Re: Summary of the Arm ports BoF at DC17

2017-09-18 Thread Lennart Sorensen
On Mon, Sep 18, 2017 at 10:50:39AM +0100, Ian Campbell wrote: > On Mon, 2017-09-18 at 10:15 +0100, Edmund Grimley Evans wrote: > > > But it did remind me that on some platforms writing "2" to > > > /proc/sys/abi/cp15_barrier will enable hw support for these > > > instructions, since some platforms

Re: Summary of the Arm ports BoF at DC17

2017-09-18 Thread Ian Campbell
On Mon, 2017-09-18 at 10:15 +0100, Edmund Grimley Evans wrote: > > But it did remind me that on some platforms writing "2" to > > /proc/sys/abi/cp15_barrier will enable hw support for these > > instructions, since some platforms do support them even thought > > they > > are deprecated. It's certain

Re: Summary of the Arm ports BoF at DC17

2017-09-18 Thread Edmund Grimley Evans
> But it did remind me that on some platforms writing "2" to > /proc/sys/abi/cp15_barrier will enable hw support for these > instructions, since some platforms do support them even thought they > are deprecated. It's certainly worth investigating what your hardware > supports. Not necessarily disa

Re: Summary of the Arm ports BoF at DC17

2017-09-18 Thread Ian Campbell
On Sun, 2017-09-17 at 12:59 -0700, Vagrant Cascadian wrote: > On 2017-09-15, Ben Hutchings wrote: > > On Thu, 2017-09-14 at 03:40 +0100, Steve McIntyre wrote: > > [...] > >> There is optional kernel support to trap the exceptions here > >> and emulate the instructions, but it's really not recommend

Re: Summary of the Arm ports BoF at DC17

2017-09-17 Thread Ben Hutchings
On Sun, 2017-09-17 at 21:30 +0100, Colin Watson wrote: > On Sun, Sep 17, 2017 at 12:59:04PM -0700, Vagrant Cascadian wrote: > > On 2017-09-15, Ben Hutchings wrote: > > > On Thu, 2017-09-14 at 03:40 +0100, Steve McIntyre wrote: > > > [...] > > > > There is optional kernel support to trap the excepti

Re: Summary of the Arm ports BoF at DC17

2017-09-17 Thread Steve McIntyre
On Fri, Sep 15, 2017 at 07:11:38PM +0100, Ben Hutchings wrote: >On Thu, 2017-09-14 at 03:40 +0100, Steve McIntyre wrote: >[...] >> There is optional kernel support to trap the exceptions here >> and emulate the instructions, but it's really not recommended for >> serious use (e.g. on a build machin

Re: Summary of the Arm ports BoF at DC17

2017-09-17 Thread Ben Hutchings
On Sun, 2017-09-17 at 12:59 -0700, Vagrant Cascadian wrote: > On 2017-09-15, Ben Hutchings wrote: > > On Thu, 2017-09-14 at 03:40 +0100, Steve McIntyre wrote: > > [...] > > > There is optional kernel support to trap the exceptions here > > > and emulate the instructions, but it's really not recomme

Re: Summary of the Arm ports BoF at DC17

2017-09-17 Thread Colin Watson
On Sun, Sep 17, 2017 at 12:59:04PM -0700, Vagrant Cascadian wrote: > On 2017-09-15, Ben Hutchings wrote: > > On Thu, 2017-09-14 at 03:40 +0100, Steve McIntyre wrote: > > [...] > >> There is optional kernel support to trap the exceptions here > >> and emulate the instructions, but it's really not re

Re: Summary of the Arm ports BoF at DC17

2017-09-17 Thread Vagrant Cascadian
On 2017-09-15, Ben Hutchings wrote: > On Thu, 2017-09-14 at 03:40 +0100, Steve McIntyre wrote: > [...] >> There is optional kernel support to trap the exceptions here >> and emulate the instructions, but it's really not recommended for >> serious use (e.g. on a build machine!). > [...] > > Why is i

Re: Summary of the Arm ports BoF at DC17

2017-09-15 Thread Wookey
On 2017-09-14 12:58 +0800, Paul Wise wrote: > Wookey, could you add something about the motivation for arm64ilp32 to > the wiki page about it? Will do. But the short version is that it's only useful if you need to run 32-bit code on hardware that only supports the 64-bit execution mode. Such hardw

Re: Summary of the Arm ports BoF at DC17

2017-09-15 Thread Ben Hutchings
On Thu, 2017-09-14 at 03:40 +0100, Steve McIntyre wrote: [...] > There is optional kernel support to trap the exceptions here > and emulate the instructions, but it's really not recommended for > serious use (e.g. on a build machine!). [...] Why is it not recommended? Terrible performance, or kno

Re: Summary of the Arm ports BoF at DC17

2017-09-14 Thread Steve McIntyre
On Thu, Sep 14, 2017 at 12:06:13PM +0200, Marco d'Itri wrote: >On Sep 14, Steve McIntyre wrote: > >> The Pine64 [6] is another alternative, based on a mobile CPU. It's >> therefore got limited RAM and I/O. Upstreaming has taken a while, but >> is getting there in current kernel releases. U-Boot he

Re: Summary of the Arm ports BoF at DC17

2017-09-14 Thread Steve McIntyre
On Thu, Sep 14, 2017 at 12:58:02PM +0800, Paul Wise wrote: >On Thu, Sep 14, 2017 at 10:40 AM, Steve McIntyre wrote: > >> It's possible to replace the installed U-Boot >> on many boards, but that depends on hardware support being properly >> upstreamed; lack of that upstreaming work is another commo

Re: Summary of the Arm ports BoF at DC17

2017-09-14 Thread Marco d'Itri
On Sep 14, Steve McIntyre wrote: > The Pine64 [6] is another alternative, based on a mobile CPU. It's > therefore got limited RAM and I/O. Upstreaming has taken a while, but > is getting there in current kernel releases. U-Boot head will work on > the board, including the UEFI implementation ment

Re: Summary of the Arm ports BoF at DC17

2017-09-13 Thread Paul Wise
On Thu, Sep 14, 2017 at 10:40 AM, Steve McIntyre wrote: > It's possible to replace the installed U-Boot > on many boards, but that depends on hardware support being properly > upstreamed; lack of that upstreaming work is another common bugbear in > vendor U-Boot binaries. If you want to use your a

Summary of the Arm ports BoF at DC17

2017-09-13 Thread Steve McIntyre
[ Please note the cross-post and Reply-To ] Hi folks, As promised, here's a quick summary of what was discussed at the Arm ports BoF session in Montréal. Apologies for the delay in posting... Thanks to the awesome efforts of our video team, the session is already online [1]. I've taken a copy of