 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -556,7 +556,7 @@ static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp,
EMIT6_PCREL_RILC(0xc0040000, 0, jit->prologue_plt);
jit->prologue_plt_ret = jit->prg;
- if (fp->aux->func_idx == 0) {
+ if (!bpf_is_subprog(fp)) {
/* Initialize the tail call counter in the main program. */
/* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */
_EMIT6(0xd703f000 | STK_OFF_TCCNT, 0xf000 | STK_OFF_TCCNT);
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 2846c21d75bf..a0d03503b3cb 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1049,7 +1049,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image
emit_prologue(&prog, bpf_prog->aux->stack_depth,
bpf_prog_was_classic(bpf_prog), tail_call_reachable,
- bpf_prog->aux->func_idx != 0);
+ bpf_is_subprog(bpf_prog));
push_callee_regs(&prog, callee_regs_used);
ilen = prog - temp;
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index b9e573159432..9171b0b6a590 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -3194,4 +3194,9 @@ static inline gfp_t bpf_memcg_flags(gfp_t flags)
return flags;
}
+static inline bool bpf_is_subprog(const struct bpf_prog *prog)
+{
+ return prog->aux->func_idx != 0;
+}
+
#endif /* _LINUX_BPF_H */
--
2.41.0
next prev parent reply other threads:[~2023-09-12 23:32 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-12 23:31 [PATCH bpf-next v3 00/17] Exceptions - 1/2 Kumar Kartikeya Dwivedi
2023-09-12 23:31 ` Kumar Kartikeya Dwivedi [this message]
2023-09-12 23:31 ` [PATCH bpf-next v3 02/17] arch/x86: Implement arch_bpf_stack_walk Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 03/17] bpf: Implement support for adding hidden subprogs Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 04/17] bpf: Implement BPF exceptions Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 05/17] bpf: Refactor check_btf_func and split into two phases Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 06/17] bpf: Add support for custom exception callbacks Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 07/17] bpf: Perform CFG walk for exception callback Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 08/17] bpf: Treat first argument as return value for bpf_throw Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 09/17] mm: kasan: Declare kasan_unpoison_task_stack_below in kasan.h Kumar Kartikeya Dwivedi
2023-09-16 16:24 ` Andrey Konovalov
2023-09-12 23:32 ` [PATCH bpf-next v3 10/17] bpf: Prevent KASAN false positive with bpf_throw Kumar Kartikeya Dwivedi
2023-09-16 16:25 ` Andrey Konovalov
2023-09-18 13:20 ` Matthieu Baerts
2023-09-18 13:26 ` Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 11/17] bpf: Detect IP == ksym.end as part of BPF program Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 12/17] bpf: Disallow fentry/fexit/freplace for exception callbacks Kumar Kartikeya Dwivedi
2023-09-13 15:24 ` Puranjay Mohan
2023-09-14 12:13 ` Kumar Kartikeya Dwivedi
2023-09-16 16:44 ` Alexei Starovoitov
2023-09-16 17:30 ` Kumar Kartikeya Dwivedi
2023-09-16 19:34 ` Kumar Kartikeya Dwivedi
2023-09-18 1:56 ` Alexei Starovoitov
2023-09-12 23:32 ` [PATCH bpf-next v3 13/17] bpf: Fix kfunc callback register type handling Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 14/17] libbpf: Refactor bpf_object__reloc_code Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 15/17] libbpf: Add support for custom exception callbacks Kumar Kartikeya Dwivedi
2023-09-20 0:25 ` Andrii Nakryiko
2023-09-20 1:02 ` Kumar Kartikeya Dwivedi
2023-09-20 17:08 ` Andrii Nakryiko
2023-09-12 23:32 ` [PATCH bpf-next v3 16/17] selftests/bpf: Add BPF assertion macros Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 17/17] selftests/bpf: Add tests for BPF exceptions Kumar Kartikeya Dwivedi
2023-09-13 15:14 ` Puranjay Mohan
2023-09-13 16:12 ` Puranjay Mohan
2023-09-12 23:37 ` [PATCH bpf-next v3 00/17] Exceptions - 1/2 Kumar Kartikeya Dwivedi
2023-09-12 23:53 ` Puranjay Mohan
2023-09-16 16:50 ` patchwork-bot+netdevbpf
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