[PATCH bpf-next v1 6/7] bpf, s390: Use resolved pointer for timed may_goto
From: Siddharth Chintamaneni <hidden>
Date: 2026-09-04 19:51:56
Also in:
bpf, linux-riscv, linux-s390
Subsystem:
bpf jit for s390, bpf [general] (safe dynamic programs and tools), s390 architecture, the rest · Maintainers:
Ilya Leoshkevich, Heiko Carstens, Vasily Gorbik, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Alexander Gordeev, Linus Torvalds
The timed may_goto fixup now passes the resolved counter pointer through
BPF_REG_AX instead of a stack offset and BPF frame pointer pair.
Copy the pointer directly into the first argument register and update the
special calling convention documentation.
Fixes: b8efa810c1db ("s390/bpf: Add s390 JIT support for timed may_goto")
Reported-by: Jeremy Jean <redacted>
Link: https://lore.kernel.org/all/20260824213158.3755932-2-Jeremy.Jean@oss.cyber.gouv.fr/ (local)
Assisted-by: Copilot:gpt-5.6-sol
Signed-off-by: Siddharth Chintamaneni <redacted>
---
arch/s390/net/bpf_jit_comp.c | 6 +++---
arch/s390/net/bpf_timed_may_goto.S | 8 ++++----
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index c46872b071ce..4098c3377c21 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c@@ -1872,9 +1872,9 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, if ((void *)func == arch_bpf_timed_may_goto) { /* * arch_bpf_timed_may_goto() has a special ABI: the - * parameters are in BPF_REG_AX and BPF_REG_10; the - * return value is in BPF_REG_AX; and all GPRs except - * REG_W0, REG_W1, and BPF_REG_AX are callee-saved. + * parameter and return value are in BPF_REG_AX; all + * GPRs except REG_W0, REG_W1, and BPF_REG_AX are + * callee-saved. */ /* brasl %r0,func */
diff --git a/arch/s390/net/bpf_timed_may_goto.S b/arch/s390/net/bpf_timed_may_goto.S
index 06f567a460d7..e34c99982c4a 100644
--- a/arch/s390/net/bpf_timed_may_goto.S
+++ b/arch/s390/net/bpf_timed_may_goto.S@@ -21,9 +21,9 @@ SYM_FUNC_START(arch_bpf_timed_may_goto) /* - * This function has a special ABI: the parameters are in %r12 and - * %r13; the return value is in %r12; all GPRs except %r0, %r1, and - * %r12 are callee-saved; and the return address is in %r0. + * This function has a special ABI: the parameter and return value are + * in %r12; all GPRs except %r0, %r1, and %r12 are callee-saved; and + * the return address is in %r0. */ stmg %r2,%r5,FRAME_OFF+R2_OFF(%r15) stg %r14,FRAME_OFF+R14_OFF(%r15)
@@ -33,7 +33,7 @@ SYM_FUNC_START(arch_bpf_timed_may_goto) lay %r15,-FRAME_SIZE(%r15) stg %r1,__SF_BACKCHAIN(%r15) - lay %r2,0(%r12,%r13) + lgr %r2,%r12 brasl %r14,bpf_check_timed_may_goto lgr %r12,%r2
--
2.43.0