From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH bpf-next v2 05/11] s390/bpf: Land on the next JITed instruction after exception
Date: Mon, 1 Jul 2024 15:24:43 +0200 [thread overview]
Message-ID: <20240701133432.3883-6-iii@linux.ibm.com> (raw)
In-Reply-To: <20240701133432.3883-1-iii@linux.ibm.com>
Currently we land on the nop, which is unnecessary: we can just as well
begin executing the next instruction. Furthermore, the upcoming arena
support for the loop-based BPF_XCHG implementation will require landing
on an instruction that comes after the loop.
So land on the next JITed instruction, which covers both cases.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
arch/s390/net/bpf_jit_comp.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 582fa3830772..ecd53f8f0602 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -747,10 +747,11 @@ static int bpf_jit_probe_post(struct bpf_jit *jit, struct bpf_prog *fp,
return -1;
ex->insn = delta;
/*
- * Always land on the nop. Note that extable infrastructure
- * ignores fixup field, it is handled by ex_handler_bpf().
+ * Land on the current instruction. Note that the extable
+ * infrastructure ignores the fixup field; it is handled by
+ * ex_handler_bpf().
*/
- delta = jit->prg_buf + probe->nop_prg - (u8 *)&ex->fixup;
+ delta = jit->prg_buf + jit->prg - (u8 *)&ex->fixup;
if (WARN_ON_ONCE(delta < INT_MIN || delta > INT_MAX))
/* JIT bug - landing pad and extable must be close. */
return -1;
--
2.45.2
next prev parent reply other threads:[~2024-07-01 13:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-01 13:24 [PATCH bpf-next v2 00/11] s390/bpf: Implement arena Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 01/11] bpf: Fix atomic probe zero-extension Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 02/11] s390/bpf: Factor out emitting probe nops Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 03/11] s390/bpf: Get rid of get_probe_mem_regno() Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 04/11] s390/bpf: Introduce pre- and post- probe functions Ilya Leoshkevich
2024-07-01 13:24 ` Ilya Leoshkevich [this message]
2024-07-01 13:24 ` [PATCH bpf-next v2 06/11] s390/bpf: Support BPF_PROBE_MEM32 Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 07/11] s390/bpf: Support address space cast instruction Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 08/11] s390/bpf: Enable arena Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 09/11] s390/bpf: Support arena atomics Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 10/11] selftests/bpf: Add UAF tests for " Ilya Leoshkevich
2024-07-01 15:22 ` Daniel Borkmann
2024-07-01 17:02 ` Ilya Leoshkevich
2024-07-01 13:24 ` [PATCH bpf-next v2 11/11] selftests/bpf: Remove arena tests from DENYLIST.s390x Ilya Leoshkevich
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