-----Original Message----- > Date: Wed, 31 Jan 2018 11:57:10 +0000 > From: Ophir Munk <[email protected]> > To: Jerin Jacob <[email protected]> > CC: "[email protected]" <[email protected]>, Thomas Monjalon <[email protected]>, > Pascal Mazon <[email protected]>, Jan Viktorin > <[email protected]>, Jianbo Liu <[email protected]> > Subject: RE: [dpdk-dev] [PATCH] net/tap: fix build issue with ARM32 > > > > > -----Original Message----- > > From: Jerin Jacob [mailto:[email protected]] > > Sent: Wednesday, January 31, 2018 1:31 PM > > To: Ophir Munk <[email protected]> > > Cc: [email protected]; Thomas Monjalon <[email protected]>; Pascal > > Mazon <[email protected]>; Jan Viktorin > > <[email protected]>; Jianbo Liu <[email protected]> > > Subject: Re: [dpdk-dev] [PATCH] net/tap: fix build issue with ARM32 > > > > -----Original Message----- > > > Date: Wed, 31 Jan 2018 10:38:32 +0000 > > > From: Ophir Munk <[email protected]> > > > To: Jerin Jacob <[email protected]> > > > CC: "[email protected]" <[email protected]>, Thomas Monjalon > > > <[email protected]>, Pascal Mazon <[email protected]>, > > Jan > > > Viktorin <[email protected]>, Jianbo Liu <[email protected]> > > > Subject: RE: [dpdk-dev] [PATCH] net/tap: fix build issue with ARM32 > > > > > > Hi, > > > Please see inline > > > > > > > -----Original Message----- > > > > From: Jerin Jacob [mailto:[email protected]] > > > > Sent: Wednesday, January 31, 2018 12:24 PM > > > > To: Ophir Munk <[email protected]> > > > > Cc: [email protected]; Thomas Monjalon <[email protected]>; Pascal > > > > Mazon <[email protected]>; Jan Viktorin > > > > <[email protected]>; Jianbo Liu <[email protected]> > > > > Subject: Re: [dpdk-dev] [PATCH] net/tap: fix build issue with ARM32 > > > > > > > > -----Original Message----- > > > > > Date: Wed, 31 Jan 2018 09:59:45 +0000 > > > > > From: Ophir Munk <[email protected]> > > > > > To: Jerin Jacob <[email protected]>, "[email protected]" > > > > > <[email protected]> > > > > > CC: Thomas Monjalon <[email protected]>, Pascal Mazon > > > > > <[email protected]>, Jan Viktorin <[email protected]>, > > > > > Jianbo Liu <[email protected]> > > > > > Subject: RE: [dpdk-dev] [PATCH] net/tap: fix build issue with > > > > > ARM32 > > > > > > > > > > Hi, > > > > > Please see comments inline > > > > > > > > > > > -----Original Message----- > > > > > > From: dev [mailto:[email protected]] On Behalf Of Jerin Jacob > > > > > > Sent: Wednesday, January 31, 2018 7:14 AM > > > > > > To: [email protected] > > > > > > Cc: Thomas Monjalon <[email protected]>; Jerin Jacob > > > > > > <[email protected]>; Pascal Mazon > > > > > > <[email protected]>; Jan Viktorin > > > > > > <[email protected]>; Jianbo Liu <[email protected]> > > > > > > Subject: [dpdk-dev] [PATCH] net/tap: fix build issue with ARM32 > > > > > > > > > > > > arm32 Linux does not support eBPF interface. > > > > > > Since tap PMD driver has a dependency on eBPF(the symbol > > > > > > __NR_bpf), disabling it armv7 config. > > > > > > > > > > > > compilation error log: > > > > > > In file included from /tmp/dpdk/drivers/net/tap/tap_bpf_api.c:15:0: > > > > > > /tmp/dpdk/drivers/net/tap/tap_bpf.h:103:4: error: #error > > > > > > __NR_bpf not defined # error __NR_bpf not defined > > > > > > ^ > > > > > > > > > > arm architecture is missing is file drivers/tap/tap_bpf.h I > > > > > suggest adding it, for example > > > > > > > > > > # elif defined(__arm__) > > > > > # define __NR_bpf 386 > > > > > > > > By looking at Linux source code > > > > > > https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fel > > > > ixi > > > > r.free- > > > > > > electrons.com%2Flinux%2Fv4.15%2Fsource%2Ftools%2Fbuild%2Ffeature%2 > > > > Ftest- > > > > > > bpf.c%23L6&data=02%7C01%7Cophirmu%40mellanox.com%7C19f50ad7f27 > > > > > > 34d00173808d56894c997%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0% > > > > > > 7C0%7C636529910613736017&sdata=ynsxHG9fvao4LyfWLo4GVJjlKNmcF0q > > > > 0BkFocJyarAE%3D&reserved=0 > > > > I am not sure, Is eBPF support available for arm32 support? > > > > > > TAP eBPF has a graceful approach: it must successfully compile on all > > > Linux distributions. If a specific kernel cannot support eBPF it will > > > gracefully refuse the eBPF netlink message sent to it. > > > Thus, there is no harm even if there is no eBPF support available for > > > arm32. > > > > OK. But, To enable grace full refuse, we should not any random system call > > number like #define __NR_bpf 386. > > It should at least unused for arm32. > > > > For arm - system call 386 seems to be used only for eBPF > http://elixir.free-electrons.com/linux/v4.15/source/arch/arm64/include/asm/unistd32.h#L796 > > > > > > > > You should enable TAP compilation for cases where you only need TAP > > without eBPF. > > > > Yes. It would have been better if new eBPF depended features would have > > under conditional compilation flag so it it can be turned off selectively. > > > > I am in favor of keeping configuration as simple as possible if possible. > I will issue a PR which includes arm BPF definition
OK. Looks like systemd is using the similar method. https://github.com/systemd/systemd/blob/master/src/basic/missing_syscall.h#L334
