From mboxrd@z Thu Jan 1 00:00:00 1970 From: Albert ARIBAUD Date: Thu, 02 Dec 2010 07:59:50 +0100 Subject: [U-Boot] [PATCH] ARMv7: Fix linker errors across toolchain versions In-Reply-To: <4CF6C09A.7050206@free.fr> References: <1291216634-7510-1-git-send-email-premi@ti.com> <4CF68230.7060107@free.fr> <4CF68693.1050406@free.fr> <4CF695B6.2010106@free.fr> <4CF6C09A.7050206@free.fr> Message-ID: <4CF743E6.60706@free.fr> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Le 01/12/2010 22:39, Albert ARIBAUD a ?crit : > This one is a conundrum. > > Using 2010q1, building omap3_evm causes a linker warning > "arm-none-linux-gnueabi-ld: u-boot: section .bss vma 0x8003e8f0 overlaps > previous sections" while building omap3_beagle does not cause any linker > warning. > > Both boards use the same armv7 u-boot.lds and have a .bss which is way > bigger than the .rel.dyn plus .dynsym sections that it does overlay. > IOW, they have a similar layout for .rel.dyn, .dynsym and .bss, but one > gets the warning and one does not. > > The one difference a readelf shows is that for beagle, there is only one > segment: > > 00 .text .rodata .hash .data .got.plt .u_boot_cmd .rel.dyn .dynsym > > While for evm there is > > 00 .text .rodata .hash .data .got.plt .u_boot_cmd .rel.dyn .bss > 01 .dynsym > > Note that .bss has appeared in segment 00 for evm, whereas it was absent > for beagle, and that .dynsym was rejected to a second segment -- why? I > don't know. > > Note: I've tried with putting input sections .rel.dyn and .dynsym into a > single output section .rel.dyn: this makes the second segment disappear, > but for evm the warning remains and .bss remains in the segment. I have a tiny clue. Starting with the fact that the linker issue is only for one board, omap3_evm, I looked up the board-specific code. First thing that I noticed was static u8 omap3_evm_version; I changed this to static u8 omap3_evm_version = 1; so that the static was moved out of BSS and the linker warning disappeared (reminder: v2010.12-rc2, omap3_evm, arm-2010q1). Now this is not the first static BSS variable we use in U-Boot, and the others did not cause linker warnings (not *all* the others, at least), so the real cause is yet unknown to me. But that's at least a lead we can follow. If this BSS variable is used before relocation (I haven't checked this), then anyway it'll have to move; in that case I'll keep an eye on this linker warning and try to sort it out if I get time. Amicalement, -- Albert.