Hello Russell, On Wed, Nov 13, 2019 at 10:39:19AM +0000, Russell King - ARM Linux admin wrote: > On Wed, Nov 13, 2019 at 11:27:29AM +0100, Geert Uytterhoeven wrote: > > The RZA2MEVB sub board has 64 MiB of SDRAM at 0x0C000000 (CS3 space). > > Hence the mask for CONFIG_AUTO_ZRELADDR needs to be changed, otherwise > > the system will crash because it will try to decompress a zImage or > > uImage to a non-RAM garbage address. > > > > Based on a patch in the BSP by Chris Brandt <chris.brandt@xxxxxxxxxxx>. > > > > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > > --- > > No idea what to do with the rest of the comment, or if this breaks > > existing platforms. > > We occasionally have discussions about this - the last one was a big > one in Edinburgh, and the answer is we can't change this in mainline. > They've also come up on the mailing lists as well. > > I'm not going to rehash this old argument yet again - the comment > details the reason for it, and is there to prevent exactly this. > > If someone is silly enough to come up with a platform that violates > the documented 32-bit ARM booting protocol, then they can't expect > the kernel to bend to their platform's requirements at the expense of > already merged platforms. While I agree to your conclusion I think the last paragraph isn't a valid justification. The "32-bit ARM booting protocol"[1] doesn't mention an alignment, it only states "The kernel should be placed in the first 128MiB of RAM." And if this is done on a platform where RAM starts at 0x0C000000 this results in writes to [0x0b000000, 0x0c000000]. Best regards Uwe [1] that's Documentation/arm/booting.rst, right? -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
