Hi Russell, > -----Original Message----- > From: Russell King - ARM Linux [mailto:li...@armlinux.org.uk] > Sent: Monday, November 27, 2017 5:20 PM > To: Peng Fan <peng....@nxp.com> > Cc: linux-arm-ker...@lists.infradead.org; linux-kernel@vger.kernel.org; > van.free...@gmail.com; Mark Rutland <mark.rutl...@arm.com>; Thomas > Gleixner <t...@linutronix.de>; Chris Brandt <chris.bra...@renesas.com>; Will > Deacon <will.dea...@arm.com> > Subject: Re: [PATCH] arm: l2c: unlock ways when in non-secure mode > > On Sun, Nov 26, 2017 at 11:56:10PM +0000, Peng Fan wrote: > > Hi Russell, > > > > > Subject: Re: [PATCH] arm: l2c: unlock ways when in non-secure mode > > > > > > On Sun, Nov 26, 2017 at 08:25:30PM +0800, Peng Fan wrote: > > > > To boot Linux in Non-secure mode with l2x0, the l2x0 controller is > > > > enabled in secure mode and ways locked to make it seems L2 cache > > > > disabled during linux boot process. So during l2x0 initialization, > > > > need to unlock the ways to make l2x0 could cache data/inst. > > > > > > Why was this chosen instead of doing what everyone else does? > > > > I am not aware of how other platform handles the l2x0 unlock in non > > secure mode. Could you please share with me what others choose? > > That's not what I was asking. > > Everyone else provides a way for the l2x0 controller to be enabled and > disabled > from non-secure mode.
Thanks for the information. I see that some platforms implements l2c_write_sec. > > Why have you decided to enable the l2x0 controller and leave it enabled, and > then lock down all the cache ways - which means you need the kernel to do > something entirely different for your platform. Currently we are running OP-TEE on i.MX6/7 with Linux in non-secure mode. See In https://github.com/OP-TEE/optee_os/blob/master/core/arch/arm/kernel/generic_entry_a32.S#L428 Pl310 is enabled. And In https://github.com/OP-TEE/optee_os/blob/master/core/arch/arm/kernel/generic_entry_a32.S#L461 pl310 locked before returning back to Linux. I see ti platform not enabled pl310 in OP-TEE, leaving Linux to enable it. platform-sam/stm/ zynq7k/imx Have pl310 enabled in OP-TEE. I could switch to use l2c_write_sec dedicated for i.MX. But I think this patch is also a valid point. What do you suggest? Thanks, Peng. > > -- > RMK's Patch system: > https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww. > armlinux.org.uk%2Fdeveloper%2Fpatches%2F&data=02%7C01%7Cpeng.fan%4 > 0nxp.com%7C35e84f76d1614037232008d535780198%7C686ea1d3bc2b4c6fa92c > d99c5c301635%7C0%7C0%7C636473711907495083&sdata=8aFy%2Fhi6hXQLyrlO > 93uABaplCKM6QOP5n9DvX7S1uJ4%3D&reserved=0 > FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up > According to speedtest.net: 8.21Mbps down 510kbps up
