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* [PATCH v3 0/6] powerpc64/bpf: Support tailcalls with subprogs & BPF exceptions
@ 2026-01-22 16:57 adubey
  2026-01-22 16:57 ` [PATCH v3 1/6] powerpc64/bpf : Moving tail_call_cnt to bottom of frame adubey
                   ` (5 more replies)
  0 siblings, 6 replies; 10+ messages in thread
From: adubey @ 2026-01-22 16:57 UTC (permalink / raw)
  To: bpf, linuxppc-dev, linux-kselftest, linux-kernel
  Cc: hbathini, sachinpb, venkat88, andrii, eddyz87, mykolal, ast,
	daniel, martin.lau, song, yonghong.song, john.fastabend, kpsingh,
	sdf, haoluo, jolsa, christophe.leroy, naveen, maddy, mpe, npiggin,
	memxor, iii, shuah, Abhishek Dubey

From: Abhishek Dubey <adubey@linux.ibm.com>

This patch series enables support for two BPF JIT features
on powerpc64. The first three patches target support for
tail calls with subprogram combinations. The first patch
supports realignment of tail_call_cnt offset in stack frame.
Implementation details are provided in the commit messages.

The last three patches add support for BPF exceptions. An
architecture-specific stack walker is implemented to assist
with stack walk during exceptions.

All selftests related to tailcalls and exceptions are passing:

# ./test_progs -t tailcalls
#442/1   tailcalls/tailcall_1:OK
#442/2   tailcalls/tailcall_2:OK
#442/3   tailcalls/tailcall_3:OK
#442/4   tailcalls/tailcall_4:OK
#442/5   tailcalls/tailcall_5:OK
#442/6   tailcalls/tailcall_6:OK
#442/7   tailcalls/tailcall_bpf2bpf_1:OK
#442/8   tailcalls/tailcall_bpf2bpf_2:OK
#442/9   tailcalls/tailcall_bpf2bpf_3:OK
#442/10  tailcalls/tailcall_bpf2bpf_4:OK
#442/11  tailcalls/tailcall_bpf2bpf_5:OK
#442/12  tailcalls/tailcall_bpf2bpf_6:OK
#442/13  tailcalls/tailcall_bpf2bpf_fentry:OK
#442/14  tailcalls/tailcall_bpf2bpf_fexit:OK
#442/15  tailcalls/tailcall_bpf2bpf_fentry_fexit:OK
#442/16  tailcalls/tailcall_bpf2bpf_fentry_entry:OK
#442/17  tailcalls/tailcall_poke:OK
#442/18  tailcalls/tailcall_bpf2bpf_hierarchy_1:OK
#442/19  tailcalls/tailcall_bpf2bpf_hierarchy_fentry:OK
#442/20  tailcalls/tailcall_bpf2bpf_hierarchy_fexit:OK
#442/21  tailcalls/tailcall_bpf2bpf_hierarchy_fentry_fexit:OK
#442/22  tailcalls/tailcall_bpf2bpf_hierarchy_fentry_entry:OK
#442/23  tailcalls/tailcall_bpf2bpf_hierarchy_2:OK
#442/24  tailcalls/tailcall_bpf2bpf_hierarchy_3:OK
#442/25  tailcalls/tailcall_freplace:OK
#442/26  tailcalls/tailcall_bpf2bpf_freplace:OK
#442/27  tailcalls/tailcall_failure:OK
#442/28  tailcalls/reject_tail_call_spin_lock:OK
#442/29  tailcalls/reject_tail_call_rcu_lock:OK
#442/30  tailcalls/reject_tail_call_preempt_lock:OK
#442/31  tailcalls/reject_tail_call_ref:OK
#442     tailcalls:OK
Summary: 1/31 PASSED, 0 SKIPPED, 0 FAILED

# ./test_progs -t exceptions
#105/1   exceptions/exception_throw_always_1:OK
#105/2   exceptions/exception_throw_always_2:OK
#105/3   exceptions/exception_throw_unwind_1:OK
#105/4   exceptions/exception_throw_unwind_2:OK
#105/5   exceptions/exception_throw_default:OK
#105/6   exceptions/exception_throw_default_value:OK
#105/7   exceptions/exception_tail_call:OK
#105/8   exceptions/exception_ext:OK
#105/9   exceptions/exception_ext_mod_cb_runtime:OK
#105/10  exceptions/exception_throw_subprog:OK
#105/11  exceptions/exception_assert_nz_gfunc:OK
#105/12  exceptions/exception_assert_zero_gfunc:OK
#105/13  exceptions/exception_assert_neg_gfunc:OK
#105/14  exceptions/exception_assert_pos_gfunc:OK
#105/15  exceptions/exception_assert_negeq_gfunc:OK
#105/16  exceptions/exception_assert_poseq_gfunc:OK
#105/17  exceptions/exception_assert_nz_gfunc_with:OK
#105/18  exceptions/exception_assert_zero_gfunc_with:OK
#105/19  exceptions/exception_assert_neg_gfunc_with:OK
#105/20  exceptions/exception_assert_pos_gfunc_with:OK
#105/21  exceptions/exception_assert_negeq_gfunc_with:OK
#105/22  exceptions/exception_assert_poseq_gfunc_with:OK
#105/23  exceptions/exception_bad_assert_nz_gfunc:OK
#105/24  exceptions/exception_bad_assert_zero_gfunc:OK
#105/25  exceptions/exception_bad_assert_neg_gfunc:OK
#105/26  exceptions/exception_bad_assert_pos_gfunc:OK
#105/27  exceptions/exception_bad_assert_negeq_gfunc:OK
#105/28  exceptions/exception_bad_assert_poseq_gfunc:OK
#105/29  exceptions/exception_bad_assert_nz_gfunc_with:OK
#105/30  exceptions/exception_bad_assert_zero_gfunc_with:OK
#105/31  exceptions/exception_bad_assert_neg_gfunc_with:OK
#105/32  exceptions/exception_bad_assert_pos_gfunc_with:OK
#105/33  exceptions/exception_bad_assert_negeq_gfunc_with:OK
#105/34  exceptions/exception_bad_assert_poseq_gfunc_with:OK
#105/35  exceptions/exception_assert_range:OK
#105/36  exceptions/exception_assert_range_with:OK
#105/37  exceptions/exception_bad_assert_range:OK
#105/38  exceptions/exception_bad_assert_range_with:OK
#105/39  exceptions/non-throwing fentry -> exception_cb:OK
#105/40  exceptions/throwing fentry -> exception_cb:OK
#105/41  exceptions/non-throwing fexit -> exception_cb:OK
#105/42  exceptions/throwing fexit -> exception_cb:OK
#105/43  exceptions/throwing extension (with custom cb) -> exception_cb:OK
#105/44  exceptions/throwing extension -> global func in exception_cb:OK
#105/45  exceptions/exception_ext_mod_cb_runtime:OK
#105/46  exceptions/throwing extension (with custom cb) -> global func in exception_cb:OK
#105/47  exceptions/exception_ext:OK
#105/48  exceptions/non-throwing fentry -> non-throwing subprog:OK
#105/49  exceptions/throwing fentry -> non-throwing subprog:OK
#105/50  exceptions/non-throwing fentry -> throwing subprog:OK
#105/51  exceptions/throwing fentry -> throwing subprog:OK
#105/52  exceptions/non-throwing fexit -> non-throwing subprog:OK
#105/53  exceptions/throwing fexit -> non-throwing subprog:OK
#105/54  exceptions/non-throwing fexit -> throwing subprog:OK
#105/55  exceptions/throwing fexit -> throwing subprog:OK
#105/56  exceptions/non-throwing fmod_ret -> non-throwing subprog:OK
#105/57  exceptions/non-throwing fmod_ret -> non-throwing global subprog:OK
#105/58  exceptions/non-throwing extension -> non-throwing subprog:OK
#105/59  exceptions/non-throwing extension -> throwing subprog:OK
#105/60  exceptions/non-throwing extension -> non-throwing subprog:OK
#105/61  exceptions/non-throwing extension -> throwing global subprog:OK
#105/62  exceptions/throwing extension -> throwing global subprog:OK
#105/63  exceptions/throwing extension -> non-throwing global subprog:OK
#105/64  exceptions/non-throwing extension -> main subprog:OK
#105/65  exceptions/throwing extension -> main subprog:OK
#105/66  exceptions/reject_exception_cb_type_1:OK
#105/67  exceptions/reject_exception_cb_type_2:OK
#105/68  exceptions/reject_exception_cb_type_3:OK
#105/69  exceptions/reject_exception_cb_type_4:OK
#105/70  exceptions/reject_async_callback_throw:OK
#105/71  exceptions/reject_with_lock:OK
#105/72  exceptions/reject_subprog_with_lock:OK
#105/73  exceptions/reject_with_rcu_read_lock:OK
#105/74  exceptions/reject_subprog_with_rcu_read_lock:OK
#105/75  exceptions/reject_with_rbtree_add_throw:OK
#105/76  exceptions/reject_with_reference:OK
#105/77  exceptions/reject_with_cb_reference:OK
#105/78  exceptions/reject_with_cb:OK
#105/79  exceptions/reject_with_subprog_reference:OK
#105/80  exceptions/reject_throwing_exception_cb:OK
#105/81  exceptions/reject_exception_cb_call_global_func:OK
#105/82  exceptions/reject_exception_cb_call_static_func:OK
#105/83  exceptions/reject_multiple_exception_cb:OK
#105/84  exceptions/reject_exception_throw_cb:OK
#105/85  exceptions/reject_exception_throw_cb_diff:OK
#105/86  exceptions/reject_set_exception_cb_bad_ret1:OK
#105/87  exceptions/reject_set_exception_cb_bad_ret2:OK
#105/88  exceptions/check_assert_eq_int_min:OK
#105/89  exceptions/check_assert_eq_int_max:OK
#105/90  exceptions/check_assert_eq_zero:OK
#105/91  exceptions/check_assert_eq_llong_min:OK
#105/92  exceptions/check_assert_eq_llong_max:OK
#105/93  exceptions/check_assert_lt_pos:OK
#105/94  exceptions/check_assert_lt_zero:OK
#105/95  exceptions/check_assert_lt_neg:OK
#105/96  exceptions/check_assert_le_pos:OK
#105/97  exceptions/check_assert_le_zero:OK
#105/98  exceptions/check_assert_le_neg:OK
#105/99  exceptions/check_assert_gt_pos:OK
#105/100 exceptions/check_assert_gt_zero:OK
#105/101 exceptions/check_assert_gt_neg:OK
#105/102 exceptions/check_assert_ge_pos:OK
#105/103 exceptions/check_assert_ge_zero:OK
#105/104 exceptions/check_assert_ge_neg:OK
#105/105 exceptions/check_assert_range_s64:OK
#105/106 exceptions/check_assert_range_u64:OK
#105/107 exceptions/check_assert_single_range_s64:OK
#105/108 exceptions/check_assert_single_range_u64:OK
#105/109 exceptions/check_assert_generic:OK
#105/110 exceptions/check_assert_with_return:OK
#105     exceptions:OK
Summary: 1/110 PASSED, 0 SKIPPED, 0 FAILED

[v1]: https://lore.kernel.org/all/20260105105212.136645-1-adubey@linux.ibm.com/
[v2]: https://lore.kernel.org/all/20260114114450.30405-1-adubey@linux.ibm.com/

Changes v1->v2:
        Move tail_call_cnt to offset 0 in stack frame
        Remove trampoline NVR remapping-patch3/6[v1]
Changes v2->v3:
	Added PPC_BCC_CONST_SHORT for short jumps of constant offset
	Optimize tailcall allocation for BPF_TRAMP_F_CALL_ORIG flag
	New helper for stack size calculation during exceptions
	Prologue JIT optimizations during non exception prog case

Abhishek Dubey (6):
  powerpc64/bpf : Moving tail_call_cnt to bottom of frame
  powerpc64/bpf: Support tailcalls with subprogs
  powerpc64/bpf: Avoid tailcall restore from trampoline
  powerpc64/bpf: Add arch_bpf_stack_walk() for BPF JIT
  powerpc64/bpf: Support exceptions
  powerpc64/bpf: Additional NVR handling for bpf_throw

 arch/powerpc/net/bpf_jit.h        |  16 ++
 arch/powerpc/net/bpf_jit_comp.c   |  90 ++++++++--
 arch/powerpc/net/bpf_jit_comp64.c | 262 ++++++++++++++++++++++++------
 3 files changed, 303 insertions(+), 65 deletions(-)

-- 
2.48.1



^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2026-01-22 17:32 UTC | newest]

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2026-01-22 16:57 [PATCH v3 0/6] powerpc64/bpf: Support tailcalls with subprogs & BPF exceptions adubey
2026-01-22 16:57 ` [PATCH v3 1/6] powerpc64/bpf : Moving tail_call_cnt to bottom of frame adubey
2026-01-22 17:20   ` bot+bpf-ci
2026-01-22 16:57 ` [PATCH v3 2/6] powerpc64/bpf: Support tailcalls with subprogs adubey
2026-01-22 16:57 ` [PATCH v3 3/6] powerpc64/bpf: Avoid tailcall restore from trampoline adubey
2026-01-22 17:20   ` bot+bpf-ci
2026-01-22 16:57 ` [PATCH v3 4/6] powerpc64/bpf: Add arch_bpf_stack_walk() for BPF JIT adubey
2026-01-22 16:57 ` [PATCH v3 5/6] powerpc64/bpf: Support exceptions adubey
2026-01-22 16:57 ` [PATCH v3 6/6] powerpc64/bpf: Additional NVR handling for bpf_throw adubey
2026-01-22 17:32   ` bot+bpf-ci

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