From: swarren@wwwdotorg.org (Stephen Warren) Date: Tue, 30 Jul 2013 17:01:27 -0600 Subject: [PATCH] ARM: allow DEBUG_UNCOMPRESS for omap2plus In-Reply-To: <20130730225233.GF21614@n2100.arm.linux.org.uk> References: <1375224558-8170-1-git-send-email-swarren@wwwdotorg.org> <20130730225233.GF21614@n2100.arm.linux.org.uk> Message-ID: <51F845C7.8020106@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/30/2013 04:52 PM, Russell King - ARM Linux wrote: > On Tue, Jul 30, 2013 at 04:49:18PM -0600, Stephen Warren wrote: >> From: Stephen Warren >> >> DEBUG_UNCOMPRESS was previously disallowed for omap2plus due to >> omap2plus.S's use of .data, which is not allowed in the decompressor. >> Solve this by placing that data into .text when building the file into >> the decompressor. This relies on .text actually being writable in the >> decompressor, which it is in practice. > > Unless you decide to use ZBOOT and flash the zImage. I knew there had to be a catch:-) I have no idea if ZBOOT is a use-case that's relevant to OMAP? On Tegra at least (the same issue applies to the other patch I just sent), that use-case is almost impossible; even if the boot ROM directly booted a kernel, the boot ROM is hard-coded to copy whatever it's booting to SDRAM first, although I suppose if that was a boot-loader it could just jump back to a ROM location. That said, NOR flash is extremely rare on Tegra. So, I don't know if we care about this issue. Is it reasonable to just say "If you use ZBOOT, don't enable DEBUG_UNCOMPRESS"? Perhaps these patches should not completely remove the !DEBUG_TEGRA_UART from config DEBUG_UNCOMPRESS, but instead say: default y if DEBUG_LL && (!DEBUG_TEGRA_UART || !ZBOOT)?