Messages in this thread | | | From | Madalin Bucur <> | Subject | RE: [PATCH net] net: fman: Use physical address for userspace interfaces | Date | Wed, 19 Oct 2022 05:20:50 +0000 |
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> -----Original Message----- > From: Sean Anderson <sean.anderson@seco.com> > Sent: 19 October 2022 00:47 > To: Andrew Lunn <andrew@lunn.ch>; Andrew Davis <afd@ti.com> > Cc: David S . Miller <davem@davemloft.net>; netdev@vger.kernel.org; > linux-kernel@vger.kernel.org; Madalin Bucur <madalin.bucur@nxp.com>; > Jakub Kicinski <kuba@kernel.org>; Eric Dumazet <edumazet@google.com>; > Paolo Abeni <pabeni@redhat.com>; Camelia Alexandra Groza > <camelia.groza@nxp.com>; Geert Uytterhoeven <geert@linux-m68k.org> > Subject: Re: [PATCH net] net: fman: Use physical address for userspace > interfaces > > > > On 10/18/22 5:39 PM, Andrew Lunn wrote: > > On Tue, Oct 18, 2022 at 01:33:55PM -0500, Andrew Davis wrote: > >> On 10/18/22 12:37 PM, Sean Anderson wrote: > >> > Hi Andrew, > >> > > >> > On 10/18/22 1:22 PM, Andrew Lunn wrote: > >> > > On Mon, Oct 17, 2022 at 12:28:06PM -0400, Sean Anderson wrote: > >> > > > For whatever reason, the address of the MAC is exposed to > userspace in > >> > > > several places. We need to use the physical address for this > purpose to > >> > > > avoid leaking information about the kernel's memory layout, and > to keep > >> > > > backwards compatibility. > >> > > > >> > > How does this keep backwards compatibility? Whatever is in user > space > >> > > using this virtual address expects a virtual address. If it now > gets a > >> > > physical address it will probably do the wrong thing. Unless there > is > >> > > a one to one mapping, and you are exposing virtual addresses > anyway. > >> > > > >> > > If you are going to break backwards compatibility Maybe it would > be > >> > > better to return 0xdeadbeef? Or 0? > >> > > > >> > > Andrew > >> > > > >> > > >> > The fixed commit was added in v6.1-rc1 and switched from physical to > >> > virtual. So this is effectively a partial revert to the previous > >> > behavior (but keeping the other changes). See [1] for discussion. > > > > Please don't assume a reviewer has seen the previous > > discussion. Include the background in the commit message to help such > > reviewers. > > > >> > > >> > --Sean > >> > > >> > [1] > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.ke > rnel.org%2Fnetdev%2F20220902215737.981341-1- > sean.anderson%40seco.com%2FT%2F%23md5c6b66bc229c09062d205352a7d127c02b8d2 > 62&data=05%7C01%7Cmadalin.bucur%40nxp.com%7Cb35d8b37f9224e4b793408dab > 1525b5a%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638017264524356126%7 > CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haW > wiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=%2BcoXaNNlcqzKLsGC5WKuk8Mwette > D51cCbzJvHfG7Vs%3D&reserved=0 > >> > >> I see it asked in that thread, but not answered. Why are you exposing > >> "physical" addresses to userspace? There should be no reason for that. > > > > I don't see anything about needing physical or virtual address in the > > discussion, or i've missed it. > > Well, Madalin originally added this, so perhaps she has some insight. > > I have no idea why we set the IFMAP stuff, since that seems like it's for > PCMCIA. Not sure about sysfs either. > > > If nobody knows why it is needed, either use an obfusticated value, or > > remove it all together. If somebody/something does need it, they will > > report the regression. > > I'd rather apply this (or v2 of this) and then remove the "feature" in > follow-up. > > --Sean
root@localhost:~# grep 1ae /etc/udev/rules.d/72-fsl-dpaa-persistent-networking.rules SUBSYSTEM=="net", DRIVERS=="fsl_dpa*", ATTR{device_addr}=="1ae0000", NAME="fm1-mac1" SUBSYSTEM=="net", DRIVERS=="fsl_dpa*", ATTR{device_addr}=="1ae2000", NAME="fm1-mac2" SUBSYSTEM=="net", DRIVERS=="fsl_dpa*", ATTR{device_addr}=="1ae4000", NAME="fm1-mac3" SUBSYSTEM=="net", DRIVERS=="fsl_dpa*", ATTR{device_addr}=="1ae6000", NAME="fm1-mac4" SUBSYSTEM=="net", DRIVERS=="fsl_dpa*", ATTR{device_addr}=="1ae8000", NAME="fm1-mac5" SUBSYSTEM=="net", DRIVERS=="fsl_dpa*", ATTR{device_addr}=="1aea000", NAME="fm1-mac6"
root@localhost:~# grep 1ae /sys/devices/platform/soc/soc:fsl,dpaa/soc:fsl,dpaa:ethernet@*/net/fm1-mac*/device_addr /sys/devices/platform/soc/soc:fsl,dpaa/soc:fsl,dpaa:ethernet@2/net/fm1-mac3/device_addr:1ae4000 /sys/devices/platform/soc/soc:fsl,dpaa/soc:fsl,dpaa:ethernet@3/net/fm1-mac4/device_addr:1ae6000 /sys/devices/platform/soc/soc:fsl,dpaa/soc:fsl,dpaa:ethernet@4/net/fm1-mac5/device_addr:1ae8000 /sys/devices/platform/soc/soc:fsl,dpaa/soc:fsl,dpaa:ethernet@5/net/fm1-mac6/device_addr:1aea000
Have a great day!
Madalin
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