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Re: [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF

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  Re: [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF Michael Ellerman <mpe@ellerman.id.au> - 2016-06-17 15:00 +0200
    [PATCH] ppc: Fix BPF JIT for ABIv2 Thadeu Lima de Souza Cascardo <cascardo@redhat.com> - 2016-06-17 15:10 +0200
      Re: [PATCH] ppc: Fix BPF JIT for ABIv2 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-06-19 20:00 +0200
        Re: [PATCH] ppc: Fix BPF JIT for ABIv2 Thadeu Lima de Souza Cascardo <cascardo@redhat.com> - 2016-06-20 21:20 +0200
          Re: [PATCH] ppc: Fix BPF JIT for ABIv2 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-06-21 12:40 +0200
            Re: [PATCH] ppc: Fix BPF JIT for ABIv2 Michael Ellerman <mpe@ellerman.id.au> - 2016-06-21 13:40 +0200
              Re: [PATCH] ppc: Fix BPF JIT for ABIv2 Thadeu Lima de Souza Cascardo <cascardo@redhat.com> - 2016-06-21 17:00 +0200
                Re: [PATCH] ppc: Fix BPF JIT for ABIv2 Michael Ellerman <mpe@ellerman.id.au> - 2016-06-22 06:10 +0200
                Re: [PATCH] ppc: Fix BPF JIT for ABIv2 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-06-22 09:20 +0200
                  Re: [PATCH] ppc: Fix BPF JIT for ABIv2 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-06-22 17:00 +0200
            Re: [PATCH] ppc: Fix BPF JIT for ABIv2 Michael Ellerman <mpe@ellerman.id.au> - 2016-06-22 07:30 +0200
      Re: [PATCH] ppc: Fix BPF JIT for ABIv2 Michael Ellerman <mpe@ellerman.id.au> - 2016-06-22 07:20 +0200
    Re: [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-06-19 19:40 +0200
      Re: [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF Michael Ellerman <mpe@ellerman.id.au> - 2016-06-21 01:50 +0200
        Re: [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-06-21 09:10 +0200
          Re: [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF Michael Ellerman <mpe@ellerman.id.au> - 2016-06-21 13:20 +0200
            Re: [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> - 2016-06-22 09:10 +0200

#1425043 — Re: [6/6] ppc: ebpf/jit: Implement JIT compiler for extended BPF

On Tue, 2016-07-06 at 13:32:23 UTC, "Naveen N. Rao" wrote:
> diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> new file mode 100644
> index 0000000..954ff53
> --- /dev/null
> +++ b/arch/powerpc/net/bpf_jit_comp64.c
> @@ -0,0 +1,956 @@
...
> +
> +static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> +{
> +	int *p = area;
> +
> +	/* Fill whole space with trap instructions */
> +	while (p < (int *)((char *)area + size))
> +		*p++ = BREAKPOINT_INSTRUCTION;
> +}

This breaks the build for some configs, presumably you're missing a header:

  arch/powerpc/net/bpf_jit_comp64.c:30:10: error: 'BREAKPOINT_INSTRUCTION' undeclared (first use in this function)

http://kisskb.ellerman.id.au/kisskb/buildresult/12720611/

cheers

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#1425052 — [PATCH] ppc: Fix BPF JIT for ABIv2

On Fri, Jun 17, 2016 at 10:53:21PM +1000, Michael Ellerman wrote:
> On Tue, 2016-07-06 at 13:32:23 UTC, "Naveen N. Rao" wrote:
> > diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> > new file mode 100644
> > index 0000000..954ff53
> > --- /dev/null
> > +++ b/arch/powerpc/net/bpf_jit_comp64.c
> > @@ -0,0 +1,956 @@
> ...
> > +
> > +static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> > +{
> > +	int *p = area;
> > +
> > +	/* Fill whole space with trap instructions */
> > +	while (p < (int *)((char *)area + size))
> > +		*p++ = BREAKPOINT_INSTRUCTION;
> > +}
> 
> This breaks the build for some configs, presumably you're missing a header:
> 
>   arch/powerpc/net/bpf_jit_comp64.c:30:10: error: 'BREAKPOINT_INSTRUCTION' undeclared (first use in this function)
> 
> http://kisskb.ellerman.id.au/kisskb/buildresult/12720611/
> 
> cheers

Hi, Michael and Naveen.

I noticed independently that there is a problem with BPF JIT and ABIv2, and
worked out the patch below before I noticed Naveen's patchset and the latest
changes in ppc tree for a better way to check for ABI versions.

However, since the issue described below affect mainline and stable kernels,
would you consider applying it before merging your two patchsets, so that we can
more easily backport the fix?

Thanks.
Cascardo.

---
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.

[root@ibm-p8-kvm-05-guest-02 ~]# echo 2 > /proc/sys/net/core/bpf_jit_enable
[root@ibm-p8-kvm-05-guest-02 ~]# tcpdump -n -i eth0 tcp port 22
device eth0 entered promiscuous mode
Pass 1: shrink = 0, seen = 0x0
Pass 2: shrink = 0, seen = 0x0
flen=1 proglen=8 pass=3 image=d000000005bb9018 from=tcpdump pid=11387
JIT code: 00000000: 00 00 60 38 20 00 80 4e
Pass 1: shrink = 0, seen = 0x30000
Pass 2: shrink = 0, seen = 0x30000
flen=20 proglen=524 pass=3 image=d000000005bbd018 from=tcpdump pid=11387
JIT code: 00000000: a6 02 08 7c 10 00 01 f8 70 ff c1 f9 78 ff e1 f9
JIT code: 00000010: e1 fe 21 f8 7c 00 e3 80 78 00 e3 81 50 78 e7 7d
JIT code: 00000020: c8 00 c3 e9 00 00 a0 38 00 c0 e0 3c c6 07 e7 78
JIT code: 00000030: 08 00 e7 64 54 1b e7 60 a6 03 e8 7c 0c 00 c0 38
JIT code: 00000040: 21 00 80 4e b0 01 80 41 00 00 00 60 dd 86 e0 38
JIT code: 00000050: 01 00 e7 3c 40 38 04 7c 9c 00 82 40 00 00 00 60
JIT code: 00000060: 00 c0 e0 3c c6 07 e7 78 08 00 e7 64 70 1b e7 60
JIT code: 00000070: a6 03 e8 7c 14 00 c0 38 21 00 80 4e 78 01 80 41
JIT code: 00000080: 00 00 00 60 06 00 04 28 68 01 82 40 00 00 00 60
JIT code: 00000090: 00 c0 e0 3c c6 07 e7 78 08 00 e7 64 54 1b e7 60
JIT code: 000000a0: a6 03 e8 7c 36 00 c0 38 21 00 80 4e 48 01 80 41
JIT code: 000000b0: 00 00 00 60 16 00 04 28 2c 01 82 41 00 00 00 60
JIT code: 000000c0: 00 c0 e0 3c c6 07 e7 78 08 00 e7 64 54 1b e7 60
JIT code: 000000d0: a6 03 e8 7c 38 00 c0 38 21 00 80 4e 18 01 80 41
JIT code: 000000e0: 00 00 00 60 16 00 04 28 fc 00 82 41 00 00 00 60
JIT code: 000000f0: 00 01 00 48 00 08 04 28 f8 00 82 40 00 00 00 60
JIT code: 00000100: 00 c0 e0 3c c6 07 e7 78 08 00 e7 64 70 1b e7 60
JIT code: 00000110: a6 03 e8 7c 17 00 c0 38 21 00 80 4e d8 00 80 41
JIT code: 00000120: 00 00 00 60 06 00 04 28 c8 00 82 40 00 00 00 60
JIT code: 00000130: 00 c0 e0 3c c6 07 e7 78 08 00 e7 64 54 1b e7 60
JIT code: 00000140: a6 03 e8 7c 14 00 c0 38 21 00 80 4e a8 00 80 41
JIT code: 00000150: 00 00 00 60 ff 1f 87 70 98 00 82 40 00 00 00 60
JIT code: 00000160: 00 c0 e0 3c c6 07 e7 78 08 00 e7 64 88 1b e7 60
JIT code: 00000170: a6 03 e8 7c 0e 00 c0 38 21 00 80 4e 78 00 80 41
JIT code: 00000180: 00 00 00 60 00 c0 e0 3c c6 07 e7 78 08 00 e7 64
JIT code: 00000190: 4c 1b e7 60 a6 03 e8 7c 0e 00 c5 38 21 00 80 4e
JIT code: 000001a0: 54 00 80 41 00 00 00 60 16 00 04 28 38 00 82 41
JIT code: 000001b0: 00 00 00 60 00 c0 e0 3c c6 07 e7 78 08 00 e7 64
JIT code: 000001c0: 4c 1b e7 60 a6 03 e8 7c 10 00 c5 38 21 00 80 4e
JIT code: 000001d0: 24 00 80 41 00 00 00 60 16 00 04 28 14 00 82 40
JIT code: 000001e0: 00 00 00 60 ff ff 60 38 01 00 63 3c 08 00 00 48
JIT code: 000001f0: 00 00 60 38 20 01 21 38 10 00 01 e8 a6 03 08 7c
JIT code: 00000200: 70 ff c1 e9 78 ff e1 e9 20 00 80 4e
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
Oops: Exception in kernel mode, sig: 4 [#1]
SMP NR_CPUS=32 NUMA pSeries
Modules linked in: virtio_balloon nfsd ip_tables x_tables autofs4 xfs libcrc32c virtio_console virtio_net virtio_pci virtio_ring virtio
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-00009-gdb06d75 #1
task: c0000004a9254500 ti: c0000004bffe4000 task.ti: c0000004a9260000
NIP: d000000005bbd000 LR: c0000000008bcad8 CTR: d000000005bbd000
REGS: c0000004bffe76d0 TRAP: 0700   Not tainted  (4.7.0-rc3-00009-gdb06d75)
MSR: 8000000000089033 <SF,EE,ME,IR,DR,RI,LE>  CR: 28002028  XER: 00000000
CFAR: c0000000008bcad4 SOFTE: 1
GPR00: c0000000008c18dc c0000004bffe7950 c000000000f19900 c0000004a9d98600
GPR04: d000000005bbb028 000000000000005c c000000002977000 000000000000004e
GPR08: 000000000000005c d000000005bbd000 0000000000000000 0000000000000700
GPR12: d000000005bbd000 c00000000fff8400 c000000000f21c38 f0000000104a3ac0
GPR16: 0000000000000000 c0000004a5b7e808 c000000002977831 c000000002977834
GPR20: c000000000f23040 0000000000000001 000000000000dd86 0000000000000000
GPR24: ffffffff80000000 000000000000005c c000000002977000 000000000000004e
GPR28: c0000004a5ede28e c000000002977000 c000000002848000 c0000004a9d98600
NIP [d000000005bbd000] 0xd000000005bbd000
LR [c0000000008bcad8] run_filter+0x48/0x90
Call Trace:
[c0000004bffe7950] [c0000004bffe7980] 0xc0000004bffe7980 (unreliable)
[c0000004bffe7970] [c0000000008c18dc] tpacket_rcv+0x13c/0x9d0
[c0000004bffe7a60] [c0000000007f060c] __netif_receive_skb_core+0x22c/0xb00
[c0000004bffe7b30] [c0000000007f3cfc] netif_receive_skb_internal+0x2c/0xc0
[c0000004bffe7b70] [c0000000007f524c] napi_gro_receive+0x11c/0x220
[c0000004bffe7bb0] [d0000000056e252c] virtnet_receive+0x2fc/0x940 [virtio_net]
[c0000004bffe7cc0] [d0000000056e2ba0] virtnet_poll+0x30/0xf0 [virtio_net]
[c0000004bffe7d00] [c0000000007f4878] net_rx_action+0x2d8/0x450
[c0000004bffe7e10] [c0000000000ae464] __do_softirq+0x164/0x3d0
[c0000004bffe7f00] [c0000000000aea68] irq_exit+0xc8/0x100
[c0000004bffe7f20] [c000000000010a98] __do_irq+0x98/0x200
[c0000004bffe7f90] [c000000000022274] call_do_irq+0x14/0x24
[c0000004a9263a00] [c000000000010c94] do_IRQ+0x94/0x110
[c0000004a9263a50] [c0000000000025d8] hardware_interrupt_common+0x158/0x180
--- interrupt: 501 at plpar_hcall_norets+0x1c/0x28
    LR = check_and_cede_processor+0x2c/0x40
[c0000004a9263d40] [c0000004a9263d90] 0xc0000004a9263d90 (unreliable)
[c0000004a9263da0] [c000000000799b90] shared_cede_loop+0x60/0x170
[c0000004a9263de0] [c0000000007974b4] cpuidle_enter_state+0xb4/0x380
[c0000004a9263e40] [c0000000000f5f84] call_cpuidle+0x44/0x80
[c0000004a9263e60] [c0000000000f64b0] cpu_startup_entry+0x380/0x450
[c0000004a9263f20] [c00000000003de94] start_secondary+0x304/0x350
[c0000004a9263f90] [c000000000008b6c] start_secondary_prolog+0x10/0x14
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
---[ end trace cc80130850d8e991 ]---

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
---
 arch/powerpc/net/bpf_jit.h      | 2 +-
 arch/powerpc/net/bpf_jit_comp.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

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;
-- 
2.5.5

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#1426015 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On 2016/06/17 10:00AM, Thadeu Lima de Souza Cascardo wrote:
> On Fri, Jun 17, 2016 at 10:53:21PM +1000, Michael Ellerman wrote:
> > On Tue, 2016-07-06 at 13:32:23 UTC, "Naveen N. Rao" wrote:
> > > diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> > > new file mode 100644
> > > index 0000000..954ff53
> > > --- /dev/null
> > > +++ b/arch/powerpc/net/bpf_jit_comp64.c
> > > @@ -0,0 +1,956 @@
> > ...
> > > +
> > > +static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> > > +{
> > > +	int *p = area;
> > > +
> > > +	/* Fill whole space with trap instructions */
> > > +	while (p < (int *)((char *)area + size))
> > > +		*p++ = BREAKPOINT_INSTRUCTION;
> > > +}
> > 
> > This breaks the build for some configs, presumably you're missing a header:
> > 
> >   arch/powerpc/net/bpf_jit_comp64.c:30:10: error: 'BREAKPOINT_INSTRUCTION' undeclared (first use in this function)
> > 
> > http://kisskb.ellerman.id.au/kisskb/buildresult/12720611/
> > 
> > cheers
> 
> Hi, Michael and Naveen.
> 
> I noticed independently that there is a problem with BPF JIT and ABIv2, and
> worked out the patch below before I noticed Naveen's patchset and the latest
> changes in ppc tree for a better way to check for ABI versions.
> 
> However, since the issue described below affect mainline and stable kernels,
> would you consider applying it before merging your two patchsets, so that we can
> more easily backport the fix?

Hi Cascardo,
Given that this has been broken on ABIv2 since forever, I didn't bother 
fixing it. But, I can see why this would be a good thing to have for 
-stable and existing distros. However, while your patch below may fix 
the crash you're seeing on ppc64le, it is not sufficient -- you'll need 
changes in bpf_jit_asm.S as well.

Regards,
Naveen

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#1426944 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On Sun, Jun 19, 2016 at 11:19:14PM +0530, Naveen N. Rao wrote:
> On 2016/06/17 10:00AM, Thadeu Lima de Souza Cascardo wrote:
> > On Fri, Jun 17, 2016 at 10:53:21PM +1000, Michael Ellerman wrote:
> > > On Tue, 2016-07-06 at 13:32:23 UTC, "Naveen N. Rao" wrote:
> > > > diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> > > > new file mode 100644
> > > > index 0000000..954ff53
> > > > --- /dev/null
> > > > +++ b/arch/powerpc/net/bpf_jit_comp64.c
> > > > @@ -0,0 +1,956 @@
> > > ...
> > > > +
> > > > +static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> > > > +{
> > > > +	int *p = area;
> > > > +
> > > > +	/* Fill whole space with trap instructions */
> > > > +	while (p < (int *)((char *)area + size))
> > > > +		*p++ = BREAKPOINT_INSTRUCTION;
> > > > +}
> > > 
> > > This breaks the build for some configs, presumably you're missing a header:
> > > 
> > >   arch/powerpc/net/bpf_jit_comp64.c:30:10: error: 'BREAKPOINT_INSTRUCTION' undeclared (first use in this function)
> > > 
> > > http://kisskb.ellerman.id.au/kisskb/buildresult/12720611/
> > > 
> > > cheers
> > 
> > Hi, Michael and Naveen.
> > 
> > I noticed independently that there is a problem with BPF JIT and ABIv2, and
> > worked out the patch below before I noticed Naveen's patchset and the latest
> > changes in ppc tree for a better way to check for ABI versions.
> > 
> > However, since the issue described below affect mainline and stable kernels,
> > would you consider applying it before merging your two patchsets, so that we can
> > more easily backport the fix?
> 
> Hi Cascardo,
> Given that this has been broken on ABIv2 since forever, I didn't bother 
> fixing it. But, I can see why this would be a good thing to have for 
> -stable and existing distros. However, while your patch below may fix 
> the crash you're seeing on ppc64le, it is not sufficient -- you'll need 
> changes in bpf_jit_asm.S as well.

Hi, Naveen.

Any tips on how to exercise possible issues there? Or what changes you think
would be sufficient?

I will see what I can find by myself, but would appreciate any help.

Regards.
Cascardo.

> 
> Regards,
> Naveen
> 

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#1427585 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On 2016/06/20 03:56PM, Thadeu Lima de Souza Cascardo wrote:
> On Sun, Jun 19, 2016 at 11:19:14PM +0530, Naveen N. Rao wrote:
> > On 2016/06/17 10:00AM, Thadeu Lima de Souza Cascardo wrote:
> > > 
> > > Hi, Michael and Naveen.
> > > 
> > > I noticed independently that there is a problem with BPF JIT and ABIv2, and
> > > worked out the patch below before I noticed Naveen's patchset and the latest
> > > changes in ppc tree for a better way to check for ABI versions.
> > > 
> > > However, since the issue described below affect mainline and stable kernels,
> > > would you consider applying it before merging your two patchsets, so that we can
> > > more easily backport the fix?
> > 
> > Hi Cascardo,
> > Given that this has been broken on ABIv2 since forever, I didn't bother 
> > fixing it. But, I can see why this would be a good thing to have for 
> > -stable and existing distros. However, while your patch below may fix 
> > the crash you're seeing on ppc64le, it is not sufficient -- you'll need 
> > changes in bpf_jit_asm.S as well.
> 
> Hi, Naveen.
> 
> Any tips on how to exercise possible issues there? Or what changes you think
> would be sufficient?

The calling convention is different with ABIv2 and so we'll need changes 
in bpf_slow_path_common() and sk_negative_common().

However, rather than enabling classic JIT for ppc64le, are we better off 
just disabling it?

--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -128,7 +128,7 @@ config PPC
        select IRQ_FORCED_THREADING
        select HAVE_RCU_TABLE_FREE if SMP
        select HAVE_SYSCALL_TRACEPOINTS
-       select HAVE_CBPF_JIT
+       select HAVE_CBPF_JIT if CPU_BIG_ENDIAN
        select HAVE_ARCH_JUMP_LABEL
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select ARCH_HAS_GCOV_PROFILE_ALL


Michael,
Let me know your thoughts on whether you intend to take this patch or 
Cascardo's patch for -stable before the eBPF patches. I can redo my 
patches accordingly.


- Naveen

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#1427640 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On Tue, 2016-06-21 at 14:28 +0530, Naveen N. Rao wrote:
> On 2016/06/20 03:56PM, Thadeu Lima de Souza Cascardo wrote:
> > On Sun, Jun 19, 2016 at 11:19:14PM +0530, Naveen N. Rao wrote:
> > > On 2016/06/17 10:00AM, Thadeu Lima de Souza Cascardo wrote:
> > > > 
> > > > Hi, Michael and Naveen.
> > > > 
> > > > I noticed independently that there is a problem with BPF JIT and ABIv2, and
> > > > worked out the patch below before I noticed Naveen's patchset and the latest
> > > > changes in ppc tree for a better way to check for ABI versions.
> > > > 
> > > > However, since the issue described below affect mainline and stable kernels,
> > > > would you consider applying it before merging your two patchsets, so that we can
> > > > more easily backport the fix?
> > > 
> > > Hi Cascardo,
> > > Given that this has been broken on ABIv2 since forever, I didn't bother 
> > > fixing it. But, I can see why this would be a good thing to have for 
> > > -stable and existing distros. However, while your patch below may fix 
> > > the crash you're seeing on ppc64le, it is not sufficient -- you'll need 
> > > changes in bpf_jit_asm.S as well.
> > 
> > Hi, Naveen.
> > 
> > Any tips on how to exercise possible issues there? Or what changes you think
> > would be sufficient?
> 
> The calling convention is different with ABIv2 and so we'll need changes 
> in bpf_slow_path_common() and sk_negative_common().

How big would those changes be? Do we know?

How come no one reported this was broken previously? This is the first I've
heard of it being broken.

> However, rather than enabling classic JIT for ppc64le, are we better off 
> just disabling it?
> 
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -128,7 +128,7 @@ config PPC
>         select IRQ_FORCED_THREADING
>         select HAVE_RCU_TABLE_FREE if SMP
>         select HAVE_SYSCALL_TRACEPOINTS
> -       select HAVE_CBPF_JIT
> +       select HAVE_CBPF_JIT if CPU_BIG_ENDIAN
>         select HAVE_ARCH_JUMP_LABEL
>         select ARCH_HAVE_NMI_SAFE_CMPXCHG
>         select ARCH_HAS_GCOV_PROFILE_ALL
> 
> 
> Michael,
> Let me know your thoughts on whether you intend to take this patch or 
> Cascardo's patch for -stable before the eBPF patches. I can redo my 
> patches accordingly.

This patch sounds like the best option at the moment for something we can
backport. Unless the changes to fix it are minimal.

cheers

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#1427852 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On Tue, Jun 21, 2016 at 09:15:48PM +1000, Michael Ellerman wrote:
> On Tue, 2016-06-21 at 14:28 +0530, Naveen N. Rao wrote:
> > On 2016/06/20 03:56PM, Thadeu Lima de Souza Cascardo wrote:
> > > On Sun, Jun 19, 2016 at 11:19:14PM +0530, Naveen N. Rao wrote:
> > > > On 2016/06/17 10:00AM, Thadeu Lima de Souza Cascardo wrote:
> > > > > 
> > > > > Hi, Michael and Naveen.
> > > > > 
> > > > > I noticed independently that there is a problem with BPF JIT and ABIv2, and
> > > > > worked out the patch below before I noticed Naveen's patchset and the latest
> > > > > changes in ppc tree for a better way to check for ABI versions.
> > > > > 
> > > > > However, since the issue described below affect mainline and stable kernels,
> > > > > would you consider applying it before merging your two patchsets, so that we can
> > > > > more easily backport the fix?
> > > > 
> > > > Hi Cascardo,
> > > > Given that this has been broken on ABIv2 since forever, I didn't bother 
> > > > fixing it. But, I can see why this would be a good thing to have for 
> > > > -stable and existing distros. However, while your patch below may fix 
> > > > the crash you're seeing on ppc64le, it is not sufficient -- you'll need 
> > > > changes in bpf_jit_asm.S as well.
> > > 
> > > Hi, Naveen.
> > > 
> > > Any tips on how to exercise possible issues there? Or what changes you think
> > > would be sufficient?
> > 
> > The calling convention is different with ABIv2 and so we'll need changes 
> > in bpf_slow_path_common() and sk_negative_common().
> 
> How big would those changes be? Do we know?
> 
> How come no one reported this was broken previously? This is the first I've
> heard of it being broken.
> 

I just heard of it less than two weeks ago, and only could investigate it last
week, when I realized mainline was also affected.

It looks like the little-endian support for classic JIT were done before the
conversion to ABIv2. And as JIT is disabled by default, no one seems to have
exercised it.

> > However, rather than enabling classic JIT for ppc64le, are we better off 
> > just disabling it?
> > 
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -128,7 +128,7 @@ config PPC
> >         select IRQ_FORCED_THREADING
> >         select HAVE_RCU_TABLE_FREE if SMP
> >         select HAVE_SYSCALL_TRACEPOINTS
> > -       select HAVE_CBPF_JIT
> > +       select HAVE_CBPF_JIT if CPU_BIG_ENDIAN
> >         select HAVE_ARCH_JUMP_LABEL
> >         select ARCH_HAVE_NMI_SAFE_CMPXCHG
> >         select ARCH_HAS_GCOV_PROFILE_ALL
> > 
> > 
> > Michael,
> > Let me know your thoughts on whether you intend to take this patch or 
> > Cascardo's patch for -stable before the eBPF patches. I can redo my 
> > patches accordingly.
> 
> This patch sounds like the best option at the moment for something we can
> backport. Unless the changes to fix it are minimal.
> 
> cheers
> 

With my patch only, I can run a minimal tcpdump tcp port 22 with success. It
correctly filter packets. But as pointed out, slow paths may not be taken.

I don't have strong opinions on what to apply to stable, just that it would be
nice to have something for the crash before applying all the nice changes by
Naveen.

Cascardo.

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#1428398 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On Tue, 2016-06-21 at 08:45 -0700, Alexei Starovoitov wrote:
> On 6/21/16 7:47 AM, Thadeu Lima de Souza Cascardo wrote:
> > > > 
> > > > The calling convention is different with ABIv2 and so we'll need changes
> > > > in bpf_slow_path_common() and sk_negative_common().
> > > 
> > > How big would those changes be? Do we know?
> > > 
> > > How come no one reported this was broken previously? This is the first I've
> > > heard of it being broken.
> > > 
> > 
> > I just heard of it less than two weeks ago, and only could investigate it last
> > week, when I realized mainline was also affected.
> > 
> > It looks like the little-endian support for classic JIT were done before the
> > conversion to ABIv2. And as JIT is disabled by default, no one seems to have
> > exercised it.
> 
> it's not a surprise unfortunately. The JITs that were written before
> test_bpf.ko was developed were missing corner cases. Typical tcpdump
> would be fine, but fragmented packets, negative offsets and
> out-out-bounds wouldn't be handled correctly.
> I'd suggest to validate the stable backport with test_bpf as well.
 
OK thanks.

I have been running seltests/net/test_bpf, but I realise now it doesn't enable
the JIT.

cheers

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#1428492 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On 2016/06/21 11:47AM, Thadeu Lima de Souza Cascardo wrote:
> On Tue, Jun 21, 2016 at 09:15:48PM +1000, Michael Ellerman wrote:
> > On Tue, 2016-06-21 at 14:28 +0530, Naveen N. Rao wrote:
> > > On 2016/06/20 03:56PM, Thadeu Lima de Souza Cascardo wrote:
> > > > On Sun, Jun 19, 2016 at 11:19:14PM +0530, Naveen N. Rao wrote:
> > > > > On 2016/06/17 10:00AM, Thadeu Lima de Souza Cascardo wrote:
> > > > > > 
> > > > > > Hi, Michael and Naveen.
> > > > > > 
> > > > > > I noticed independently that there is a problem with BPF JIT and ABIv2, and
> > > > > > worked out the patch below before I noticed Naveen's patchset and the latest
> > > > > > changes in ppc tree for a better way to check for ABI versions.
> > > > > > 
> > > > > > However, since the issue described below affect mainline and stable kernels,
> > > > > > would you consider applying it before merging your two patchsets, so that we can
> > > > > > more easily backport the fix?
> > > > > 
> > > > > Hi Cascardo,
> > > > > Given that this has been broken on ABIv2 since forever, I didn't bother 
> > > > > fixing it. But, I can see why this would be a good thing to have for 
> > > > > -stable and existing distros. However, while your patch below may fix 
> > > > > the crash you're seeing on ppc64le, it is not sufficient -- you'll need 
> > > > > changes in bpf_jit_asm.S as well.
> > > > 
> > > > Hi, Naveen.
> > > > 
> > > > Any tips on how to exercise possible issues there? Or what changes you think
> > > > would be sufficient?
> > > 
> > > The calling convention is different with ABIv2 and so we'll need changes 
> > > in bpf_slow_path_common() and sk_negative_common().
> > 
> > How big would those changes be? Do we know?

I don't think it'd be that much -- I will take a stab at this today.

> > 
> > How come no one reported this was broken previously? This is the first I've
> > heard of it being broken.
> > 
> 
> I just heard of it less than two weeks ago, and only could investigate it last
> week, when I realized mainline was also affected.
> 
> It looks like the little-endian support for classic JIT were done before the
> conversion to ABIv2. And as JIT is disabled by default, no one seems to have
> exercised it.

Yes, my thoughts too. I didn't previously think much about this as JIT 
wouldn't be enabled by default. It's interesting though that no one else 
reported this as an issue before.

> 
> > > However, rather than enabling classic JIT for ppc64le, are we better off 
> > > just disabling it?
> > > 
> > > --- a/arch/powerpc/Kconfig
> > > +++ b/arch/powerpc/Kconfig
> > > @@ -128,7 +128,7 @@ config PPC
> > >         select IRQ_FORCED_THREADING
> > >         select HAVE_RCU_TABLE_FREE if SMP
> > >         select HAVE_SYSCALL_TRACEPOINTS
> > > -       select HAVE_CBPF_JIT
> > > +       select HAVE_CBPF_JIT if CPU_BIG_ENDIAN
> > >         select HAVE_ARCH_JUMP_LABEL
> > >         select ARCH_HAVE_NMI_SAFE_CMPXCHG
> > >         select ARCH_HAS_GCOV_PROFILE_ALL
> > > 
> > > 
> > > Michael,
> > > Let me know your thoughts on whether you intend to take this patch or 
> > > Cascardo's patch for -stable before the eBPF patches. I can redo my 
> > > patches accordingly.
> > 
> > This patch sounds like the best option at the moment for something we can
> > backport. Unless the changes to fix it are minimal.

Right -- I will take a look today to see what changes would be needed.

- Naveen

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#1428872 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On 2016/06/22 12:42PM, Naveen N Rao wrote:
> On 2016/06/21 11:47AM, Thadeu Lima de Souza Cascardo wrote:
> > On Tue, Jun 21, 2016 at 09:15:48PM +1000, Michael Ellerman wrote:
> > > On Tue, 2016-06-21 at 14:28 +0530, Naveen N. Rao wrote:
> > > > On 2016/06/20 03:56PM, Thadeu Lima de Souza Cascardo wrote:
> > > > > On Sun, Jun 19, 2016 at 11:19:14PM +0530, Naveen N. Rao wrote:
> > > > > > On 2016/06/17 10:00AM, Thadeu Lima de Souza Cascardo wrote:
> > > > > > > 
> > > > > > > Hi, Michael and Naveen.
> > > > > > > 
> > > > > > > I noticed independently that there is a problem with BPF JIT and ABIv2, and
> > > > > > > worked out the patch below before I noticed Naveen's patchset and the latest
> > > > > > > changes in ppc tree for a better way to check for ABI versions.
> > > > > > > 
> > > > > > > However, since the issue described below affect mainline and stable kernels,
> > > > > > > would you consider applying it before merging your two patchsets, so that we can
> > > > > > > more easily backport the fix?
> > > > > > 
> > > > > > Hi Cascardo,
> > > > > > Given that this has been broken on ABIv2 since forever, I didn't bother 
> > > > > > fixing it. But, I can see why this would be a good thing to have for 
> > > > > > -stable and existing distros. However, while your patch below may fix 
> > > > > > the crash you're seeing on ppc64le, it is not sufficient -- you'll need 
> > > > > > changes in bpf_jit_asm.S as well.
> > > > > 
> > > > > Hi, Naveen.
> > > > > 
> > > > > Any tips on how to exercise possible issues there? Or what changes you think
> > > > > would be sufficient?
> > > > 
> > > > The calling convention is different with ABIv2 and so we'll need changes 
> > > > in bpf_slow_path_common() and sk_negative_common().
> > > 
> > > How big would those changes be? Do we know?

So, this does need quite a few changes:
- the skb helpers need to emit code to setup TOC and the JIT code needs 
  to be updated to setup r12.
- the slow path code needs to be changed to store r3 elsewhere on ABIv2
- the above also means we need to change the stack macros with the 
  proper ABIv2 values
- the little endian support isn't complete as well -- some of the skb 
  helpers are not using byte swap instructions.

As such, I think we should just disable classic JIT on ppc64le.


- Naveen
 

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#1428424 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

On Tue, 2016-06-21 at 14:28 +0530, Naveen N. Rao wrote:
> On 2016/06/20 03:56PM, Thadeu Lima de Souza Cascardo wrote:
> > On Sun, Jun 19, 2016 at 11:19:14PM +0530, Naveen N. Rao wrote:
> > > On 2016/06/17 10:00AM, Thadeu Lima de Souza Cascardo wrote:
> > > > 
> > > > Hi, Michael and Naveen.
> > > > 
> > > > I noticed independently that there is a problem with BPF JIT and ABIv2, and
> > > > worked out the patch below before I noticed Naveen's patchset and the latest
> > > > changes in ppc tree for a better way to check for ABI versions.
> > > > 
> > > > However, since the issue described below affect mainline and stable kernels,
> > > > would you consider applying it before merging your two patchsets, so that we can
> > > > more easily backport the fix?
> > > 
> > > Hi Cascardo,
> > > Given that this has been broken on ABIv2 since forever, I didn't bother 
> > > fixing it. But, I can see why this would be a good thing to have for 
> > > -stable and existing distros. However, while your patch below may fix 
> > > the crash you're seeing on ppc64le, it is not sufficient -- you'll need 
> > > changes in bpf_jit_asm.S as well.
> > 
> > Hi, Naveen.
> > 
> > Any tips on how to exercise possible issues there? Or what changes you think
> > would be sufficient?
> 
> The calling convention is different with ABIv2 and so we'll need changes 
> in bpf_slow_path_common() and sk_negative_common().
> 
> However, rather than enabling classic JIT for ppc64le, are we better off 
> just disabling it?
> 
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -128,7 +128,7 @@ config PPC
>         select IRQ_FORCED_THREADING
>         select HAVE_RCU_TABLE_FREE if SMP
>         select HAVE_SYSCALL_TRACEPOINTS
> -       select HAVE_CBPF_JIT
> +       select HAVE_CBPF_JIT if CPU_BIG_ENDIAN
>         select HAVE_ARCH_JUMP_LABEL
>         select ARCH_HAVE_NMI_SAFE_CMPXCHG
>         select ARCH_HAS_GCOV_PROFILE_ALL
> 
> 
> Michael,
> Let me know your thoughts on whether you intend to take this patch or 
> Cascardo's patch for -stable before the eBPF patches. I can redo my 
> patches accordingly.

Can one of you send me a proper version of this patch, with change log and
sign-off etc.

cheers

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#1428421 — Re: [PATCH] ppc: Fix BPF JIT for ABIv2

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

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#1426010

On 2016/06/17 10:53PM, Michael Ellerman wrote:
> On Tue, 2016-07-06 at 13:32:23 UTC, "Naveen N. Rao" wrote:
> > diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> > new file mode 100644
> > index 0000000..954ff53
> > --- /dev/null
> > +++ b/arch/powerpc/net/bpf_jit_comp64.c
> > @@ -0,0 +1,956 @@
> ...
> > +
> > +static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> > +{
> > +	int *p = area;
> > +
> > +	/* Fill whole space with trap instructions */
> > +	while (p < (int *)((char *)area + size))
> > +		*p++ = BREAKPOINT_INSTRUCTION;
> > +}
> 
> This breaks the build for some configs, presumably you're missing a header:
> 
>   arch/powerpc/net/bpf_jit_comp64.c:30:10: error: 'BREAKPOINT_INSTRUCTION' undeclared (first use in this function)
> 
> http://kisskb.ellerman.id.au/kisskb/buildresult/12720611/

Oops. Yes, I should have caught that. I need to add:

#include <asm/kprobes.h>

in bpf_jit_comp64.c

Can you please check if it resolves the build error?

Regards,
Naveen

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#1427135

On Sun, 2016-06-19 at 23:06 +0530, Naveen N. Rao wrote:
> On 2016/06/17 10:53PM, Michael Ellerman wrote:
> > On Tue, 2016-07-06 at 13:32:23 UTC, "Naveen N. Rao" wrote:
> > > diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> > > new file mode 100644
> > > index 0000000..954ff53
> > > --- /dev/null
> > > +++ b/arch/powerpc/net/bpf_jit_comp64.c
> > > @@ -0,0 +1,956 @@
> > ...

> > > +
> > > +static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> > > +{
> > > +	int *p = area;
> > > +
> > > +	/* Fill whole space with trap instructions */
> > > +	while (p < (int *)((char *)area + size))
> > > +		*p++ = BREAKPOINT_INSTRUCTION;
> > > +}
> > 
> > This breaks the build for some configs, presumably you're missing a header:
> > 
> >   arch/powerpc/net/bpf_jit_comp64.c:30:10: error: 'BREAKPOINT_INSTRUCTION' undeclared (first use in this function)
> > 
> > http://kisskb.ellerman.id.au/kisskb/buildresult/12720611/
> 
> Oops. Yes, I should have caught that. I need to add:
> 
> #include <asm/kprobes.h>
> 
> in bpf_jit_comp64.c
> 
> Can you please check if it resolves the build error?

Can you? :D

cheers

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#1427366

On 2016/06/21 09:38AM, Michael Ellerman wrote:
> On Sun, 2016-06-19 at 23:06 +0530, Naveen N. Rao wrote:
> > On 2016/06/17 10:53PM, Michael Ellerman wrote:
> > > On Tue, 2016-07-06 at 13:32:23 UTC, "Naveen N. Rao" wrote:
> > > > diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
> > > > new file mode 100644
> > > > index 0000000..954ff53
> > > > --- /dev/null
> > > > +++ b/arch/powerpc/net/bpf_jit_comp64.c
> > > > @@ -0,0 +1,956 @@
> > > ...
> 
> > > > +
> > > > +static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> > > > +{
> > > > +	int *p = area;
> > > > +
> > > > +	/* Fill whole space with trap instructions */
> > > > +	while (p < (int *)((char *)area + size))
> > > > +		*p++ = BREAKPOINT_INSTRUCTION;
> > > > +}
> > > 
> > > This breaks the build for some configs, presumably you're missing a header:
> > > 
> > >   arch/powerpc/net/bpf_jit_comp64.c:30:10: error: 'BREAKPOINT_INSTRUCTION' undeclared (first use in this function)
> > > 
> > > http://kisskb.ellerman.id.au/kisskb/buildresult/12720611/
> > 
> > Oops. Yes, I should have caught that. I need to add:
> > 
> > #include <asm/kprobes.h>
> > 
> > in bpf_jit_comp64.c
> > 
> > Can you please check if it resolves the build error?
> 
> Can you? :D

:)
Sorry, I should have explained myself better. I did actually try your 
config and I was able to reproduce the build error. After the above 
#include, that error went away, but I saw some vdso related errors. I 
thought I was doing something wrong and needed a different setup for 
that particular kernel config, which is why I requested your help in the 
matter. I just didn't do a good job of putting across that message...

Note to self: randconfig builds *and* more time drafting emails :)

Do you want me to respin the patches?


Thanks,
Naveen

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#1427618

On Tue, 2016-06-21 at 12:28 +0530, Naveen N. Rao wrote:
> On 2016/06/21 09:38AM, Michael Ellerman wrote:
> > On Sun, 2016-06-19 at 23:06 +0530, Naveen N. Rao wrote:
> > > 
> > > #include <asm/kprobes.h>
> > > 
> > > in bpf_jit_comp64.c
> > > 
> > > Can you please check if it resolves the build error?
> > 
> > Can you? :D
> 
> :)
> Sorry, I should have explained myself better. I did actually try your 
> config and I was able to reproduce the build error. After the above 
> #include, that error went away, but I saw some vdso related errors. I 
> thought I was doing something wrong and needed a different setup for 
> that particular kernel config, which is why I requested your help in the 
> matter. I just didn't do a good job of putting across that message...
 
Ah OK. Not sure why you're seeing VDSO errors?

> Note to self: randconfig builds *and* more time drafting emails :)

No stress. You don't need to do randconfig builds, or even build all the
arch/powerpc/ configs, just try to do a reasonable set, something like - ppc64,
powernv, pseries, pmac32, ppc64e.

I'm happy to catch the esoteric build failures.

> Do you want me to respin the patches?

No that's fine, I'll fix it up here.

cheers

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#1428491

On 2016/06/21 09:04PM, Michael Ellerman wrote:
> On Tue, 2016-06-21 at 12:28 +0530, Naveen N. Rao wrote:
> > On 2016/06/21 09:38AM, Michael Ellerman wrote:
> > > On Sun, 2016-06-19 at 23:06 +0530, Naveen N. Rao wrote:
> > > > 
> > > > #include <asm/kprobes.h>
> > > > 
> > > > in bpf_jit_comp64.c
> > > > 
> > > > Can you please check if it resolves the build error?
> > > 
> > > Can you? :D
> > 
> > :)
> > Sorry, I should have explained myself better. I did actually try your 
> > config and I was able to reproduce the build error. After the above 
> > #include, that error went away, but I saw some vdso related errors. I 
> > thought I was doing something wrong and needed a different setup for 
> > that particular kernel config, which is why I requested your help in the 
> > matter. I just didn't do a good job of putting across that message...
> 
> Ah OK. Not sure why you're seeing VDSO errors?

'Cause I wasn't paying attention. I tried your .config on a LE machine.  
It works fine on BE, as it should.

> 
> > Note to self: randconfig builds *and* more time drafting emails :)
> 
> No stress. You don't need to do randconfig builds, or even build all the
> arch/powerpc/ configs, just try to do a reasonable set, something like - ppc64,
> powernv, pseries, pmac32, ppc64e.

Ok, will do.

> 
> I'm happy to catch the esoteric build failures.
> 
> > Do you want me to respin the patches?
> 
> No that's fine, I'll fix it up here.

Thanks,
Naveen

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