From: Michael Ellerman <mpe@ellerman.id.au>
To: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
netdev@vger.kernel.org, Matt Evans <matt@ozlabs.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <ast@fb.com>,
Denis Kirjanov <kda@linux-powerpc.org>,
Paul Mackerras <paulus@samba.org>,
"David S. Miller" <davem@davemloft.net>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Subject: Re: [PATCH] ppc: Fix BPF JIT for ABIv2
Date: Wed, 22 Jun 2016 15:18:10 +1000 [thread overview]
Message-ID: <1466572690.19785.4.camel@ellerman.id.au> (raw)
In-Reply-To: <20160617130042.GO3516@indiana.gru.redhat.com>
On Fri, 2016-06-17 at 10:00 -0300, Thadeu Lima de Souza Cascardo wrote:
> From a984dc02b6317a1d3a3c2302385adba5227be5bd Mon Sep 17 00:00:00 2001
> From: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
> Date: Wed, 15 Jun 2016 13:22:12 -0300
> Subject: [PATCH] ppc: Fix BPF JIT for ABIv2
>
> ABIv2 used for ppc64le does not use function descriptors. Without this patch,
> whenever BPF JIT is enabled, we get a crash as below.
>
...
> diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
> index 889fd19..28b89ed 100644
> --- a/arch/powerpc/net/bpf_jit.h
> +++ b/arch/powerpc/net/bpf_jit.h
> @@ -70,7 +70,7 @@ DECLARE_LOAD_FUNC(sk_load_half);
> DECLARE_LOAD_FUNC(sk_load_byte);
> DECLARE_LOAD_FUNC(sk_load_byte_msh);
>
> -#ifdef CONFIG_PPC64
> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF != 2)
> #define FUNCTION_DESCR_SIZE 24
> #else
> #define FUNCTION_DESCR_SIZE 0
> diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
> index 2d66a84..035b887 100644
> --- a/arch/powerpc/net/bpf_jit_comp.c
> +++ b/arch/powerpc/net/bpf_jit_comp.c
> @@ -664,7 +664,7 @@ void bpf_jit_compile(struct bpf_prog *fp)
>
> if (image) {
> bpf_flush_icache(code_base, code_base + (proglen/4));
> -#ifdef CONFIG_PPC64
> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF != 2)
> /* Function descriptor nastiness: Address + TOC */
> ((u64 *)image)[0] = (u64)code_base;
> ((u64 *)image)[1] = local_paca->kernel_toc;
Confirmed that even with this patch we still crash:
# echo 1 > /proc/sys/net/core/bpf_jit_enable
# modprobe test_bpf
BPF filter opcode 0020 (@3) unsupported
BPF filter opcode 0020 (@2) unsupported
BPF filter opcode 0020 (@0) unsupported
Unable to handle kernel paging request for data at address 0xd0000000054f65e8
Faulting instruction address: 0xc0000000008765f8
cpu 0x0: Vector: 300 (Data Access) at [c0000000034f3480]
pc: c0000000008765f8: skb_copy_bits+0x158/0x330
lr: c00000000008fb7c: bpf_slow_path_byte+0x28/0x54
sp: c0000000034f3700
msr: 800000010280b033
dar: d0000000054f65e8
dsisr: 40000000
current = 0xc0000001f857d8d0
paca = 0xc000000007b80000 softe: 0 irq_happened: 0x01
pid = 2993, comm = modprobe
Linux version 4.7.0-rc3-00055-g9497a1c1c5b4-dirty (michael@ka3.ozlabs.ibm.com) () #30 SMP Wed Jun 22 15:06:58 AEST 2016
enter ? for help
[c0000000034f3770] c00000000008fb7c bpf_slow_path_byte+0x28/0x54
[c0000000034f37e0] d000000007bb004c
[c0000000034f3900] d000000005331668 test_bpf_init+0x5fc/0x7f8 [test_bpf]
[c0000000034f3a30] c00000000000b628 do_one_initcall+0x68/0x1d0
[c0000000034f3af0] c0000000009beb24 do_init_module+0x90/0x240
[c0000000034f3b80] c0000000001642bc load_module+0x206c/0x22f0
[c0000000034f3d30] c0000000001648b0 SyS_finit_module+0x120/0x180
[c0000000034f3e30] c000000000009260 system_call+0x38/0x108
--- Exception: c01 (System Call) at 00003fff7ffa2db4
cheers
next prev parent reply other threads:[~2016-06-22 5:19 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 13:32 [PATCH 0/6] eBPF JIT for PPC64 Naveen N. Rao
2016-06-07 13:32 ` [PATCH 1/6] ppc: bpf/jit: Fix/enhance 32-bit Load Immediate implementation Naveen N. Rao
2016-06-07 13:32 ` [PATCH 2/6] ppc: bpf/jit: Optimize 64-bit Immediate loads Naveen N. Rao
2016-06-07 13:32 ` [PATCH 3/6] ppc: bpf/jit: Introduce rotate immediate instructions Naveen N. Rao
2016-06-07 13:32 ` [PATCH 4/6] ppc: bpf/jit: A few cleanups Naveen N. Rao
2016-06-07 13:32 ` [PATCH 5/6] ppc: bpf/jit: Isolate classic BPF JIT specifics into a separate header Naveen N. Rao
2016-06-07 13:32 ` [PATCH 6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF Naveen N. Rao
2016-06-07 22:56 ` Alexei Starovoitov
2016-06-08 17:17 ` Naveen N. Rao
2016-06-09 3:19 ` Nilay Vaish
2016-06-09 6:07 ` Naveen N. Rao
2016-06-17 12:53 ` [6/6] " Michael Ellerman
2016-06-17 13:00 ` [PATCH] ppc: Fix BPF JIT for ABIv2 Thadeu Lima de Souza Cascardo
2016-06-19 17:49 ` Naveen N. Rao
2016-06-20 18:56 ` Thadeu Lima de Souza Cascardo
2016-06-21 8:58 ` Naveen N. Rao
2016-06-21 11:15 ` Michael Ellerman
2016-06-21 14:47 ` Thadeu Lima de Souza Cascardo
2016-06-21 15:45 ` Alexei Starovoitov
2016-06-22 4:06 ` Michael Ellerman
2016-06-22 7:12 ` Naveen N. Rao
2016-06-22 14:57 ` Naveen N. Rao
2016-06-22 5:20 ` Michael Ellerman
2016-06-22 5:18 ` Michael Ellerman [this message]
2016-06-19 17:36 ` [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF Naveen N. Rao
2016-06-20 23:38 ` Michael Ellerman
2016-06-21 6:58 ` Naveen N. Rao
2016-06-21 11:04 ` Michael Ellerman
2016-06-22 7:06 ` Naveen N. Rao
2016-06-22 10:37 ` [PATCH 6/6] " Michael Ellerman
2016-06-22 12:32 ` Naveen N. Rao
2016-06-11 5:47 ` [PATCH 0/6] eBPF JIT for PPC64 David Miller
2016-06-13 5:40 ` Naveen N. Rao
2016-06-18 4:57 ` mpe
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