Le 16/03/2011 09:39, Aneesh V a écrit : > On Tuesday 15 March 2011 05:24 PM, Loïc Minier wrote: >> On Tue, Mar 15, 2011, Aneesh V wrote: >>> Please note that I am enabling armv7-a in the second patch in omap4 >>> config.mk file. The reason I didn't do this here was some ARMv7 SoCs do >>> not want to use -march=armv7-a even if the compiler supports it. Tegra2 >>> is an example. Please see the below from Tegra2 config.mk: >>> >>> # Use ARMv4 for Tegra2 - initial code runs on the AVP, which is an >>> ARM7TDI. >>> PLATFORM_CPPFLAGS += -march=armv4 >> >> Good point, I wonder whether it would make sense to have >> arch/arm/cpu/armv7/config.mk default to -march=armv7 and Tegra2 to > > Sounds reasonable. I will do that. > >> override this with -march=armv4. Maybe this code doesn't belong under >> armv7 though; or perhaps -march=armv4 should only be set when building >> a subset of the files rather than by default. > > I don't understand it either. Maybe, the early boot code runs on one > processor and the rest run on another processor all in the same SoC. > >>> This being the case I would have had to define another CONFIG flag if I >>> had to add -march=armv7-a in arch/arm/cpu/armv7/config.mk. I thought it >>> un-necessary and instead put it in the SoC specific file. So, Tegra2 >>> can continue to use -march=armv4 and will get Thumb-1 if they enable >>> CONFIG_SYS_THUMB_BUILD. Or do you think we should define something like >>> CONFIG_SYS_MARCH_ARMV7 >> >> Up to you, but I would expect that code udner arch/arm/cpu/armv7/ would >> build with -march=armv7 (maybe not -a though), with specific overrides > > I tried -march=armv7 yesterday. I am getting several errors from the > assembly files. Particularly, it doesn't support high registers, spsr > etc. Looks like it defaults to the armv7-m variant(just my guess) > >> where that's not the case; it would feel a bit odd to me to have this >> as a "config" option. > > Yes, me too didn't like having a CONFIG option for this. But that > doesn't seem to be needed either as it can be over-ridden in the SoC > directory. > > Albert, > Your thoughts on this?
Some toolchains in current use (notably the one provided with ELDK 4.2, and possibly others) do not support -march=armv7[-a]. Do we really need armv7 instructions? > best regards, > Aneesh Amicalement, -- Albert. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
